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ESCCAP Guideline 01 Sixth Edition – May 2021
Worm Control
in Dogs and Cats
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ESCCAP
Malvern Hills Science Park, Geraldine Road, Malvern,
Worcestershire, WR14 3SZ, United Kingdom
First Edition Published by ESCCAP in December 2006
© ESCCAP 2006–2021
All rights reserved
This publication is made available subject to the condition that any redistribution or
reproduction of part or all of the contents in any form or by any means, electronic,
mechanical, photocopying, recording or otherwise is with the prior written
permission of ESCCAP.
This publication may only be distributed in the covers in which it is first published
unless with the prior written permission of ESCCAP.
A catalogue record for this publication is available from the British Library.
ISBN: 978-1-913757-18-2
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ESCCAP Guideline 01 Sixth Edition – May 2021
Worm Control
in Dogs and Cats
1
TABLE OF CONTENTS
INTRODUCTION 6
SCOPE 7
PRESENT SITUATION AND EMERGING THREATS 7
LIFELONG CONTROL OF COMMON WORMS 7
BIOLOGY, DIAGNOSIS AND CONTROL OF WORMS 11
1. Roundworms (Toxocara spp.) 11
2. Tapeworms 13
Echinococcus granulosus and Echinococcus multilocularis 13
Dipylidium caninum 16
Taenia spp. 17
3. Heartworm and Subcutaneous Worms 19
Dirofilaria immitis 19
Dirofilaria repens 20
Zoonotic potential of D. immitis and D. repens 21
4. French Heartworm (Angiostrongylus vasorum) 22
5. Hookworms (Ancylostoma spp. and Uncinaria spp.) 23
6. Whipworm (Trichuris vulpis) 24
DIAGNOSIS OF HELMINTH INFECTIONS 25
IMPACT OF PET HEALTH AND LIFESTYLE FACTORS 26
RESISTANCE TO ANTHELMINTICS 26
ENVIRONMENTAL CONTROL OF PARASITE TRANSMISSION 27
OWNER CONSIDERATIONS IN PREVENTING ZOONOTIC DISEASES 28
STAFF, PET OWNER AND COMMUNITY EDUCATION 29
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FIGURES
Figure 1: Scheme for individual deworming of dogs 9
Figure 2: Scheme for individual deworming of cats 10
Figure 3: Toxocara canis life cycle 11
Figure 4: Toxocara cati life cycle 11
Figure 5: Adult worms live in the small intestine of infected dogs and cats 11
Figure 6: Toxocara cati infective egg 12
Figure 7: Echinococcus granulosus life cycle 13
Figure 8: Echinococcus multilocularis life cycle 13
Figure 9: Approximate summary of distribution of Echinococcus granulosus and related species in Europe 14
Figure 10: Approximate distribution of Echinococcus multilocularis in the fox in Europe 15
Figure 11: Dipylidium caninum life cycle 16
Figure 12: Taenia spp. life cycle 17
Figure 13: Taeniid egg 18
Figure 14: Adult worms live in the pulmonary arteries 19
Figure 15: Dirofilaria immitis life cycle 19
Figure 16: The worm may cause skin nodules and swelling 20
Figure 17: Dirofilaria repens life cycle 20
Figure 18: Approximate distribution of Dirofilaria immitis and Dirofilaria repens in Europe 21
Figure 19: A. vasorum larvae measure approximately 345 μm and 22
are characterised by a wavy tail with a dorsal notch
Figure 20: Angiostrongylus vasorum life cycle 22
Figure 21: Hookworms are small nematodes that live in the intestine of infected dogs and cats 23
Figure 22: Hookworm life cycle 23
Figure 23: Infection can be diagnosed by faecal examination and identification of eggs 24
Figure 24: Trichuris vulpis worm 24
Figure 25: Trichuris vulpis life cycle 24
Figure 26: A heavy infection of Trichuris vulpis in the large intestine of a dog 25
Figure 27: Trichuris vulpis eggs 25
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TABLES
Table 1: Summary of Taenia spp. found in dogs and cats 18
Table 2A: Characteristics of worms of dogs in Europe: intestinal nematodes 30
Table 2B: Characteristics of worms of dogs in Europe: tapeworms (cestodes) 30
Table 2C: Characteristics of worms of dogs in Europe: non-intestinal nematodes 31
Table 3: Risk factors for worms of dogs in Europe 32
Table 4: Characteristics of worms of cats in Europe: nematodes and tapeworms (cestodes) 33
Table 5: Risk factors for worms of cats in Europe 35
Table 6: Worm infection of dogs: main clinical signs and diagnosis 36
Table 7: Worm infection of cats: main clinical signs and diagnosis 38
APPENDIX
APPENDIX 1 – GLOSSARY 40
APPENDIX 2 – BACKGROUND 41
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INTRODUCTION
There is a wide range of helminths including nematodes, cestodes and trematodes that can infect dogs and
cats in Europe. Major groups by location in the host are:
Intestinal worms
Ascarids (Toxocara spp.)
Tapeworms
Hookworms (Ancylostoma and Uncinaria spp.)
Whipworm (Trichuris vulpis)
Non-intestinal worms
Heartworm (Dirofilaria immitis)
Subcutaneous worms (Dirofilaria repens)
French heartworm (Angiostrongylus vasorum†)
Lungworms
Eye worms (Thelazia callipaeda)
These groups are further summarised in Tables 2A, 2B and 2C. Factors affecting the importance of these
worms include:
Prevalence
Pathogenicity for the host
Zoonotic potential
A combination of these factors
This guideline aims to give an overview of these worms and their significance and to suggest control measures
for the most important species in order to prevent animal and/or human infection.
For simplicity, the nematodes, cestodes and trematodes mentioned in this guideline will be referred to as
“worms” and therapeutic compounds as “anthelmintics”.
† A. vasorum is sometimes referred to as a lungworm and sometimes named ‘the French Heartworm’, which is due to the fact that
the adult worms are located in the circulatory system and not the lungs.
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SCOPE
ESCCAP provides research-based, independent advice. It is the aim of ESCCAP to produce a guideline which
delivers comprehensive information and support to assist both veterinarians and pet owners to successfully
control worm infection in dogs and cats. This guideline concentrates on the most important groups of
companion animal worms, both intestinal and non-intestinal. Other canine and feline parasites are addressed
in other guidelines; these will be referred to, where appropriate, in the text. For more information on the
control of ectoparasites, superficial mycoses, vector-borne diseases and intestinal protozoa see ESCCAP
guidelines at www.esccap.org/guidelines/.
PRESENT SITUATION AND EMERGING THREATS
In Europe, an increase in pet travel plus climatic changes will probably influence the present epidemiological
situation of certain endoparasites or may introduce them into different regions. Rare diseases may rise in
frequency due to increased importation into presently non-endemic areas. Furthermore, within the European
Union, removal of border controls under the Schengen Treaty and implementation of the PETS Travel Scheme
in the United Kingdom have led to easy travel between the various countries within continental Europe and,
except for the UK, there are no or limited customs controls of pet animals moving from one country to another.
Whilst pets travelling with their owners account for the majority of pet movement, a large number of dogs and,
to a lesser extent cats, are now being relocated by welfare organisations from, for example, Mediterranean
countries to private households all over Europe. This is particularly significant as the Mediterranean is an area
where parasites such as Dirofilaria immitis are highly prevalent.
Veterinary medicinal products go through a rigorous testing process prior to their approval by European or
national authorities and each indication for use has to be scientifically justified. Veterinarians are trained in the
appropriate use of these compounds according to current national legislation. Most modern endoparasiticidal
compounds for companion animals can be used prophylactically or therapeutically to control endoparasites.
LIFELONG CONTROL OF COMMON WORMS
Parasite infections should be controlled through endoparasite and ectoparasite management and treatment.
Few parasite infections are strictly age-related; the risk continues as the animal ages and so consideration
should be given to provide each dog and cat with appropriate worm control throughout its lifetime. The
routine treatment and prevention of all worms depends upon legislation in individual countries, veterinary
professionals taking local epidemiological circumstances into account, owner perception and individual risk
assessments i.e. hunting pets, previous lungworm exposure, raw meat diets etc. Deworming practices
should therefore always be on the advice of a veterinary professional. See Figures 1 and 2: Schemes for
individual deworming of dogs and cats.
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Please be advised that:
In countries or regions where routine treatments are not acceptable for legislative or other reasons, regular
faecal examinations are recommended. See specific parasite sections within this guideline for more
tailored treatment and control recommendations.
Feeding commercial diets or cooked food (internal temperature of at least 65°C for 10 minutes) or deep
frozen (at least for one week at -17 to -20°C) will prevent raw meat- transmitted parasite infections (see
Tables 3 and 5).
Dogs and cats should not be allowed access to rodents, carcasses, placentae or aborted foetuses of
cattle or sheep.
Dogs and cats should always be provided with fresh, potable water.
Where a specific worm infection is diagnosed, the infection should be appropriately treated and then preventive
measures put in place. Symptomatic dogs or cats should have a physical examination, including relevant
parasitic diagnostic procedures, and complete history considered as these are crucial for the diagnosis,
treatment and control of parasitic infections.
For healthy dogs and cats, the prevention of worm infection is essential. To simplify preventive measures,
ESCCAP has identified three “key” parasite groups that can cause severe disease, pose a zoonotic risk and
have high prevalence in some or all areas of Europe:
Ascarids (Toxocara spp., Toxascaris leonina) (prevalent in all areas)
Echinococcus spp. (see Figures 9 and 10 for distribution)
Heartworm (Dirofilaria immitis see Figure 18 for distribution; Angiostrongylus vasorum occurs Europe-wide
in endemic spots).
Ascarid infections occur across Europe, whilst the distribution of other infections is geographically related. By
adding Echinococcus spp. and/or D. immitis/A. vasorum control to ascarid control measures, basic control
plans can be produced for dogs and cats anywhere in Europe.
In areas endemic for Echinococcus multilocularis, dogs that may hunt and eat small prey should be treated
monthly with a product effective against this parasite.
In areas endemic for Echinococcus granulosus, dogs with access to offal or livestock carcasses should be
treated with a product effective against this parasite at least every 6 weeks.
In areas endemic for Dirofilaria spp., administration of a monthly preventive or a long-acting injectable
preventive during the vector season is recommended. In areas endemic for Angiostrongylus vasorum,
regular diagnostic controls or monthly anthelmintic treatments against this parasite prevent the onset of
important clinical signs.
In areas where only Toxocara spp. is a concern, deworming at least four times a year is recommended if
dogs and cats are housed outside or have access to the outdoors.
Control of other parasites, such as hookworms, whipworms and lungworms can be added as necessary.
Appropriate anthelmintic treatment for all parasites can be identified and the animals treated at suitable intervals.
Responsible ownership of cats and dogs includes regular health controls with faecal diagnostics and
deworming accompanied by regular testing for efficacy.
More detailed considerations for each of the companion animal parasites can be found in the individual
parasite sections.
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Figure 1: Scheme for individual deworming of dogs
ADDITIONAL TREATMENTS FOR DOGS
Roundworms
Puppies From the age of 2 weeks, then every 14 days up to 2 weeks after weaning and then
monthly treatments up to six months of age.
Pregnant bitches To reduce transmission to the puppies, pregnant females can be given macrocyclic
lactones on the 40th and 55th day of pregnancy or fenbendazole daily from the 40th
day of pregnancy continuing to 2 days postpartum.
Lactating bitches Should be treated concurrently with the first treatment of puppies (see above).
Dogs with increased risk of infection i.e.
those used in sport, competitions, shows
or those kept in kennels etc.
Two treatments: a maximum of 4 weeks before and 2–4 weeks after the event.
For kennels: use planned deworming once a month or examine faecal samples
every four weeks and treat according to findings.
Professional dogs i.e. therapy, rescue
or police dogs
Depending on the risk assessment, use planned deworming once a month or
examine faecal samples once a month and treat according to findings.
Dogs sharing homes with children below
5 years or immunocompromised individuals
Depending on the risk assessment, use planned deworming once
a month or examine faecal samples once a month and treat according to findings.
Tapeworms
Travel or import into/from endemic areas
for Echinococcus spp.
Dogs with a high risk of infection should be treated 4 weeks after starting the
trip, then every 4 weeks until 4 weeks after return. After importation, immediate
examination and treatment is recommended.
Eats raw meat and/or offal, eats prey
or goes hunting
Dogs should be tested every 2–3 months by faecal examination and treated
accordingly to findings or dewormed every 6 weeks.
Flea or chewing lice infestation
(as a vector for Dipylidium)
Once when the infestation is established.
Heartworm (Dirofilaria immitis)*
Dogs living in heartworm endemic areas
(see Fig. 18)
Prophylactic larval treatment with macrocyclic lactones at monthly intervals during
the mosquito season.
Travel or importation to/from endemic
areas for heartworm
No later than 30 days after departure to 30 days after last possible travel date at
monthly intervals.
• Deworming practices should always be on the advice of a veterinary professional. Regular coprological examination of faeces,
as suggested in Groups A and B, is a good alternative to standard deworming advice.
• If the individual risk of an animal cannot be judged clearly, the animal should be examined or dewormed at least 4 times a year.
Studies have shown that deworming 1–3 times a year does not provide sufficient protection. Deworming every 3 months does
not necessarily eliminate patent infections.
* Detailed information about heartworm infection in dogs and cats can be found in ESCCAP Guideline 5: Control of Vector-Borne
Diseases in Dogs and Cats at www.esccap.org
GROUP B
Treat 4 times
a year against
roundworms or
carry out faecal
examination
GROUP D
Treat monthly against
tapeworms; 4–12
times a year against
roundworms depending
on risk analysis
GROUP C
Treat 4–12 times
a year against
roundworms and
tapeworms depending
on risk analysis
GROUP A
Treat 1–2 times
a year against
roundworms or
carry out faecal
examination
YES
YES
NO
NO
Eats prey animals and/or goes outdoors to hunt without
supervision, has a propensity to eat ‘anything’
Eats snails and slugs and/or raw meat
and/or has access to raw meat/offal
Lives indoors only or goes
outdoors but has no direct contact
with other dogs, parks, sandpits,
playgrounds, snails and slugs, raw
meat or prey animals
Goes outdoors and has direct
contact with parks, sandpits,
playgrounds, and other dogs
Dog lives in a fox tapeworm
(Echinococcus multilocularis)
endemic area, eats prey animals
and/or goes outdoors to hunt
without supervision
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Figure 2: Scheme for individual deworming of cats
ADDITIONAL TREATMENTS FOR CATS
Roundworms
Kittens From 3 weeks of age, then every 2 weeks until weaning and then
monthly treatment until the age of 6 months.
Pregnant queens A single treatment of emodepside spot-on approximately seven
days before expected parturition prevents lactogenic transmission
of Toxocara cati larvae to the kittens.
Lactating queens Should be treated concurrently with the first treatment of kittens
(see above).
Cats with increased risk of infection i.e. those used in
competitions, shows or those kept in catteries etc.
Two treatments: a maximum of 4 weeks before and 2–4 weeks
after the event. For catteries: use planned deworming once a
month or examine faecal samples every four weeks and treat
according to findings.
Cats sharing homes with children below 5 years or
immunocompromised individuals
Depending on the risk assessment, use planned deworming
once a month or examine faecal samples once a month and treat
according to findings.
Tapeworms
Eats raw meat and/or offal, eats prey or goes hunting Cats should be tested at least 4 times a year by faecal
examination and treated accordingly to findings or dewormed
at least 4 times a year.
Flea infestation (as a vector for Dipylidium) Once when the infestation is established.
Echinococcus multilocularis Cats rarely shed E. multilocularis eggs and therefore infection is of
little epidemiological significance.
Heartworm (Dirofilaria immitis)*
Cats living in heartworm endemic areas (see Fig. 18) Prophylactic larval treatment with macrocyclic lactones at monthly
intervals during the mosquito season.
Travel or importation to/from endemic areas for heartworm No later than 30 days after departure to 30 days after last possible
travel date at monthly intervals.
• Deworming practices should always be on the advice of a veterinary professional. Regular coprological examination of faeces,
as suggested in Groups A and B, is a good alternative to standard deworming advice.
• If the individual risk of an animal cannot be judged clearly, the animal should be examined or dewormed at least 4 times a year.
Studies have shown that deworming 1–3 times a year does not provide sufficient protection. Deworming every 3 months does
not necessarily prevent patent infections.
* Detailed information about heartworm infection in dogs and cats can be found in ESCCAP Guideline 5: Control of Vector-Borne
Diseases in Dogs and Cats at www.esccap.org
Cat lives indoors
Infection pressure with worm stages
is low, eating rodents unlikely
Cat is free to roam
Infection pressure with worm stages
is high, eating rodents likely
RISK GROUP B
To minimise the risk of excretion of Toxocara
and Taenia eggs, carry out faecal examination
(and treatment according to findings) at least
4 times a year or treat against roundworms
and tapeworms* at least 4 times a year
(*Taenia taeniaeformis infections often occur while
cats rarely shed E. multilocularis eggs and infection
has a low epidemiological significance)
RISK GROUP A
1–2 times per year faecal examination
(and treatment according to findings) or treat
1–2 times a year against roundworms
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BIOLOGY, DIAGNOSIS AND CONTROL OF WORMS
1. Roundworms (Toxocara spp.)
Toxocara canis is a large, intestinal nematode, with adults measuring as much as 15 cm in length that
can cause disease in young dogs. Similarly, Toxocara cati, an intestinal nematode with adults measuring up
to 10 cm in length, can cause disease in young cats.
Toxocara spp. infection can occur in puppies and kittens but also in older dogs and cats. Infection of humans
can occur as a result of accidentally ingesting infective eggs or eating undercooked meat containing larvae.
Adult worms inhabit the small intestine (Figure 5)
where they lay eggs that are then passed in the
faeces. The eggs can become infective after several
weeks and these can survive in the environment
for years. Dogs and cats become infected when
they ingest infective eggs from the environment
(Figure 6). Dogs and cats can also become infected
when they eat undercooked meat or prey on an
infected paratenic host (e.g. rodents).
The eggs hatch in the intestine releasing larvae
that penetrate the intestinal wall and undergo a
hepato- tracheal migration, with the life cycle
completed when larvae are coughed up and
swallowed, returning to the small intestine to
complete their migration (Figure 3 and Figure 4).
In puppies, infection can occur by the passage of
larvae across the placenta from about the 42nd day
of pregnancy and later through the milk (Figure 3).
Kittens can be infected through the milk (Figure 4).
Somatic migration can occur in older canines and
felines and non-canid/felid hosts that can then act
as paratenic hosts.
Figure 4: Toxocara cati life cycleFigure 3: Toxocara canis life cycle
Figure 5: Adult worms live in the small intestine of infected
dogs and cats
eggs can survive
in the environment
for years
eggs passed in faeces
humans can be
infected by ingesting
infective eggs
humans can be
infected by ingesting
infective eggs
eggs ingested
by small mammals
eggs passed
in faeces
eggs passed
in faeces
transmission
to kittens
via milk
transmission
to kittens
via milk
cats infected by ingesting
small mammals, infective
eggs or undercooked meat
humans can be
infected by ingesting
infective eggs
humans can be
infected by ingesting
infective eggs
eggs ingested
by small mammals
eggs can survive
in the environment
for years
eggs passed
in faeces
eggs passed
in faeces
eggs passed in faeces
dogs infected by ingesting
infective eggs, small mammals
or undercooked meat
transmission
to pups via
placenta or milk
transmission
to pups via
placenta or milk
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In adult animals, infections are extremely unlikely
to be associated with clinical signs therefore it is
difficult to determine whether a dog is infected unless
regular faecal examinations are conducted. Puppies
can be heavily infected by T. canis worms in utero
or via nursing and these may cause serious illness
before diagnosis is possible by faecal examination.
In addition, these parasites are prolific egg-layers
and just a few worms can produce large numbers of
eggs which are able to survive for a long time in the
environment.
Roundworms have an elevated zoonotic potential.
After oral intake of infective roundworm eggs, the
larvae may begin somatic migration (larva migrans
complex). This can have serious consequences
on human health (see chapter on OWNER
CONSIDERATIONS IN PREVENTING ZOONOTIC
DISEASES). For these reasons Toxocara spp.
infections in dogs and cats of all ages merit
consideration.
Puppies should be treated with appropriate anthelmintics from 14 days old. The treatment should then
be repeated fortnightly until two weeks after weaning and then monthly treatments carried out up to six
months of age.
Because prenatal infection does not occur in kittens, fortnightly treatment can begin at 3 weeks of age
and be repeated fortnightly until two weeks after weaning, then monthly treatments carried out up to six
months of age.
To reduce transmission to the puppies, pregnant bitches can be given macrocyclic lactones on the 40th
and 55th day of pregnancy, or fenbendazole daily from the 40th day of pregnancy continuing to 2 days
postpartum.
Pregnant queens should be treated with emodepside spot-on approximately seven days before expected
parturition to prevent lactogenic transmission of Toxocara cati larvae to the kittens.
Nursing bitches and queens should be treated concurrently with the first treatment of their offspring, as
they often develop patent infections at this time.
For adult dogs and cats, ESCCAP recommends an individual risk assessment for each animal to determine
whether anthelmintic treatment is necessary, and how often. There is surprisingly little information about
the impact of re-treatment intervals on parasite burdens and environmental contamination on which to
base a maximum re-treatment interval under different epidemiological conditions. Current information
suggests that annual or twice yearly treatments do not have a significant impact on preventing patent
infection within a population. Therefore, a treatment frequency of at least 4 times per year is a general
recommendation.
As the pre-patent period for Toxocara spp. after ingestion of larvae via predation of paratenic hosts
(rodents) or infective eggs from the environment is a little over four weeks, monthly treatment will minimise
the risk of patent infections and is recommended in risk scenarios, for example when the pet shares a
house with small children and has frequent risk of infection (free roaming, access to garden).
As an alternative to repeated treatments, faecal examinations can be performed at suitable intervals followed
by anthelmintic treatment where positive results are found (see chapter on DIAGNOSIS OF HELMINTH
INFECTIONS). This approach should be adopted in countries where routine treatments are not acceptable
for legislative reasons. Nevertheless, between faecal examinations the excretion of infective eggs is still
possible and cannot be prevented. Caution must be taken in cases of negative results following faecal
examination: it cannot be assumed with certitude that an animal is not infected with roundworms in case
of prepatent infections or when the number of excreted eggs is under the detection limit of the analysis.
For further information on Toxocara spp. characteristics, risk factors, clinical signs, diagnosis and treatments
see Tables 2A and 3–7.
Figure 6: Toxocara cati infective egg
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2. Tapeworms
Echinococcus granulosus and Echinococcus multilocularis
Echinococcus granulosus (dog tapeworm) is a small cestode that inhabits the small intestine of dogs and
some other canids, excluding foxes. Echinococcus multilocularis (fox tapeworm) is a small cestode that
inhabits the small intestine of foxes, raccoon dogs, some other canids and rarely dogs and very seldom cats.
See Figures 7 and 8 for life cycles.
Both the tapeworms, E. granulosus and E. multilocularis induce extra-intestinal metacestode stages in
intermediate hosts and both are zoonoses of major public health concern. In humans, E. granulosus causes
cystic echinococcosis and E. multilocularis causes alveolar echinococcosis, which if untreated can have
potentially fatal consequences. Both infections result in the formation of cysts, most commonly in the liver
(E. multilocularis, E. granulosus) or in the lung (E. granulosus). These occur following the oral ingestion of eggs
or proglottids excreted in the faeces of the definitive hosts. They are immediately infective to intermediate
hosts including humans.
Figure 8: Echinococcus multilocularis life cycle
Figure 7: Echinococcus granulosus life cycle
DEFINITIVE HOSTS
ingest infected rodents
eggs passed in
faeces into the
environment
eggs passed in
faeces into the
environment
humans can be infected
by contaminated food
humans can
ingest eggs by
hand-to-mouth
contact with
dog faeces
humans can
ingest eggs by
hand-to-mouth
contact with
dog faeces
INTERMEDIATE HOSTS
ABERRANT HOSTS
ingest eggs from the environment
eggs contain
oncospheres
alveolar
hydatid
cyst
DEFINITIVE HOST
ingests raw
offal containing
hydatid cysts
eggs passed in
faeces into the
environment
eggs passed in
faeces into the
environment
humans can ingest eggs by
hand-to-mouth contact with
dog faeces or direct contact
with dog and/or can be
infected by ingestion of eggs
from the environment
INTERMEDIATE HOSTS
ABERRANT HOST
ingest eggs from the environment
eggs contain
oncospheres
hydatid cysts develop
from oncospheres
14
In the central and Eastern European endemic area of E. multilocularis (Figure 10) with red foxes as main
definitive hosts and voles as intermediate hosts, dogs that have access to rodents should also be treated at
four weekly intervals with an effective anthelmintic containing praziquantel or epsiprantel. Cats, in contrast to
dogs, are epidemiologically insignificant as sources of egg output. Whilst in dogs, it is common to find eggs
in the fur of infected animals, no eggs have been recovered to date from the coat of infected cats and their
zoonotic potential is also probably limited because there is only a small risk of cats excreting large numbers
of eggs. Specific diagnosis of Echinococcus infections in definitive hosts is difficult as taeniid eggs (including
Echinococcus spp. and Taenia spp.) cannot be differentiated morphologically and are passed intermittently.
Figure 9: Approximate summary of distribution of Echinococcus granulosus and related species in Europe (© ESCCAP)
In areas where E. granulosus and related species are endemic (Figure 9), care should be taken to prevent dogs
having access to raw offal and carcasses. Where dogs may have access to carcasses or raw viscera especially
from sheep, pigs, cattle or horses (depending on the Echinococcus genotypes present locally) they should be
treated at least every six weeks with an effective anthelmintic containing praziquantel or epsiprantel.
Echinococcus granulosus
Sheep strain – high prevalence
Pig strain – high prevalence
15
Figure 10: Approximate distribution of Echinococcus multilocularis in the fox in Europe (© ESCCAP)
DNA-based tests for species and/or genotype identification are only performed in specialised laboratories.
Therefore in Echinococcus endemic areas, taeniid infections based on egg detection should be handled
as potential Echinococcus infections since eggs are directly infective. Where animals are infected with
an Echinococcus species, it is advisable that they are treated under the supervision of a veterinarian with
praziquantel or epsiprantel on two consecutive days, and that the dogs are shampooed to remove any
parasite eggs adhering to the coat. The faeces of treated dogs should be appropriately eliminated (in waste
that will be burned) up to three days after anthelmintic treatment. The personnel involved should use suitable
protective clothing such as gloves and a mask.
E. multilocularis
16
Prevention is achieved through the following recommendations:
If possible, dogs should not have access to wild rodents.
Dogs and cats should not be given slaughter waste or raw meat but only commercial food or meat that has
been heated for 10 minutes (inner temperature: 65°C) or frozen for one week at -17 to -20°C.
For dogs with a high risk of infection with Echinococcus spp., ESCCAP promotes monthly treatments with
an appropriate anthelmintic containing praziquantel or epsiprantel.
Dogs travelling into areas with a high risk of Echinococcus spp. infections should be treated four weeks
after starting the trip and for four weeks after returning with an appropriate anthelmintic containing
praziquantel or epsiprantel.
Dogs imported from endemic areas should be promptly seen by a veterinarian and treated with an
appropriate anthelmintic containing praziquantel or epsiprantel.
Cats are comparatively unsuitable hosts for E. multilocularis. Even in infected cases, cats only excrete
a low number of eggs which have not shown to be infective under experimental conditions, therefore
representing a fractional risk. However, as a precaution, cats with excretion of taeniid eggs should be
treated appropriately.
For further information on Echinococcus spp. characteristics, risk factors, clinical signs, diagnosis and
treatments see Tables 2B and 3–7.
Dipylidium caninum
Dipylidium caninum is a tapeworm of dogs and cats. The parasite is common throughout Europe.
The intermediate hosts are the flea or the chewing dog louse and dogs and cats become infected when
they ingest the infected insects. The adult tapeworm develops within the dog or cat in the small intestine
(Figure 11). D. caninum is zoonotic and if humans ingest infected fleas or lice they can become infected,
although this is rare. The prepatent period is approximately three weeks.
Figure 11: Dipylidium caninum life cycle
dogs and cats
ingest infected
fleas or lice
dogs and cats
ingest infected
fleas or lice humans can ingest
infected fleas or lice
humans can ingest
infected fleas or lice
adult tapeworm develops
in the dog or cat
adult tapeworm develops
in the dog or cat
proglottids
passed in faeces
egg packets
containing
oncospheres
released
oncospheres ingested by
developing flea larvae or lice
infected larvae
develop into adult
fleas or lice
fleas or chewing lice
INTERMEDIATE HOSTS
17
Infection with D. caninum is rarely associated with clinical signs in dogs and cats. The mature segments
leaving the anus may result in anal irritation (pruritus) causing an animal to rub its bottom along the ground.
The white proglottids may be seen in fresh faeces or in the coat around the anus. When dry, these are shaped
like rice grains and may be evident around the perianal area and in samples from the animal’s bedding.
Treatment is performed with praziquantel or epsiprantel and control management is achieved by additional
control of fleas and lice.
For further information on D. caninum characteristics, risk factors, clinical signs, diagnosis and treatments
see Tables 2B and 3–7.
Taenia spp.
Taenia spp. are tapeworms that can infect dogs, cats and foxes by the ingestion of intermediate hosts. They
are common throughout Europe.
Dogs and cats become infected when they eat the tissue or viscera of infected intermediate hosts. Infection
of the intermediate host occurs by ingestion of tapeworm eggs in proglottids passed in the faeces of the
definitive host (Figure 12). The effects on the intermediate host may be more profound than on the definitive
host. The intermediate hosts are varied and, depending on the Taenia spp., range from sheep and cattle
(Taenia multiceps) to rabbits (Taenia serialis, Taenia pisiformis), rodents (Taenia taeniaeformis), ruminants and
pigs (Taenia hydatigena) and sheep and goats (Taenia ovis) (Table 1).
The prepatent period for Taenia spp. ranges from about four to ten weeks in dogs (depending on the species)
and is approximately five to ten weeks for T. taeniaeformis in cats, which uses rodents as intermediate hosts.
Patency can last for several months up to several years, for example T. ovis, a Taenia species infecting dogs,
can be patent for up to five years.
Taenia spp. infections are rarely associated with clinical signs in dogs or cats. The mature segments leaving
the anus may result in anal pruritus causing an animal to rub its bottom along the ground. Owners may also
notice motile segments crawling on the animal’s coat after leaving the anus.
Figure 12: Taenia spp. life cycle
infected by ingesting
eggs or proglottids
oncospheres circulate to tissues
in intermediate hosts
humans
infected by
ingesting
embryonated
eggs
embryonated egg
proglottids
containing infective
eggs passed in faeces
adult worms
develop in the
small intestine
INTERMEDIATE HOSTS
infected
by ingesting
intermediate
hosts
HOSTS
18
Taeniid eggs (Figure 13) may be detected upon
faecal examination. Taenia spp. eggs cannot be
differentiated microscopically from Echinococcus
eggs. Therefore in Echinococcus endemic areas,
taeniid infections based on egg detection should be
considered as a potential Echinococcus infection.
Macroscopic examination of the faeces may
demonstrate the presence of white proglottids;
microscopically, unlike D. caninum each has only
one genital pore.
Treatment is by the administration of an effective
anthelmintic at suitable intervals which will most
likely depend upon evidence of an existing infection.
Eggs can remain viable for lengthy periods in the
environment. Owners should try and prevent dogs
and cats having access to the various intermediate
hosts. The feeding of raw meat and viscera should
be discouraged.
Table 1: Summary of Taenia spp. found in dogs and cats
Definitive
hosts DOGS CATS
Species Taenia
multiceps
Taenia serialis Taenia
crassiceps*
Taenia
pisiformis
Taenia
hydatigena
Taenia
ovis
Taenia
taeniaeformis
Prepatent
period (approx.
in weeks)
6 4–6 6–8 7–10 6–8 5–10
Intermediate
host
Sheep, goats
and cattle
Rabbits
(and rodents) Rodents Rabbits/hares
(and rodents)
Sheep, goats,
cattle and pigs
Sheep
and goats Rodents
Intermediate
stage and site
Coenurus
larvae in brain
and spinal
cord
Coenurus
larvae in
connective
tissue
Cysticercus
larvae in body
cavities or
subcutaneous
tissue
Cysticercus
larvae in
abdomen
or liver
Cysticercus
larvae in
abdomen
or liver
Cysticercus
larvae in
muscles
Strobilocercus
larvae in liver
and abdomen
* much more frequently found in red foxes
For further information on Taenia spp. characteristics, risk factors, clinical signs, diagnosis and treatments
see Tables 2B and 3–7.
Figure 13: Taeniid egg
19
3. Heartworm and Subcutaneous Worms
Dirofilaria immitis
Dirofilaria immitis is a filarial worm that resides in
pulmonary arteries of dogs and cats (Figure 14). Also
known as heartworm, it is transmitted by intermediate
mosquito hosts (Figure 15). Heartworm infection
(D. immitis) is endemic in many southern and south-
eastern European countries (Figure 18). Climatic
changes favourable to parasite development and the
increasing number of travelling pets have increased
the risk of infection for dogs, cats and pet ferrets.
Although cats are potential hosts for heartworm,
their relevance as definitive hosts is clearly reduced
compared to dogs.
Infection with D. immitis may cause severe and
potentially fatal disease in dogs and cats. Low
worm burdens can be asymptomatic. Increasing
worm burdens can cause clinical signs such as loss
of condition, weakness, dyspnoea and chronic
cough. If untreated, the disease can progress to right
side heart failure and death. In cats, the disease is
mostly asymptomatic but in rare cases may cause
sudden death.
In most parts of Europe where infection is endemic,
the transmission season of heartworm lasts from
April to October (depending on the climate). Yearlong
transmission of D. immitis is only actually reported
for the Canary Islands (Spain).
In dogs and cats, control depends upon the use
of heartworm preventive treatments (macrocyclic
lactones) that kill the juvenile heartworm stages prior
to their migration towards the pulmonary artery and
right side of the heart. Infection cannot be hindered,
but the use of appropriate products can effectively
prevent development into adult heartworm and the
onset of clinical signs of infection.
The combination of heartworm preventatives with repellents/insecticides designed to prevent mosquito
blood-feeding activity during the heartworm transmission season could be useful in protecting dogs from
infection. Recently, topical administration of permethrin with dinotefuran has shown repellent efficacy against
mosquitoes on dogs for at least 4 weeks.
In endemic areas, puppies and kittens need to be placed on preventive heartworm treatment as soon as
possible after birth (consistent with label recommendations). Most preventive anthelmintics effective against
heartworm also control a range of other worms, therefore a product should be chosen to control all relevant
worms. In addition, treatment can be extended throughout the year to ensure the continued control of non-
seasonal parasites such as Echinococcus spp. and Toxocara spp., where necessary. The use of such products
should commence within the first four weeks after the start of a potential transmission and maintained monthly
until 30 days after the last potential date of an infection. As a principle, all dogs previously exposed to the risk
of D. immitis infection should receive a complete clinical check-up, including blood tests to detect microfilariae
and/or serology to detect circulating antigens or antibodies for the diagnosis of heartworm infections.
Detailed information about heartworm infection in dogs and cats can be found in ESCCAP Guideline 5:
Control of Vector-Borne Diseases in Dogs and Cats at www.esccap.org
Figure 14: Adult worms live in the pulmonary arteries
Figure 15: Dirofilaria immitis life cycle
humans can also
become infected
humans can also
become infected
adult parasites
sexually reproduce in the
vertebrate host
adult parasites
sexually reproduce in the
vertebrate host
mosquito feeds
and infective larvae
enter the host
mosquito feeds
and microfilariae
are ingested
third stage
larvae migrate
to proboscis
of mosquito
third stage
larvae migrate
to proboscis
of mosquito
larvae develop
inside the mosquito
larvae develop
inside the mosquito
20
Dirofilaria repens
Dirofilaria repens can infect both dogs and cats
and is also transmitted by mosquitoes (Figure 17).
D. repens is the species most frequently associated
with subcutaneous filariosis of dogs and cats. Most
infections are subclinical, though cold, painless
nodules (unique or multiple) containing the adult
parasites and microfilariae can be found under the
skin of infected animals (Figure 16). In cases of heavy
infection or in sensitised animals, a mild to severe
dermatitis can sometimes be observed.
Areas where D. repens is endemic overlap with
endemic D. immitis areas in many regions of Europe.
D. repens is the main species occurring in areas
such as northern France and Hungary and is the
most important Dirofilaria species responsible
for zoonotic infections in Europe. There have
been recent reports of autochthonous infection
in Germany, the Netherlands, Poland, Austria and
Portugal. Autochthonous infections are contracted in
the country where they are reported. The distribution
of D. repens is shown in Figure 18.
Despite infections of D. repens being mostly
asymptomatic, therapy is recommended because of
the zoonotic potential of the parasite. The nodules
can be eliminated by surgery but it is preferable to
extract the adult worms by aspiration with a catheter.
Before and after travelling, dogs and cats should be
examined for infection by D. repens microfilariae. In
dogs, blood tests can demonstrate the presence of
microfilariae. In cats, detection of microfilariae in the
blood is unlikely to be successful as the density of
the microfilariae in the circulation is very low.
When microfilariae are present in a blood sample,
dogs and cats should not travel to non-endemic
areas without prior microfilaricidal treatment.
Treatment using an appropriate prophylactic will give
protection before entry into an endemic area.
See ESCCAP Guideline 5: Control of Vector-Borne
Diseases in Dogs and Cats for a range of diagnostic
options that may be appropriate.
Figure 16: The worm may cause skin nodules and swelling
Figure 17: Dirofilaria repens life cycle
humans can also
become infected
humans can also
become infected
mosquito feeds
and infective larvae
enter the host
mosquito feeds
and microfilariae
are ingested
third stage
larvae migrate
to proboscis
of mosquito
third stage
larvae migrate
to proboscis
of mosquito
larvae develop
inside the mosquito
larvae develop
inside the mosquito
adult worms
mature in subcutaneous
connective tissues
adult worms
mature in subcutaneous
connective tissues
21
Zoonotic potential of D. immitis and D. repens
Most cases of zoonotic Dirofilaria infections in Europe are caused by D. repens. After being bitten by a
mosquito infected with D. repens the most common findings have been subcutaneous nodules and under the
conjunctiva of the eye. D. immitis can develop into granulomas in different organs (mainly the lungs), which
nevertheless remain mostly without clinical relevance. Since Dirofilaria spp. infections are asymptomatic they
usually do not require therapy. Often the infection is diagnosed after surgical removal of a nodule containing
worms. Together with the classical solitary lung nodules, worms can also be found in the eye and in deep
body cavities, occasionally simulating tumours.
For further information on Dirofilaria spp. characteristics, risk factors, clinical signs, diagnosis and treatments
see Tables 2C and 3–7 and ESCCAP Guideline 5: Control of Vector-Borne Diseases in Dogs and Cats at
www.esccap.org
Figure 18: Approximate distribution of Dirofilaria immitis and Dirofilaria repens in Europe (© ESCCAP)
Dirofilaria immitis
Dirofilaria repens
Canary Islands
22
4. French Heartworm (Angiostrongylus vasorum)
Angiostrongylus vasorum is a nematode that resides
as the adult stage in the pulmonary arteries and the
right side of the heart in dogs and other carnivores
(excluding cats).
The distribution of A. vasorum includes endemic
areas in several European countries. However,
former reports of isolated endemic foci are being
increasingly replaced by the description of larger
endemic areas, involving dogs and wildlife. Foxes in
particular are considered an important reservoir, with
wolves, coyotes and jackals being further potential
sources of infection.
Like other metastrongylids, the life cycle of A. vasorum includes some species of slugs and snails as
intermediate hosts. Dogs acquire infection through the ingestion of intermediate hosts or frogs or possibly
birds acting as paratenic hosts (Figure 20).
Following the ingestion of infective L3 by a dog,
larvae (Figure 19) develop and migrate to the right
side of the heart and pulmonary artery. Female
worms begin to produce eggs from 38–60 days after
infection (prepatency). Eggs hatch rapidly and larvae
penetrate the alveoli. They are then coughed up and
excreted in faeces as first stage larvae (L1). Without
treatment, lifelong infections can persist.
Clinical manifestations of A. vasorum infection in
dogs are variable. Naturally infected subclinical dogs
are reported but respiratory signs such as coughing
and dyspnoea induced by verminous pneumonia
are frequently observed, complemented by bleeding
disorders, neurological, gastrointestinal or non-
specific signs. In chronic infections, anorexia,
anaemia, weight loss, depression, pulmonary
hypertension and signs of coagulopathy (e.g.
melaena, haemoptysis, prolonged bleeding from
minor injuries and subcutaneous haematomas) can
be seen. In rare cases sudden death may occur.
Occasionally, larvae and rarely adult stages of A. vasorum are located in ectopic locations such as the
brain, bladder, kidney or anterior chamber of the eye. This may result in clinical signs relating to the invasion
of these organs.
Diagnosis can be performed by detecting first stage larvae from (at least) 4 g of fresh faeces using the Baermann
method. Faeces are preferentially sampled on three consecutive days due to large daily variation in larval
excretion. Alternatively, microscopic detection of first stage larvae in bronchial lavage material can be used.
Furthermore, serology, in particular a commercial serological test for detection of circulating antigen is available.
Anthelmintic therapy includes the use of a macrocyclic lactone-based anthelmintic with varying treatment
protocols or repeated daily administration of a benzimidazole-based anthelmintic (for three weeks). Supportive
treatment, with antibiotic and glucocorticoid-based products as well as blood substitute fluids, may be needed
in severe clinical cases, and the animal should be rested during the treatment period (at least two to three days).
In local areas of high endemicity and/or if the dog is exposed, e.g. used for hunting or eats grass, slugs or
snails (“hoovers”), prevention can be achieved with the monthly administration of macrocyclic lactones.
For further information on A. vasorum characteristics, risk factors, clinical signs, diagnosis and treatments
see Tables 2C, 3 and 6.
Figure 19: A. vasorum larvae measure approximately 345 μm
and are characterised by a wavy tail with a dorsal notch
Figure 20: Angiostrongylus vasorum life cycle
larvae ingested
by intermediate host
(slugs and snails)
larvae
passed in faeces
eggs hatch in lungs
then larvae coughed
up and swallowed
larvae mature into
adults in the pulmonary
arteries and heart
intermediate
host ingested by
dog (definitive host)
intermediate
host ingested by
dog (definitive host)
23
5. Hookworms (Ancylostoma spp. and Uncinaria spp.)
Hookworms are small nematodes characterised
by large mouthparts that are at an angle to the rest
of the worm, hence the common name. There are
three significant species in Europe: Ancylostoma
caninum (dogs), Ancylostoma tubaeforme (cats) and
Uncinaria stenocephala (dogs and rarely cats).
U. stenocephala, known as the northern hookworm,
tolerates colder climates than A. caninum and is
found throughout Europe. A. caninum is found
predominantly in central and southern Europe and A.
tubaeforme is found throughout continental Europe.
The adult worms (Figure 21) inhabit the small intestine
and have a direct life cycle with eggs passed in the
faeces developing to third stage larvae (L3) in the
environment. When these are ingested, they develop
within two to three weeks to adult worms (Figure 22).
Hookworms, most notably Ancylostoma spp. larvae,
can be transmitted through milk from the lactating
mother to the puppies and are also capable of
penetrating skin and thus making their way to the
intestine. It is unlikely that this latter route of infection
contributes greatly to the U. stenocephala life cycle.
All species feed by grasping the intestinal mucosa
with their mouthparts and damaging the surface
to obtain nutrients: largely blood in the case of
Ancylostoma spp., as they require oxygen from the
blood, whilst U. stenocephala obtain nourishment
from tissue components on the surface of the
intestine.
Diarrhoea, weight loss and anaemia are the common
clinical signs and in the case of A. caninum and
A. tubaeforme the diarrhoea may contain blood.
Skin lesions can appear on the foot pads of dogs
and cats caused by larvae burrowing into and along
the skin. Ancylostoma species can cause significant
anaemia when present in high numbers or over a
period of time. Lactogenic transmission of larvae
by A. caninum can result in acute anaemia and
even the death of young pups. U. stenocephala is
less pathogenic.
Figure 21: Hookworms are small nematodes that live
in the intestine of infected dogs and cats
larvae
ingested
by dog
larvae
penetrate
skin
eggs hatch
and develop into
infective larvae
transmammary
transmission
to offspring
transmammary
transmission
to offspring
eggs passed
in faeces
adult worms
lay eggs in small
intestine
Figure 22: Hookworm life cycle
24
Immunity develops after exposure, but is unlikely to
be absolute. Infection thrives best where animals
have access to outdoor environments such as
kennel runs. Diagnosis is based on identifying
hookworm eggs in fresh or fixed faecal samples
using a flotation method, although the eggs of the
two genera are indistinguishable (Figure 23). When
they are detected, anthelmintic treatment should be
administered. Diagnosis in young puppies can be
complicated by signs of disease occurring before
infection is patent i.e. before eggs are passed in
faeces. Animals in heavily infected environments
may require regular anthelmintic therapy to control
hookworm infections. Where young animals are
clinically affected by the infection, supportive
therapy may be necessary in addition to anthelmintic
treatment.
For further information on hookworm characteristics, risk factors, clinical signs, diagnosis and treatments see
Tables 2A and 3–7.
6. Whipworm (Trichuris vulpis)
Trichuris vulpis is a nematode of the large intestine
in dogs (Figure 24). T. vulpis is most likely to occur
in central and southern parts of Europe where
temperatures are suitable for the environmental
development of eggs and in specific premises, such
as kennels and animal shelters. Considerable and
persistent contamination of the environment with
infective eggs can occur. Control can therefore be
difficult, as dogs may become re-infected if they
remain in the same environment.
Eggs are passed in the faeces of infected dogs and
the infective L1 develops within the egg in one to
two months at temperatures above 4°C. The larvae
are protected by the eggshell and can survive in the
environment for years. Dogs become infected when
they ingest infective eggs (Figure 25). The prepatent
period is two to three months, after which infected
dogs may continue to shed eggs for up to a year.
Figure 23: Infection can be diagnosed by faecal
examination and identification of eggs
Figure 24: Trichuris vulpis worm
Figure 25: Trichuris vulpis life cycle
dogs become
infected when
they ingest
infective eggs
infective eggs can
survive in the
environment for years
infected dogs may
shed eggs for up
to a year
ingested eggs
hatch in the
intestine
eggs passed
in faeces
25
A heavy infection (Figure 26) will result in diarrhoeic,
bloody, mucus-filled faeces accompanied by weight
loss and ultimately, the animal will no longer be
able to compensate and will develop metabolic
disturbance including hyponatraemia.
Infection can be diagnosed by finding characteristic
“lemon-shaped” eggs (Figure 27) on examination of
3–5 g of faecal samples using a suitable flotation
technique. Most modern anthelmintics are effective
against T. vulpis. To be effective, repeated deworming
is often required.
Where possible, dogs should be removed from
contaminated areas and put on repeated anthelmintic
treatment. Since the eggs are difficult to eliminate
from the environment, it may be necessary to
consider resurfacing kennel flooring (e.g. by paving
or laying concrete) to facilitate thorough cleaning.
Rotavating and reseeding may also help to eliminate
contamination.
For further information on T. vulpis characteristics,
risk factors, clinical signs, diagnosis and treatments
see Tables 2A, 3 and 6.
DIAGNOSIS OF HELMINTH INFECTIONS
Patent infections of all of the worms mentioned can be identified by faecal examination, except for D. immitis
and D. repens where a blood sample is examined for microfilariae or for antigens (dogs). Faecal examination
for worm eggs should be carried out with at least 5–10 g fresh faeces and can be conducted using flotation
techniques with solutions of appropriate density (Tables 6 and 7). The analysis of faecal samples collected
over different days increases the sensitivity of the employed methods.
Eggs of ascarids, hookworms, whipworm and most taeniids are easily recognisable. In some cases, worm
burden can be crudely estimated from the number of eggs present in the sample. However, it should be noted
that for ascarids such as Toxocara, a negative correlation between fecundity per worm and number of adult
worms has been reported. Furthermore, there is poor correlation between taeniid infection and the detection
of eggs in faeces. Since dogs and potentially also cats may ingest or eat faeces, care should be taken to
identify and eliminate false positive results caused by coprophagia.
Where larvae (L1) are produced (lungworms and A. vasorum), faecal samples should be examined using
the Baermann technique (Tables 6 and 7). If possible, faeces should be sampled on three consecutive days
due to daily variation in larval excretion. Faeces should be collected from a fresh sample and not from the
ground in a kennel or run. Differentiation of the metastrongylid L1 is based on size measurements and
morphology of the tail. Re-testing is recommended approximately three weeks after starting the anthelmintic
treatment(s) to check that treatment has resulted in the removal of adult worms. Dogs clinically affected by
angiostrongylosis should be further investigated to evaluate pulmonary and circulatory status and clotting
parameters. Alternatively, a commercially available test for serological detection of circulating antigens of
A. vasorum can be used for clinical suspect cases.
Figure 26: A heavy infection of Trichuris vulpis in the large
intestine of a dog
Figure 27: Trichuris vulpis eggs
26
IMPACT OF PET HEALTH AND LIFESTYLE FACTORS
The type and frequency of diagnostic, preventive and therapeutic measures need to be tailored to suit individual
needs based upon where the animal is kept. When recommending a parasite management programme,
veterinarians should consider the following (see Tables 3 and 5 for more details).
The animal
Age: puppies, kittens and geriatric animals are at greater risk than healthy adults.
Reproductive status: pregnant bitches may pass T. canis larvae to the foetus in utero.
Lactation: lactating bitches may pass T. canis to their sucking pups via milk (lactating bitches often have
patent T. canis infections as they become infected by their offspring). Lactating queens can pass T. cati to
their sucking kittens via milk. A. caninum infections can also be transmitted to pups via milk.
Health status: e.g. ectoparasite infestation.
Environment/use of the animal
Shared accommodation: animals kept in kennels, shelters or breeding stations or those living with other
dogs or cats are at greater risk of acquiring parasites and may require special consideration.
Roaming: dogs and cats who live outdoors or those with unrestricted access to the outdoors are at greater
risk of acquiring parasites.
Working dogs: hunting and working dogs may also be at a greater risk.
Nutrition
Dogs and cats with access to the following may be at risk of acquiring specific parasites:
Rodents
Slugs and snails
Raw fish
Raw meat including viscera without appropriate heating or freezing
Carcasses, placenta or aborted foetuses
Location and travel
Dogs and cats living in or travelling to specific geographic areas (e.g. holidays, relocation, boarding facilities,
shows and field trials) may be at increased risk of acquiring infections that occur in those areas. Non-endemic
diseases can be a diagnostic challenge for veterinarians who are unfamiliar with them. Dogs imported from
areas endemic for particular parasites (e.g. E. multilocularis) should be promptly visited by a veterinarian and
treated with an appropriate anthelmintic.
In each case, diagnostic methods can be used to verify the success of the prevention measures taken and
medication chosen.
RESISTANCE TO ANTHELMINTICS
To date there have been no proven cases of anthelmintic resistance to intestinal and extraintestinal worms
in dogs and cats in Europe. However, in the USA, anthelmintic resistance of D. immitis larvae is commonly
recognised and there are a number of studies suggesting that drug resistance is present in hookworm
populations in Australia and the USA. Recent studies also report on single resistant Toxocara canis and
Dipylidium caninum worm populations in the USA. At present there is no way of detecting anthelmintic
resistance in vivo in dogs or cats other than the faecal egg count reduction test.
Traditional anthelmintic treatment of dogs and cats has always left many parasite stages outside the definitive
host that are unselected for resistance by treatment. If the frequency of anthelmintic treatment increases,
this could increase the selection pressure for resistance and is most likely to occur in the case of the kennel
situation, where there may be simultaneous treatment of a group of dogs or cats with the same product. It is
therefore recommended that careful consideration should be given to worm control programmes for dogs in
a kennel situation and faecal monitoring should be conducted regularly to identify worm species present and
the effectiveness of any control programme.
27
ENVIRONMENTAL CONTROL OF PARASITE TRANSMISSION
For parasites whose eggs or larvae are passed in the faeces, the control of parasite stages in the environment
is essential to minimise the infection risk to other animals or humans (zoonosis).
Parasitic contamination of the environment can occur in a number of ways, including the excretion of parasitic
eggs or larvae in the faeces and the release of cestode proglottids.
Environmental infection pressure of dog-transmitted parasites can be maintained by wild foxes and stray
dogs in both rural and urban areas. Similarly, feral and wild cats can form a reservoir of feline infection.
The infection of intermediate or paratenic hosts (i.e. birds, rodents, slugs and snails) can contribute to a longer
survival time of parasitic stages in the environment.
Most environmental parasite stages are highly resistant to environmental degradation (from months to years).
Freshly excreted stages of many parasites can be directly infective (e.g. Taenia spp. and Echinococcus
spp. eggs). Other parasites, such as nematode eggs, require anything from a few days to a few weeks at
appropriate temperatures, usually above 16°C, to reach the infective stage. It is therefore important to prevent
initial parasite environmental contamination by implementing comprehensive parasite control programmes
based on local epidemiological knowledge.
The safe disposal of animal faeces is essential. This should be on a daily basis and faeces should not be
flushed down the toilet or disposed of in compost intended for edible crops. In countries or regions where
legislation permits, faeces can be disposed of in household waste collections or dedicated “poo bins”.
Measures to facilitate faecal removal, such as the provision of disposal bins and bags should be
encouraged. As it is difficult to control where outdoor cats defecate, particular attention should be given
to worm control in cats.
Leash-control and faecal clean-up laws should be enforced by the local authorities, especially in urban areas.
Legislation to control stray dogs and feral cat populations should also be enforced by the appropriate
authorities.
Parasitised animals should be treated to minimise environmental contamination. In justified cases,
animals should be monitored by faecal examination (e.g. animals with persistent clinical signs or
suspected resistance).
Because eggs may persist in the soil for months or years for very contaminated areas, such as highly
populated kennels, extreme measures are needed for decontamination, including the removal of sand/soil
or covering the soil with concrete or asphalt.
In kennels or multi-animal households, the strict treatment and quarantine of new entrants is essential to
avoid the introduction of infected animals.
Children’s playgrounds should be well fenced to prevent entry of animals, especially cats. Sandboxes
should be covered when not in use. Sand, particularly if it is uncovered and is likely to have been
contaminated with faeces, should be replaced regularly e.g. at least once or twice a year.
Desiccation and ultraviolet light are highly detrimental to worm eggs, so allowing exposure to sunlight and
drying of contaminated areas can assist in reducing the level of contamination.
28
OWNER CONSIDERATIONS IN PREVENTING ZOONOTIC DISEASES
Since some dog and cat parasites can also potentially cause infection in humans, veterinarians have an
additional responsibility for human health. A particular zoonotic risk comes from the widely present Toxocara
spp. roundworms: after oral ingestion of infective eggs, the larvae can perform a somatic migration (larva
migrans complex). If larvae become blocked in the human eye, nerve tract and/or brain during migration,
serious health problems can occur.
After infection with E. multilocularis or E. granulosus, humans develop alveolar or cystic echinococcosis,
respectively, with formation of cysts in the liver and/or other organs. Alveolar echinococcosis is a carcinoma-
like disease, which without treatment can have fatal consequences. Human infection occurs as a result of
oral ingestion of worm eggs. The main source of contamination of the environment is the fox. Infection can
also occur by the ingestion of eggs found on a dog’s fur or of eggs that have been excreted in dog faeces.
Important preventive measures for pet owners include:
Practicing good personal hygiene, particularly washing hands after handling pets and before eating food.
Minimising the exposure of children in particular to potentially contaminated environments and teaching
them good personal hygiene. Keeping nails short. Teaching children the importance of such practices.
Wearing gloves when gardening.
Washing raw fruit, vegetables and mushrooms before eating.
Controlling pet parasite infections through repeated treatments and/or regular diagnostic testing.
Preventing infection by reducing, where possible, the risk of the pet acquiring infection.
Cleaning up pet faeces regularly to reduce environmental contamination with infective parasite stages.
Not disposing of faeces or cat litter in recyclable waste or compost.
Grooming dogs regularly to minimise the risk of coat contamination with worm eggs.
Changing shoes to prevent contamination of domestic areas.
People who are in regular contact with animals that may potentially transmit zoonotic parasites should be
made aware of the risks and advised that these health risks are greater for pregnant women and those
suffering from underlying illnesses or immunosuppression. This information should be made available through
physicians and veterinarians, without the need for a medical history of the client and his/her family.
With this in mind, special care should be taken in the case of:
Immunocompromised individuals such as the elderly, diabetics, people with HIV-infection and those
undergoing immunosuppressive chemotherapy, organ transplantation or treatment for autoimmune
diseases.
Other susceptible groups such as pregnant women, babies, toddlers and those with learning disabilities.
People with occupational risks such as farmers, kennel workers and hunters.
29
STAFF, PET OWNER AND COMMUNITY EDUCATION
Protocols and recommendations for the control of parasitic infection should be communicated clearly to
veterinary and para-veterinary staff and consistently applied.
Cooperation between the medical and veterinary professions should be encouraged wherever possible
and its benefits underlined in the case of zoonoses. Pet owners should be made aware of the potential
health risks of parasitic infection, not only to their pets but also to themselves and their family and friends.
Professional brochures and posters placed in veterinary practices and pet shops are useful tools to facilitate
this, as are websites.
The importance of regular anthelmintic treatment or joining a “pet health-check programme” should be made
clear to the general public by veterinary surgeons, veterinary nurses and other animal health professionals and
promoted consistently. Responsible dog and cat ownership can ease public health concerns and encourage
the acceptance of dogs and cats as human companions.
Additional information and resource materials can be obtained from www.esccap.org
30
Table 2A: Characteristics of worms of dogs in Europe: intestinal nematodes
Worm species Pre-patent period Patent period Infective stages and
route of infection
Distribution
in Europe
Definitive hosts
Roundworms or ascarids
Toxocara canis Variable, typically
16–21 days after
prenatal infection;
27–35 days after
lactogenic infection;
32–39 days after
ingestion of eggs
4–6 months Ingestion of
embryonated eggs
from soil or on fur,
larvae in milk or
paratenic hosts
In utero from dam
Everywhere Dogs and foxes
Toxascaris leonina About 8 weeks
4–6 months Ingestion of
embryonated eggs
from soil or larvae
from paratenic
hosts
Everywhere Dogs, cats
and foxes
Hookworms
Ancylostoma
caninum
2–3 weeks Can be prolonged
depending on
immune status (7
months to 2 years)
Ingestion of L3 from
environment, larvae
in bitches’ milk or
paratenic hosts
Percutaneous
infection of larvae
Predominantly
southern Europe,
sporadic in other
parts of Europe
Dogs and foxes
Uncinaria
stenocephala
3–4 weeks Can be prolonged
depending on
immune status
L3 orally from
environment
Predominantly
central and northern
Europe
Dogs and foxes
(and cats)
Threadworms (Strongyloides)
Strongyloides
stercoralis
Variable, from
9 days
Several months
(3–15 months)
L3 orally from
environment or
through milk
Percutaneously
Auto-infections
Rarely everywhere
but more
predominant in
southern Europe
Dogs (and humans
and cats)
Whipworm
Trichuris vulpis At least 8 weeks Up to 18 months Ingestion of
embryonated
eggs from the
environment
Everywhere Dogs and foxes
Table 2B: Characteristics of worms of dogs in Europe: tapeworms (cestodes)
Worm species Pre-patent period Patent period Infective stages and
route of infection
Distribution
in Europe
Definitive hosts
Tapeworms
Taenia spp. 4–10 weeks
Months up to
several years
Ingestion of larval
stages (cysticercus
or coenurus type) in
intermediate hosts
Everywhere,
with differences
depending on
the species
Dogs and foxes
(and cats)
Mesocestoides spp. 4–10 weeks Several years Ingestion of larval
stages in meat or
tissues of prey
Everywhere (rare) Dogs, cats
and foxes
Dipylidium
caninum
3 weeks Several months Ingestion of larval
stages in fleas
or lice
Everywhere Dogs, cats
and foxes
Echinococcus
granulosus
complex*
45 days Several months Ingestion of
larval stages in
intermediate hosts
(herbivores and
omnivores)
See map (Figure 9) Dogs (foxes)
Echinococcus
multilocularis
28 days Several months Ingestion of
larval stages in
intermediate hosts
(rodents)
See map (Figure 10) Foxes, dogs,
racoon dogs
(and cats)
* There are different species and strains: E. ortleppi (cattle), E. equinus (horse), sheep-, pig-, cervid- and other strains,
see Figure 9 for distribution.
31
Table 2C: Characteristics of worms of dogs in Europe: non-intestinal nematodes
Worm species Pre-patent period Patent period Infective stages and
route of infection
Distribution
in Europe
Definitive hosts
Heartworm
Dirofilaria immitis 6–7 months Several years L3 transmitted by
mosquito vector
(intermediate host)
Southern Europe
and parts of Central
Europe, see map
(Figure 18)
Dogs (and cats)
and ferrets
French heartworm
Angiostrongylus
vasorum
40–49 days Up to 5 years L3 within mollusc
or paratenic host,
infection orally
Everywhere in
endemic foci
Foxes and dogs
Lungworms
Oslerus osleri 10 weeks Unknown Direct oral
transmission from
bitch to pups mostly
by coprophagia
Everywhere
sporadically
Foxes and dogs
Filaroides spp.
(F. hirthi, F. milksi)
10–18 weeks Unknown Direct oral
transmission from
bitch to pups mostly
by coprophagia
Everywhere
sporadically
Dogs
Eucoleus
aerophilus
(syn. Capillaria
aerophila)
4 weeks 10–11 months Ingestion of larvae
or infective eggs
from environment
or via earthworms
Everywhere Foxes, dogs
and cats
Crenosoma vulpis 3 weeks Up to 10 months L3 within mollusc
or paratenic hosts,
infection orally
Everywhere Dogs and foxes
Subcutaneous worms
Dirofilaria repens 27–34 weeks Several years L3 transmitted by
mosquito vectors
(intermediate hosts)
Southern Europe
and parts of Central
Europe, see map
(Figure 18)
Dogs (and cats)
Eye worms
Thelazia callipaeda About 3 weeks Months to years Arthropod dipteran
vectors (intermediate
hosts) while feeding
lachrymal fluids
Italy, France
(Dordogne), southern
Switzerland, Spain,
Portugal, Balkan
area and Hungary
Dogs, cats
and foxes
Spirocerca lupi
(oesophagus
worm)
6 months Ingestion of
infective larvae in
intermediate hosts
(coprophagus
insects) and
paratenic hosts
(rodents, lizards)
Everywhere (rare) Dogs
32
Table 3: Risk factors for worms of dogs in Europe. Shaded boxes indicate increased risk.
Some dogs are more likely to have parasite infections than others, although the difference is rarely absolute.
This table highlights those factors that are likely to increase the probability of dogs carrying specific parasites.
It has been drawn up on the basis of available understanding, but is not the result of a formal risk assessment.
Shaded boxes indicate increased risk.
Worm species
Dog type Health Environment Nutrition
Location
and travel
Pup Lactating Stray Fleas
or lice
In
kennels Outdoors
Rodents/
amphibians/
reptiles
Molluscs
Raw
meat/
viscera
INTESTINAL WORMS
Ascarids
Toxocara canis
Toxascaris
leonina
Hookworms
Ancylostoma
caninum
More in southern
Europe
Uncinaria
stenocephala
In colder climate
(northern Europe)
Threadworms (Strongyloides)
Strongyloides
stercoralis
Whipworm
Trichuris vulpis
Tapeworms
Taenia spp.
Mesocestoides
spp.
Dipylidium
caninum
Echinococcus
granulosus*
Central, southern
and eastern
Europe, see map
(Figure 9)
Echinococcus
multilocularis
Central, eastern
and northern
Europe, see map
(Figure 10)
NON-INTESTINAL WORMS
Heartworm
Dirofilaria
immitis
See map
(Figure 18)
French heartworm
Angiostrongylus
vasorum
Lungworms
Oslerus osleri
Filaroides spp.
Eucoleus
aerophilus
(syn. Capillaria
aerophila)
Crenosoma
vulpis
Subcutaneous worms
Dirofilaria
repens
See map
(Figure 18)
* There are different species and strains: E. ortleppi (cattle), E. equinus (horse), sheep-, pig-, cervid- and other strains,
see Figure 9 for distribution.
33
Table 4: Characteristics of worms of cats in Europe: nematodes and tapeworms (cestodes)
Worm species Pre-patent period Patent period Infective stages and
route of infection
Distribution
in Europe
Definitive hosts
INTESTINAL WORMS
Roundworms or ascarids
Toxocara cati Variable, usually
around six weeks
after ingestion of
eggs
4–6 months Ingestion of
embryonated eggs
from soil, larvae in
milk or paratenic
hosts
Everywhere Cats
Toxascaris leonina 8–10 weeks 4–6 months Ingestion of
embryonated eggs
from soil, larvae from
paratenic hosts
Everywhere Dogs, cats
and foxes
Hookworms
Ancylostoma
tubaeforme
2–3 weeks Can be prolonged
depending on
immune status
Primarily ingestion
of larvae from soil
Some percutaneous
infection
Continental Europe Cats
Uncinaria
stenocephala
3–4 weeks Can be prolonged
depending on
immune status
Ingestion of larvae
from soil
Predominantly
northern and
central Europe
Dogs, foxes
(and cats)
Other worms
Ollulanus tricuspis
(stomach worm)
5 weeks 33–37 days Ingestion of larvae
or adults in vomitus
Everywhere (rare) Cats
Tapeworms
Taenia
taeniaeformis
5–10 weeks Several years Ingestion of larvae
in rodents
Everywhere Cats
Mesocestoides
spp.
4–10 weeks Several years Ingestion of larval
stages in meat
or tissues
Everywhere (rare) Cats, dogs
and foxes
Dipylidium
caninum
3 weeks Several months Ingestion of larval
stages in fleas
or lice
Everywhere Dogs, cats
and foxes
Echinococcus
multilocularis
28 days Several months Ingestion of
larval stages in
intermediate hosts
(rodents)
See map (Figure 10) Foxes, dogs,
racoon dogs
(and cats)
Liver trematodes
Opisthorchis
felineus
3–4 weeks Several months Larval stages
(metacercariae) in
fresh water fish
North-eastern
Germany, locally in
central Europe
Cats, foxes, dogs,
(humans rarely)
34
Table 4: Characteristics of worms of cats in Europe: nematodes and tapeworms (cestodes) (continued)
Worm species Pre-patent period Patent period Infective stages and
route of infection
Distribution
in Europe
Definitive hosts
NON-INTESTINAL WORMS
Heartworm
Dirofilaria immitis about 6 months Rarely occurs with
cats, and usually
short
L3 transmitted by
mosquito vectors
(intermediate host)
See map (Figure 18) Dogs (and cats)
Lungworms
Aelurostrongylus
abstrusus
7–9 weeks Several years L3 in mollusc or
paratenic host
Everywhere Cats
Troglostrongylus
spp.
L3 in mollusc or
paratenic host (and
transplacentally)
Italy, Spain, Greece,
Portugal
Cats
Eucoleus
aerophilus
(syn. Capillaria
aerophila)
4 weeks 10–11 months Ingestion of larvae
or infective eggs
from environment
or via earthworms
Everywhere Foxes, dogs
and cats
Subcutaneous worms
Dirofilaria repens 27–34 weeks Several years L3 transmitted by
mosquito vectors
(intermediate host)
See map (Figure 18) Dogs (and cats)
Eye worms
Thelazia
callipaeda
About 3 weeks Several months Dipteran vectors
(intermediate hosts)
while feeding
lachrymal fluids
Italy, France
(Dordogne),
southern
Switzerland,
Spain, Portugal,
Balkan area
Dogs and cats
35
Table 5: Risk factors for worms of cats in Europe
Some cats are more likely to have parasite infections than others, although the difference is rarely absolute.
This table highlights those factors that increase the likelihood of cats carrying specific parasites. It has been
drawn up on the basis of available understanding, but is not the result of a formal risk assessment. Shaded
boxes indicate increased risk.
Worm species
Cat type Health Environment Nutrition
Location
and travel
Kitten Lactating Stray Fleas
or lice
In
cattery Outdoors
Rodents/
amphibians/
reptiles
Molluscs
Raw
meat/
viscera
INTESTINAL WORMS
Roundworms or ascarids
Toxocara cati
Toxascaris
leonina
Hookworms
Ancylostoma
tubaeforme
Continental
Europe
Uncinaria
stenocephala
Stomach worm
Ollulanus
tricuspis
Tapeworms
Taenia
taeniaeformis
Mesocestoides
spp.
Dipylidium
caninum
Joyeuxiella
pasqualei
Echinococcus
multilocularis Central Europe
Liver trematodes
Opisthorchis
felineus
North-eastern
Germany
NON-INTESTINAL WORMS
Heartworm
Dirofilaria
immitis
See map
(Figure 18)
Lungworms
Aelurostronylus
abstrusus
Troglostrongylus
spp.
Italy, Spain,
Greece,
Portugal
Eucoleus
aerophilus
(syn. Capillaria
aerophila)
Subcutaneous worms
Dirofilaria
repens
See map
(Figure 18)
36
Table 6: Worm infection of dogs: main clinical signs and diagnosis
Worm species Clinical signs Material Diagnosis
INTESTINAL WORMS
Roundworm or ascarids
Toxocara canis Low burden asymptomatic,
higher burden may appear
as cachexia and pot-bellied
appearance in pups
Large numbers of worms may
cause intestinal blockage or
intussusception
At least 10 g faeces
(fresh or fixed)
Egg detection by centrifugation-flotation or antigen test
Toxascaris
leonina
Mostly asymptomatic At least 10 g faeces
(fresh or fixed)
Egg detection by centrifugation-flotation or antigen test
Hookworms
Ancylostoma
caninum
Diarrhoea, bloody diarrhoea,
weight loss and anaemia
May be acute or
chronic signs
At least 10 g faeces
(fresh or fixed)
Egg detection by centrifugation-flotation or antigen test
Uncinaria
stenocephala
Clinical signs rarely occur.
In rare cases: diarrhoea,
weight loss and anaemia.
At least 10 g faeces
(fresh or fixed)
Egg detection by centrifugation-flotation or antigen test
Threadworms (Strongyloides)
Strongyloides
stercoralis
Heavy infections: watery
diarrhoea and occasionally
bronchopneumonia
At least 10 g faeces
(fresh or fixed)
Eggs (larvated) detection by centrifugation-flotation
Whipworm
Trichuris vulpis Asymptomatic but heavy
infections associated with
anaemia, diarrhoea and
weight loss
At least 10 g faeces
(fresh or fixed)
Egg detection by centrifugation-flotation or antigen test
Tapeworms
Taenia spp. Asymptomatic, sometimes
anal pruritus
At least 10 g fresh
faeces or separate
proglottids in faeces,
sampling on 3
consecutive days
Proglottids grossly visible with only one genital pore.
Taeniid eggs in faeces (see Echinococcus below for
methods of distinguishing taeniid eggs)
Dipylidium
caninum
Mostly asymptomatic,
anal pruritus
At least 10 g fresh
faeces or separate
proglottids in faeces,
sampling on 3
consecutive days
Proglottids similar in size to Taenia spp. proglottids
but morphologically distinct as they have two genital
pores. Eggs within proglottids are grouped in egg
packets. These can be seen microscopically in faecal
samples.
Echinococcus
granulosus
Asymptomatic At least 10 g faeces,
sampling on 3
consecutive days
Freezing faeces at
-80°C for 7 days
kills eggs
Morphology and size of proglottids. Egg detection with
flotation, sedimentation or combined techniques (not
very sensitive and taeniid eggs cannot be differentiated
morphologically). Coproantigen detection enables
detection of prepatent infections 10 days p.i. Sensitivity
more than 90% if more than 50 worms are present, less
if under 50 worms*. PCR/sequencing allows species
identification (from isolated eggs or proglottids)*.
Echinococcus
multilocularis
Asymptomatic At least 10 g faeces,
sampling on 3
consecutive days
Freezing faeces at
-80°C for 7 days
kills eggs
Morphology and size of proglottids. Egg detection with
flotation, sedimentation or combined techniques (not
very sensitive and taeniid eggs cannot be differentiated
morphologically). Coproantigen detection enables
detection of prepatent infections 10 days p.i. Sensitivity
more than 90% if more than 50 worms are present, less
if under 50 worms*. PCR/sequencing allows species
identification (from isolated eggs or proglottids)*.
* In specialised laboratories only
p.i. post infection
37
Table 6: Worm infection of dogs: main clinical signs and diagnosis (continued)
Worm species Clinical signs Material Diagnosis
NON-INTESTINAL WORMS
Heartworm
Dirofilaria
immitis
Low worm burdens
asymptomatic. First clinical
manifestation 5–7 months p.i.:
loss of condition, dyspnoea,
cough
Chronic disease: cough,
tachycardia, “Caval syndrome”,
tachypnoea, exercise
intolerance, asthenia
2–4 ml EDTA** blood
1 ml serum or plasma
Circulating antigens* (from 5 months p.i.) (sensitivity
around 90% if 1 female worm or approximately
100% if more are present). Detection of microfilariae
from 6–7 months p.i. Detection improved by
concentration of microfilariae with Difil-Test or Knott’s
Test. Microfilariae can be identified to species level
using morphological, biochemical or molecular
species identification. Thoracic radiography and
echocardiography are complementary diagnostic
measures.
French heartworm
Angiostrongylus
vasorum
Highly variable: from
asymptomatic to respiratory
and cardiovascular signs: cough,
dyspnoea; coagulopathy (e.g.
subcutaneous haematomas);
neurological signs
At least 10 g fresh
faeces, sampling on
3 consecutive days,
bronchial lavage fluid
1 ml serum or plasma
Detection of live larvae from fresh faeces using the
Baermann method, or microscopic detection of
larvae in bronchial lavage material (less sensitive),
detection of circulating antigens in serum or plasma
with a commercially available kit.
Lungworms
Crenosoma
vulpis
Respiratory signs such as
coughing, dyspnoea and
possibly exercise intolerance
Fresh faeces (at least
10 g) or bronchial
lavage fluid
Detection of live larvae from fresh faeces using the
Baermann method, or microscopic detection of
larvae in bronchial lavage material (less sensitive).
Oslerus osleri Respiratory signs such as
coughing, dyspnoea and
possibly exercise intolerance
Fresh faeces (at least
10 g) or bronchial
lavage fluid
Detection of live larvae from fresh faeces using the
Baermann method, or microscopic detection of
larvae in bronchial lavage material (less sensitive).
Filaroides spp. Respiratory signs such as
coughing, dyspnoea and
possibly exercise intolerance
Fresh faeces (at least
10 g) or bronchial
lavage fluid
Detection of live larvae from fresh faeces using the
Baermann method, or microscopic detection of
larvae in bronchial lavage material (less sensitive).
Capillaria spp. Respiratory signs such as
coughing, dyspnoea and
possibly exercise intolerance
Fresh faeces (at least
10 g) or bronchial
lavage fluid
Egg detection by flotation.
Subcutaneous worms
Dirofilaria repens Mostly asymptomatic,
subcutaneous lesions.
Sometimes skin irritation.
2–4 ml EDTA** blood Detection of microfilariae from 6 months p.i.
Detection improved by concentration of microfilariae
with Difil- Test or Knott’s Test. Microfilariae can be
identified to species level using morphological,
biochemical or molecular species identification*.
Eye worms
Thelazia
callipaeda
Blepharospasm and epiphora Material from the
surface of the eye or
under the nictitating
membrane
Detection of adult or larval stages from samples of
the tear film from the surface of the conjunctiva or
from the conjunctival sac.
* In specialised laboratories only
** acid
p.i. post infection
38
Table 7: Worm infection of cats: main clinical signs and diagnosis
Worm species Clinical signs Material Diagnosis
INTESTINAL WORMS
Roundworms or ascarids
Toxocara cati Low burden asymptomatic,
higher burden may appear
as cachexia and pot-bellied
appearance in kittens. Large
number of worms may
cause intestinal blockage or
intussusceptions. Occasional
pneumonia in kittens.
If possible 10 g faeces
(fresh or fixed)
Egg detection by centrifugation-
flotation or antigen test
Toxascaris leonina Mostly asymptomatic If possible 10 g faeces
(fresh or fixed)
Egg detection by centrifugation-
flotation or antigen test
Hookworms
Ancylostoma tubaeforme Diarrhoea, bloody diarrhoea,
weight loss and anaemia. May
be acute or chronic signs.
If possible 10 g faeces
(fresh or fixed)
Egg detection by centrifugation-
flotation or antigen test
Uncinaria stenocephala Clinical signs rarely occur. In
rare cases: diarrhoea, weight
loss and anaemia.
If possible 10 g faeces
(fresh or fixed)
Egg detection by centrifugation-
flotation or antigen test
Tapeworms
Taenia taeniaeformis Asymptomatic If possible 10 g faeces
(fresh or fixed), sampling
on 3 consecutive days,
proglottids in faeces
Proglottids grossly visible:
morphology of proglottids,
particularly that each proglottid
has a single genital pore.
Taeniid eggs in faecal sample
(see Echinococcus section
for methods to differentiate
taeniid eggs).
Dipylidium caninum Mostly asymptomatic If possible 10 g faeces
(fresh or fixed), sampling
on 3 consecutive days,
proglottids or eggs in faeces
Proglottids similar in size but
morphologically distinct to
proglottids of Taenia spp., as
each proglottid has two genital
pores. Eggs within proglottids
are grouped within egg
packets which can be seen
microscopically within faecal
samples.
Echinococcus multilocularis Asymptomatic If possible10 g faeces,
sampling on 3 consecutive
days
Freezing faeces at -80°C
for 7 days kills eggs
Morphology and size of
proglottids. Egg detection
with flotation, sedimentation
or combined techniques (not
very sensitive and taeniid
eggs cannot be differentiated
morphologically). PCR/
sequencing allows species
identification (from isolated
eggs or proglottids)*.
Stomach worm
Ollulanus tricuspis Gastritis, vomitus Vomitus Detection of larvae
or adult worms
Liver trematodes
Opisthorchis felineus Vomitus, anorexia,
digestive problems
If possible 10 g faeces
(fresh or fixed)
Egg detection through
sedimentation or other
special procedures
39
Table 7: Worm infection of cats: main clinical signs and diagnosis (continued)
Worm species Clinical signs Material Diagnosis
NON-INTESTINAL WORMS
Heartworm
Dirofilaria immitis Often asymptomatic. Initial
signs as the worms reach
the heart. Later disease:
acute signs associated with
worm death including cough,
tachycardia, tachypnoea,
sudden death.
2–4 ml EDTA** blood,
1 ml serum or plasma
Microfilariae and/or antibody
detection. Detection of
microfilariae from 8 months p.i.
(low sensitivity). Detection may
be improved by concentration
of microfilariae with Difil-Test or
Knott’s Test. Microfilariae can be
identified to species level using
morphological, biochemical or
molecular species identification*.
Often a definite diagnosis of
heartworm infection can only
be obtained by haematological
tests in conjunction with
thoracic radiography and
echocardiography.
Lungworms
Aelurostrongylus abstrusus Respiratory signs, coughing
and possibly exercise
intolerance
Fresh faeces (at least 4 g)
or bronchial lavage material
Detection of live larvae
from fresh faeces using
the Baermann method or
microscopic detection of
larvae in bronchial lavage
material (less sensitive)
Troglostrongylus spp. Respiratory signs, coughing
and possibly exercise
intolerance
Fresh faeces (at least 4 g)
or bronchial lavage material
Detection of live larvae
from fresh faeces using
the Baermann method or
microscopic detection of larvae
in bronchial lavage material
(less sensitive)
Subcutaneous worms
Dirofilaria repens Mostly asymptomatic,
subcutaneous lesions
2–4 ml EDTA** blood Detection of microfilariae
from 6 months p.i. Detection
improved by concentration
of microfilariae with Difil- Test
or Knott’s Test. Microfilariae
can be identified to species
level using morphological,
biochemical or molecular
species identification*
Eye worms
Thelazia callipaeda Blepharospasm and epiphora Material from the surface of
the eye or under the nictitating
membrane
Detection of adult or larval
stages from samples of
the tear film from the surface
of the conjunctiva or
subconjunctival sac
* In specialised laboratories only
** acid
p.i. post infection
40
APPENDIX 1 – GLOSSARY
Application Like treatment, but describing the various forms of veterinary medicinal products
which can be given (applied) to animals, such as spot-ons, pour-ons, oral products,
injectables etc.
Control General term comprising ‘therapy’ (treatment) and ‘prevention’ (prophylaxis).
Endoparasiticide Compound developed for the animal. Use as a therapeutic agent to eliminate any
existing endoparasite infection and prevent reinfection.
Integrated control The use of several measures to control different parasites or parasite stages present
in the animal and stages present in the environment.
Pesticide Compound developed for the elimination of different stages of parasites in the
environment.
Prevention Measures taken prior to any infection of the pet animal with endoparasites, to
prevent the establishment of an infection. Prevention for an extended period may
be achieved by the use of a product with persistent activity for certain periods of
time following treatment.
Therapy Any medical intervention to cure a disease; this includes the use of veterinary
medicinal products (treatment), to eliminate an existing parasite infection.
Treatment Administration of veterinary medicinal products (medication) as deemed necessary
based on any given diagnosis.
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APPENDIX 2 – BACKGROUND
ESCCAP (European Scientific Counsel Companion Animal Parasites) is an independent, not-for-profit
organisation that creates guidelines based on up-to-date scientific information and promotes good practice
for the control and treatment of parasites in companion animals. With application of the proper advice, the
risk of diseases and parasitic transmission between animals and humans can be minimised. ESCCAP aspires
to see a Europe where companion animal parasites no longer threaten the health and well-being of animals
and humans.
There is a great diversity in the range of parasites and their relative importance across Europe and the ESCCAP
guidelines summarise and highlight important differences which exist in different parts of Europe and, where
necessary, specific control measures are recommended.
ESCCAP believes that:
Veterinarians and pet owners must take measures to protect their pets from parasitic infections.
Veterinarians and pet owners must take measures to protect the pet population from risks associated with
travel and its consequent potential to change local parasite epidemiological situations through the export
or import of non-endemic parasite species.
Veterinarians, pet owners and physicians should work together to reduce the risks associated with zoonotic
transmission of parasitic diseases.
Veterinarians should be able to give guidance to pet owners regarding risks of parasite infection and
diseases and measures which can be taken to minimise these risks.
Veterinarians should attempt to educate pet owners about parasites to enable them to act responsibly
not only for their own pet’s health but for the health of other pet animals and people in their communities.
Veterinarians should wherever appropriate utilise diagnostic tests to establish parasite infection status in
order to provide the best possible advice.
To achieve these objectives, ESCCAP produces guidelines in different formats:
A detailed guideline for veterinary surgeons and veterinary parasitologists.
Translations, extracts, adaptations and summarised versions of guidelines which address the varied
requirements of European countries and regions.
Versions of ESCCAP guidelines can be found at www.esccap.org
Disclaimer:
Every effort has been taken to ensure that the information in the guideline, which is based on the authors’
experience, is accurate. However, the authors and publishers take no responsibility for any consequence
arising from the misinterpretation of the information herein nor is any condition or warranty implied. ESCCAP
emphasises that national, regional and local regulations must be borne in mind at all times before following
ESCCAP advice. All dosages and indications are provided for guidance. However, vets should consult
individual data sheets for details of locally approved treatment regimens.
42
ESCCAP Guideline 01 Sixth Edition – May 2021
Worm Control
in Dogs and Cats
1
ISBN: 978-1-913757-18-2
ESCCAP Secretariat
Malvern Hills Science Park, Geraldine Road, Malvern,
Worcestershire, WR14 3SZ, United Kingdom
0044 (0) 1684 585135
info@esccap.org
www.esccap.org
