ESCCAP Guideline 01 Sixth Edition – May 2021

Worm Control

in Dogs and Cats

ESCCAP

Malvern Hills Science Park, Geraldine Road, Malvern,

Worcestershire, WR14 3SZ, United Kingdom

First Edition Published by ESCCAP in December 2006

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

ESCCAP Guideline 01 Sixth Edition – May 2021

Worm Control

in Dogs and Cats

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

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

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

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.

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.

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.

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

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

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

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

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

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

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

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

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

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

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

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