Tapeworms- Dogs and Cats Flashcards by Patrick Enion

Describe the general life cycle of tapeworms

Adults in the small intestine
Proglottids break off
Egg/proglottids shed in faeces
Eggs immediately infective
Eggs eaten by intermediated host
Metacestode develops in intermediate host
Metacestode eaten by definitive host
Adult tapeworm develops in small intestine

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What are the 4 types of metacestodes found in intermediate hosts?

Cysticerus- single envaginated protoscolex

Coenurus- complex, several protoscolices

Cysticercoid- microscopic, single protoscolex found in invertebrae intemediate host

Hyatid- highly complex, numerous protoscolices potential for metastasis

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What are the 5 species of taenia in which dogs are the definitive host?

Taenia ovis

Taenia hydatigena

Taenia multiceps

Taenia pisiformis

Taenia serialis

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What are the two species of echinococcus that dogs are the definitive host of?

Echinococcus granulosus

Echinococcus multiocularis

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What is the species of dipylidium that has dogs as its definitive host?

Dipylidium caninum

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Where are taenia spp founf?

What size are normal taenia- what do they sometomes have?

What is their pre-patent period and patency?

Adult worms found in the small intestine

Large- 30cm-5m with or without armed rostellum

The pre-patent period is 4-10 weeks

Patency is months-years

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What species of tapeworms eggs is this?

Characteristic eggs- thick embryophore, hexacanth embryo

40um in diameter

Taenia spp

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What are the intermediate hosts of T. ovis, T. hydatigena, T. multiceps?

What are the intermediate hosts of T. pisiformis and T. Serialis?

T. Ovis, T. hydatigena, T. multiceps- sheep

T. pisiformis, T. serioalis- rabbit

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What does this image show?

Cysticercus in muscles of Taenia ovis- sheep measles

Adult tapeworm 1.2-1.5m

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What tapeworm does the following image show?

Taenia hydatigena

Cysticercus in peritoneum of sheep- grapes

Thin-necked bladder worm

Liver-liver capsule-peritoneum

Adult tapeworm- 1m

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What tapeworm can be diagnosed from the following image?

Taenia multiceps

Coenurus in brain

Gid cyst- neurological disease

Space occupying cyst in CNS

Leads to circling, head pressing and tilting

Adult tapeworm- 1.2m

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This was found in a rabbit, what is the species of tapeworm and how long would the adult tapeworm be?

Taenia pisiformis- rabbit is intermediate

Cysticercus in peritoneum

Adult tapeworm- 2m

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What intermediate host would this be found in?

What species of tapeworm is it and what size is the adult?

Rabbit- coenrus in connective tissue/sub-cutaneous

Taenia serialis

Adult tapeworm 5m

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What is the intermediate host for Taenia taeniaeformis?

Where is it found in the intermediate host?

What is the PPP?

Intermediate host- mouse

Found as cysticercus in the liver

PPP- 4 weeks

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How can a taenia taeniaeformis tapeworm be identified?

Adult is 60cm and has typical bell shaped protoglottids

In a cat

What symptoms do taenia spp cause?

How is its diagnosed, treated and controlled?

Disease- rarely associated with clinical signs, anal pruitus

Diagnosis- faecal sample- eggs or proglottids- 10g, sampling on 3 consecutive days

Treatment and control-
Praziquantel treatment to remove adult tapeworm (treatment interval dictated by PPP)
Break the life cycle through controlling access to intermediate host/metacestode stage

Where is dipylidium caninum found in the final host?

What is its intermediate host?

What is the size of an adult?

Found in the small intestine of dogs and cats

Intermediate hosts are:
Ctenocephalides felis- flea
Trichodected canis- canine chewing lice

Adult- 50cm

What is the anterior end of a tapeworm called?

Scolex

What can be found on a dipylidium caninum scolex?

What do their gravid segments loos like?

4 unarmed suckers

Protrusable rostellum bearing 4-7 rows of small hooks

Gravid segments are barrel shaped (rice grains) with 2 genital pores on each proglottid

What species of tapeworm are these eggs from?

Dipylidium caninum

each egg capsule containing 10-15 eggs

Describe the life cycle of D. caninum

Adult tapeworm in small intestine of cat/dog- PPP- 3 weeks

Actively motile proglottis are passed in faeces
Disintegrate and eggs released

Eggs eated by flea larvae on floors, carpets, nooks etc
Oncospheres hatch and develop into cysticercoids in body cavity of adult flea

Infected adult flea earten as animal grooms

Describe the pathogenesis and control of D. caninum

Very little pathogenesis and rarely any disease
Crawling, motile proglottids can be irritating
Owners distressed by presence of motile proglottids
Gravid proglottids- white, rice grains/cucumber seeds
Treatment using praziquantel and flea control

What is the definitive host and intermediate hosts of echinococcus granulosus

Definitive host- dog- asymptomatic

Intermediate hosts- sheep and cattle

Which Echinococcus species are zoonotic?

Echinoccus granulosus- severe disease Echinococcus multilocularis- poor prognosis

What disease can echinococcus spp cause with their metacestodes? How do they appear slighlty differently between species?

Hyatid disese- hyatic cyst Highly complex, numerous protoscolices, potential for metastasis Echinoccous granulosis- cystic/hyatid echinococcosis Echinococcus multilocularis- alveolar echinococcosis

Describe an adult echinococcus and its eggs

Adult tapeworms: * Very small- 5mm * Only have three proglottids * Final proglottis largest and gravis- shed in faeces * Normally non-pathogenic in the dog Eggs: * 40um * Thick embrophore * Indistinguishable from Taenia eggs

Describe the life cycle of echinococcus spp

* Adult in small intestine * Embroyated egg in faeces- ingestion by intermediate host * Oncosphere hatches- penetrates intestinal wall * Hyatid cyst in organs- commonly liver and lung * Protoscolex from cyst ingested * Scolex attached to small intestine * Possible for human to ingest embronated eggs leading to hyatid cysts in various organs

How many species of Echinococcus granulosus sensu lato are there?

Origially considered 1 not split into 5 with wide host variety and zoontoic portential

What is the definitive host of echinococcus granulosus? Where is the adult worm found? What are the intermediate hosts? Where is the metacestode found?

Definitive host- dog Adult worm in small intestine- no disease Intermediate host- sheep, cattle, camels Metacestode forms a hyatid cyts- lungs, liver can be all over Found int UK

Where is echinococcus multilocularis found in the world?

Parasite of the northern hemisphere Present in east and central Europe Not in the UK- surveillance present

What is the definitive host of echinococcus multilocularis? What is the intermediate hosts? Where are the metacesodes in the intermediate hosts found?

Definitive host- fox and dog Intermediate hosts- small mammals and rodents Metacestodes form hyatid cytsts- small, multiocular lesions

How are echinococcus species in dogs diagnosed, treated and controled?

Disease is rarely associated with clinical signs- may cause anal pruritus Diagnosis- faecal sample- egg or proglottids 10g, sampling on 3 consecutive days Treatment and control: Preziquantel treatment to remove adult tapeworm (interval indicated by PPP) Break life cylce thrugh controlling access to intermediate host/metacestode stage

How are humans infected with Echinococcus granulosus and what are the symptoms? Where is the infection commonly found in humans?

Infection by ingesting eggs from dogs in contaminated soil, water and food Space occupying cyst forms- liver, lungs, bone marrow brain Slow growing Asymptomatic incubation period- several years Symptoms- depends on the location of the cyst Hepatic and pulmonary symptoms common Jaundice, cholangitis, abdominal pain Rupture of the cyst- fever, anapylactic reaction Common in developing countries- Asia ~10 cases a year in UK

What happens with a human case of Echinococcosis multicularis Alveolar Echinococcosis infection?

Very serious pathogen in humans Large, slow growing cysts- asymptomatic incubation period of 5-15 years tumour like lesions in the liver- metastasize and spread to the lungs and brain Invade and destroy tissues: Pain, weight loss, malaise, liver failure Difficult to diagnose and treat- under reported, mortality rate 50-75%

Where are cases of Echinococosis multilocularis alveolar echinococcosis found in the world?

Parasite of the northern hemisphere Public health concern in Asia Cases reported in Alaska and Canada Europe- prevalence has increased

How is Echinococcus spp in humans diagnosed, treated and controled?

Diagnosis: Ultrasonography imaging and CT/MRI scans Serology Treatment: Cystic echinococcosis- percutaneous treatment of the hyatid cysts with the PAIR technique, drug treatment, surgery Alveolar echinococcosis- early diagnosis and radical surgery followed by treatment with albendazole Control: Controlling disease is definitive and intermediate hosts Improved hygiene in slaughtering animals Education programmes

What specific features apply to tapeworms in the PET travel scheme?

All dogs must be treated with praziquantel 1-5 days before entry into the UK A vet must record treatment in the animals passport Repeat transport again 28 days after returning