Tapeworms- Dogs and Cats Flashcards
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
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
What are the 5 species of taenia in which dogs are the definitive host?
Taenia ovis
Taenia hydatigena
Taenia multiceps
Taenia pisiformis
Taenia serialis
What are the two species of echinococcus that dogs are the definitive host of?
Echinococcus granulosus
Echinococcus multiocularis
What is the species of dipylidium that has dogs as its definitive host?
Dipylidium caninum
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
What species of tapeworms eggs is this?
Characteristic eggs- thick embryophore, hexacanth embryo
40um in diameter
Taenia spp
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
What does this image show?
Cysticercus in muscles of Taenia ovis- sheep measles
Adult tapeworm 1.2-1.5m
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
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
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
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
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
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
