Cestoda Flashcards
What is the common name for Dipylidium Caninum?
Common tapeworm
What are the hosts of Dipylidium Caninum?
Final host dogs, cats, and humans. Intermediate hosts are fleas and louse
What are the characteristic features of Dipylidium Caninum?
Fresh segment looks like cucumber seed, dried segment like a grain of rice. Up to 50cm in length. Egg packets contain 10-20 eggs
What can you distinguish about this image?
Dipylidium Caninum proglottid with bilateral genital pores
What is this image showing you?
Dipylidium Caninum scolex and neck
Does this look like bacon to you?
No! That’s because it’s a small intestine infested with Dipylidium Caninum
What is this image showing you?
Dipylidium Caninum egg packets containing eggs
What parasitic species does this larvae stage belong to? And why is it important in the tapeworm life cyle?
Ctenocephalides spp. aka dog flea larvae. Egg is ingested by flea larvae.
Describe the life cycle of Dipylidium Caninum?
Posterior segments of adult worms are passed in the feces -> Segments and egg packets are in the feces or on the fur -> eggs are ingested by flea larvae or occasionally the louse -> larval flea develops into adult and tapeworm eggs hatch into larval stages (synchronous development of tapeworm and flea)-> final host is infected by ingestion of infected flea or louse containing infective tapeworm larvae (cysticercoids). PPP 21 days
Where are the sites of infection for Dipylidium Caninum?
Adult worms in small intestine. Larval stage (cysticercoid) in flea and louse
What are the pathogenesis and lesions for Dipylidium Caninum?
Adults are non-pathogenic, though the segments cause discomfort
What are the clinical signs for Dipylidium Caninum infestation?
Excessive grooming around the perineum.
How is Dipylidium Caninum diagnosed?
Demonstrate segments in bedding, adhesive tape or scotch tape method
What is the treatment or prevention for Dipylidium Caninum?
Treat final host with cestocide, treat for intermediate hosts with insecticide
Cats become infected with Dipylidium Caninum by ingesting fleas containing cysticercoids. The fleas become infected with this cestode by ingesting:
a. cysticerci in circulating blood
b. tapeworm eggs in larval fleas
c. tapeworm eggs in young adult fleas
d. mesocercariae in circulating blood
e. infected orbatid mites
b. tapeworm eggs in larval fleas
What is the common name for Echinococcus Granulosus?
Hydatid Tapeworm
What are the hosts for Echinococcus Granulosus?
Final hosts are dogs and other canids. Intermediate hosts are herbivores and humans.
What are the characteristic features of Echinococcus Granulosus?
Adult tapeworms are small, 6 mm. Larval stages (hydatid cysts) in liver, lungs, and other organs. Taeniid eggs 25-40 micrometers and may be recovered in feces.
What can you see in this image?
Echinococcus Granulosus egg
What parasitic species is shown in this image?
Echinococcus Granulosus Adult - notice the scolex with 3 proglottids
Is this a larval stage of Echinococcus Granulosus?
No, this is the adult stage because it has a mature proglottid containing thick shelled eggs in the posterior
What does the larvae of Echinococcus Granulosus develop into when ingested by intermediate host?
Hydatid cyst with endogenous budding.
What do you see in this image?
Hydatid cysts in the liver from Echinococcus spp.
Holy guacamole what is going on in this image?
Lungs infected by Echinococcus Granulosus Hydatid cysts
What can you distinguish about this histological slide?
Hydatid cysts containing scolices
Describe the life cycle of Echinococcus Granulosus
Adult worms shed 1 gravid segment with eggs in the feces -> these develop to oncospheres -> eggs are ingested by intermediate host -> eggs hatch and larvae penetrate intestine and migrate to the liver and lungs -> hydatid cysts develop and is infective stage to the final host -> final host ingests infected intermediate host -> then the scolices evaginate and attach to mucousa of small intestine and mature. PPP 45-60 days
Where are the sites of infection for Echinococcus Granulosus?
Adults in small intestine. Larval stage (hydatid cyst) in liver and lungs
What are the pathogenesis and lesions of Echinococcus Granulosus?
Adults nonpathogenic in dogs but hydatid cysts are pathogenic in humans
What are the clinical signs of Echinococcus Granulosus infection?
Clinical disease is rare in canids. In humans, hydatid can cause disease
How is Echinococcus Granulosus diagnosed?
Eggs are Taenia and Echinococcus are indistinguishable
What are the treatment and prevention for Echinococcus Granulosus?
Regular anthemintic treatment of dogs, do not feed uncooked offal, sylvatic cycle (wildlife) becomes a challenge
What is the common name for Echinococcus Multilocularis?
Alveolar hydatid tapeworm
What are the hosts for Echinoccous Multilocularis?
Final hosts are wild canids and domestic dogs. Intermediate hosts are cattle, horses, swine, rodents and humans
What are the characteristic features of Echinococcus Mulitlocularis?
Adults are 6 mm in length. Alveolar hydatid cysts in liver and other organs. Taeniid eggs may be in feces
What is different about the alveolar hydatid cyst in E. Multilocularis as opposed to the hydatid cyst in E. Granulosus?
Alveolar hydatid cyst is not confined by a capsule and performs exogenous budding as opposed to endogenous budding in E. Granulosus
The life cycle of E. Granulosus and E. Multilocularis are quite similar but what makes them different?
Alveolar hydatid cyst in E. Multilocularis is more invasive because of the exogenous budding and is capable in systemic matastases.
What can you distinguish about this image?
Egg of Taenia spp. containing a hexacanth embryo and surrounded by a embryophore
What is this image showing?
Alveolar hydatid cyst containing larval stage
Where are the sites of infection for Echinococcus Mulitlocularis?
Adults in small intestine. Larval stages develop alveolar hydatids in liver with metastases to other organs
What are the pathogenesis and lesions for Echinococcus Multilocularis?
Final host usually non-pathogenic. Intermediate host develops an alveolar cyst. Alveolar hydatid is slow growing and eventually fatal.
What are the clinical signs for E. Multilocularis?
Rare in final host. Invasive growth of hydatid cyst in humans can be fatal.
What order of trematodes does this parasite belong to and how can you tell?
Cyclophyllidea becaue it has a scolex with suckers
What order of trematodes does this parasite belong to and how can you tell?
Pseudophyllidea because it has a scolex with bothria which is a slot-like groove that allows it to stay in place
What parasitic species do these eggs belong to?
Taenia spp.
What species cestodes possess a cysticercus larval stage?
Taenia Crassiceps and Taenia Pisiformis
What species of cestodes possess a Strobilocercus larval stage?
Teania taeniaeformis
Oh my lanta what is this image showing?
Cysticerci of Taenia Pisiformis
What are the hosts for Taenia Crassiceps?
Final hosts are foxes and dogs. Intermediate hosts are small rodents. Zoonotic
What are the characteristic features of Taenia Crassiceps?
Adult with scolex and suckers, 2 m long. Unilateral genital pores. Cysticerci in intermediate host. Eggs taeniid type, brown color.
What species and structure of cestode is this image showing?
Taenia Pisiformis scolex
What is unique about the Taeniae Pisiformis proglottid?
Unilateral proglottid as opposed to bilateral in Dipyllidium Caninum
Where are the sites of infection for Taenia Crassiceps?
Adult tapeworm in small intestine. Larval stages (cysticerci) in adominal cavity of intermediate hosts
What are the hosts of Taenia Pisiformis?
Final hosts are dogs, wolves, foxes. Intermediate hosts are rabbits. NON-ZOONOTIC
Where are the sites of infection of Taenia Pisiformis?
Adult tapeworm in small intestine of final host. Larval stage (cysticercus) in liver and peritoneum of intermediate host.
What are the hosts of Taenia Taeniaeformis?
Final hosts include cats. Intermediate hosts include mice and rats, rarely humans so it is zoonotic.
What are the characteristic features of Taenia taeniaeformis?
Adults up to 60cm. Larval stage (strobilocercus) in liver of intermediate.
What parasitic species causes Strobilocercus cyst in the liver of rodents?
Taenia Taeniaeformis
Explain the life cycle of Taenia spp.
Gravid taeniid segments are shed from carnivore final host -> segments release eggs in environment and develop to oncospheres -> ocosphere is ingested by intermediate host and enters the wall of small intestine to migrate to organ of predilection -> then they develop to second stage larva (cysticercus) -> after final host ingests cysticercus, it is digested and develops in the small intestine to an adult tapeworm. PPP depending on species 6 weeks to 14 weeks
Adult taeniid tapeworms are found in dogs, cats, and humans. The life cycle is characterized by the requirement of what kind of intermediate host?
Mammalian intermediate host
Cats become infected with Taenia Taeniaeformis by ingesting infected:
a. fleas
b. fish
c. earthworms
d. rodents
e. snails
d. Rodents
What is the common name for Diphyllobothrium Latum?
Broad fish tapeworm
What are the hosts for the Broad fish tapeworm?
Final hosts: humans, fish eating mammals (dogs). Intermediate host: Copepod crustacean infected with proceroid and freshwater fish infected with plerocercoid. Paratenic hosts involved too
What are the characteristic features of the Broad Fish tapeworm?
Adults 12 m long, scolex with bothria, square shaped segments
What do you see in the image below?
Diphyllobothrium Latum eggs. Notice the operculum present too!
How is Diphyllobothrium Latum diagnosed?
Fecal sedimentation although can be confused with Fasciola Hepatica
What is the common name for Spirometra spp.?
Zipperworm also known as Sparganosis in humans
What are the hosts of Spirometra spp.?
Final hosts: bobcats, dogs, cats, lynxes, raccoons. Intermediate hosts: 1) crustacean and 2) water snakes, frogs, rodent, birds but not fish
What are characteristic features of Spirometra spp.?
Adults 2 m long, scolex with bothria, reproductive organs at centers of segments where eggs are discharged
What species of cestode is in the image below? What is the arrow pointing to?
Spirometra spp. Reproductive organs concentrated at center of segments
How is Spirometra spp. diagnosed?
Fecal sedimentation, may resemble that of Fasciola Hepatica.
What are some diagnostic methods for cestodes?
- Adhesive tape swab
- Centrifugation/flotation
- Fecal flotation
- Necropsy (gold standard)
