Parasitology - Lecture 14 (Cestodes) Flashcards
When considering Helmniths, discuss the general breakdown of them into the different categories
- Helminths is broken down into PLayhelminths (flatwiorms) and meatodes (roundworms)
Discuss the moprhology of cestodes
Againm, discuss the moprhology of cestodes in terms of the proglottid and scolex
- view picture
- each segemnt has both male and female reproductive organs
There are two major classifications of cestodes in vte med: discuss these
1) Cyclophyllidea includrs Dipylidium caninum, Taenia sp, and Echinococcus spp; this group is much more comon
2) Psedupphyllidea –> includes Diphyllobothrium sp, Spirometra sp,
Discuss the general life cycle of Cycllophillidean spp
- Adult tapeworms are in carnivore (dog/cat/human) small intestine
- Individual eggs or whole proglottids are shed in feces
- Eggs/proglottids eaten by the intermediate host
- Intermediate stages develop such as cysticeroid, cysticerucus, strobilocercus or hyatid cyst
- Intermedoiarte host eaten by definitive host
- Adults develo in the defintive hosts small intestine
Discuss thr cyclophyllidean intermediate stages
- Larval stages of cesrtodes are unique, usually do not resemble adult tapeworms, often shaped like tiny balloons
- Dipylidum -> Cysticeroid
- Taenia psiformis (dogs) –> Cysticercus –> fluid filled cyst with one scolex
- Taenia taeniaformis (cats) –> Strobilocercus –> looks like a tiny tapeworm
- Echinocccus –> Hyatid cyst –> fluid filled cyst with many scolices
Discuss the life ycle of Cyclophyllidean in general
- ## Often there is a predator prey relationship between the definitive host and the intermediate host
Discuss th eclinical signs and treatment of Cyclphyllidean spp
- Clinical signs –> 1) usually the intermediate stage of the tapeworm is the pathogenic stage 2) adult tapeworms tend to cause mild intestinal lesions
Treatment: ) Praziquantel 2) fenbendazole
Discuss Dipylidium caninum
– the most common tapewomr of dogs and cats in many parts of the US
Lifecycle:
- Infected dog or cat sheds proglottids
- Eggs in proglottid eaten by fleas
- Cysticercoid develops in the flea
- Dog (or cat or human) eats flea
- Cysticercoid in the flea develops into an adult tapeworm in intestine
Also: whole proglottids are shged and crawl around anus or foudn in poop
Discuss the main points of clinical signs, treatment, and prevention for Dipylidum caninum
- Diagnosis: eggs will not be detected by fecal float
- Treatment: praziquantel
- Prevention: control the flea
Zoonotic potential: Humans become infected with the adult tapeworm if they accidentally ingest an infected flea
Discuss the basics of Taenia Psiformis life cycle and just general info
- common tapeworm of dogs
- Found worldwide
Life cycle:
- Infected dog sheds proglottids and/or eggs
- Proglottid/egg is eatemn by a rabit
- Cysticercus develops in rabbit liver
- Dog eats rabbit
- Cysticercus from the adult rabbit develops into an adult tapeworm in dog intestine
Discuss Taenia psiformis in terms of clinical signs, diagnossi, and treatment
- Diagnosis: 1) Fecal float –> eggs may be shed 2) segemnts crawling around the anus
Treatment: 1) praziquantel 2) Fenbendazole
Discuss Taenia Taeniaofrmis
- Common tapeworm of cats
Lifecycle:
- infected cat sheds proglottids/eggs
- proglottid is aten by mouse
- Strobilocercus develops in the mouse liver
- Cat eats mouse
- Strobilocercus from mouse develops into adult tapeworm in cat intestine
Discuss the Echinococcus species
Echincoccus spoecies includes: 1) echincoccus Granulosus and 2) Echinococcus multiocularis
- adult worms are very small and are rarely seen
- ## important zoonotic potential
Discuss the Echinoccous Lifecycle
- infected dog sheds eggs
- Eggs are eaten by intermediate host: many ammmals - sheep/humans/pigs/hoats
- **hyatid cuyst ** develops in the intermediate host
- Dog eats intermediate host
- Ingested hyatid cyst develops into m,any adult tapewormns
-
Discuss more of the specifics when it comes to Echinococcus granulosus and Echincoccus Multiocularis
Echincoccus Granulosus:
- Hyatid cyst –> usually in sheep lung and liver, can be naywhere (uniocular and noninfiltrative)
- Can cause pressure atrophy in tissues
- Rptured cysts can result in allergic repsonses
Echinoccus Multiocularis;
- Curculates primarily in iwld canids – mostly in foxes
- Intermediate host: rodents, other mamals including humans
- The hyatid cyst is multiocular and invasive
Discuss the clinical signs, treatnment, and diagnosis for the Echinococcus soecies
- adult tapeworm is asymtpoamtic in dogs: importance is that dogs are the soruce of the eggs
- Diagnosis: fecal float to identift eggs; eggs are indistinguishable from Taenia
- Treatment: praziwuantel and Fenbendazole
Discuss prevention and controkl for the Echincoccus species
- Break the cycle
- Treat all dogs in endemic areas
- ## Practice good hyguene to prevent infestation
Discuss the species invovled in the class of cestodes knonwnas Pseudophyllidea
- Diphyllobothrium sp
- Spirometra sp
Discuss the differences between Pseudophyllideans and Cyclophyllidean tapeworms
Differences from cyclophyllidean tapeworms:
- 1) No hooks or sucker on scolex –> just grooves called bothria
- Eggs loook like fluke eggs
- single, central genital pore
- Requires two intermediate hosts
Discuss the Pseudophyllidean life cycle in genral terms
Two intermediate host required:
Discuss the main points for the both of the Pseudophyllidean species
Diphyllobothrium:
- 1st intermediate host –> cope pod
- 2nd intermediate host –> fish
- Definitive hosts: carnivores such as dogs, cats, bears, humans, etc
Spirometra:
- 1st intermediate host –> cope pod
- 2 intermediate hosts –> any vertebrate except fish (especially snbakes)
- Definitive hosts: cats dogs, racoons
Discuss Spirometra species in terms of Proliferative Sparganosis
- if a dog or cat consumes the copepod, they become an accidental 2nd intermediate host
- The larva (spargana) reproduce asexually and develop in all tissues
- very rare
- no effective treatment
Discuss Diphyllobothrium in terms of lcinical signs,m diagnosi, tretament,
- Infection with the adult tapeworm
- Clinical signs: diahhrea, weight loss, and vmoiting
- Diagnosis: fecal float to idewntify eggs; fecal sedimentation
- Treatment: Praziquantel –> high off label dose required
