Flashcards in Lecture 5: Tapeworms Deck (50)
What is the name given to a class of parasitic flatworms, commonly called tapeworms
Cestodes are live in the _______ of vertebrates
1000 species belong to the Cestodes class of parasites wide a wide range of animal hosts
Life cycle of Echinococcosis involves what number of mammalian hosts
______ are the definitive hosts of Echinococcosis
___________ harbor the adults which shed eggs within their feces
Eggs hatch when ingested by ________ hosts, including goats sheep cattle
Life cycle of Echinococcosis
completed when ______________
definitive hosts reingest the organ tissue of intermediate hosts which contain eggs aka cysts
Disease caused by Echinococcosis is caused by how many species in humans?
four species in humans
What are the two most common species of Echinococcosis in humans?
E granulosus and E multilocularis are most common
- Causes cystic echinococcosis and alveolar echinococcosis respectively
What are the two least common species of Echinococcosis in humans?
E vogeli and E oligarthrus are also pathogenic but are much less common in humans
_______ forms are referred as hydatid cysts and the diseases caused by them are commonly referred as cystic, alveolar, or polycystic hydatid disease
Metacestode (larval) refer to ______________
hydatid cysts and the diseases caused by them are commonly referred as cystic, alveolar, or polycystic hydatid disease
The fully grown metacestode in E. granulosus is typically ____________
fluid filled and unilocular
In humans the slowly growing hydatid cysts many contain many liters of fluid and thousands of protoscolices
E. Granulosus causes ____________
This form is most frequently encountered
E. Granulosus is distributed
E. Granulosus is most frequently in what areas?
Areas of rural side where sheep raising occurs
E. Granulosus is how long and has what features?
Rostellum contains 28-50 hooks
Definitive host of E. Granulosus
Dogs and other carnivore
Intermediate host of E. Granulosus
Sheep, goats, camels, horses, cattle
Incidental host of E. Granulosus
Human (do not play a role in transmission)
A heavily infected dog may have as many as 40,000 tapeworms and each worm sheds 1000 eggs every 2 weeks
(Eggs can adhere to hair around dog anus and also around the muzzle of the )
Eggs can survive on pasture > 1 year and survive scorching temperatures
Eggs can survive on pasture > 1 year and survive FREEZING temperatures
(Die off after a few hours of direct sunlight)
Describe life cycle of E. Granulosus
1. Adult worm inhabits small intestine of definitive host
2. Following egg ingestion by the intermediate or incidental host, eggs hatch and penetrate the intestinal mucosa and enter the blood stream
3. A few days later, cysts start to form and grow with time
E. multilocularis causes _________ that looks like alveoli
(Can travel to any part of the body, like cancer and are 1.2 mm-3.7 mm long)
Definitive and intermediate Host of E. multilocularis
Definite host: mainly foxes but dogs, cats, coyotes and wolves also
Intermediate Host: small rodents
E. multilocularis is found in what geographical type of countries?
Mostly found in northern countries, cooler temperature countries
(Associated with dogs feeding on infected rats)
Clinical manifestations of Echinococcus are similar.
Clinical manifestations are highly variable
- Depends on the organs involved and surrounding organs
- Size of the cysts at time of presentation