Flatworms-trematode (liver fluke) Flashcards
How do flukes cause disease
Suck blood
Obstruct blood
Destroy organs
Egg accumlations
What are the stages of fluke
Miracidum > sporocyst > Redia > Cercaria > Metacercaria
What are the three ways Cercaria becomes Metacercaria
- Penetrate by 2nd I. host
- attach to vegetation and encyst
- penetrate D. host directly
How do the miricidium come out
“pop-top” on the egg
pop out into water
Eperculum
What happens when fluke gets into snail
produce rediae or cercariae
What happens when fluke leaves snail (one of 3 things)
- 2nd host.
- Encyst.
- Direct host
What happens during last stage of fluke
loses tail
Metacercaria
infects direct host
What are some characteristics of schistosomes
Tubular body Dioecious slit where female fits in no 2nd host found in blood
How do you diagnose fluke infections
Sedimentation
eggs are very heavy
need a very heavy sedimentation solution
Faciola hepatica
liver fluke
what does faciola hepatic use as intermediate host
Aquatic snail
What are characteristics of faciola hepatica identification
large shoulders
highly branched internal organs
large eggs
eperculum on egg
Where is fasciola heptica found
snails in neutral pH soil
Life cycle of fasciola hepatica
Eggs in feces > egg contacts water and miracidium emerges > miracidia penetrates snail > cercariae develop from snail sink to bottom of pond and encyst > water with egg ingested by host > goes to liver > go to bile ducts as mature
What is the transmission of faciola hepatica
seasonal
need mild temperatures
Where does fasciola hepatica survive during summer
the entire population survives in ruminates
What are characteristics of fasciola hepatica pathology
depends on number ingested
Primary lesions: liver parenchyma or bile ducts
acute, subacute, chronic
Fasciola hepatica pathology in cattle
low grade, chronic disease
Fasciola hepatica pathology in sheep
acute
Prepatent
sheep do not acquire immunity
Traumatic hepatitis: Migration of large numbers of juvenile flukes
Death: massive exposure of juvenile flukes
What is chronic fasiolasis
Most common- cattle and sheep moderate number of adults eggs in feces hepatic fibrosis anemia
Chroic fasciolasis clinical signs in sheep
bottle jaw
Chronic fascioliasis in cattle
not much
What are some charcteristics of Digenea
Sexual and asexual 2+ hosts (always a snail) Leaflike 2 attachment organs Have Ceca
