TREMATODA
Chinese liver fluke
- Common in Asia
- Feed on epithelial tissue and lood in liver blie ducts
- Adults release embryonated eggs into common bile duct->intestine->feces->snail ingests feces->eggs become mirucidia->produce sporocyst or radiae->emerge to become cercariae. If cercariae contacts a fish (2nd int.) it penetrates, loses tail and encysts. Humans eat the raw/uncooked fish with the metacercaria and then the parasite develops into an adult
- Raw fish=delicacy
Fasciloa hepatica
- Sheep liver fluke
- Adults live in live bile duct
- eggs->snail->emerge from snail to encyst on aqautic vegetaion->sheep or human eats vegetation cycle starts all over again
Schistosomes
- Blood flukes
- Common in Africa, S/Central Amer., SE Asia.
- Adults are dioecious, live in human bloodstream
- continuous copulation between M/F
- each egg contains a spine which aids in escape from host. Schistosome eggs LACKS OPERCULUM
- Miracidium escapes via slit that develops in the eggs when the egg reaches freshwater
- Miracidium seeks a snail via chemotaxis
- penetrates->sporocyst->daughter sporocysts->fork-tailed cercariae, NO REDIAL GENERATION ->human, loses tail and develops into adults in the intestinal veins skipping metacercaria stage
CESTOIDEA
Taeniarynchus Saginatus (beef)
many eggs per proglottid
eggs->6 hooked (hexacanth larva (oncosphere)
cattle (int. host) eats grass with human feces ingesting the oncospheres or proglottids
digestive enzymes break the egg releasing the larva to burrow into the bloodstream->skeletal muscles->encyst and forms fluid filled bladder called a cysticercus or bladder worm->human eats infected meat and the cysticerus is released from the meat and the scolex attaches to the human intestine maturing the tapeworm into an adult
eggs->6 hooked (hexacanth larva (oncosphere)
cattle (int. host) eats grass with human feces ingesting the oncospheres or proglottids
digestive enzymes break the egg releasing the larva to burrow into the bloodstream->skeletal muscles->encyst and forms fluid filled bladder called a cysticercus or bladder worm->human eats infected meat and the cysticerus is released from the meat and the scolex attaches to the human intestine maturing the tapeworm into an adult
Taebua Solium (pork)
Similar to the beef tapeworm
Gravid proglottids frequently released which increases the chance to leave the small intestine
life cycle: hatch->intestine->bloodstream->tissue->cysticerci->may cause cysticercosis
Gravid proglottids frequently released which increases the chance to leave the small intestine
life cycle: hatch->intestine->bloodstream->tissue->cysticerci->may cause cysticercosis
Diphyllobothrium Latum (broad fish)
Common in N America, Great Lakes and Northern Europe.
Scolex= 2 longitudinal groves which are adhesives (hooks),
Makes 1,000,00 eggs per day which are released through uterine pores->freshwater->becomes ciliated larvae->coracidia->invades small crustaceans->copepods->procercoid larva->fish eat the crustacean->burrow into fish msucle->plerocercoid larva->larger fish eats smaller fish repeats till eaten by human->attach to human small intestine->matures into adult
Scolex= 2 longitudinal groves which are adhesives (hooks),
Makes 1,000,00 eggs per day which are released through uterine pores->freshwater->becomes ciliated larvae->coracidia->invades small crustaceans->copepods->procercoid larva->fish eat the crustacean->burrow into fish msucle->plerocercoid larva->larger fish eats smaller fish repeats till eaten by human->attach to human small intestine->matures into adult