Parasite Summary 2 - Instructor: Paul Sharp PDF

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Instructor: Paul Sharp...

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Phylum Platyhelminthes Class Digenea Prosthogonimus macrorchis wm

Parasitize oviduct of female birds, wild & domestic - damages oviducts and can decrease or prevent egg laying - embryonated egg (via feces) → eaten by snail → dragonfly nymph → bird

Fasciola hepatica

Parasitizes liver ruminants & sometimes humans (no 2nd intermediate host) -inflammation of bile ducts, damage liver - egg (via feces )→ miracidium → snail → sporocyst → rediae → cercaria (encyst)→ metacercaria → human (via eating raw plants)

Schistosoma mansoni

Parasitize portal vein of large intestine

sporocyst → cercaria →

- embryonated egg (via feces) → miracidium → snail → sporocyst → cercaria → human - intermediate host specificity - no metacercarial cyst forms S. japonicum

Parasitize veins of small intestine

- embryonated egg (via feces)→ miracidium → snail → sporocyst → cercaria → human - least host specific - no metacercarial cyst forms S. haematobium

Clonorchis sinensis

Parasitize vein of urinary bladder plexus - embryonated egg (urine)→ miracidium → snail → sporocyst → cercaria → human - most host specific - no metacercarial cyst forms Human liver fluke - damage bile duct & interferes with liver function

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embryonated egg (via feces) → eaten by snail → sporocyst → rediae → cercaria → fish (via skin) → metacercaria → human

Paragonimus westermani

Parasitize human lungs & ectopic sites - unembryonated egg (via feces or sputum)→ embryonated egg → miracidium → snail → sporocyst → rediae → cercaria → crab (via skin or ingest snail) → metacercaria → human

Fasciolopsis buski

Parasitizes small intestine of humans

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immunopathologic, obstructive, & traumatic unembryonated egg (via feces)→ embryonated egg → miracidium → snail → sporocyst → rediae → cercaria (encyst)→ metacercaria → human (via eating raw plants)

Heterophyes heterophyes

Taenia pisiformis

Parasitizes small intestine of fish eating birds & mammals, including humans - embryonated egg (via feces) → eaten by snail → sporocyst → rediae → cercaria (encyst) → fish (via skin) → metacercaria → human Class Cestoidea Parasites of dogs & wild canids - gravid proglottids (via feces)→ embryonated eggs ingested by rabbit (oncosphere in liver, then cysticerci goes to mesenteries and encysts) → dog eats cyst

Taenia solium

Parasites of pigs - gravid proglottids (via feces) or crawl out of anus→ embryonated eggs ingested by pig (oncosphere hatches, “hexacanth” in muscle, then cysticerci develop) → human eats infected beef

Taenia saginata

Parasites of cows & humans - gravid proglottids (via feces) or crawl out of anus→ embryonated eggs ingested by cow (oncosphere hatches, “hexacanth” in muscle, then cysticerci develop) → human eats infected beef

Echinococcus granulosus

Parasites of dogs, related carnivores & infective to humans - eggs (via feces) → ingested by sheep, deer, moose, other large herbivores and humans (oncosphere hatches, penetarates gut and enters blood vessels → hydatid cyst forms in liver and other organs → protoscolices from hydatid cyst digested by canid & scolex attaches to intestine

Diphyllobothrium latum

Parasites of humans, bears, cats, dogs, & possibly other fish eating carnivores - unembryonated egg (via feces)→ embryonated egg (in water) → coracidia (eaten by crustacean) → procercoid in hemocoel of copepod (eaten by fish)→ plerocercoid in muscle of freshwater fish (small fish) → adult in fish-eating mammal (human) - scolex has no suckers, it has bothria (muscular flaps of tissues) Parasites of rats & infective to humans - eggs (via feces) → ingested by human → cystercecoid in intestinal villus → adult in small intestine - can follow same life cycle as diminuta (not necessary)

Hymenolepis nana

Hymenolepis diminuta

Parasites of rats & infective to humans - eggs (via feces) → ingested by larval f eas or beetles → oncosphere hatches → cystercercoid in hemocoel → adult insect ingested by rat

Dypilidium caninum

Parasites of dogs & infective to humans - egg capsule (via feces) → ingested by flea juveniles (oncosphere hatches from egg, then cysticercoid in hemocoel of flea), adult flea ingested by dog...