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Unformatted text preview: Parasitic Worm Lifecycle Biological Sciences 102 Animal Biology LIFECYCLES OF HELMINTHS (Worms)
TREMATODES Clonorchis (= Opisthorchis) sinensis = The oriental liver fluke HOST (human) adult worm in liver shelled embryo miracidium SNAIL sporocyst FISH metacercaria (in muscle) cercaria redia Schistosoma mansoni -- Blood fluke HOST (human) adult worm in liver cercaria
CESTODES Taeniarhynchus saginatus - The beef tapeworm shelled embryo miracidium sporocyst SNAIL ADULT HOST (humans) adult worm in intestine shelled embryos in proglottid consumed with grass by cattle cysticercus (bladder worm) in beef muscle
Diphyllobothrium latum -- The giant fish tapeworm ADULT HOST (humans who eat raw freshwater fish) adult worm in intestine - to 30' shelled embryos in proglottids onchospheres in blood liberated embryos mature (12 days) into cilate larvae coracidium FISH HOST plerocercoid (in fish muscle) COPEPOD HOST onchosphere (larvae) procercoid into coelom of copepod coracidium consumed by copepod (in 24 hours) Parasitic Worm Lifecycle
NEMATODES Biological Sciences 102 Animal Biology Ascaris lumbricoides -- Intestinal roundworm Adults (male & female) in human intestine shelled embryos in feces shelled larvae develop (10-15 days) on soil. in lung, larvae leave blood, move to trachea, esophagus larvae emerge in duodenum, penetrate gut wall and enter blood stream shelled larvae ingested by humans with food or water Ancylostoma duodenale -- Hookworm Adults in human intestine thin shelled embryos in feces larvae develop, hatch in soil larvae grow, feed on feces in lung, larvae leave blood, enter alveoli larvae attach, penetrate skin, enter blood stream esophagus bronchi Trichinellaspiralis -- Trichina worm (of pork) larvae encyted in muscle of pig (or rats or humans) ingestion of raw or rare contaminated meat (by pigs or humans) larvae released by digestion larvae pass into lymphatics into hepatic & pulmonary circulation female burrows into mucosa, deposits larvae larvae mature in 2 days, mate larvae invade intestinal mucosa Enterobius vermicularis -- Pinworm Adults (male & female) in human large intestine and cecum females migrate to anus at night deposited shelled embryos cause itching hatch in duodemum reinfection of self, others, water and food. Also in air or dust. fingernails and clothing pick up shelled embryos ...
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This note was uploaded on 10/13/2008 for the course BIO 102 taught by Professor B during the Spring '08 term at University of California, Berkeley.
- Spring '08