Worm Life Cycles

Below are 5 different life cycles of the worms we discussed in class. Rearange each sequence so that it is in the correct order and name the species that each life cycle belongs to.

·         Metacercarial cyst dissolves in the intestine

·         Miracidium are eaten by snail, enter tissues and transform into sporocyst and eventually redia

·         Young flukes migrate up the bile duct where they become adults

·         Egg containing miracidium are shed into the water with feces

·         Metacercariae encyst in Fish muscle

·         Mammal consumes raw infected fish

·         Cercaria escape into the water bore under scales into a fish’s muscles

 

·         Sporocyst develops in snail host

·         Ciliated miracidia hatch

·         Miracidium finds and penetrates host snail

·         Cercaria released into water

·         Eggs travel to the gut and are voided with feces or urine

·         Cercariae enter the circulatory system and make their way to the liver

·         Eggs are discharged in human feces or urine into water

·         Eggs are released by adult females that extrude through the walls of veins

·         Cercaria penetrate human skin and shed tail

 

·         Shelled larva are released in feces

·         Cysts travel to the muscle of the cow

·         Evaginated cysticercus are in upper intestine

·         Cysticercus is eaten by human in rare beef

·         Gravid proglottid are released into the digestive tract

·         Invaginated cysticercus survive in undercooked beef

·         Grass, contaminated with eggs are ingested by a cow

 

·         Microfilariae pass through mosquito gut and develop into infective juveniles

·         Adult worms develop to sexual maturity in afferent lymphatic vessels

·         Microfilariae migrate to bloodstream

·         Mosquito ingests microfilariae from human blood

·         Juveniles migrate via lymphatics to regional lymph nodes

·         Mosquito transmits juveniles through wound puncture

·         Adult worms mate and female gives birth to microfilariae

 

·         Juveniles migrate to small intestine via the trachea

·         Infective juvenile develops in soil

·         Infective juveniles penetrate skin of human

·         Eggs are passed in feces onto soil, embryo develops and first stage juvenile hatches

·         Juveniles break out of circulatory system into alveoli

·         Juveniles migrate through circulatory system to lungs

·         Adult worms develop in small intestine, mate and produce eggs