Trematodes

Schistosomiasis Caused by blood flukes –Most common S. haematobium –Africa and Middle East S. japonicum –Far east Asia S. mansoni –South America, Caribbean and Africa

Schistosomiasis

S. mansoni and S. japonicum Can be asymptomatic Acute disease –Skin Dermatitis at site of cercaria entry –GI tract Abdominal pain, diarrhea, ascites –Hepatosplenomegaly Enlarged liver and spleen –Brain Ectopoic eggs can cause lesions

S. haematobium Infects urinary tract –Cystitis, ureteritis, hematuria –Bladder cancer Leading cause in affected areas

Schistosoma Eggs S. mansoni S. japonicum S. haematobium

Schistosoma mansoni

Clonorchiasis Clonorchis sinensis –Asia including Korea, China, Taiwan and Vietnam Inflammation and obstruction of biliary ducts –Chronic infections can cause cancer of the biliary ducts

Clonorchiasis

Clonorchis eggs

Clonorchis sinensis

Key for Images Key AC=acetabulum (ventral sucker) IN=intestine CE=cecum OS=oral sucker CL=collar OV=ovary CS=cirrus sac PH=pharynx EB=excretory bladder SR=seminal receptacle EG=eggs (within uterus) TE=testes ES=esophagus UT=uterus GA=genitoacetabulum VT=vitellaria

Fascioliasis Fasciola hepatica (sheep liver fluke) –Worldwide Fasciola gigantica –Asia, Africa, Hawaii Inflammation and obstruction of biliary ducts –Abdominal pain, fever vomiting and diarrhea –Hepatomegaly (enlarged liver)

Fascioliasis

Fasciola hepatica Egg

Fasciola hepatica

Key for Images Key AC=acetabulum (ventral sucker) IN=intestine CE=cecum OS=oral sucker CL=collar OV=ovary CS=cirrus sac PH=pharynx EB=excretory bladder SR=seminal receptacle EG=eggs (within uterus) TE=testes ES=esophagus UT=uterus GA=genitoacetabulum VT=vitellaria

Fasciolopsiasis Fasciolopsis buski Light infections are asymptomatic Heavy infections –Diarrhea, abdominal pain, fever and ascites –Intestinal obstruction can occur Eggs indistinguishable from Fasciola hepatica

Fasciolopsis and Fasciola Eggs FasciolopsisFasciola

Fasciolopsis buski

Fasciolopsiasis

Dicrocoelium dendricitum Most common in grazing ruminants –Rare in humans, carnivores and other herbivores Worldwide distribution Metacercariae in ants cause change in behavior Dicrocoeliasis

Dichrocoeliasis