Trematodes Schistosomiasis Caused by blood flukes Most common

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 Fasciolopsis Fasciola

Fasciolopsis buski

Fasciolopsiasis

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

Dichrocoeliasis