Bailey & Scott's Diagnostic Microbiology: Blood Trematodes Flashcards

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blood flukes

adult schistosomes not flattened; males 1.5 cm and wider than female, females 2 cm in length and thin; oral sucker surrounds mouth; ventral sucker below oral sucker; adult worms live in veins that supply intestines or bladder depending on species; eggs passed in feces or urine


Schistosoma haematobium

common in Africa and Arabian peninsula; found in vessels surrounding bladder in humans; mostly asymptomatic; blood in urine, painful urination, tissue granulomas, associated with bladder cancer


Schistosoma japonicum

common in China, Indonesia, and Phillipines; RH-domestic animals; oriental blood fluke found in vessels in small intestine in humans; causes Katayama and Tangtze River fever


Schistosoma mekongi

common in lower Mekong River basin (Laos), SE Asia; RH-dogs and pigs; found in vessels in small intestine of humans


Schistosoma mansoni

common in Africa, Arabian peninsula, and Brazil; rodents and marsupials are reservoir hosts; found in vessels in lower intestine of humans; causes swamp fever, intestinal schistosomiasis, abdominal pain, splenomegaly, hepatic or pulmonary cirrhosis


Schistosoma intercalatum/guineensis

common in Central and Western Africa; RH-rodents, marsupials, and nonhuman primates; found in vessels in rectum and sigmoid colon in animals


Schistosoma spp.

transmission occurs by penetration of intact skin by cercariae


Schistosoma spp. clinical presentation

cercariae cause localized swelling and itching at site of entry, enter blood causing allergic symptoms, fever, EOS, abdominal pain, and hepatosplenomegaly; jaundice with hepatitis-like syndrome; larval migration causes fever and malaise; severe tissue damage when eggs reach intestine and bladder; can cause swimmer's itch in humans


Schistosoma spp. lab diagnosis

eggs are detected in feces or rectal, urinary, or bladder biopsy, wet mounts, and some antibody-based assays available


Schistosoma haematobium lab diagnosis

eggs in urine 110-170 by 40-70 um; light yellow-brown, conspicuous terminal spine, no operculum, embryonated


Schistosoma mansoni lab diagnosis

eggs from stool 114-180 by 45-70 um elongated with large lateral spine, light yellow-brown, adults in large intestine venules;


Schistosoma japonicum lab diagnosis

eggs in stool 70-100 by 55-65 um spherical, very small lateral spine; venules of small intestines