Trematodes: Bood trematodes, Schistosomes

Question 1

Life cycle: eggs-miracidia-( find a snail host) -sporocysts-cercariae-adults
Route of infection: cercariae penetrate skin
Geography: West and Central Africa, Egypt, Brazil, Venezuela, West Indies, Puerto Rico
Specimen source: stool sample, blood sample
Morphology: eggs-114-180 micrometers by 55 micrometers, lateral spine
adults-male 1.2 cm, female 1.6 cm, in mesenteric vessels of rectum
Lab tests: wet prep, conc. stool, Kato-Katz- 50 mg stool, glycerin soaked cellulose coverslip; hatching test – stool in water, watch for eggs hatching to miracidia, ELISA and EITB, acid fast positive
Pathology: fever, headache, dysentery/bloody diarrhea, hepatomegaly ( D,F,H2)

Answer 1

Schistosoma mansoni

Question 2

Life cycle: eggs-miracidia-sporocysts-cercariae-adults
Route of infection: cercariae penetrate skin
Geography: China, Indonesia, Japan, Philippines
Specimen source: blood sample, stool sample.
Morphology: egg- 70-100 micrometers by ~50 micrometers, small lateral spine, acid fast positive
adult-similar to S. mansoni, found in mesenteric vessels of bowel
Lab tests: wet prep, conc. stool, Kato – Katz smear – 50 mg stool, glycerin soaked cellulose coverslip, ELISA, enzyme-linked immunoelectrotransfer blot test (EIBT)
Pathology: Similar to S. mansoni, but S. japonicum has a higher egg production-more severe potential, Katayama fever

Answer 2

Schistosoma japonicum

Question 3

Life cycle: eggs-miracidia-sporocysts-cercariae-adults
Route of infection: cercariae penetrate skin
Geography: Mekong river valley-Laos, Thailand
Specimen source: stool sample, blood sample
Morphology: egg-similar to S. japonicum, but smaller, 50 - 65 micrometers by 30-55 micrometers, acid fast-?
adult- similar to S. japonicum
Lab test: wet prep, conc. stool
Pathology: Similar to S. japonicum
hepatosplenomegaly, portal venous hypertension

Answer 3

Schistosoma mekongi

Question 4

Life cycle: eggs-miracidia-sporocysts (snail host)-cercariae-adults
Route of infection: cercariae penetrate skin
Geography: Africa, Asia minor, Cyprus, S. Portugal
Specimen source: stool sample, blood sample
Morphology: Egg-112-170 micrometers by 55 micrometers. Adults- similar to other schistosomes, female in bladder vessel walls ( venous plexus)
Lab test: wet prep, urine, acid fast negative
ELISA, enzyme-linked immunoelectrotransfer blot test ( EIBT) testing.
Pathology: dysuria, hematuria, granulomas, fibrosis, ulcerations, bladder cancer

Answer 4

Schistosoma haematobium

Question 5

Life cycle: eggs-miracidia-sporocysts-cercariae-adults
Route of infection: cercariae penetrate skin
Geography: Central and Western Africa
Specimen source: stool sample, blood sample
Morphology: eggs- 140-240 micrometers, morphology similar to S. haematobium, acid fast positive
adults - similar to the other schistosomes, adults in intestinal vessel walls
Lab test: wet prep, conc. stool
Pathology: Similar to S. mansoni infections
pathology confined to mesenteric-portal system – rectal bleeding, anorexia, nausea, diarrhea

Answer 5

Schistosoma intercalatum