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Schistosoma mansoni
Epidemiology:
- infection is acquired through freshwater contact, from which larvae infect humans via skin penetration.
- Nile river, Uganda, Africa
Pathology:
1) Schistosoma mansoni resides in mesenteric venules
2) eggs migrate to liver, lung & CNS
3) immunologic response to the antigens present during the maturation process of the schistosomal worm
Clinical manifestations:
- diarrhea, hematochezia may occur
- hepatosplenomegaly & abdominal pain may occur
Laboratory:
- Schistosoma mansoni serology
- ova & parasites in stool
- eggs are not shed in excreta until 2 months after initial infection
- shedding of eggs varies over time
- complete blood count (CBC)
- eosinophilia may be observed
Special laboratory:
- colonoscopy with colonic biopsy
Complications:
- appendicitis
- intestinal stenosis
- protein-losing enteropathy
- periportal fibrosis, portal hypertension, variceal bleeding, &ascites
- pulmonary hypertension
Management:
- praziquantel
- inactive against immature worms
- treatment 6-8 weeks after last exposure to contaminated water
- 40 mg/kg in 2 doses (same day)
- second course of treatment is indicated if symptoms persistent or if eosinophilia after treatment
Related
schistosomiasis (bilharziasis, Katayama fever)
General
Schistosoma
Properties
KINGDOM: animal
PHYLUM: helminth
References
- Gleeson SE, Zhang X, Azar MM
Recurrent Hematochezia in a Returning Traveler.
JAMA. Published online March 5, 2021.
PMID: 33666646
https://jamanetwork.com/journals/jama/fullarticle/2777393