Schistosoma mansoni

Epidemiology

• infection is acquired through freshwater contact, from which larvae infect humans via skin penetration.
• Nile river, Uganda, Africa

Pathology

• Schistosoma mansoni resides in mesenteric venules
• eggs migrate to liver, lung & CNS
• 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

Diagnostic procedures

• 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

More general terms

• Schistosoma

Additional terms

• schistosomiasis (bilharziasis, Katayama fever)