Schistosoma mansoni in Family 5 Years after Safari

To the Editor: Each year ≈350,000 Americans travel to Africa and ≈500,000 travel to Brazil and the Far East, all schistosomiasis-endemic regions. Data from the European Network on Imported Infectious Diseases Surveillance (TropNetEurop) suggest that most schistosomiasis cases imported to Europe are acquired in Africa; 80% of new cases worldwide occur in sub-Saharan Africa (1,2). Travelers to Africa from the United States are also at high risk for infection. Schistosoma mansoni has the greatest impact on residents of disease -endemic areas who have high-grade infection and progressive hepatosplenic disease with portal hypertension and its manifestations. Most infected, short-term travelers sustain a low-level of fluke infestation with few symptoms, although serious complications can occur. We report a 38-year-old American man with ectopic S. mansoni fluke migration that led to neural schistoso-miasis. His symptoms prompted us to test family members who had accompanied him on a trip to Kenya 5 years earlier. The family members had been unaware of the risk for schistosomia-sis that the trip posed. Five years after a Kenyan safari during which the index patient visited northeastern Lake Victoria and swam 1 afternoon, vertigo, nausea, and nystagmus developed. The results of liver function tests were normal and peripheral blood showed no eosinophilia. Biopsy of a large cerebellar lesion noted on magnetic resonance imaging (MRI) was diagnostic, yielding multiple S. mansoni ova within large eosinophilic granulomas, consistent with tumoral neuroschistosomiasis. We tested 24 of 25 family members who had accompanied him to Kenya for schistosomi-asis (Figure). All of the accompanying family members, except 3 women, had gone into the water. All members were well, except an 8-year-old boy, in whom granulomatous colitis had developed after the trip. Eighteen of 25 enzyme-linked immunosorbent assays (ELISA) were positive for S. mansoni infection, including that of samples from the index patient and the boy (Figure). ELISA was performed on 18 samples at the Centers for Disease Control and Prevention (CDC) and 7 samples at Focus Technologies. Both tests used the same CDC-produced antigen, the microsomal fraction of adult S. man-soni fluke, which has both a sensitivity and specificity for S. mansoni of 99%. Confirmatory immunoblots were performed at CDC on samples from 19 of the 25 ELISA-tested family members, with 1 discordant result, a positive ELISA and negative S. mansoni and hematobium immuno-blots. Three of 7 ELISA-negative family members were the nonswim-mers. Analyses of single stool specimens from 7 family members, including the …