Characteristics of Schistosomiasis in Travelers Reported to the GeoSentinel Surveillance Network 1997–2008

Abstract

Among ill returned travelers to Schistosoma-endemic areas reported to the GeoSentinel Surveillance Network over a decade 410 schistosomiasis diagnoses were identified: 102 Schistosoma mansoni, 88 S. haematobium, 7 S. japonicum, and 213 Schistosoma unknown human species. A total of 83% were acquired in Africa. Unlike previous large case series, individuals born in endemic areas were excluded. Controlling for age and sex, those traveling for missionary or volunteer work, or as expatriates were more likely to be diagnosed with schistosomiasis. Sixty-three percent of those with schistosomiasis presented within six months of travel. Those seen early more often presented with fever and respiratory symptoms compared with those who presented later. One-third of patients with schistosomiasis were asymptomatic at diagnosis. Half of those examined for schistosomiasis were diagnosed with infection. Screening for schistosomiasis should be encouraged for all potentially exposed travelers and especially for missionaries, volunteers, and expatriates.

Evaluation of Eight Serological Tests for Diagnosis of Imported Schistosomiasis

“…Apart from this, imported schistosomiasis has been recognized as an emerging clinical problem in countries where the disease is not endemic. The infection affects expatriates and immigrants but also travelers, especially in association with adventure and ecotourism (9,17,23,35).…”

Urinary schistosomiasis

“…2b) may occur in response to cercarial skin penetration [12,13]. However, newly infected patients are often asymptomatic [7].…”

“…The ease of access to wider geographical regions for tourism has increased the infection rate among travelers [12]. Such individuals lack any acquired immunity and within 6 weeks after infection they may experience a severe hypersensitivity reaction in response to the first bout of egg antigen release by adult worms.…”

Imported Schistosomiasis

“…Those with S. haematobium and S. mansoni infections presented with more respiratory symptoms than did those ruled-out for schistosomiasis. Moreover, returned travelers with schistosomiasis who were seen within six months of travel more often presented with fever and respiratory symptoms compared with those who presented later (Nicolls et al, 2008). Imported travel-related infections were studied in a retrospective and descriptive study of travelers returning from the tropics and attended at the Tropical Medicine Unit, Infectious Diseases Department of Hospital Ramon y Cajal in Madrid (Spain) during the period January 1989 to November 2006.…”