Owing to increased population flow from areas where schistosomiasis is endemic, emergent management of acute schistosomiasis is likely to become a matter of increased concern. Schistosomiasis (also known as bilharzia, bilharziasis, bilharziosis, or snail fever) is a human disease syndrome caused by infection from one of several species of parasitic trematodes of the genus Schistosoma. Schistosomiasis is a major source of morbidity and mortality for developing countries in Africa, South America, the Caribbean, the Middle East, and Asia.
Tourism to and immigration from endemic areas can result in schistosomiasis cases presenting anywhere in the developed world. Acute schistosomiasis among travelers may be increasing, and rates of emigration from endemic areas are rising. In the complete absence of routine presymptomatic screening of these groups in developed countries, it is increasingly likely that patients with acute or chronic schistosomiasis will present to emergency departments (EDs) with a variety of complaints in nonendemic areas.
Pediatric and adolescent patients who have traveled or lived in endemic areas are at the highest risk for exposure to schistosomes and are at risk for serious long-term complications. These patients usually respond well to drug therapy and should receive aggressive treatment and follow-up care.
Most human schistosomiasis is caused by S haematobium, S mansoni, or S japonicum, with the former causing urinary symptoms and the latter two causing intestinal symptoms. Less prevalent species, such as S mekongi and S intercalatum, may also cause systemic human disease. Less importantly, other schistosomes with avian or mammalian primary hosts can cause severe dermatitis in humans (eg, swimmer’s itch secondary to Trichobilharzia ocellata).
Schistosomiasis is transmitted via eggs excreted in feces or urine of infected individuals. The larvae are then maintained in a freshwater snail intermediate host, where they mature and are eventually released. Infection occurs when humans come into contact with infested freshwater, allowing the larvae to penetrate the skin.