In the two reported cases,

symptoms appeared between 11 and 14 days after exposure, respectively. This is much shorter than might be expected according to the literature. Both patients presented with fever, cough, urticaria, and eosinophilia, manifestations that are most commonly associated with acute schistosomiasis (Katayama fever)6 and occasionally with other helminth infections in returned travelers.7 Helminth infections learn more are difficult to diagnose during the invasive stage. In the reported cases, the diagnosis was made about 3 weeks after the onset of symptoms by positive agar-plate stool cultures in both patients, the presence of Strongyloides stercoralis larvae in the stools of one patient and a serologic Vincristine diagnosis in the other.1 When faced with a returned traveler from the tropics with eosinophilia, an helminth infection should be at the top of a differential diagnosis. Not only are serologic tests frequently not positive early in the infection but also they may lack specificity, particularly in the case of strongyloidiasis8; both schistosomiasis and filariasis may lead to false positive tests for strongyloidiasis. Repeat stool examinations (and urinalyses

in case of Schistosoma haematobium schistosomiasis) may be necessary to detect parasites in the first few weeks after exposure. Even then, tests may be negative because of a long prepatent period (eg, 2 mo in schistosomiasis). Chronic strongyloidiasis is usually asymptomatic or gives rise to mild gastrointestinal symptoms, most often peptic ulcer-like symptoms. Of greater concern is its potential to become a fulminant, fatal illness in appropriate circumstances. Strongyloides hyperinfection syndrome and dissemination result from decreased cell-mediated immunity, including that associated with corticosteroid treatment and HTLV1.5,9 below Disseminated strongyloidiasis carries mortality rates from 50% to 87%, even with treatment.3 This

infection is now considered the leading cause of death from a parasitic disease in the United States.10 In Western countries chronic, usually asymptomatic, strongyloidiasis was classically associated with immigration. However, it is now increasingly seen in tourists. In a series of 43 travelers with strongyloidiasis in Canada, the infection was associated with visiting friends and relatives in 37% of the cases, tourism in 30%, and immigration in 21%.11 These results may illustrate an epidemiological change in the acquisition of strongyloidiasis in Canada; on the other hand, they may be the result of referral bias. However, it is interesting to note that in an older series of 76 persons in Canada with confirmed strongyloidiasis, nonmigrants made up only 4% of the cases, whereas 96% were persons who had immigrated a median of 48 months (range 2–480 mo) prior to presentation.