Graham Fry

Schistosomiasis remains one of the most prevalent parasitic diseases worldwide and the infection is frequently found in travelers and migrants. The European Network for Tropical Medicine and Travel Health conducted a sentinel surveillance study on imported schistosomiasis between 1997 and 2010. This report summarizes epidemiological and clinical data from 1,465 cases of imported schistosomiasis. Direct pathogen detection and serology were the main diagnostic tools applied. Of these, 486 (33%) cases were identified among European travelers, 231 (16%) among long-term expatriates, and 748 (51%) among non-European immigrants. Overall, only 18.6% of travelers had received pretravel advice; 95% of infections were acquired in the African region. On species level, Schistosoma mansoni was identified in 570 (39%) and Schistosoma haematobium in 318 (22%) cases; 57.5% of patients were symptomatic. Acute symptoms were reported in 27% of patients leading to earlier presentation within 3 months. Praziquantel was used in all patients to treat schistosomiasis. Many infections were detected in asymptomatic patients. In 47.4% of asymptomatic patients infection was detected by microscopy and in 39% by serology or antigen testing. Schistosomiasis remains a frequent infection in travelers and migrants to Europe. Travelers should be made aware of the risk of schistosomiasis infection when traveling to sub-Saharan Africa. Posttravel consultations particularly for returning expatriates are useful given the high potential for detecting asymptomatic infections.

Background. Two single-point mutations of the Plasmodium falciparum cytochrome b gene (Tyr268Asn and Tyr268Ser) were recently reported in cases of atovaquone/proguanil (Malarone) treatment failure. However, little is known about the prevalence of codon-268 mutations and their quantitative association with treatment failure. Methods. We set out to assess the prevalence of codon-268 mutations in P. falciparum isolates imported into Europe and to quantify their association with atovaquone/proguanil treatment failure. Isolates of P. falciparum collected by the European Network on Imported Infectious Disease Surveillance between April 2000 and August 2003 were analyzed for codon-268 mutations, by use of polymerase chain reaction-restriction fragment-length polymorphism. Results. We successfully screened 504 samples for the presence of either Tyr268Ser or Tyr268Asn. One case of Ser268 and no cases of Asn268 were detected. Therefore, we can be 95% confident that the prevalence of Ser268 in the European patient pool does not exceed 0.96% and that Asn268 is less frequent than 0.77%. In 58 patients treated with atovaquone/proguanil, Tyr268Ser was present in 1 of 5 patients with treatment failure but in 0 of 53 successfully treated patients. Conclusions. Tyr268Ser seems to be a sufficient, but not a necessary, cause for atovaquone/proguanil treatment failure. The prevalence of both codon-268 mutations is currently unlikely to be >1% in the European patient pool.