Factors influencing the pattern of imported malaria.

BACKGROUND: Data on imported malaria in industrialized areas are known to be incomplete because of underreporting and lack of homogeneity. These facts and the complexity of factors influencing the transmission of malaria render their interpretation difficult. The relevance of various factors is usually not fully considered, although their impact on recommendations for chemoprophylaxis may be important. METHODS: All malaria cases imported from Kenya from 1988 to 1996 that were reported to the Federal Office of Public Health of Switzerland were analyzed. The reciprocal impact on data interpretation with regard to Plasmodium species, chemoprophylaxis, onset of first symptoms after return, male or female sex, seasonal fluctuation, duration of stay, nationality groups, and fatal outcome was analyzed. RESULTS: Multivariate analysis showed a significant impact of Plasmodium species, regular chemoprophylaxis, and long duration of stay on the latency of malaria attacks. African origin and repeated stays were confounders with regard to adherence to chemoprophylaxis. The local situation of malaria transmission and the development of tourist figures were found to influence the evolution of malaria rates. These factors must be analyzed simultaneously to prevent errors in data interpretation. A higher proportion of tertian malaria cases (caused by Plasmodium vivax or Plasmodium ovale) than in previous reports was recorded owing to the impact of chemoprophylaxis and longer outbreak latencies. Seventy-five percent of tertian malaria cases were diagnosed within 6 months after return. CONCLUSIONS: Factors influencing the pattern of imported malaria must be assessed in relation to each other, especially if data from different countries and various chemoprophylaxis regimens are compared. Furthermore, regular malaria chemoprophylaxis with mefloquine given until 4 weeks after return from an endemic area is not adequate to prevent tertian malaria. Regular chemoprophylaxis was found to cause longer latencies for all malaria species.

Imported strongyloidosis: a longitudinal analysis of 31 cases.

BACKGROUND: Attention regarding imported tropical diseases is typically focused on malaria, although other parasitic diseases such as strongyloidosis may also cause serious health problems. The importance of assessing clinical features and of proper diagnosis and treatment is presented on the basis of 31 patients with imported strongyloidosis. METHODS: A retrospective analysis was performed regarding patients treated for strongyloidosis in two referral centers in Switzerland from 1998 to 2002. RESULTS: Imported strongyloidosis was investigated in 12 travelers and 19 immigrants. The reasons for diagnostic work-up were clinical symptoms in 84% and eosinophilia and screening in each of 22.5%. All patients had a history of travel or residence in endemic areas. Initial therapy was effective in 20 patients, and there was a tendency for a better response to ivermectin compared with the response to other drugs. A significant reduction in blood eosinophil count and serologic antibody titer was observed in patients responding to therapy after an average of 96 and 270 days, respectively. CONCLUSIONS: Strongyloidosis must be suspected in travelers and immigrants with skin or abdominal symptoms from regions where Strongyloides stercoralis is highly endemic. The results of this case series confirm that ivermectin is the drug of choice in treating imported strongyloidosis. Response to therapy can be assessed by serology and differential white blood count performed over 6 months after therapy.