Migrants as a Major Risk Group for Imported Malaria in European Countries

Methods and Results\udSystematic searches of MEDLINE and available national malaria statistics were scanned to identify studies and reports showing the proportions of malaria cases occurring in nonnationals in European countries.Nonnationals were defined as being foreign born residents, which embraces various categories of migrants, including immigrants, refugees, asylum seekers, foreign workers, illegal migrants, or aliens. Only reports describing more than 250 malaria cases were included in the analysis. The period of the search was January 1991 to September 2001. A total of five MEDLINE reports2–6 were found that satisfied the inclusion criteria, and personal communication with surveillance groups provided additional information.\udProportion of Nonnationals\udDepending on the country of origin of the report, the proportion of cases varied from 33% in the United Kingdom to 86% in a region of France, reflecting the profile of immigration in various areas at different time points. On pooling the reports, 43% of malaria cases registered in important European centers occur in nonnationals, frequently settled immigrants VFR. In Italy, where 44% of cases were related to foreigners, VFRs accounted for 72% of the cases reported in this group.2 Increasing Proportion of Nonnationals\udAll reports describe an increasing proportion of malaria cases occurring in nonnationals. In the report describing imported malaria cases in northern Italy,4 the proportion of immigrants increased from 34% in 1991 to 59.9% in 1995 (p = .002). In the Netherlands, for the period 1979 to 1988, only 15% of cases were in persons originating in a malaria-endemic area, whereas for the period 1991 to 1994, 40% of cases were in persons from malaria-endemic areas, and 8% of cases were in children born to settled immigrants resident in the Netherlands.5 Comment\udData from the aforementioned studies show that residents of foreign origin represent a growing proportion of imported cases, reflecting to some extent the increasing number of migrants in western Europe. In Britain, an older study has shown that migrants VFRs have a malaria incidence rate almost three times higher that that of tourists to Africa,7 suggesting a higher risk of exposure and/or insufficient protection measures. Although no prospective studies exist that confirm the hypothesis, migrants VFRs may be more exposed as they visit their families in rural areas with higher transmission rates and simple nonair-conditioned living conditions.Many return home during summer holidays, a period corresponding to the rainy season in West Africa or to the monsoon season in India when malaria transmission is at its peak.Many migrants VFRs mistakenly believe that they retain lifetime immunity and although immunity does wane when constant reexposure stops, some immunologic memory remains that partly explains the lower case fatality in Migrants