”1 In the UK, there was an average of 1,965 laboratory-confirmed reports of imported NVP-BGJ398 in vitro malaria infections between 1987 and 2006,2 and this country, together with France, Germany, and Italy, accounts for about three-quarters of the 10,000 to 12,000 annual cases imported into the World Health Organization European region.3 The majority of imported malaria infections reported in European countries
are caused by Plasmodium falciparum,3 the Plasmodium species associated with the most severe disease and mortality. Data from TropNetEurop,4,5 a European sentinel surveillance system, describe how most cases originate from West Africa and affect travelers of African ethnicity. The most commonly reported reason for travel is to visit
friends and relatives (VFRs), with 64.5% of all travelers citing this as a reason for travel in malaria reports between 1987 and 2006 to the UK’s Malaria Reference Laboratory and 76.4% in reports to TropNetEurop in 2007.5 Those VFRs who were born and lived for some time in malaria-endemic countries before moving to Europe will have acquired partial immunity from exposure to malaria during childhood. Without repeated exposure, immunity appears to wane with time, although the time period during which this occurs is unknown. Bouchaud and colleagues6 have demonstrated that levels of parasitemia and severe disease were lower in African migrants who were YAP-TEAD Inhibitor 1 chemical structure resident outside malarious areas for more than 4
years but acquired falciparum malaria on a short visit to a malaria-endemic area, when compared to patients who had always lived outside these areas. However, a recent study of African migrants in Italy7 suggests that living for Non-specific serine/threonine protein kinase more than 12 years outside a malarious area could result in a more serious clinical presentation with malaria. This highlights the importance for ex-residents of malarious countries to maintain the same malaria preventative measures as other travelers. National and international malaria prevention policies recommend awareness of the risk of malaria, bite avoidance, the use of appropriate chemoprophylaxis, and early diagnosis of malaria-type symptoms when traveling to a malarious country. A number of studies confirm that the use of chemoprophylaxis is low among VFRs. In a study of 302 malaria cases presenting at a hospital in Italy, Castelli and colleagues8 found only 11% of “immigrants” compared to 55% of “non-immunes” had used chemoprophylaxis on their last trip to an endemic area, whereas Driessen and colleagues9 in a Dutch study reported that statistically fewer children of immigrants had used chemoprophylaxis compared to those children in the indigenous Dutch population (not all study authors use the term “VFR” although it is clear from the context that they are referring to those who are going to visit friends or relatives).