Although the number of imported malaria cases in France appears to be stable, significant changes may have occurred in the population that developed malaria after travel in endemic areas, which implies that preventative strategies need to be adapted, according to a study published in JAMA Network Open.

Among European countries, France has the highest number of imported malaria cases, with approximately 2000 cases reported annually. This presents a concern, as France has established significant programs for malaria prevention to reduce the risk for malaria among travelers. Therefore, the persistence of a high number of imported malaria cases is curious. Some of these preventative measures include personal antivector protection, dissemination of prevention messages, and chemoprophylaxis adapted to the context of travel. Because the purchase of protective equipment remains the responsibility of the travelers, costs may present an obstacle, which is particularly for those returning to their country of origin, as the standard of living of immigrant households has been shown to be lower than that of nonimmigrant households in France.

It has been hypothesized that a change in the epidemiologic characteristics of travelers may be associated with the high persistence of malaria in France. Therefore, this cross-sectional study reported epidemiologic trends of imported cases of malaria in travelers in metropolitan France (geographic territories of France on the European continent) from 1996 to 2016 in an effort to explain the persistence of the high incidence of imported malaria cases, despite national preventative measures.

In total, 43,333 cases of imported malaria among civilian travelers living in metropolitan France were included in the study. Researchers analyzed the collected data for trends in association with age, sex, ethnicity, malaria species, case mortality rate, severity of illness, purpose of travel, and endemic countries visited. Of these cases, 62.4% were male, 19.9% were age < 18 years, 71.5% were African, and 26.5% were European. The primary outcome was the evolution of the main epidemiologic characteristics of patients with imported malaria.

During the study period, the number of malaria cases peaked in 2000, with 3400 cases; declined in 2005, to 1824 cases; and then stabilized to 1720 cases per year. Throughout this period, mortality remained stable at 0.4%, although the proportion of severe cases has increased from 8.9% of cases in 1996 to 16.7% of cases in 2016 (P <.001). In addition, Plasmodium vivax was the most frequently observed etiology of malarial infection, occurring in 85.5% of cases. Of note, the proportion of malaria cases in African individuals rose from 53.5% in 1996 to 83.4% in 2016, with the most frequent reason for travel being visiting friends and relatives (77.1%; P <.001). The increase rate in African individuals showed a mirrored decrease in European individuals (46.5% in 1996; 16.6% in 2016).

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Overall, the study authors concluded that, “Although prophylactic measures appeared to be efficient among European individuals traveling for tourism or business purposes, progress is needed to ensure better protection for African individuals visiting friends or relatives.”

Reference

Kendjo E, Houzé S, Mouri O, et al. Epidemiologic trends in malaria incidence among travelers returning to metropolitan France, 1996-2016. JAMA Network Open. 2019;2(4):e191691.