Epidemiological Situation from 1970 to 2015

Malaria is endemic in the Comoros archipelago. In Mayotte, transmission is carried out by two vectors: Anopheles gambiae and Anopheles funestus. By the late 1970s, the implementation of an integrated control program against this disease had led to a significant reduction in the number of cases.This strategy relied on controlling mosquito vectors through indoor residual spraying (IRS) of insecticides and larval habitat treatment, combined with chemoprophylaxis and presumptive treatment of all febrile cases. This downward trend continued through the late 1980s despite a small epidemic in 1984, and the annual number of cases remained below 100 until 1990. The reduction in malaria control efforts in Mayotte between 1990 and 2000, particularly the weakening of systematic vector control, led to an explosion in the number of cases (more than 1,000 annually) and a gradual increase in the number of deaths due to malaria (ten in 2001).Between 2002 and 2010, the reorganization of malaria control efforts—including the resumption of systematic insecticide-treated bed net distribution and larval control, alongside improvements in diagnosis (introduction of rapid diagnostic tests) and changes to the therapeutic arsenal—reduced the annual number of cases to below 1,000. In 2012, a new vector control strategy (VCS) was adopted, involving the distribution and installation of deltamethrin-treated mosquito nets (DTNs) throughout the territory of Mayotte. The distribution report indicates that more than 140,000 mosquito nets were distributed or installed in 47,000 households, with an average of 3 ITN per household. The coverage rate was 91.4%. Starting in 2011, the number of cases dropped sharply in Mayotte, reaching 25 locally acquired cases in 2012 and then only one locally acquired case per year between 2013 and 2015 (Figure 1). At the same time, the number of cases imported from the Comoros also decreased due to programs implemented by the Union of the Comoros’ national malaria control program. According to the WHO, Mayotte officially entered the malaria elimination phase in 2014. Given the efforts undertaken in the Union of the Comoros, elimination across the entire archipelago is possible if control efforts are sustained. In 2016, there was a concerning resurgence in the number of locally acquired cases in Mayotte.