Anopheles mascarensis, a Malaria Vector Endemic to Madagascar and the Comoros Archipelago: A Review.

Anopheles mascarensis (An. mascarensis; De Meillon, 1947) is a mosquito species endemic to Madagascar and the Comoros Archipelago. In the past, it was confused with Anopheles marshalli (Theobald, 1929), a continental African species that does not exist in Madagascar. Malaria transmission is highly heterogeneous in Madagascar. Principal and secondary mosquito vectors, as well as malaria parasite species, may vary from one region to another. Anopheles mascarensis has been identified as the main vector of malaria in the east and southeast of Madagascar, while it plays the role of a secondary vector in other Malagasy regions. Differences in behavior between An. mascarensis populations from the east coast and those from the Central Highlands of Madagascar suggest that An. mascarensis may be composed of sibling species. In the present review, unpublished data on the geographical distribution of An. mascarensis were assembled to update the previous distribution map published in 1966. In addition, published data on the biology of this mosquito, its geographical variants, and records of its role in malaria transmission were analyzed. The published data highlight a significant difference between populations from the east coast and those from the Central Highlands, revealing a possible gradient along different climatic and biogeographic regions of Madagascar. This analysis supports the idea that An. mascarensis may consist of a complex of sibling species. With advances in molecular tools, testing this hypothesis is increasingly within reach.