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Nineteen species of Anopheles have been observed in the Republic of Niger but only Anopheles gambiae, An. arabiensis and An. funestus are of epidemiological importance as malaria vectors. The two species of the An. gambiae complex have the same breeding sites. But in a large part of the country they disappear all during the dry season because of the lack of adequate pools of water. Their survival is as yet an unexplained phenomenom. The most northern wet season distribution of An. gambiae complex, depending on the latitude of the intertropical front. An. funestus was no longer found after 1970 because its breeding places were destroyed both by dryness and human activity.

The Republic of Niger is a border area between the palearctic Mediterranean biogeographical region and the Afrotropical one. Two different vectorial systems of malaria transmission are separated by the Sahara desert. The risk of importation of an African vector such as An. gambiae and a parasite such as Plasmodium falciparum must be considered. For the time being, the low volume of road traffic limits the risk but the construction of a paved Transsaharian highway with new human settlements and developping cultivated areas with irrigation increases the dangers of epidemic outbreaks in these oases.