Malaria parasites successively infect two types of hosts—humans and female mosquitoes of the genus Anopheles. The mosquito acts as a vector, carrying the parasite from one human to another, without itself developing apparent illness. Malaria transmission occurs when a female mosquito carrying the malaria parasite bites and feeds on a human host.
The parasites that most commonly cause malaria in the Americas are Plasmodium vivax and P. falciparum. P. vivax is the most prevalent species in the Americas and can cause malaria that relapses months or years after infection; P. falciparum can cause severe, potentially fatal malaria. Dominant mosquito vectors in the Americas include Anopheles albimanus, A. darlingi, A. nuneztovari, A. pseudopuntipennis, and A. aquasalis.
Effective, long-term malaria vector control requires an integrated approach employing several complementary measures—such as environmental management, chemical control, and biological control methods—used singly or in combination.
Environmental management can be used to reduce larval habitats through, for example, the use of water-conserving agricultural irrigation techniques or efforts to fill depressions that collect water. Chemical control techniques include the use of insecticide-treated bed nets, indoor residual spraying with insecticides, and the application of insecticides to larval habitats. Biological control may be appropriate in some cases; such methods include the use of larvivorous fish or bacterial toxins that target mosquitoes.
To be effective, integrated vector control strategies must be applied across a large proportion of households and potential larval habitats. These approaches should be combined with personal protection measures, including the installation of window screens in houses and otherwise securing homes against mosquito entry; wearing light-colored clothing, long pants, and long-sleeved shirts; and the use of repellents.