QUESTION

What countries have malaria?

ANSWER

Prior to the advent of modern methods for controlling malaria, it was present on every continent in the whole except Antarctica. The transmission of malaria depends on an appropriate climate, both for the development of the parasite and the mosquitoes that it requires as a vector. This limits malaria to areas that are sufficiently warm and with sufficient rainfall to provide pools of stagnant water for the development of mosquito larvae.

In practice, this means that malaria can be transmitted year round in the tropics (apart from areas of high altitude and deserts), most of the year in the sub-tropics (predominantly during rainy periods) and even seasonally in temperate latitudes (during the warmer months). As a result, malaria has historically been present in the United States and even in England, at a latitude of over 50 degrees north.

However, modern control measures, such as insecticide spraying and epidemiological surveillance, has greatly reduced transmission of malaria in many parts of the world, and especially in temperate regions where the force of infection was already lower than elsewhere in the world. As such, nowadays malaria is confined to tropical and sub-tropical Central and South America, certain Caribbean islands (such as Haiti), sub-Saharan Africa (apart from most of Namibia and South Africa), parts of the Middle East, the Indian sub-continent, south-east Asia (excluding major cities such as Singapore) and many of the Indo-Pacific islands (including Papua New Guinea). Of these, by far the largest number of deaths from malaria occur in sub-Saharan Africa.

See the CDC’s interactive map of malaria distribution for more information.