Key points
- Malaria is typically transmitted in tropical and subtropical areas.
- Temperature is key to Anopheles mosquito survival and the malaria parasite completing its growth cycle within the mosquito.
- Generally, in warmer regions closer to the equator, malaria transmission is more intense and can occur year-round.
Overview
Altitude and climatic factors including temperature, humidity, and rainfall impact where malaria spreads. Malaria is typically transmitted in tropical and subtropical areas, where
- Anopheles mosquitoes can survive and multiply, and
- Malaria parasites can complete their growth cycle in the mosquitoes ("extrinsic incubation period").
Temperature is particularly critical. For example, at temperatures below 20°C (68°F), Plasmodium falciparum (which causes severe malaria) cannot complete its growth cycle in the Anopheles mosquito. Therefore, it cannot spread in these areas.
Resource
In many countries where malaria spreads, you will not find it in all parts of the country. Even within tropical and subtropical areas, you will not find malaria
- At very high altitudes,
- During colder seasons in some areas,
- In deserts (excluding the oases), and
- In some countries where spread has been interrupted through successful control/elimination programs.
Generally, in warmer regions closer to the equator, malaria transmission is more intense and year-round.
Most cases of malaria occur in sub-Saharan Africa, but it also occurs in parts of Oceania (such as Papua New Guinea) and in parts of Central and South America and Southeast Asia.
In cooler regions, spread is less intense and more seasonal. There, P. vivax might be more prevalent because it is more tolerant of lower average temperatures.
In many temperate areas, such as western Europe and the United States, economic development and public health measures have succeeded in eliminating malaria. However, most of these areas have Anopheles mosquitoes that can spread malaria, and reintroduction of the disease remains a risk.