Malaria

Epidemics and emergencies

Malaria epidemics are serious public health emergencies that can have a major impact on population health and on countries’ economic growth prospects. Epidemics can be triggered by man-made or natural factors which modify the environment and increase the mosquito population and the capacity of vectors to transmit the malaria parasite. Often, epidemics and resurgences occur as a result of weakened malaria control interventions in a particular area.

Emergencies, such as violent conflict or natural disasters, often trigger malaria epidemics in displaced populations who may have little or no immunity to malaria. Prevention, diagnostic testing and treatment can be challenging among these displaced populations.

In marginal transmission areas, such as desert or highland fringe areas bordering malarious regions, increased rainfall or temperatures can also trigger epidemics. Global climate change may also lead to changes in malaria transmission patterns, and may gradually alter the geographical distribution of malaria.

Early detection systems

Malaria early warning systems using remote sensing of climatic conditions are increasingly being employed to predict epidemics. Early detection systems aim to detect the early stages of an epidemic by measuring changes in the incidence of malaria cases through weekly disease surveillance at sentinel sites. To limit impact, malaria epidemics should be detected and effective control measures implemented within two weeks of onset.

Control of epidemics

The first priority in the acute stage of a malaria epidemic is the prompt and effective diagnosis and treatment of people with the disease. Well-planned and prompt vector control that is applied in a timely manner before the epidemic has reached its peak can contribute to reducing the risk of infection. According to the World Malaria Report 2013, 38 countries use indoor residual spraying (IRS) to control malaria epidemics.

WHO assists countries to improve the prevention and control of epidemics, including preparedness, early recognition and effective and timely response.

Last updated: 6 March 2014

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