2001-2010 United Nations Decade to Roll Back Malaria
What Is Malaria? PDF version |  Malaria in Africa  PDF version |  Malaria in Pregnancy PDF version |  Insecticide-Treated Mosquito Nets PDF version |  Children and Malaria PDF version |  RBM and Complex Emergencies PDF version | Epidemic Prediction and Response PDF version |  Facts on ACTs PDF version |  Economic Costs of Malaria PDF version |  Monitoring and Evaluation PDF version

Epidemic prediction and response

EPIDEMICS can occur when malaria attacks vulnerable populations with little or no immunity. In such situations, people of all age groups are at risk of death or severe disease. Epidemics of Plasmodium falciparum malaria, the most severe form of the disease, can be devastating if not controlled in a timely manner. The populations most at risk of epidemics are those living in highlands, arid and desert-fringe zones, as well as those living in areas where successful control measures have not been consolidated or maintained.

Factors which may precipitate a malaria epidemic fall into two categories: natural (climatic variations, natural disasters), and man-made (conflict and war, agricultural projects, dams, mining, logging). Most of these factors modify the physical environment, and increase the capacity of mosquitoes to transmit malaria. Some factors also result in massive population movements that expose non-immune populations to malaria infection.

Because malaria epidemics occur in populations not normally exposed to the disease, or who are exposed for only a short part of the year, local health services are usually unprepared to predict, detect and control such epidemics in time, resulting in severe cases and high death rates. When control measures are taken, they are often too late and are implemented with minimal coordination and expertise, resulting in only a marginal benefit. Then, with the epidemic over, hard-won lessons are gradually forgotten, until the next epidemic comes along.

To a large extent malaria epidemics are predictable, through a combination of socioeconomic and meteorological information and local epidemiological knowledge. Man-made epidemics, in particular, can be predicted with considerable precision, for example in relation to irrigation projects. Multisectoral action can help prevent them from occurring.

It is harder to predict malaria epidemics arising from natural causes. However, such epidemics tend to recur, and it is important to learn from past experiences. WHO is currently supporting retrospective analyses of malaria epidemics in seven African countries. The findings will form a basis for practical WHO guidelines on malaria epidemic prevention and control in Africa. RBM and its partners are also supporting epidemic-prone countries in their efforts to develop comprehensive multisectoral epidemic warning systems that combine early detection, early warning and long-range forecasting.

Such systems must include the use of valid and accurate indicators. Research aimed at validating epidemic indicators is currently taking place in Eastern and Southern African countries, including Kenya, the United Republic of Tanzania and Uganda. RBM is exploring the possibility of establishing a regional technical network for Asian countries, focusing on analysing past experiences and establishing accurate forecasting indicators.

Forecasting and early warning can reinforce local preparedness, and allow authorities and communities to use cost-effective and timely control options to prevent excessive deaths. RBM is also assisting countries to develop strategies for epidemic preparedness and emergency action. RBM provides standard treatment protocols for potential epidemic situations, and promotes the stockpiling of efficacious antimalarial drugs and other essential supplies for rapid distribution in emergency situations.


 

WHO WB UNICEF UNDP
Roll Back Malaria is a global partnership initiated by WHO, UNDP, UNICEF and the World Bank in 1998. It seeks to work with governments, other development agencies, NGOs, and private sector companies to reduce the human and socio-economic costs of malaria.
 
RBM Roll Back Malaria, World Health Organization, 20 Avenue Appia, CH-1211 Geneva 27, Switzerland
Tel: +41 22 791 2891 E-mail: inforbm@who.int

www.rollbackmalaria.org