Malaria Early Warning System

The Malaria Early Warning System (MEWS) aids in the prediction of malaria outbreaks. The system consists of four elements; Vulnerability, Seasonal Climate Forecasts, Monitoring the Environment and Observed Malaria Morbidity. In certain regions, these products may be used to determine the timing and severity of an outbreak.

This maproom outlines each element of the MEWS. Each element contains products, some of which may be used to help determine the risk of a malaria outbreak in a specific region.

Using all of the elements as a system may be useful in understanding the socioeconomic and climatic drivers of malaria in particular regions. The diagram above depicts how the four elements can be employed on different time scales using flags to raise concern of a potential outbreak.

Climatic and environmental variables can indicate an increased risk in vector (mosquito) and malaria parasite development (when inside its mosquito host). Examples of such indicators include precipitation, temperature, humidity and surface water. The Seasonal Climate Forecasts can predict likely changes in climatic and environmental risk several months in advance while climate and environmental monitoring products provide concrete evidence of such changes and can be used to indicate changes in malaria risk several months ahead of a potential epidemic. The Vulnerability indicators are necessary to indicate the likely severity of any change in malaria transmission risk while the observed case data from health facilities provides the first evidence that an epidemic is underway.

References:

Thomson M., Indeje M., Connor S., Dilley M., Ward N. Malaria early warning in Kenya and seasonal climate forecasts. The Lancet. 2003, 362:9383.

WHO: Malaria Early Warning Systems - Concepts, Indicators and Partners - A Framework for Field Research in Africa. WHO/CDS/RBM/2001.32..Geneva: World Health Organization; 2001.

Vulnerability
Drug Resistance Maps is a project that maps the geographical distribution of resistance genes of malaria in Africa. These maps were developed by the London School of Hygiene and Tropical Medicine.
The Insecticide Resistance (IR) Mapper is a tool used to map results from World Health Organization susceptibility tests and insecticide studies using malarial mosquitoes collected from sites throughout the world.
Seasonal Climate Forecast
This map shows seasonal precipitation forecasts from the International Research Institute for Climate and Society. In areas of Africa where the presence of water allows for mosquito vector development, skillful seasonal precipitation forecasts may provide early warning of risk of an epidemic.
This tool produces maps of seasonal temperature forecasts from the International Research Institute for Climate and Society. In areas of Africa where temperature drives mosquito vector development and parasite development, skillful seasonal temperature forecasts may provide early warning of risk of an epidemic.
Monitoring The Environment
This map shows dekadal (10-day) precipitation estimates from the Climate Prediction Center.
This map shows dekadal (10-day) precipitation estimates as the difference from the short term average (from 2000 to last recent complete year).
This map shows dekadal (10-day) precipitation estimates as a percentage of the short term average (from 2000 to last complete year).
This map shows minimum land surface temperature (LST) used as a proxy for monitoring minimum air temperature.
This map shows approximated maximum air temperatures at 2 meters above the ground.
This tool produces maps of estimated vegetation using data from NASA's MODIS sensor.
This map shows a Vectorial Capacity (VCAP) model that defines precipitation and temperature as the limiting factors of malaria incidence. VCAP is the daily rate at which future malaria inoculations could arise from a currently infected case.
Observed Malaria Morbidity
The Program for Monitoring Emerging Diseases (ProMED) is dedicated to rapid global dissemination of information on outbreaks of infectious diseases. By providing early warning of outbreaks of emerging and re-emerging diseases, public health precautions at all levels can be taken in a timely manner to prevent epidemic transmission and to save lives.