The world knows malaria as an endemic problem. Nearly half the world’s people live in areas where the disease is present. Every year it kills or is a contributing factor in the deaths of as many as 2.7 million people, according the US Centers for Disease Control and Prevention.
The disease can also break out unexpectedly among populations with little or no immunity. When that happens, health services are often wrong-footed by the disease’s sudden arrival, according to the World Health Organization, and help can come too late.
The epidemics kill over 100,000 people every year and many occur in the wake of war or following the construction of irrigation ditches, dams or other pools of sitting water that rapidly increase mosquito populations.
But outbreaks that result from natural causes are harder to predict. Forecasting models that monitor climate variations are one method of doing so. In Africa, where 124 million people live at risk of seasonal epidemics, early detection mechanisms receive weekly data from over 15 countries but their predictions come only days or weeks before the event.
However, a team of research scientists led by Madeleine Thomson at Columbia University’s Earth Institute in New York now claim to have developed a forecasting model that can predict an epidemic five months in advance.
In an article published this week in the journal Nature, Thomson and her colleagues reportedly describe a new model they have developed, which combines several climate models with data on average rainfall and seasonal malaria.
The system produced retrospective predictions for malaria outbreaks that occurred between 1982 and 2002, according to Reuters.
Such early predictions could be of invaluable help in saving lives. However, The Economist magazine writes that there is a tradeoff: The model is slightly less accurate than those that offer later warnings. The sooner the prediction comes, the less the scientists can be confident it is true, it said.
“Since 1998, there have been no outbreaks [in Cambodia] because there are no more areas controlled by the Khmer Rouge,” said Dr Duong Socheat, an adviser to the Health Ministry and director of the National Center for Parasitology, Entomology and Malaria Control.
The communist forces had barred government health workers from the areas they controlled, he said.
Since then, he said, the number of Cambodians who die from malaria each year has dropped from about 1,000 to around 300.
“Less than car accidents,” he said, which kill around 1,200 people in Cambodia every year.
Nevertheless, said Dr Duong Socheat, the ministry does regularly prepare for possible outbreaks, but the ministry’s budget does not routinely include a line for programs forecasting epidemics.
Each year, just under 100,000 people are infected with malaria in Cambodia, he added.