A new study published in the Science journal has advised governments and health authorities as well as travelers wishing to visit Africa, Asia, Central and Southern America to up their proactive measures against the malaria-carrying mosquitoes as cases of the disease will multiply each year due to global warming.

Researchers at the London School of Hygiene, and Tropical Medicine, and at the University of Michigan found that people living at higher elevations experienced more malaria infections in warmer years than they do in cooler years.

"This is indisputable evidence of a climate effect," Mercedes Pascual, University of Michigan theoretical ecologist, said. "The main implication is that with warmer temperatures, we expect to see a higher number of people exposed to the risk of malaria in tropical highland areas like these."

The researchers based their analysis on records gathered from highland regions of Ethiopia and Colombia from 1990 to 2005.

"We saw an upward expansion of malaria cases to higher altitudes in warmer years, which is a clear signal of a response by highland malaria to changes in climate," Ms Pascual said.

She said climate warming will aggravate the situation and push to create a significant jump in malaria cases in densely populated regions of Africa and South America.

Menno Bouma of the London School of Hygiene and Tropical Medicine told AFP that at risk are also people who have never built up immunity against the disease. They are located in areas previously unaffected by malaria.

A mosquito-borne disease caused by a parasite, people infected with people if left untreated may develop severe complications and die. Symptoms of malaria include fever, chills, and flu-like illness. An estimated 219 million cases of malaria occurred worldwide in 2010, of which 660,000 people died. Most of the cases at 91 per cent were recorded as coming from the African Region.

Mr Bouma pointed out other tropical highland areas surrounded by malaria-endemic regions "are likely to be affected by a similar principle," including parts of Peru, Ecuador, Kenya, Uganda, Tanzania, Madagascar, Pakistan, India, Nepal and Papua New Guinea.

The spread of malaria among regions or areas is influenced by temperature. The mosquitoes that transmit the malaria-causing parasites, Plasmodium falciparum and Plasmodium vivax, thrive in warmer temperatures. Moreover, the parasite rapidly matures into its infectious form when supported by high temperatures.

"Our latest research suggests that with progressive global warming, malaria will creep up the mountains and spread to new high-altitude areas," Mr Bouma said. "And because these populations lack protective immunity, they will be particularly vulnerable to severe morbidity and mortality," he said.