Nairobi — African countries must work together to mitigate the health impacts of global warming to avoid a "continental disaster," climate and health experts who met recently in Nairobi have said.

According to the experts, climate change will lead to the emergence of new infections and the spread of old ones, further straining cash-strapped public health systems.

"A warmer world will generally be a sicker world," said Prof Onesmo ole-MoiYoi, the director of research and partnerships at the International Centre of Insect Physiology and Ecology (Icipe) in Nairobi. "We scientists need to adopt a new way of working, one that makes African communities bearing the burden of disease part of the solution rather than part of the problem."

The Nairobi meeting was sponsored by Google.org and organised by researchers from the Igad Climate Predictions and Applications Centre (ICPAC), the Kenya Medical Research Institute (Kemri), the International Centre of Insect Physiology and Ecology (Icipe), and the International Livestock Research Institute (ILRI). It was held at ILRI headquarters.

The meeting was the first of a number planned across Africa to bring climate and health researchers together in a bid to reduce the continent's infectious diseases burden.

Among the diseases that are already spreading to hitherto pristine regions such as the highlands due to global warming, experts say, are malaria and human sleeping sickness.

The incidence of relatively newer viral infections, such as yellow fever and Marburg, could also rise as the stresses brought about by global warming bring people closer to their natural reservoirs and vectors, the experts say.

Other diseases cited at the Nairobi meet that could hitch hike on the rising global temperatures are Rift Valley Fever (RVF) and bird flu.

According to the researchers, global warming-driven diseases will require a multisectoral approach, bringing together health and climate experts as well as affected communities.

"To combat the diseases, we will need a holistic approach that involves local communities," Prof ole-MoiYoi said. "We can control malaria across Africa, for instance, if we divorce ourselves from the linear thinking that looks for a solution and adopt an integrated approach."

During the Nairobi meeting a Kemri researcher, Dr Rosemary Sang, said that East Africa was already experiencing a surge in diseases linked to global warming, citing an outbreak of RVF in late 2006 and early 2007 that killed over 150 Kenyans.

The RVF virus, which belongs to the group of haemorrhagic diseases that also include Ebola and Marburg, is transmitted from livestock to people either through handling of infected animal material or by mosquito vectors. The natural reservoirs are however thought to be wild animals, which domestic livestock may encounter during the search for pasture.

According to Dr Sang, the initial response to the December 2006 outbreak was slow, mainly because no link was initially made between the heavy rains that had pounded northeastern Kenya and parts of the Rift Valley and unexplained deaths of livestock.

The first veterinary interventions did not take place until mid-January 2007, almost three months after the onset of the heavy rains, and two-and-a-half months after mosquito swarms were reported. The investigations also came two and one-and-a-half months after the first livestock and the first human cases were recorded, respectively.

"We need to move up our response times to these outbreaks," said Dr Sang. "All of the warning signs of an outbreak were there but we weren't able to connect the dots."

Once the response to the outbreak got going, however, Kenyan health and livestock authorities were able to limit the spread of the outbreak, leading to a lower human death toll than occurred during an earlier outbreak in 1998, which killed more than 600 people.

According to the World Health Organisation, global warming is already causing five million more cases of serious disease and more than 150,000 more deaths each year. By 2030, the number of climate-related diseases is likely to more than double.

"We need to prepare now to avoid future catastrophe," said Prof ole-MoiYoi at the Nairobi meeting. "Climate variability is playing a bigger and bigger role in the spread and severity of diseases across the globe.