the ebola virus is threatening lowland gorillas of central Africa, states the World Conservation Union (iucn). The warning is significant as the area has one of the largest concentrations of these gorillas, and they are already endangered by factors such as deforestation and trade in wild animals.

Ebola haemorrhagic fever is one of the most virulent viral diseases known to mankind, which kills 50-90 per cent of infected people. Richard Preston in his acclaimed book Hot Zones startled the world saying that the resurfacing of viruses like ebola was due to ecological degradation. Deforestation around forest fringes exposes land to sunlight and promotes the development of pools of water. Such conditions favour the breeding of human-biting, fever-transmitting mosquitoes. Almost all biting insects carry or can potentially carry a pathogen. More than 80 people have died during an outbreak of the disease in the Gabon/Congo-Brazzavile border area this year. The presence of the ebola virus in animals was confirmed in Congo in December 2002, when six gorillas (all from one family) were found dead in Lossi sanctuary of Congo. At the end of January 2003, eight more gorilla families were found to have disappeared in just two months. Their disappearance was also attributed to ebola.

iucn says primates are especially susceptible to many diseases affecting humans because of their genetic similarity to mankind. William Karesh, co-chair of the veterinary specialist group of iucn's Species Survival Commission, says there is a possibility that thousands of great apes have succumbed to the virus in the last five or six years. "For years, many of us have been trying to point out that diseases are critical factors that have to be included in effective conservation planning. But nobody listens,' he says.