An outbreak of Ebola virus in northwestern Republic of Congo has killed 5,000 gorillas, helping to push the threatened species even closer to extinction, a study says. The estimate is made by a team of scientists in Europe and central western AFrica, who say there was a "massive die-off" of gorillas in Congo's Lossi Sanctuary park from 2002 to 2004.
The great apes which died were western gorillas (Gorilla gorilla), one of two gorillas species.
The other species is the eastern gorilla (Gorilla beringei).
"The Lossi outbreak killed about as many gorillas as survive in the entire eastern gorillas species," laments the paper, carried in Friday's issue of the US journal Science.
But the death toll is probably only a "small fraction" of gorillas likely to have been killed by Ebola in the past decade, it says.
"Add commercial hunting to the mix, and we have a recipe for rapid ecological extinction. Ape species that were abundant and widely distributed a decade ago are rapidly being reduced to remnant populations."
Lead author is Magdalena Bermejo of Ecosystemes Forestiers d'Afrique Centrale (ECOFAC) in Libreville, Gabon.
Ebola first came to light in 1976 in Zaire, now the Democratic Republic of Congo (DRC), and is named after the river with which this outbreak is associated.
It is of four categories of viruses that cause viral haemorrhagic fever (VHF), a disease whose outbreaks among humans are sometimes traced to the bushmeat trade -- gorillas and chimpanzees that are killed, butchered and sold for meat.
VHF causes the feverish patient to bleed under the skin and in severe cases, from the mouth, ears and eyes. Blood loss, shock and organ failure lead to coma and delirium and, in many cases, to death.
The new study suggests that the gorillas were not only infected by some animal reservoir -- last year, three species of African fruit bat were fingered as an Ebola source -- but also by contact between ape groups themselves.
