Socialising spreads Ebola
2006-07-11 13:07
Washington - Social contact helped the
Ebola virus virtually wipe out a population of gorillas in the
Democratic Republic of Congo, French researchers reported on
Monday.
A 2004 outbreak of the virus, which also kills people,
killed 97% of gorillas who lived in groups and 77%
of solitary males, Damien Caillaud and colleagues from
the University of Montpellier and the University of Rennes in
France reported.
Overall, it wiped out 95% of the gorilla population
within a year, they reported in the journal Current Biology.
"Thousands of gorillas have probably disappeared," they
wrote.
The study shows that the deadly virus spreads directly from
gorilla to gorilla and does not necessarily depend on a
still-unidentified third species of animal, perhaps a bat, that
can transmit the virus without getting ill from it.
It also may shed light on how early humans evolved, they
suggested. The findings may show that pre-humans were slow to
live in large social groups because disease outbreaks could
wipe out those who did.
Ebola hemorrhagic fever is one of the most virulent viruses
ever seen, killing between 50% and 90% of
victims. The World Health Organisation says about 1 850 people have been infected and 1 200 have died since the Ebola virus was discovered in 1976.
WHO and other experts say people probably start outbreaks
when they hunt and butcher chimpanzees. The virus is
transmitted in blood, tissue and other fluids.
Caillaud's team said Ebola is a serious threat to the
survival of endangered gorillas and chimpanzees, along with
hunting and the destruction of the forests they live in.
The researchers documented one outbreak of Ebola and its
effects on gorillas and people in Odzala-Kokoua National Park.
"On October 13, 2003, two villagers from Mbandza hunting at
an undetermined site inside the park got contaminated and
became index cases of an outbreak that killed 29 people in
seven weeks," they wrote.
They were able to identify 400 individual gorillas.
"Overall, 109 distinct gorilla social units visiting Lokoue
were reliably identified and monitored during a 1 360-day
period."
By July 2004, nearly all the gorillas were dead. "Due to
intra-group transmission, the death rate was highest among
gorillas living in groups," the researchers wrote.
- Reuters