September 29, 2005

More evidence links SARS to bats

By Maggie Fox, Health and Science Correspondent

WASHINGTON (Reuters) - Many species of bats found across
China are infected with viruses similar to the SARS virus, an
international team of researchers reported on Thursday.

Zhengli Shi of the Chinese Academy of Sciences in Beijing
and colleagues sampled more than 400 bats of various species
across China and found up to 70 percent of some species showed
evidence of infection with SARS-like viruses.

This would support the idea that bats are the reservoir --
the natural host -- of the virus. Animals that act as
reservoirs carry and spread a virus without themselves becoming

Severe acute respiratory syndrome or SARS first emerged in
China in 2002 and in 2003 spread around the world via jet,
killing more than 700 people and infecting about 8,000. Strict
quarantines and other measures stopped its spread.

It is caused by a new virus called SARS coronavirus.
Coronaviruses are common in people and animals and usually
cause nothing more serious than a cold.

Animals such as palm civets were found to be infected but
study showed they were not the true reservoir of the SARS

Earlier this month a team of Hong Kong researchers reported
that bats found in Hong Kong carried a virus very similar to
the SARS virus.

They said the horseshoe bats, used both as food and in
Chinese medicine, should be handled with great care.

Shi, Wendong Li and colleagues studied other bats found in
four different parts of China. They found that anywhere between
28 percent and 71 percent of the bats, depending on the species
and location, had evidence of infection with a SARS-like
coronavirus. Theirs was different from the virus found by the
Hong Kong researchers, they said.

"A plausible mechanism for emergence from a natural bat
reservoir can be readily envisaged," they wrote in their
report, published in the journal Science.

They said an infected bat could have been kept in a cage
next to a civet in a market with the civet becoming infected
and passing the virus to humans.

Bats are hosts of several other new viruses, including
Hendra and Nipah viruses, and rarely become ill.