September 9, 2005

Bats May Have Been Source of SARS, Says Study

WASHINGTON (Reuters) - Bats found in Hong Kong carry a virus very similar to the severe acute respiratory syndrome or SARS virus and might be able to spread it, Chinese researchers reported on Friday.

They said the horseshoe bats, valued both as food and for their use in Chinese medicine, should be handled with great care. They may have helped spread the virus among different species of animals, the researchers said.

SARS first emerged in China in 2002 and in 2003 spread around the world via jet, killing more than 700 people and infecting around 8,000.

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.

But SARS was different.

"The isolation of SARS-coronavirus from caged animals, including Himalayan palm civets and a raccoon dog, from wild live markets in mainland China suggested that these animals are the reservoir for the origin of the SARS epidemic," Kwok-yung Yuen of the University of Hong Kong and colleagues wrote in their report, published in the Proceedings of the national Academy of Sciences.

"However, several lines of evidence suggested that the civet may have served only as an amplification host for SARS virus and provided the environment for major genetic variations permitting efficient animal-to human and human-to-human transmissions," they added.

So they studied wild animals in the Hong Kong countryside that may have come into contact with civets.

They found a coronavirus similar to SARS in nearly 40 percent of wild Chinese horseshoe bats they examined.

Genetic analysis of the bat SARS virus showed it was closely related to the human SARS coronavirus.

The researchers could not determine how the bats were originally infected or whether bats were responsible for transmitting the SARS coronavirus to other mammals including the civets.

But because bat feces are used in Chinese traditional medicine, and bat meat is considered a delicacy in parts of Asia, the researchers suggest caution in handling them

"Interestingly, the nearest wildlife market previously found to have animals with SARS in Shenzhen is only 10 miles away from the locations with bats harboring bat-SARS in (Hong Kong)," the researchers wrote.