Post by L Roebuck on Sept 9, 2005 21:19:35 GMT -5
Close relative to SARS coronavirus found in bats in Hong Kong: study
Helen Branswell
Canadian Press
Friday, September 09, 2005
www.canada.com/health/story.html?id=c921e9cc-06fc-4cc0-9891-a1c676a20bdd
TORONTO (CP) - Another clue to the mystery of where the SARS virus came from may have come to light Friday with the revelation that researchers in Hong Kong have found a close relative of the human virus in bats.
"It's really another piece of the puzzle in furthering our understanding of the animal origins of the SARS coronavirus," said Dr. Mark Loeb, an infectious diseases expert at McMaster University in Hamilton.
"It doesn't prove that bats are the reservoir, but it's interesting."
Scientists from State Key Laboratory of Emerging Infectious Diseases and the University of Hong Kong found a new coronavirus that was 40 per cent similar to the human SARS coronavirus in cave-dwelling Chinese horseshoe bats in Hong Kong. They proposed that the newly identified virus be known as the bat SARS coronavirus.
Their findings were published online Friday by the journal the Proceedings of the National Academy of Sciences.
The research team, lead by Susanna Lau, warned the discovery means that great care must be used in handling bats, which are considered a delicacy in China and parts of Malaysia. Bat feces are also used in some traditional Chinese medicines, they noted.
Bats have previously been identified as important reservoirs for a number of zoonotic viruses - viruses that can jump from animals to humans - including rabies, the Hendra and Nipah virus and St. Louis encephalitis.
The scientists ran tests on anal swabs taken from 59 bats; 39 per cent of them carried the virus. Blood drawn from the bats suggested between 67 and 84 per cent (the differences related to the test used) had previously been infected with the virus.
The team has yet to test the bat virus to see how pathogenic it is, or whether it can infect other species.
Molecular analysis of the virus showed it is the closest known virus to the human SARS virus, with the exception of a SARS virus isolated from palm civets and raccoon dogs.
Dr. Earl Brown, an expert in viral evolution at the University of Ottawa, said the bat and human viruses are probably separated by 100 years of evolution, suggesting there are other as-yet unidentified species carrying coronaviruses that gave rise to the virus that jumped into humans.
"If you're trying to link up the dots . . . there's a bunch of dots missing in between," Brown said.
"So there's another virus or viruses that this thing has come from. But this is the closest thing they've got on the trail of dots."
To date, scientists have been unclear on the natural reservoir or source of the SARS coronavirus, which burst out of southern China in early 2003 and spread around the globe. There were nearly 8,100 probable cases of SARS; 774 people died of the disease, including 44 in Canada.
Early in the investigation, civet cats and raccoon dogs were found to carry a virus that is nearly identical to the human coronavirus and were felt by some to be the source of the outbreak. As a consequence, Chinese authorities ordered a mass slaughter of civet cats in live animal markets.
But evidence later emerged that threw that theory into question. For instance, the virus was found only in civet cats in the crowded markets, not in wild or farmed civet cats. That suggests the market cats were infected by another as-yet unidentified animal.
Brown said the finding underscores the importance of learning more about the range of viruses lurking in nature.
"Historically we worry about viruses that infect ourselves or our pets or the things we eat. And otherwise we just don't care," he noted.
"I think probably in the long run we have to care a bit more about the whole biosphere to try to link things up. . . . We do have to know a bit of what's out there and moves into people and that sort of thing."
Helen Branswell
Canadian Press
Friday, September 09, 2005
www.canada.com/health/story.html?id=c921e9cc-06fc-4cc0-9891-a1c676a20bdd
TORONTO (CP) - Another clue to the mystery of where the SARS virus came from may have come to light Friday with the revelation that researchers in Hong Kong have found a close relative of the human virus in bats.
"It's really another piece of the puzzle in furthering our understanding of the animal origins of the SARS coronavirus," said Dr. Mark Loeb, an infectious diseases expert at McMaster University in Hamilton.
"It doesn't prove that bats are the reservoir, but it's interesting."
Scientists from State Key Laboratory of Emerging Infectious Diseases and the University of Hong Kong found a new coronavirus that was 40 per cent similar to the human SARS coronavirus in cave-dwelling Chinese horseshoe bats in Hong Kong. They proposed that the newly identified virus be known as the bat SARS coronavirus.
Their findings were published online Friday by the journal the Proceedings of the National Academy of Sciences.
The research team, lead by Susanna Lau, warned the discovery means that great care must be used in handling bats, which are considered a delicacy in China and parts of Malaysia. Bat feces are also used in some traditional Chinese medicines, they noted.
Bats have previously been identified as important reservoirs for a number of zoonotic viruses - viruses that can jump from animals to humans - including rabies, the Hendra and Nipah virus and St. Louis encephalitis.
The scientists ran tests on anal swabs taken from 59 bats; 39 per cent of them carried the virus. Blood drawn from the bats suggested between 67 and 84 per cent (the differences related to the test used) had previously been infected with the virus.
The team has yet to test the bat virus to see how pathogenic it is, or whether it can infect other species.
Molecular analysis of the virus showed it is the closest known virus to the human SARS virus, with the exception of a SARS virus isolated from palm civets and raccoon dogs.
Dr. Earl Brown, an expert in viral evolution at the University of Ottawa, said the bat and human viruses are probably separated by 100 years of evolution, suggesting there are other as-yet unidentified species carrying coronaviruses that gave rise to the virus that jumped into humans.
"If you're trying to link up the dots . . . there's a bunch of dots missing in between," Brown said.
"So there's another virus or viruses that this thing has come from. But this is the closest thing they've got on the trail of dots."
To date, scientists have been unclear on the natural reservoir or source of the SARS coronavirus, which burst out of southern China in early 2003 and spread around the globe. There were nearly 8,100 probable cases of SARS; 774 people died of the disease, including 44 in Canada.
Early in the investigation, civet cats and raccoon dogs were found to carry a virus that is nearly identical to the human coronavirus and were felt by some to be the source of the outbreak. As a consequence, Chinese authorities ordered a mass slaughter of civet cats in live animal markets.
But evidence later emerged that threw that theory into question. For instance, the virus was found only in civet cats in the crowded markets, not in wild or farmed civet cats. That suggests the market cats were infected by another as-yet unidentified animal.
Brown said the finding underscores the importance of learning more about the range of viruses lurking in nature.
"Historically we worry about viruses that infect ourselves or our pets or the things we eat. And otherwise we just don't care," he noted.
"I think probably in the long run we have to care a bit more about the whole biosphere to try to link things up. . . . We do have to know a bit of what's out there and moves into people and that sort of thing."