香港大学最新研究发现：菊头蝙蝠或携SARS病毒 http://www.biotech.org.cn/news/news/show.php?id=26708
More evidence links SARS to bats http://www.biotech.org.cn/news/news/show.php?id=27300
以中国科学院科学家为主进行的联合研究调查结果表明，蝙蝠携带有类SARS病毒。该项研究结果发表在9月29日出版的美国《科学》杂志上。中国科学院武汉病毒研究所石正丽研究员和动物研究所张树义研究员等科学家组成的联合研究小组在研究中关注到，蝙蝠近年来已被证实是一些重要动物源传染病病毒病原(既可以感染人又可以感染动物)的自然宿主，而这些被病毒感染的蝙蝠基本不出现临床症状。因此，联合研究小组将SARS病毒溯源集中在蝙蝠身上。
从2004年3月开始，联合研究小组在广西、广东、湖北和天津四个地区采集3个科6个属9个种共408只蝙蝠的血清、咽拭子和肛拭子样本。在武汉的病毒学国家重点实验室和澳大利亚Geelong的动物健康研究室(AAHL)同时对这些样本进行了SARS病毒抗体和基因的检测，结果在菊头蝠属的4个种里发现SARS病毒抗体和基因，其中大耳菊头蝠显示70%以上的抗体阳性率。基因序列分析表明，蝙蝠类SARS病毒与人SARS病毒基因组序列同源性达92%。但是二者之间的差异对于蝙蝠类SARS病毒是否能够跨物种传播起关键作用，也就是说，目前科学家在蝙蝠体内检测到的类SARS病毒还不会直接感染人类。
在研究中，科学家们在采样过程中严格遵循国际保护动物的准则，尽量减少对蝙蝠的伤害。科学家们指出：包括蝙蝠在内的野生动物携带各种病毒是自然进化的结果，是正常现象。包括菊头蝠在内的食虫蝙蝠是很多农、林业害虫的重要天敌，对维护生态系统平衡发挥着重要作用。我国很多地区的虫灾泛滥与蝙蝠数量急剧下降密切相关。我们切不可因为此项研究结果的公布而对蝙蝠开杀戒。蝙蝠数量少了，蚊子携带的登革热等流行病暴发的可能性便会大大增加。
9月27日在美国国家科学院院报(PNAS)上也发表了香港科学家类似的研究结果。
该项研究成果获得了国家科技部和欧盟等项目的资助。参加研究的单位有中国科学院武汉病毒研究所、中国科学院动物研究所、澳大利亚科工委组织(CSIRO)的动物健康研究室(AAHL)、澳大利亚昆士兰主要工业和渔业部、美国保护医学中心和中国科学院广州生物医药与健康研究院。
中国、澳大利亚和美国科学家通过对野生蝙蝠的广泛调查表明，野生蝙蝠可能才是非典病毒的源头宿主，而先前广受怀疑的果子狸不过是将病毒从野外传染到人类身上的中间宿主。
香港大学袁国勇教授等人在中国香港特别行政区的野外调查中发现，当地的野生鲁氏菊头蝠身上带有一种非常像果子狸非典病毒的冠状病毒，并将其命名为“蝙蝠非典病毒”，并怀疑野生蝙蝠才是非典病毒的源头宿主。中国科学院动物研究所李文东等与澳大利亚、美国科学家合作的最新研究成果，为上述猜测提供了更多支持。他们的论文将发表在３０日出版的新一期《科学》杂志网络版上。
研究人员在中国广东、广西、湖北和天津地区，捕捉了４０８只野生蝙蝠，涵盖了蝙蝠的３个科、６个属、９个种。他们采集了蝙蝠的血样、粪便、咽喉分泌物，并分别在武汉和澳大利亚吉朗的病毒实验室用不同方法检验。结果发现，其中采集自广西和湖北的３个种的菊头蝠携带“类非典冠状病毒”。
蝙蝠是“汉塔”病毒、“尼帕”病毒等引起人畜传染病的病毒的野生宿主，它们能携带多种病毒而不显示任何症状，而且一些地区的人们把蝙蝠当作野味或药材在市场上销售，增加了蝙蝠与人类接触的机会。
李文东等发现，“类非典冠状病毒”基因与非典冠状病毒平均有９２％的相似度，因此非典冠状病毒是属于“类非典冠状病毒”这一大类的，可以统称为“冠状病毒非典群”。而香港大学科学家发现的“蝙蝠非典病毒”，与它们的差异相对大一些，反而是这一群病毒的“亲戚”。
中国、澳大利亚和美国科学家最新的研究表明，野生蝙蝠可能是非典病毒的源头宿主，而先前广受怀疑的果子狸不过是将病毒从野外传染到人类身上的中间宿主。
研究人员在中国广东、广西、湖北和天津地区，捕捉了４０８只野生蝙蝠，并采集了蝙蝠的血样、粪便、咽喉分泌物，并分别在武汉和澳大利亚吉朗的病毒实验室用不同方法检验。结果发现，其中采集自广西和湖北的蝙蝠携带“类非典冠状病毒”,这种“类非典冠状病毒”基因与非典冠状病毒平均有９２％的相似度。
一项新的研究表明，一种名为蹄鼻蝠的蝙蝠可能是导致萨斯(SARS)的罪魁祸首。
研究人员在中国三个地区生活的蝙蝠身上发现了，与萨斯冠状病毒极为相似的病毒。
研究人员在《科学》杂志上发表的文章中指出，这些病毒在通过蹄鼻蝠最终感染人类之前，很有可能先被传染给了果子狸。
有关专家建议，在病毒传播途径尚未了解清楚之前，应暂时禁止蹄鼻蝠在市场上的流通。
谁是真凶？
2003年5月曾有迹象表明，人们可能是由于食用了果子狸肉才感染了萨斯。于是，中国政府下令屠杀了近10,000只果子狸。
然而，一些科学家们却认为果子狸并不是萨斯的元凶，因为果子狸对萨斯病毒的抵抗力极弱。
倘若果子狸真是病毒的源头，那么它的身体应该已在某种程度上适应了病毒，并具备更强的抵抗力。
另一种理论则认为，鸟类是萨斯病毒的元凶。但香港大学的研究人员本月在蝙蝠的身上发现了一种与萨斯病毒极其相似的病毒。
揭开谜团
目前，中国、澳大利亚和美国的科学家正在携手合作，力图确认并搞清在蝙蝠身发现的萨斯疑似病毒。
相关的基因分析专家指出，在蝙蝠身上发现的病毒，和在果子狸以及在人身上发现的病毒是有密切联系的。
专家们还说，可以确定的是，蝙蝠身上的这种病毒是不会直接感染人类的。
所以，最大的问题就是弄清，病毒究竟是如何从蝙蝠传染给人类的？但专家们目前还尚未找到答案。
Two Teams Identify Chinese Bat as SARS Virus Hiding Place
By LAWRENCE K. ALTMAN（The New York Times）
The SARS virus, which has killed 774 people worldwide, has long been known to come from an animal. Now two scientific teams have independently identified the Chinese horseshoe bat as that animal and as a hiding place for the virus in nature.
The bats apparently are healthy carriers of SARS, which caused severe economic losses, particularly in Asia, as it spread to Canada and other countries. In Asia, many people eat bats or use bat feces in traditional medicine for asthma, kidney ailments and general malaise.
The Chinese horseshoe bat does not exist in the United States.
The finding is important in preventing outbreaks of SARS and similar viruses carried by bats because it provides an opportunity for scientists to break the transmission chain.
One team from China, Australia and the United States reported its findings yesterday in the online version of Science. The other team, from the University of Hong Kong, reported its findings on Tuesday in The Proceedings of the National Academy of Sciences.
"It's pretty pleasant to see two teams that did not know each other reach similar findings," Dr. Lin-Fa Wang, a virologist at the Australian Animal Health Laboratory, said in a telephone interview. After collecting hundreds of bats from the wild and from Chinese markets, each team reported identifying different viruses from the coronavirus family that are very closely related to the SARS virus.
SARS, or sudden acute respiratory syndrome, first appeared in China in 2002. It spread widely in early 2003 to infect at least 8,098 people in 26 countries, according to the World Health Organization. The disease died out later in 2003, and no cases have been reported since.
SARS now appears to join a number of other infectious agents that bats can transmit. Over the last decade, bats have been found as the source of two newly discovered human infections caused by the Nipah and Hendra viruses that can produce encephalitis and respiratory disease. In the SARS outbreak, attention focused on the role of Himalayan palm civets in transmitting it after scientists identified the virus in this species and in a raccoon dog sold in markets in Guangdong. But W.H.O. officials and scientists elsewhere cautioned that these species were most likely only intermediaries in the transmission, largely because no widespread infection could be found in wild or farmed civets. So, the teams assembled a variety of specialists, including veterinarians, zoologists, virologists and ecologists.
Dr. Wang said his group focused on bats largely because of the team members' earlier pioneering work on the Hendra and Nipah viruses. One member, Dr. Jonathan H. Epstein, a veterinary epidemiologist at the Consortium for Conservation Medicine in Manhattan, led the scientists in gathering bats from the wild and market places.
After obtaining fecal and blood samples, the scientists released the bats into the wild or returned them to the markets. The specimens were tested for a variety of viruses that infect animals.
Laboratory analysis of the coronaviruses' makeup provided strong genetic evidence of the close relationship between those found in the bats and the SARS virus.
Although it is logical to assume that the bat viruses infected the animals in the live markets to cause the outbreak, the studies were not planned to prove that point.
"The genetic relationships do not tell you anything mechanistically about if or how the virus moved from the bats to civets and from the civets to the humans," said Dr. Donald S. Burke, a virologist and professor at Johns Hopkins. "It's not a perfect story yet. But until I see otherwise, the working assumption will be that this is the reservoir species."
Dr. Wang said that "there is no rule" to establish proof that a certain species is the reservoir, or hiding place, of a virus, but that scientists make the judgment based on criteria like how widely the infectious agent is distributed in a species, the absence of symptoms among the animals and finding high levels of antibody but low amounts of virus in the animal.
The Chinese horseshoe bat fits those criteria and the civets do not, Dr. Wang said. The bat feeds on moths and other insects and generally does not bite animals. It was highly unlikely that insects transmitted the SARS viruses to bats, because the viruses do not grow in insect cells in the laboratory, Dr. Wang said.
Most civets that are sold in China as a delicacy are farmed, Dr. Wang said, and the government should ensure civet farms are distant from bat colonies, monitor farmed civets for SARS-like viruses and allow just noninfected animals to go to market.
Bats found to carry SARS-related virus : study
Agence France Presse
Bats have been found to be natural hosts of so-called coronaviruses closely related to those responsible for deadly outbreaks of SARS among humans, according to a study published this week.
Severe Acute Respiratory Syndrome (SARS) triggered a global health crisis after emerging in China's southern Guangdong province in November 2002, causing nearly 800 deaths worldwide, including 349 in China.
Scientists are vying to unravel the origins of its etiological agent, the SARS coronavirus (SARS-CoV), which sparks the full-blown SARS virus.
A team of international researchers work have found that bats are a natural host of these coronaviruses. Their findings were published in the journal Science on Wednesday.
The researchers hope the finding will give them new insights into SARS and its potentially lethal origins.
The viruses, termed SARS-like coronaviruses (SL-CoV), display greater genetic variations than SARS-CoV isolated from humans or some carnivorous mammals, according to the team's findings.
The team includes researchers in China, Australia and the United States.
The human and mammal isolates of SARS-CoV "nestle phylogenetically within the spectrum of SL-CoVs," suggesting that the virus responsible for the SARS outbreak was a member of the coronavirus group, the study said.
"Without knowledge of the reservoir host distribution and transmission routes of SARS-CoV, it will be difficult to prevent and control future outbreaks of SARS," the study's authors noted.
They said that bats "may be persistently infected with many viruses but rarely display clinical symptoms."
The researchers said such characteristics and the increasing presence of bats and bat products in food and traditional medicine markets in southern China and elsewhere in Asia led them to focus on bats the search for the origin of the SARS virus.
The study was conducted between March and December 2004, and involved 408 bats of nine different species.
Researchers from the Institute of Zoology of Chinese Academy of Sciences in Beijing, China, the Australian Animal Health Laboratory in Geelong, Australia, and The Consortium for Conservation Medicine in New York, among other centers, supported the research.
SARS probably originated in bats
By Anna Salleh for ABC Science Online
Bats are highly likely to be the original source of the deadly severe acute respiratory syndrome (SARS), scientists say.
An international team of scientists report evidence of a SARS-like virus in wild Chinese horseshoe bats in today's issue of the journal Science.
The findings into the origins of the virus that causes SARS support those in a recent issue of the Proceedings of the National Academy of Sciences.
"We're looking here at two independent observations," said the Australian co-author of the Science paper, Dr Bryan Eaton.
"There's a high likelihood that the origin of SARS coronavirus is this particular genus of bats."
Last year, researchers found that although civet cats in Chinese markets were infected with the SARS virus, animals bred on farms were free of antibodies to the virus.
"So the source was somewhere else," Dr Eaton, a virologist with CSIRO's Australian Animal Health Laboratory (AAHL) in Geelong, Victoria, which was also involved in the cat research, said.
Bats prime suspects
Dr Eaton says bats were a prime suspect as the virus host because they can carry a large number of viruses and not become ill.
"Some 40 different viruses have been isolated from bats ever since rabies in 1934," he said, noting the association of bats with Hendra virus and lyssavirus in Australia, and Nipah virus in Malaysia.
Bats are used for medicinal purposes in China.
For the research published in Science, researchers at the Chinese Academy of Sciences' Wuhan Institute of Virology trapped a large number of species of bats from caves and tested their serum.
They found that antibodies in three species of horseshoe bats cross-reacted with the SARS virus.
But the bat antibodies could not kill the SARS virus, which suggests the animals had actually formed in response to a SARS-like virus.
Bat poo clues
The researchers then examined the bat faeces. Here they found fragments of viral DNA they stitched together to form a complete sequence of a virus that was 90 per cent genetically similar to SARS.
"These bats were infected with a virus that was closely related to SARS," Dr Eaton said.
"It's close enough for us to be very highly suspicious that [the bats were] the source of the SARS virus."
This bat virus differed genetically from the human SARS virus in the area of the virus responsible for binding to human cells.
The researchers also found fragments of several other viruses that all differed only slightly from human SARS.
"There is a whole family of SARS-like viruses and they're all subtly different," Dr Eaton said.
He says the human SARS virus sits in the middle of this family in terms of its genetic make-up.
And a recombination of DNA from such viruses could easily have led to the virus that binds to human cells.
The three species of horseshoe bats identified by the Science researchers as carrying SARS-like viruses are Rhinolophus pearsoni from Guangxi and R. macrotis and R. ferrumequinum from Hubei.
The PNAS study carried out by Hong Kong researchers found a SARS-like virus in another species, R. sinicus.
SARS came from bats, say researchers
Friday Sep 30 08:40 AEST AAP
Australian researchers have helped identify bats as the likely source of the SARS epidemic that killed hundreds of people around the world.
A collaborative research project involving scientists in Australia, China and the United States has found that bats are highly likely to be the natural host of the virus responsible for Severe Acute Respiratory Syndrome.
SARS emerged in China's southern province of Guangdong in 2002. It spread across the world, killing 774 people and infecting another 8,000 by July 2003.
Initial studies indicated that the civet, a cat-sized mammal found in Asia, was probably the natural host of the previously unrecorded coronavirus.
But SARS research team leader Linfa Wang, from the CSIRO Livestock Industries' Australian Animal Health Laboratory in Geelong, said further research showed no widespread infection in wild or farmed civets.
"Bats are known reservoir hosts of an increasing number of zoonotic viruses but they rarely display clinical signs of infection," he said.
"It was these characteristics and the fact that bats are present in Asian food markets that led us to survey them."
Zoonotic viruses are those capable of infecting both animals and people.
The research, for which scientists sampled more than 400 bats from four areas of China, has been published in the journal Science.
The team collected blood, faecal and respiratory swabs which were analysed at the Geelong laboratories and the Chinese Academy of Sciences' Wuhan Institute of Virology.
More than 70 per cent of types of horseshoe bats sampled from China had SARS coronavirus antibodies in their blood.
Genetic analysis of the faecal samples supported the findings.
"The viruses detected from bats show greater genetic variation than those SARS coronaviruses which cause disease in humans and other animals," Dr Wang said.
"This variation suggest it's highly likely that the 2002-03 SARS outbreak originated from bats."
Research team member Hume Field, from the Queensland Department of Primary Industries, said discovering how the virus jumps from bats to other animals and humans will be the next step.
"This is crucial if we are to manage the risk of future outbreaks," Dr Field said.
Another research team, including scientists from the University of Hong Kong, published similar findings in the Proceedings of the National Academy of Sciences earlier this week.
