South China Agricultural University have issued a statement saying that research has identified pangolins as a possible coronavirus host.
Professor Andrew Cunningham, Deputy Director of Science, ZSL (Zoological Society of London), said:
“From the virology evidence available to date, the virus is almost certainly from a species of bat. It is, however, entirely possible that a relatively promiscuous virus could jump from bats to pangolins – or other species – in a wet market or similar unnatural situation, and then from pangolins to people. Hendra virus, for example, jumped from bats to horses to people. Although all humans known to have been infected by Hendra have been infected from horses, it is still a bat virus.
“Where large numbers of live animals of different species are brought together from different areas and held in captivity in overcrowded and unhygienic conditions, the likelihood of an animal being present that carries a potentially zoonotic virus is increased. Also, the chances that that animal will be stressed and will be shedding (or excreting) the virus will be increased.
“Live wild animal markets, such as the huge “wet” markets in China, therefore, are ideal places for zoonotic virus emergence to occur. Just as SARS did, the new coronavirus is thought to have emerged from a wet market in China. The highest priority for the protection of human health is, therefore, to ban “wet” (live wild animal) markets and to carefully regulate any future legal wildlife trade.
“A number of reasons have been proposed for bats being the source of many recently emerging zoonotic viruses. Bats are widely harvested as a source of food, and both the number of people eating bats and the number of bats being harvested has increased over recent years, possibly because populations of many traditionally eaten larger wild animals have been so depleted by hunting. Also, bats are thought to carry a larger number of some types of viruses (such as coronaviruses) than most, if not any, other group of animal. This might be because they often live in huge congregations and can fly, covering large distances to infect far-away populations of other bats.
“Importantly, if we understand the risk factors for zoonotic virus spill-over, we can take steps to prevent it happening in the first place without adversely affecting wild animals in which the viruses occur naturally. Although bats are thought to carry many potentially zoonotic viruses, they are also essential for ecosystems to function. Insectivorous bats eat huge volumes of insects such as mosquitoes and agricultural pests, while fruit bats pollinate trees and spread their seeds. It is imperative that these species are not culled through misguided “disease control” measures.”
Dr Efstathios Giotis, Research Fellow in Department of Infectious Disease, Imperial College London, said:
“The South China Agriculture University announced their research suggests pangolins could be an intermediate host earlier on today and the story was then propagated by the Chinese and international media. To my knowledge we don’t have the actual data and the announcement was brief; for example, it didn’t provide information about the study/parameters/researchers involved. Nonetheless, this does not mean the news is not credible. Due to the evolving nature of the outbreak, scientists are often under pressure to communicate their findings in real time. All research claims need to be rigorously and independently scrutinised by experts in the subject area to confirm whether they are valid. Information on the source and transmission of a virus is crucial and can inform prevention and treatment strategies. Zoonotic viruses transmit to humans either directly or via an intermediate host. Identifying a 99% identical virus in pangolins suggests that pangolins have an important role in the lifecycle of the virus, presumably as intermediary hosts.”
Prof James Wood, Head of Department of Veterinary Medicine, University of Cambridge, said:
“The evidence for the potential involvement of pangolins in the outbreak has not been published, other than by a university press release. This is not scientific evidence; investigations into animal reservoirs are extremely important, but results must then be published for international scrutiny to allow proper consideration. Simply reporting detection of viral RNA with sequence similarity of >99% is not sufficient. Could these results have been caused by contamination from a highly infected environment? Pangolins are one of the most widely traded species in China and South East Asia, despite CITES regulations prohibiting this; several Pangolin species are critically endangered. Whatever the outcome of these investigations, working to end the trade in wildlife can help to resolve some of the longer-term risks associated with animal reservoirs of zoonoses.”
Prof Jonathan Ball, Professor of Molecular Virology, University of Nottingham, said:
“This is a very interesting development – the potential source of the novel coronavirus has been a key unknown. Whether or not the endangered pangolin really is the reservoir is still unclear. We would need to see all of the genetic data to get a feel for how related the human and pangolin viruses are, and also gain an understanding of how prevalent this virus is in pangolins and whether or not these were being sold in the Wuhan wet markets.”
Prof Mark Harris, Professor of Virology, University of Leeds, said:
“The report that pangolins could be the intermediate host of the virus is intriguing. Although 2019-nCoV has been shown to be most closely related to coronaviruses isolated from bats, it has been reported that there were no bats in the Hunan Seafood Market where the first cases of 2019-nCoV infection of people occurred. This led scientists to speculate that the virus must have been transmitted to humans via an intermediate animal species. Pangolins are most closely related genetically to carnivores (cats, dogs, etc), and notably the SARS virus was shown to be related to bat coronaviruses but to have infected civet cats as a likely intermediate host before spreading to humans. It will be interesting to see the data that support this claim, which has not as yet been placed in the public domain.”
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