Preprint Article Version 2 Preserved in Portico This version is not peer-reviewed

How One Pandemic Led To Another: Was African Swine Fever Virus (ASFV) The Disruption Contributing To Severe Acute Respiratory Syndrome Coronavirus 2 (Sars‑cov‑2) Emergence?

Version 1 : Received: 24 February 2021 / Approved: 25 February 2021 / Online: 25 February 2021 (16:57:13 CET)
Version 2 : Received: 20 January 2022 / Approved: 25 January 2022 / Online: 25 January 2022 (10:01:12 CET)

How to cite: Xia, W.; Hughes, J.; Robertson, D.; Jiang, X. How One Pandemic Led To Another: Was African Swine Fever Virus (ASFV) The Disruption Contributing To Severe Acute Respiratory Syndrome Coronavirus 2 (Sars‑cov‑2) Emergence?. Preprints 2021, 2021020590. Xia, W.; Hughes, J.; Robertson, D.; Jiang, X. How One Pandemic Led To Another: Was African Swine Fever Virus (ASFV) The Disruption Contributing To Severe Acute Respiratory Syndrome Coronavirus 2 (Sars‑cov‑2) Emergence?. Preprints 2021, 2021020590.


The spillover of a virus from an animal reservoir to humans requires both molecular and ecological risk factors to align. While extensive research both before and after the emergence of SARS-CoV-2 in 2019 implicates horseshoe bats as the significant animal reservoir for the new human coronavirus, it remains unclear why it emerged at this time. One massive disruption to animal-human contacts in 2019 is linked to the on-going African swine fever virus (ASFV) pandemic. Pork is the major meat source in the Chinese diet. We hypothesize that the dramatic shortage of pork following large-scale culling and restrictions of pig movement (resulting in marked price increases) led to alternative sources of meat and unusual animal and meat movements nationwide, e.g., involving wildlife, and thus greatly increased opportunities for human-sarbecovirus contacts. Pork prices were particularly high in southern provinces (Guangdong, Guangxi, Fujian, Jiangxi, Hunan, and Hubei), where wildlife is farmed and more frequently consumed. Major wildlife farming provinces are spread from Northern to Southern China, which overlaps with horseshoe bat host ranges, potential hosts of the proximal SARS-CoV-2 ancestor, and wildlife sourcing provinces of Wuhan Huanan market and possibly other markets. Trading of SARS-CoV-2 susceptible wildlife in these markets, such as minks, raccoon dogs, foxes and palm civets in Wuhan markets, could have increased the risk of SARS-CoV-2 from an intermediary host. Moreover, large quantities of animals raised for fur could have entered the human food chain undetected and significantly increased risks of animal-human contact. Performing retrospective testing of stored susceptible animals and their meat sold before December 2019 may be helpful in the next stage of tracing the animal origin of SARS-CoV-2 as spillover events are more likely to have taken place in 2019 when China was experiencing the worst effects of the ASFV pandemic.


African swine fever virus (ASFV); Pork shortage; Alternative meat consumption; Wildlife; Human-animal contact; Zoonotic spillover; SARS-CoV-2


Biology and Life Sciences, Virology

Comments (2)

Comment 1
Received: 25 January 2022
Commenter: Xiaowei Jiang
Commenter's Conflict of Interests: Author
Comment: This is a major revision in light of the WHO report and other previously published new data regarding wildlife trade in China.
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Comment 2
Received: 20 July 2022
Commenter: Darrell Boone
The commenter has declared there is no conflict of interests.
Comment: This article appears to promote a hypothesis which speculates that a crash in pork availability in China may have laid the groundwork for the spread of SARS-CoV-2 by way of increased trade in wildlife for their meat - to compensate for lack of hog production. Consequently, it strikes me as a huge oversight of these authors NOT to have obtained the raw monthly wildlife sales data collected for the 2021 paper by Xiao Xiao and coauthors. If this article's hypothesis has merit, then the Xiao et al. (2021) study should be able to confirm whether there was a surge in wildlife numbers sold for meat in the 4 Wuhan "wet markets" during the several (5?) months prior to December 2019 outbreak of SARS-CoV-2 in Wuhan, China.

It is also disconcerting that this article fails to account for the wildlife species and numbers that were being sold in Wuhan's 4 "wet markets" for 31 months prior to Dec. 2019 - as described in Table 1 of Xiao et al (2021) paper. Although no bats or pangolins were sold in these Wuhan wet markets according to Xiao et al (2021), this article fails to mention this salient fact. It was disturbing that this article failed to even mention that there is no evidence of the SARS2 virus infecting any animals other than mammals, which would render as superfluous this article's mention of birds, snakes and other kinds of animals that are NOT MAMMALS being sold or slaughtered at wildlife markets in China. And no effort was made by authors of this article to evaluate the numbers sold of the mammals listed in Table 1 of Xiao et al. (2021), which would reveal that VERY FEW likely were present EACH DAY on average in any of the stalls operated by the 17 wildlife vendors throughout all 4 Wuhan wet markets.

According to Table 1 provided in Xiao et al. (2001) paper, even fewer animals likely were present each day in Wuhan's infamous "Huanan Seafood Market" - which on a "pro rata" basis sold only 7/17ths of the total numbers of wildlife being sold in Wuhan's 4 "wet markets". Again, obtaining the raw monthly data for the Xiao et al. (2021) paper could greatly strengthen the arguments being advanced in this article (or, conversely, help to refute its hypothesis). Unfortunately, all we have to go on as to what wildlife species and their numbers that were sold monthly in Wuhan is the summary data provided in Table 1 of Xiao et al. (2021). But nonetheless this information clearly shows that "on average" only about 1 Palm Civet was being sold "on average" every 3 days by just 1 of the 17 wildlife vendors operating in the 4 Wuhan "wet markets". However, for the Huanan Seafood Market, only about 1 Palm Civet likely was sold by just 1 of its 7 vendors every 7 days - based on a "pro rata" share of the total number cumulatively being sold on average per month within all 4 of Wuhan's wet markets. Raccoon-dog sales numbers are just a bit higher - averaging 1.24 animals sold daily within Wuhan's 4 wet markets, which amounts to a prorated share of only 1 animal being sold every 2 days by a vendor at the Huanan Seafood Market. The numbers of mink that likely were sold daily in Wuhan are even lower than I just elaborated for Palm Civet.

In addition, this article appears to give the false impression that all the new roads and rail lines built in China were to move people and cargo directly to Wuhan. The authors seem to ignore in their analysis any likelihood that a Covid-19 outbreak could have occurred in the dozens of other very large Chinese cities which are along the way to Wuhan or otherwise equidistant to the "virus source areas" - where probable wildlife "hosts" were most likely initially infected with SARS2 virus. The fact that this pandemic's initial outbreak occurred in Wuhan - where several low-biosafety labs were actively working with bat Coronaviruses - is puzzlingly treated as mere coincidence, without any real discussion as to the likelihood of this happening WITHOUT also any evidence of a host animal or of early human cases detected elsewhere in China.

Lastly, this article fails to divulge the current state of knowledge regarding the likelihood of captive wildlife species to serve as an effective intermediate host for the SARS2 virus. It makes repeated mention of animals sold in wildlife trade - such as Bamboo Rats & Wild Boar, but never reveals whether such species would be susceptible to infection by SARS2 virus, let alone be able to pass along live virus so as to likely infect conspecifics or humans. For Bamboo Rats, there is no current evidence published showing these animals CAN become infected with the SARS2 virus. For Wild Boar, there is only limited evidence of these animals becoming infected with the SARS2 virus and NO EVIDENCE that this species is able to spread this virus to conspecifics or other species.

As far as I am aware, the only wildlife species so far KNOWN to effectively host and transmit the SARS2 virus IN THE WILD is the White-tailed Deer (American Mink may also have this dubious distinction, but lack sufficient corroborating evidence). However, in captivity, several other wildlife species have been found to be capable of effectively hosting and transmitting the SARS2 virus. These include the Palm Civet and Raccoon-dog, Red Fox, Mink, Domestic Cat and Ferret, at least one species of Deer Mouse, Syrian Hampster & White-tailed Deer. It's worth noting that a "poster-child" for wildlife hosts of SARS2-virus - the Raccoon-dog - has ONLY been documented to transmit the virus to conspecifics via "direct contact"; no evidence of aerial or respiratory transmission has been found.
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