The novel coronavirus, 2019-nCoV, may have come from snakes according to an evolutionary analysis of the virus.
Research published in the Journal of Medical Virology compared the genetic information of the virus with already-available information on other viruses and found that 2019-nCoV appears to have formed from a combination of a coronavirus found in bats and another from snakes. The researchers say this recombination may have allowed transmission from snakes to humans.
The Australian Science Media Centre gathered expert comments on the study and the outbreak.
Associate Professor Phill Cassey, Director of the Centre for Applied Conservation Science, University of Adelaide, comments
“A bat and then snake origin for the novel coronavirus is definitely a very interesting hypothesis. Regardless of whether it has an origin in snakes or not, it is highly likely to be zoonotic (a disease that spreads from animals to humans). One of the highest risk sources for exposure are wildlife and bushmeat markets, which constitute a massive risk for novel emerging diseases. Globally there is an increasing pressure for live animals (as well as products and derivatives) in the wildlife trade. In many cases the trade is unregulated and illegal with major risks to biodiversity and environments, including human health. Unfortunately, the illegal wildlife trade is a pervasive and increasing component of transnational environmental crime(1).
No conflict of interest declared.
Associate Professor Rietie Venter, Head of Microbiology, University of South Australia, comments:
“Ever since the Spanish Flu swept through post-war Europe and killed a larger number of people than even the Great War, pandemic virus outbreaks that would wipe out a significant proportion of the world’s population has stoked fear in the hearts of people. The new outbreak of 2019-nCoV in China is no exception.
“There are some causes for concern. Firstly, this type of virus is spread by close human-human contact. Hence, dense co-habitation and international travel makes outbreaks harder to contain than outbreaks such as Ebola which spread through contact with contaminated bodily fluid.
“Secondly, the recent discovery that snakes are the most probable wildlife animal reservoir for this virus (the first time that snake to human viral transmission has been observed) has implications for the possibility of other viral outbreaks linked to exotic pets or bushmeat.
“However, medical epidemiology has progressed greatly in the 100 years since the Spanish Flu; all other viral outbreaks in the last century (Ebola, SARS, swine flu, MERS etc) were effectively contained with minimal loss of life. In addition, according to the WHO, the mortality rate of 2019-nCoV is very low (only about 3.8%). There is, therefore, no reason for panic and all reason to believe this outbreak will be similarly effectively dealt with.”
No conflict of interest declared.
Dr Farhid Hemmatzadeh, Associate Professor in Virology, University of Adelaide, comments:
“Coronaviruses contain the largest genome among in all RNA viruses. It provides higher flexibility for them to adapt themselves to the different species or create new viruses.
“Coronaviruses are common in human, cats, dogs, horses, pigs, cattle, camels, rabbits, ferrets, mink, rodents, birds, bats plus other birds and reptile and wildlife species. Coronaviruses regularly cause common cold in humans.
“In one study in China, some kind of similarity has been detected between the genome of the snakes coronaviruses and new virus in human. It is too early to say this change was responsible for the establishment and spreading of this new coronavirus in human or snake was the source of this infection.”
What do we know about the virulence of the novel virus and how concerned should we be?
“Due to the unique structure of the genome of the coronaviruses and their behaviour in human cells, it is highly likely to have new coronaviruses time to time in human or different species of animal.
“The chance for transmission of the coronaviruses from animals to humans is not that high. But strong evidence exists to confirm transmission of some animal coronaviruses to human the well-known examples are SARS that transmitted from bats to cats then human and MERS that has a camel origin. When a coronavirus established in humans, the most possible way of transmission is human to human.”
The Brisbane man has now been found to be clear of the virus but how likely is it that Australia will see cases of the virus here?
“The diagnostic tools and monitoring system are efficient enough to detect the viruses in clinically sick individuals, means if a sick person can be detectable at the point of the entry or even in flight. The biggest concern is the people who have been exposed to the virus but not showing the clinical signs yet are not detectable using the existing screening systems.
“The incubation period for this infection is not well known and it is a possibility for a person been exposed to the virus a day or two before then, travel to different countries with no or minor signs then start shedding the virus to the others and spread the infection in different places.”
What can Australia do to avoid it and what can individuals do to protect themselves from it?
“Australia has one of the best biosecurity systems for incoming passengers. However, it is almost impossible to monitor all individuals coming to Australia mostly from China or neighbouring countries for coronaviruses. That means regarding the well-established biosecurity system in Australia, it is highly likely to be exposed to the new coronavirus. Until now, the virus has detected in China, Hong Kong, Thailand, South Korea, Japan, Taiwan, US.
More restricted screening system, more effective in-flight monitoring procedures and more effective responding to any suspected cases is highly recommended.
“Finally, the spreading pattern of the virus and recently released molecular studies showing that the human-human transmission of the virus is not as fast as the other acute respiratory viruses. and the chance for super-fast spreading of the virus is not as high as the other acute respiratory viruses like the 2009 outbreak of Swine flu. The World Health Organization’s emergency committee hasn’t decided yet if it should be declared as an international public health emergency or not.”
No conflict of interest declared.
Associate Professor Sanjaya Senanayake, The Australian National University, comments:
How likely is it that the virus jumped from snakes to humans and how could this have happened?
“It is highly likely that this virus jumped from animals. A study appears to have shown that the novel coronavirus seems to be a combination of two viruses: one from a bat and a snake. This is plausible since both snakes and bats can be found in live food markets in China.
“The proximity of the live animals and humans in the market could have allowed the passage of the coronavirus. Also, the preparation and/or consumption of undercooked meat could also have allowed transmission of the coronavirus.”
What do we know about the virulence of the novel virus and how concerned should we be?
“The mortality or death rate appears to be relatively low [around 3 per cent], when compared to other coronaviruses like SARS and MERS; however, if it turns out to be very infectious between people, then even a low death rate can still mean a large absolute number of deaths. And as the outbreak has progressed, concern about its infectivity has escalated, even within the last couple of days.”
The Brisbane man has now been found to be clear of the virus but how likely is it that Australia will see cases of the virus here?
“One would think that it is highly likely to see cases in Australia, given our large Chinese diaspora and our proximity to China with multiple flights into the country. Interestingly, SARS, which also originated in China, only led to one probable case being diagnosed in Australia. But since 2004, one would imagine that travel between our two countries has increased a lot.”
What can Australia do to avoid it and what can the individual do to protect themselves from it?
“At this stage, avoid travel to Hubei province, and probably China if possible. For Australians in China, avoid live markets, large gatherings and wash your hands as much as possible. Masks can be effective for short periods.”
No conflict of interest declared.
Further expert reactions can be found on scimex.org.