#SciFri: Snakes and coronavirus
I remember the day well, it was late January and I’d just got into the office and fired up my desktop. I do what I always do once I arrive, grab a cuppa and then check my email inbox and Twitter notifications. It was at this point that my attention was drawn to a study looking at the origins of the Wuhan coronavirus, that was yet to become a global pandemic. I almost ended up wearing my tea as I read the headline that the coronavirus had most likely come from a snake that had been by a bat before coming into contact with people. We now know that the virus likely came from pangolins (the most heavily trafficked animal in the world), which isn’t a surprise when you think about it.
There has been a long history of emerging infectious diseases that affect both humans and wildlife being spread or originating in the legal and illegal trade of animals. One example off the top of my head is the amphibian chytrid fungus (Batrachochytrium dendrobatidis) which has been spread around the globe by the trade in amphibians. In terms of diseases that affect people, HIV/AIDS likely originated through the bushmeat trade in Africa with people coming into contact with the contaminated blood of primates. Here lies part of the problem, with a lack of biosecurity or other protective measures diseases are going to keep emerging from the animals we keep and trade with those diseases potentially causing devastation to the human population. The 2009 swine flu (H1N1) outbreak is one example of just that.
Back to the coronavirus (SARS-CoV-2), so why were snakes and bats implicated first but aren’t anymore? You’ve got to remember that at the time, teams around the world were scrambling for answers which would have created some competition. The paper reported that two snakes, the many-banded krait (Bungarus multicinctus) and the Chinese cobra (Naja atra) were the likely culprits for a reservoir and an intermediate host before infecting people. Now this is quite unlikely to begin with as whether snakes can infected with coronaviruses in the first place still hasn’t been answered. Secondly the binding receptors on the cells of mammals and receptors are quite different as well. The only evidence we have is that coronaviruses can infect mammals and birds – which were also on sale at the wet market where the coronavirus emerged.
So how did the researchers come to this result? There are a number of factors that could have come into play here such as contamination or a failure to double-check results. Working with DNA (and it’s products) is a slippery slope with room for error or contamination at every step. Also the lack of a number of isolates may have been to blame to. It’a hard to know for sure as we weren’t there and so therefore can only postulate.
Initially following the news I was slightly concerned, what impacts would it have for working with snakes if we could pass the virus between one another and how would it affect my grass snakes? I know that the Bat Conservation Trust announced a suspension to bat related work/research following advice from the IUCN Bat Specialist Group. It was my initial fear that this may have happened with snakes, but thankfully they were vindicated. The only real problem standing in my way is lockdown restrictions which are still a thorn in my side, for now.
This brief moment of negative limelight is likely to have damaged the image of snakes and bats, that are already negatively impacted by the media and their portrayal. The somewhat paradoxical consequence of this is that if people feel the need to persecute snakes, they first need to find them. Then comes the moment of conflict where that individual either shoots the animal or beheads it with a shovel etc. This is where most snakebites occur, when coming into close contact with snakes. In this example, it’s like walking into a horde of zombie expecting to walk out the other side. Why would you actively seek out something that could potentially infect you with a life-threatening disease?
Since January we’ve discovered a lot more about SARS-CoV-2 and it’s origins at the expense of both human life and liberties. If we want to prevent the further spread and emergence of such diseases we need to act to combat the illegal wildlife trade and increase biosecurity/testing on the legitimate trade. Research also has to continue on the factors effecting emergence and identifying potential hotpots.
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