Scientists now agree that Covid-19 is caused by a coronavirus from an animal. Though not absolutely certain, it is likely to have originated in a bat species. The closest viral match has been isolated from a bat in China’s Yunnan province, sharing 96 per cent of its DNA with the 2019 novel coronavirus.
This is not altogether a surprise. As David Quamman, author of the prescient 2012 book Spillover, told Geographical for an article in the May edition: ‘We knew that the next pandemic would be caused by a quickly mutating virus; that it would be transmitted from a wild animal, very possibly a bat; that it would spillover from [an animal] at a place where they come into contact with humans; and that people would shed the virus when they are asymptomatic – all of that has come true.’
However, that’s not to say that humans picked up the virus from bats, and there is no evidence to suggest that one person eating a bat was the cause. In fact, many have pointed out that bat doesn’t even tend to be eaten in Wuhan, where the virus is believed to have originated from. A widely circulated video showing a woman eating a bat was actually filmed in Palau. Scientists think the virus may have reached humans through an intermediary species – pangolins have frequently been suggested. What’s more, subsequent transmission of Covid-19 is from person to person. As the Bat Conservation Trust (BCT) makes plain: ‘It is transmission between people that has spread the disease globally’. This means that in many countries there is no chance of getting the virus from a bat. For example, in the UK, there are no known zoonotic (harmful to humans) coronaviruses found in bats.
For this reason, conservationists are now working hard to dispel the image of bats as dangerous. The fault, they argue, lies not with bats, but with human interference with the environment, such as deforestation and the wildlife trade, which brings all forms of wildlife much closer to humans and livestock than would naturally happen. ‘The live wildlife trade, in which many different species of wild animals are brought together in markets, can provide the conditions for spillover events,’ explains Joe Nunez-Mino, director of communications and fundraising at the BCT.
‘The traded animals are held in cramped, stressful, unsanitary conditions, with many different species caged side by side and slaughtered to order. The species in these markets would not be found together in such close proximity in the wild. Such trade increases the chances that viruses can jump from one species to another, and ultimately from animals to humans. To prevent future outbreaks we need to stop uncontrolled habitat destruction and control the trade in wild animals.’
He adds that recently published research has showed that bats don’t host any more disease-causing viruses than any other groups of animals (mammals and birds) of similar species diversity. ‘There are more than 1,400 different bat species, the second largest group of mammals by species. Taken as a group, bats are considered ‘reservoirs’ (long-term hosts) of a number of viruses but most of these are not harmful and cannot be passed to humans.’
It is for these reasons that 236 wildlife protection groups came together at the start of April to pen an open letter to the World Health Organisation, the Office International Epizoologie and the United Nations Environment Programme, calling on them to permanently ban live wildlife markets and the use of wildlife in traditional medicine. The letter states that: ‘The Covid-19 outbreak is believed to have originated at wildlife markets in China, and transmitted to humans as a result of close proximity between wildlife and people. Further research suggests that bats and pangolins may have been involved in the transmission chain of the virus to people. But let us stress that it was the actions of people that created the environment in which this transmission was possible.’
The letter goes on to state that the risk of disease transmission is prevalent across all aspects of the wildlife trade – it is not just the species we hear most about that have the potential to pass diseases to humans. Bovine tuberculosis has been documented among wild and captive-bred lions, posing a substantial risk of spillover viruses to consumers and people involved in the lion bone trade, particularly those who work in breeding farms, slaughter and processing facilities in South Africa. Reptiles such as snakes and geckos, which are also used in traditional medicine, are frequent sources of Salmonellosis infections in people.
Unfortunately however, misunderstanding as to the true causes of the virus and its spread has increased fear of bats. The BCT has heard reports that in some tropical countries bat roosts have been destroyed as a result of Covid-19, a practice that is both harmful to bats and counterproductive, since stressed animals may become more disease prone.
Such a practice could also be counterproductive to wider ecosystems. Far from being frightening vessels of disease, bats provide a whole host of ecosystem services, many with clear economic value. Accounting for more than 20 per cent of the world’s mammals, bats suppress agricultural pests and pollinate plants. It has been estimated that Mexican free-tailed bats in central Texas save cotton farmers in that area more than $740,000 annually while, in Thailand, bats benefit rice farmers at the equivalent of supplying rice to 26,000 people per year (an economic value of more than $1.2 million). Bats also act as seed dispersers for many other plants making a vital contribution to forest regeneration.
The answer to the question – should we be scared of bats? – is unequivocally no. What we should be scared of is human practices that crowd wild animals together in dangerous and unhygienic conditions.