The current pandemic has caused more than 170,000 deaths worldwide. But just where did the coronavirus (COVID-19) originate… and how?
The novel coronavirus (or COVID-19, as the disease was named by the World Health Organisation in February 2020) is widely believed to have started in the now-infamous Huanan seafood market, in the capital of China’s Hubei province, Wuhan.
Known to be a ‘wet market’, where live wild animals were being traded, it’s thought the virus somehow ‘jumped’ from an animal to a human host. But how did this happen… and in which species did it originate?
‘COVID-19 is an example of a zoonotic disease – one that can spread from animals to humans,’ explains Dr Mark Jones, head of policy at Born Free. ‘Many infectious agents have the potential to be zoonotic. The World Health Organisation estimates that 60 per cent of all human infectious diseases recognised so far are zoonoses, and about 75 per cent of emerging infectious diseases that have affected people over the past three decades originated from wild animals.
‘Recent human zoonotic epidemics include Severe Acute Respiratory Syndrome (SARS), another coronavirus that also emerged in southern China in 2002, which infected more than 8,000 people and resulted in 774 deaths. SARS is thought to have originated in bats and made its way to people via civets. Other notable examples of zoonotic epidemics include Ebola, Middle Eastern Respiratory Syndrome (MERS) and HIV.’
Covid-19 origin theories
While it’s highly likely that Huanan market was the site of the start of COVID-19, there are some early cases that cannot be linked there, suggesting the first human infections may have actually happened before the market-related cases occurred.
In a study published in Nature, ‘The proximal origin of SARS-CoV-2’ (the name of the virus that causes COVID-19), scientists propose three different theories as to the origin of the pandemic:
1) It started in an animal host
Due to the fact that so many of the early cases of COVID-19 can be linked directly to the Wuhan market, the most widely accepted theory is that the virus came from an animal source. But which animal?
‘COVID-19, the strain of coronavirus responsible for the pandemic, is thought to have originated from wildlife,’ says Dr Jones. ‘There has been much speculation over whether snakes, bats or pangolins were the sources of the original human cases in Wuhan, in China.’
‘COVID-19 is thought to have originated from wildlife.’
Indeed, current analysis suggests that bats and/or pangolins are the most likely sources. In fact, in a separate study, virologists at the Wuhan Institute for Virology demonstrated that SARS-CoV-2’s make-up is a 96 per cent match to coronavirus found in bats.
However, the Nature study comments that, while the bat virus remans genetically closest to the new coronavirus, some pangolin coronaviruses also exhibit strong similarities.
2/ It mutated in humans
The second theory proposed in the Nature study suggests that a progenitor (predecessor) to COVID-19 somehow jumped from an animal species to a human, where it then mutated and adapted to its new host during a period of undetected human-to-human transmission.
3/ It escaped from a laboratory
The final theory proposed by the study is that SARS-CoV-2 could have escaped from a laboratory.
‘Basic research involving passage of bat SARS-CoV-like coronaviruses in cell culture and/or animal models has been ongoing for many years in biosafety level 2 laboratories across the world, and there are documented instances of laboratory escapes of SARS-CoV,’ the study reports.
However, the study authors themselves say that, while it’s important to examine this possibility, the first theory is far stronger in explaining the origin of COVID-19, due to the similarity in viruses and the location.
Could coronavirus be man-made?
There are conspiracy theories circulating that perhaps COVID-19 was a man-made virus – a product of laboratory engineering, rather than a natural process.
However, scientists have proven these to be false.
There are conspiracy theories circulating that perhaps COVID-19 was a man-made virus.
‘It is improbable that SARS-CoV-2 emerged through laboratory manipulation of a related SARS-CoV-like coronavirus,’ says Kristian G Andersen et al in the Nature study. One reason for this is that ‘if genetic manipulation had been performed, one of the several reverse-genetic systems available for beta coronaviruses would probably have been used. However, the genetic data irrefutably show that SARS-CoV-2 is not derived from any previously used virus backbone.’
Don’t blame the wildlife
While coronavirus is likely to have an animal origin, it’s important not to blame wildlife for the current pandemic we are experiencing.
‘Importantly, whichever species are ultimately confirmed as the agents that transmitted the virus to people, wildlife isn’t to blame for the current pandemic,’ says Dr Jones. ‘Rather, the reasons why zoonoses are becoming so problematic in today’s world lie in the way we humans interact with – and exploit – wildlife.
It’s important not to blame wildlife for the current pandemic we are experiencing.
‘Relentless development in pursuit of economic growth has carved inroads into wild habitats, granting easy access to poachers, traders and traffickers, and facilitating the collection and export of wildlife. Trade in wild animals, both legal and illegal, has grown exponentially. Wild animals are collected, farmed, transported, exported and traded in huge numbers, more often than not enduring appalling conditions. Crowding, stress and injury among such animals provide the perfect environment for pathogens to spread and mutate, and their close proximity to people when they are traded and sold creates the opportunity for human transmission.’
Dr Jones says that, once COVID-19 is hopefully behind us, returning to a ‘business as usual’ approach to the treatment of wild animals cannot be an option.
Instead, he says we must ‘reset our fundamental relationship with the natural world, rethink our place in it, and treat our planet and all its inhabitants with a great deal more respect – for its sake and for ours.’