Pearls and Irritations

The WHO report into the origins of the COVID-19 pandemic, released on March 30, supported what the scientists have long known: that the SARS-CoV2 virus most likely originated in an animal reservoir and, after a process of mutations, in complex settings of environmental and ecological change, eventually found its way into human populations. It also raised a curious question: why, if it is clear that the origin of COVID-19 is no different to other zoonoses to have emerged in the last century, are the public debates focusing on quite different issues?

Indeed, much of the discussion about the origins of COVID-19 has focused not on the biological processes but on conspiracy theories, which, despite the clarity of the WHO findings, have continued to surge. The most commonly cited claim – which originated with the Trump administration and appears still to be supported by the Australian government – is that the virus had been manufactured by Chinese scientists who, either accidentally or by design, released it into the Wuhan population. There is no evidence to support this theory, or its many competitors—such as the claims that the pandemic is the fault of the CIA, or the pharmaceutical companies, or George Soros, or 5G WIFI, or the Canadians, or the Israelis, or an international paedophile ring, or Bill Gates. Nor is there evidence for the counter-theories propounded by the Chinese themselves, which postulate cold-chain transmission from overseas sources and deliberate acts of sabotage by the US government.

The WHO’s investigation, by a high-level international team, addressed key questions about the sources of the pandemic. The epidemiology working group examined a vast quantity of data relating to historical infections in China, finding no evidence of previous significant infections with SARS-Cov2 virus.

The molecular epidemiology and bioinformatics working group showed that the coronaviruses most highly related to SARS-CoV2 are found in bats and pangolins, suggesting that these mammals may be the reservoir of the virus that causes COVID-19. The animal and environment working group reviewed existing knowledge on coronaviruses that are phylogenetically related to SARS-CoV-2 identified in different animals, including horseshoe bats and pangolins. While they found evidence that some domesticated wildlife, of which products were sold in the Hubei market, was susceptible to SARS-CoV2, none of the animal products sampled in the market tested positive.

The team considered four scenarios: direct zoonotic transmission to humans; introduction through an intermediate host followed by spill-over to humans; introduction through the cold food chain; and dissemination from a laboratory incident. For each possible pathway, the relative probabilities were assessed, with the conclusion that by far the most likely scenario was that of transmission of a protovirus from a bat to an intermediate host and then to humans. This process would have required a number of mutations in favourable conditions over an underdetermined period of time. Direct transmission from an animal (most probably a bat) reservoir to humans was possible, but much less likely. Introduction through the cold food route was possible but unsupported by evidence. A laboratory incident was dismissed as being “extremely unlikely”.

These conclusions closely fit the evidence painstakingly gathered by a whole generation of scientists. Virologists, epidemiologists and ecologists have been sounding an increasingly urgent alarm about the growing dangers associated with zoonotic infections. They have pointed out that more than 60% of new infectious diseases in humans now originate in animals. After the disastrous 1918 “Spanish Flu” pandemic there was a long break, followed by the emergence of HIV in the early 1980s. Since then, more than thirty previously unknown diseases have emerged, including SARS, Zika, MERS, Lassa, Hendra, monkeypox, Ebola, West Nile fever, Nipah, various avian influenza epidemics, and COVID-19.

The research has begun to elaborate the biological mechanisms underlying the transmission of viruses across species, which involve genetic changes by which the viral proteins are matched to the host systems. But what is better understood are the reasons for the increasing frequency of transmission of infective agents across species. Here, it comes as no surprise that sociological and ecological factors play a central role. While details vary geographically in relation to natural, cultural, social and economic conditions, there are widespread, common processes.

Changes in vegetation, land cover and land use and increasing deforestation transform the relationships between humans and animals. Population growth, and the intensified agriculture and livestock production demanded by it, often in the context of inappropriate use of chemicals and insecticides, is a major driver for this process. Natural wild animal habitats and traditional food sources are depleted, causing species hitherto isolated from each other to be forced into close and frequent contact. Global warming and climate change contribute fundamentally to the ecological transformation, but they are not the only factors operating.

Some deeply ingrained cultural practices increase the dangers further. The trade of wildlife and wild meat consumption, often focused on wet markets like the one in Wuhan, bring exotic species into unprecedented close contact. Large and rapid movements of populations associated with international travel guarantee rapid dissemination of new pathogens.

The multiple factors are complex, closely interconnected and difficult to untangle, but together they produce risks that are clear and inexorable. It is estimated that the HIV pandemic has killed about forty million people. The death toll from COVID-19, presently said to be around three million, will undoubtedly continue to rise. What is more, it is not just new zoonotic diseases that pose risks but also old diseases like TB, malaria and cholera that have re-emerged and extended worldwide, often in drug-resistant forms. It is estimated that the incidence of malaria (which already kills about one million people a year) increases by nearly 50% with every 4% increase in deforestation of the Amazon rainforest.

If this story were not alarming enough, what is of even greater concern are the prospects ahead. Unless urgent action is taken it is inevitable that further pandemics will follow the present one, maybe with even more devastating effects, particularly if effective vaccines are not developed, manufactured and disseminated as quickly as they have following the emergence of COVID-19.

All of this returns us to the question that was posed at the beginning of this essay, which may be restated more baldly: if so much is known about the nature, causes and risks of new zoonotic infections, and if the evidence regarding COVID-19 is so clear-cut, why is all this largely ignored in the public debates, in favour of irrelevant, distracting and untrue conspiracy theories?

We suggest it is because recognition of the gravity and root causes of this and other pandemics would force governments to acknowledge their own role in causing it and make urgent action unavoidable. Most obviously, it would force us to address the economic and cultural drivers of climate change. This has historically presented major obstacles, especially in Australia where the government has repeatedly refused even to admit the existence of the phenomenon.

However, as intractable as this may seem, addressing the dangers associated with new zoonotic infections would require much more still. Setting large scale targets for carbon emissions and global warming would help, but would not be enough to prevent another pandemic. The complexity of the ecological relationships requires action in all of the social, cultural and economic domains.

Wet markets that bring exotic species into close proximity with each other will have to be regulated, or even closed. The wildlife trade, and use of wildlife for food, will have to be ended. The destruction of the forests will have to cease. Areas of protected bushland will need to be established to avoid the need for animals formerly living in isolation from humans to enter into close contact with them. Native habitats will need to be preserved to provide wild animals with sufficient access to food. The use of pesticides and fertilisers will need to be limited. Global surveillance measures introduced in response to COVID-19, such as testing both at international borders and within communities, may need to be made permanent. It may be necessary to strategically cull animals that act as reservoirs for dangerous viruses.

A coordinated early warning system will need to be developed to identify and track potentially dangerous pathogens and to monitor interactions between species that could transmit them. Infection control procedures for health monitoring and quarantine will need to be developed, along with new diagnostic tests, drugs and vaccines, and coordinated rapid response plans for when new outbreaks arise will need to be agreed to by governments across the world.

The task is a big one but the dangers associated with failure are overwhelming. We must not allow our attention to be diverted from these challenges by vested interests, short-term political ambitions, unfounded conspiracy theories and inflexible ideological positions. If disaster is to be averted we must recognise how our economic and cultural structures and practices have adversely impacted the planet and jointly raise our sights to address these greater tasks.

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