• Virologists have long warned governments of the evolution and spread of coronavirus
• Covid's molecular structure indicates its likely origins is in bats, not labs or the military
The Covid-19 pandemic now threatens lives and livelihoods all over the world, leading many to ask, where do these viruses come from?
In places as distant as Boston, America’s capital of biotechnology, and Turkana, Kenya’s pastoralist north, we’ve heard friends and family describe similar conspiracy theories to explain Covid-19.
These theories, mostly shared on social media, are so pervasive that the World Health Organisation (WHO) has warned of an “infodemic”.
Where did Covid-19 come from?
According to some conspiracies, the virus was created or released from a laboratory, a hostile military or even by billionaire Bill Gates.
Despite this, all available genetic evidence supports our understanding that the virus causing the pandemic, which scientists have named SARS-CoV-2, evolved naturally at the end of 2019 by spreading from animals to humans.
These conclusions are made possible by the high degree of similarity between SARS-CoV-2’s genetic code — the RNA molecule responsible for building the virus — to other coronaviruses found in wild animals.
Investigation of the molecular structure of SARS-CoV-2 places its likely origins in bats. It is possible that before evolving to infect humans, SARS-CoV-2 first passed from bats into another animal intermediary, and then infected humans. All this strongly indicates that SARS-CoV-2 was not artificially created by humans and instead evolved in nature.
Today, scientists from China, the United States and countries all over the world are collaborating to better understand where SARS-CoV-2 came from, and how we can protect ourselves from it.
RED FLAG RAISED IN 2007
In a 2007 study, scientist Vincent Cheng and colleagues wrote in Clinical Microbiology Reviews that new coronaviruses were likely to spread into humans, and could cause epidemics.
This was more likely to occur, the researchers argued, near markets with wild or exotic animals and meat, including from bats.
Where do coronaviruses come from?
SARS-CoV-2 is just one lineage of coronavirus, but there are many more. Coronaviruses are ancient and found in animals that they infect all over the world. Some coronavirus species can easily infect wild animals or the livestock we raise near our homes.
The name SARS-CoV-2 has a special meaning: it is the second coronavirus (CoV) to evolve from animals into humans and cause severe acute respiratory syndrome (SARS) in recent history.
A 2017 study by scientist Ying Tao and colleagues published in the Journal of Virology found that in Kenya, a sample of bats were infected with dozens of natural coronavirus lineages.
Many of those coronaviruses were previously unknown to science. In some cases, the viruses had recently jumped from one bat species into another, showing that coronaviruses can adapt and evolve quickly.
Scientists have long known that coronaviruses can evolve to leave one species of animal and infect a new one because this regularly happens to humans.
One review of coronavirus biology, published last year by scientist Jie Cui and colleagues in Nature Reviews Microbiology, explained that before SARS-CoV-2, we knew of six instances where animal coronaviruses had evolved from previous animal species to infect humans.
In four of those cases, the coronaviruses were mostly harmless and only caused minor colds. But in two cases — SARS-CoV in 2002-03 and MERS-CoV in 2012-13 — the viruses caused severe illness.
For this reason, scientists who study viruses, known as virologists, have long warned governments to prepare for the evolution and spread of new species of coronavirus.
In a 2007 study, scientist Vincent Cheng and colleagues wrote in Clinical Microbiology Reviews that new coronaviruses were likely to spread into humans, and could cause epidemics. This was more likely to occur, the researchers argued, near markets with wild or exotic animals and meat, including from bats.
One 2016 study published by Liam Brierley and colleagues explained that viruses are more likely to spread from animals into humans when high densities of humans and their livestock live close to wild animals, and close to bat populations, in particular.
How do coronaviruses make us sick?
Some outlandish theories have proposed that the illness Covid-19 is caused by 5G technology. While 5G is a technology for wireless information transfer using radio waves, coronaviruses are biological organisms that infect humans through entirely different processes. Radio waves used for cellphone technology have no impact on viruses, nor on the human immune system.
SARS-CoV-2 is a microscopic bundle of genetic code, called RNA, surrounded by a protective shell made out of proteins. Some of these, called “spike” proteins on the outside of the virus, point outwards in the shape of a crown, giving coronaviruses their name; “corona” means “crown” in Latin. Virus spike proteins are able to bind to a specific type of protein on the surface of our own cells, called “ACE2.”
After the virus binds to the ACE2 protein, it enters the cell, where it multiplies. This occurs when we inhale or ingest SARS-CoV-2 virus particles by being close to a sick person, causing our respiratory tracts or gastrointestinal systems to become infected. The disease Covid-19, and the symptoms we experience, result from the spread of the virus SARS-CoV-2 in the body. Multiple investigations have revealed that we can be sick and spread the virus to others while showing so symptoms of illness.
COUNTDOWN TO VACCINE
Because it is difficult to test and manufacture vaccines, it will be at least 18-24 months before a vaccine can be developed and produced.
Will warm temperatures or medicine stop the virus?
While scientists are working around the clock to find vaccines or treatment for coronavirus, no proven medication yet exists. One antiviral drug, Remdesivir, appears to have a minor impact on Covid-19. Because it is difficult to test and manufacture vaccines, it will be at least 18-24 months before a vaccine can be developed and produced.
Furthermore, analysis of the spread of the Covid-19 pandemic globally has shown us that neither temperature, skin colour nor ancestry afford protection from infection. Coronavirus epidemics have now emerged in nations throughout Africa. In the United States, there are indications that communities with African heritage have fared worse than others, as a result of decreased access to public health resources.
One analysis by researchers Qasim Bukhari and Yusuf Jameel at MIT indicated that warmer temperatures and higher humidity may slow the spread of coronavirus infection. However, the researchers also stressed that warm temperatures are no protection against the spread of the pandemic, and public health measures are needed for containment.
What can we do to protect ourselves and our communities?
We are fortunate that we can do much to protect ourselves against the coronavirus pandemic. Many decades of public health research have shown that acting quickly and decisively in the early stages of a pandemic is the most reliable method of saving lives.
When SARS-CoV-2 first began to infect people in the city of Wuhan, China, in December 2019, local doctors did not at first realise that a newly evolved coronavirus was threatening their city. However, as explained by Dr Qun Li in a recent report in the New England Journal of Medicine, public health measures established after the SARS-CoV outbreak in 2002–2003 allowed Chinese doctors and public health officials to identify and contain the new coronavirus this time.
These measures included reporting strange illnesses to local authorities on December 29, notifying regional and national health authorities on the 31st, and beginning an investigation into the disease. International health organisations were warned of a possible epidemic on January 3.
Later, on January 23, larger quarantines were established that included banning all public and unnecessary transit, the construction of emergency medical facilities, and stricter quarantines for health workers and those at risk of infection. Testing was conducted as widely as possible. The outcome of these actions was the containment of the epidemic in China.
We can learn from these and similar experiences. We know that social distancing measures can save lives; all people should avoid gathering in groups, and sick people or those in contact with them should be quarantined at home.
Hygiene is also crucial; we must wash our hands frequently, refrain from touching our faces and wear masks. Employers and community leaders must ensure people have the resources they and their families need to safely practise social distancing and achieve proper hygiene.
Above all, we must share accurate information about this pandemic with our family and friends. This means critically evaluating claims we hear from others, learning all we can about biology and public health, and encouraging our children to do the same. By educating ourselves, we can protect our communities and defeat this virus together.
Daniel Russell Green, PhD, is a lecturer of human evolutionary biology at Harvard University, and Eipa Emmanuel Aoron is a Master's student at Turkana University College and research technician at the Turkana Basin Institute.
Edited by T Jalio