Where Did the Deadly Virus Come from?
By Dr Syed Amir
Bethesda, MD
Did the deadliest virus known to man, the novel Coronavirus (SARS-CoV-2) that causes the respiratory disease Covid-19, originate in a research laboratory in Wuhan, China, or jump naturally from an animal reservoir to humans? The subject is being debated and is of great interest to scientists around the world.
The pandemic has extracted a terrible toll as the worldwide number of infections at the time of this writing has reached 4.5 million, with 300,500 fatalities, according to the World Health Organization (WHO). In Pakistan, as reported by Dawn, there have been 39,500 confirmed cases, with 847 deaths. The numbers are relatively low, but the pandemic may not yet have peaked.
The controversy over the origin of the virus has been fueled recently by the statements of President Donald Trump and Secretary of State Mike Pompeo, who have asserted that they have some unspecified evidence that the coronavirus was genetically modified and created in the Chinese Virology Institute at Wuhan and that it, perhaps accidentally, escaped the laboratory causing the pandemic. However, based on the genetic signature of the virus, most reputable scientists in the West and the WHO have discounted the possibility that it is manmade. While China may have no responsibility for the creation of the virus, it certainly covered up for a while its spread and extreme contagiousness. A new variant of the virus has now been recognized to be causing serious inflammatory illness among children who had thus far been relatively immune to Covid-19.
Why did questions arise about the human involvement in the creation of the coronavirus? There is some, albeit weak, basis for the accusation. The city of Wuhan is home to a world-class, top-security virology laboratory, headed by an internationally respected scientist, Professor Shi Zhengli, who has published many scientific articles in international journals. While the Trump administration has accused China of creating the coronavirus, a number of American epidemiologists who worked at the Wuhan Institute with Dr Zhengli under an international exchange program praised her as an extremely painstaking scientist, unlikely to permit any security lapses. Notable among them is Dr Peter Daszak, a famed British zoologist and expert on diseases that jump from animals to humans, who has collaborated with Dr Zhengli. He and his research organization, EcoHealth Alliance, have been attempting to identify before it is too late bet-derived viruses that could unleash another pandemic on humanity. To enable him and his team to conduct these collaborative studies, the National Institutes of Health (NIH) has awarded him millions of dollars. After he earned President Trump’s displeasure for failing to link the virus to the Wuhan laboratory, the NIH abruptly cancelled the grant. No plausible reason for the cancellation was provided.
Writing recently in The Washington Post, Joby Warrick and colleagues have provided a detailed account of the nature of scientific research going on in the Wuhan Virology Institute. The laboratory has a record of pioneering work on another respiratory disease, Severe Acute Respiratory Syndrome (SARS), and identified its causative virus in 2003. Unlike the current coronavirus, SARS-related virus was quickly controlled and is believed to be a zoonotic, having sprung from horseshoe bats to humans. Chinese investigators have established that bats are rich reservoirs of many deadly viruses, and bats have been the focus of their attention for the past ten years. They have scoured various South Asian countries, wading into dark, dingy, and damp caves in search of bats. Their mission is to capture bats, collect their saliva and excrements, and bring the specimens back to the laboratory in Wuhan. They also collect blood sample of villagers living nearby who normally hunt the mammals for food and use their body parts in traditional Chines medicine.
If CoV-2 virus did not escape from the Wuhan Virology Institute, where else could it have come from? The city is also known for its wet animal market, a flourishing wildlife bazaar where exotic as well as ordinary animals, ranging from bats to live snakes, rats, foxes, turtles, wild pigs and a number of others, are slaughtered and their meat soldfor food. The Chinese Government, following the Coronavirus pandemic, placed a temporary ban on the trade in all wildlife, but the long-term effectiveness of such a ban is uncertain.
Most viruses are comprised of DNA as their genetic material, while others, such as the coronavirus, are RNA-based. The latter are prone to much higher rate of mutation. It is estimated that nearly three-quarter of all new disease-causing viruses originate in animal species. The viruses causing SARS, MERS, swine flu, bird flu and Ebola are known to have come from animals. Normally these viruses do not infect humans, but occasionally they mutate and acquire the ability to do so, as appears to be the case with the current novel corona virus.
The transition of lethal viruses from animals to humans is facilitated by close interactions between the two species. The wild animal markets serve as important facilitators of such evolutions. The coronavirus, SARS-CoV-2, almost certainly originated in bats and jumped to humans through another animal suspected to be pangolins. These scaly mammals are listed as threatened species and are protected by international agreement. They are, however, prized in China for their meat, a delicacy, and especially for their scales that are used in traditional medicine.
The SARS epidemic in 2003 is also believed to have started in China by another coronavirus resulting from consumption of the meat of the palm civet, an animal like the cat. Similarly, the virus that sparked the Middle East Respiratory Syndrome (MERS), identified in Saudi Arabia 2012, arose from close contact with camels Fortunately, neither SARS nor MERS proved as lethal, or as contagious as the current coronavirus, and both petered out relatively quickly.
Although tens of thousands of corona viruses exist in nature, only six are known to infect humans; the new virus is the seventh among these pathogens. In addition to the SARS and MERS, four of the viruses cause common cold and lack both the infectivity and lethality of the other three.
While the international community struggles to gain control over the pandemic Covid-19, a source of unparalleled morbidity and mortality, there is general agreement that all opportunities for close interactions between wild animals and humans that is increasingly happening now, resulting in the emergence of deadly new pathogens, should be minimized or eliminated.
(The writer is a former assistant professor, Harvard Medical School, and a retired health scientist administrator, US National Institutes of Health)
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