Where did covid come from? We may never know the answer

Where did the virus that causes COVID-19 come from? It is the ongoing mystery of the pandemic.

Scientists know that SARS-CoV-2, the agent that causes the disease, is part of a family of viruses found in some horseshoe bats, a species common in tropical and subtropical regions outside the Americas.

Scientists also mostly agree that many of the earliest known infections and deaths were concentrated around a wild animal market in Wuhan, China.

But researchers have not been able, in the three years since the emergence of Covid-19, to determine how the first victim became infected with it, which set off a pandemic that has since killed nearly seven million people, according to an official count of the World Health Organization, and much more if the number includes deaths caused. for unreported injuries.

The controversy intensified recently after a Chinese research team added DNA evidence removed from the market during the pandemic to an international database of gene sequences.

Previously undisclosed data indicated the presence of wild animals in the same section of the market where the team found SARS-CoV-2.

Raccoon dogs, bamboo rats and porcupines were among the animals known to be susceptible to bat viruses.

Some scientists have said, though not conclusively, that the data adds evidence to the theory that the virus passed from animals to humans through what is known as “zoonosis,” and is the source of many infectious diseases in humans.

Other scientists suspect that the disease-causing agent may have somehow leaked from a laboratory in Wuhan, 27 kilometers from the market, where researchers study bat viruses.

The idea gained more traction earlier this year when the US Department of Energy said, with “low confidence” in a report, that the outbreak likely resulted from a virus leak from a laboratory.

Other American agencies that have studied the matter tend to normal proliferation processes, although they are also not conclusive.

He did not publicly disclose the exact basis for the assessments.

Although how the virus arrived in Wuhan remains a mystery, the risks of spread are increasing dramatically in China, including several areas within 400 kilometers of the market. Chinese court records abound with cases of hunting wild animals from dangerous areas, and scientists from the Wuhan laboratory collected samples from bats in them.

A Reuters data analysis showed that human encroachment on bat habitats in recent decades has turned parts of China into an epidemic minefield.

These areas, which news agencies call “jumping grounds”, combine a combination of tree loss, rainfall and the presence of bat species to create conditions in which infection is most likely to spread.

The data shows that between 2002 and 2019 China’s “jumping areas” expanded by 54 percent, an increase of 150,000 square kilometers, an area larger than that of Nepal.

One of these jumping areas includes mountains and lakes, 175 km southeast of the Wuhan market.

The area around China’s giant Poyang Lake has been severely degraded by dam construction, mining and pig farming.

Scientists continue to seek definitive evidence about the geographic or biological origins of COVID-19. The mystery persists, in part, because Beijing has not allowed an independent investigation into either hypothesis, an infected animal or the virus leaking from a laboratory.

The Chinese government says it supports and participates in research to determine the origin of COVID-19. And accuses the United States of politicizing the matter, especially because of the efforts of American intelligence agencies to investigate.

“Assigning responsibility to a scientific issue to the intelligence community is a clear sign that the issue has been politicized,” Chinese Foreign Ministry spokeswoman Mao Ning told a news conference in March.

Early in the outbreak, Chinese scientists found the causative agent of COVID-19 on bathroom surfaces and water drains in a Wuhan market where wild animals were sold. But there is no evidence yet that they tested live animals before the government shut down the market.

Without further evidence, theories began to circulate about the virus leaking from a laboratory.

Both possibilities have a history in China.

In late 2002, the SARS-CoV-1 virus appeared in Guangdong, southern China, and the SARS epidemic broke out in 2003. At that time, scientists tested animals in the local market and found the virus in a palm civet, as well as evidence of infection in a raccoon dog and a mongoose badger.

Scientists have widely identified animal-to-human transmission as the source of the pandemic.

After the end of the SARS pandemic, two postgraduate students were infected with SARS while working at the National Institute of Virology in Beijing, where scientists were studying the disease-causing agent. That epidemic, although contained, infected nine people and killed one.

This incident has become a reference for those who suspect that a leak from a laboratory is responsible for the outbreak of Covid-19.

In 2010, Zhong Nanshan, a doctor who led China’s program for dealing with SARS and in the years after COVID-19, told a Chinese newspaper that “the ecological balance between man and nature is overexploited.” He noted the discovery of SARS-like viruses in Wuhan and Hong Kong in horseshoe bats. A research paper cited his comments.

“If we take strict measures, I think SARS will not return. And if we do not strengthen our measures, it will certainly return,” he added.

Chung did not respond to a Reuters request for comment.

Since the emergence of SARS-CoV-2, scientists have discovered close matches with the virus in samples collected from bats in Yunnan. Researchers also found viruses closely related to the cause of COVID-19 in bats across the border in Laos.

But none of them were close enough to the SARS-CoV-2 virus to be its direct ancestor. Locating an exact match can be like finding a needle in a haystack, as the saying goes.

Without conclusive evidence, predictions are likely to persist.

Western governments and much of the world’s scientific community have urged China to be more open and cooperative with the findings of its researchers.

“We continue to call on China to be transparent in sharing data, conducting necessary investigations and sharing results,” WHO Director-General Tedros Adhanom Ghebreyesus said in a briefing in March. “Understanding how the pandemic started remains a moral and scientific imperative.”