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What are the origins of COVID-19?

This article was published on
May 6, 2021

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April 20, 2021: An international team of experts led by WHO’s zoonotic expert, Dr. Peter Ben Embarek, traveled to Wuhan, China in January-February 2021 to investigate the zoonotic origin of the Sars-CoV-2 virus. The team included experts from different fields veterinarians, medical doctors, epidemiologists, virologists, and experts who study diseases that originate in animals and jump humans. They worked with Chinese counterparts to better understand the origin of the coronavirus.

The study report published on March 30, 2021 did not point to a specific source of the virus. While the Huanan animal market and other animal markets had widespread contamination, it could not be determined if any of them was the source of the virus. The team did not eliminate the theory of a possible leak of the virus from a laboratory either but noted it to be extremely unlikely. The team's assessment was that the virus could have been most likely introduced through an intermediate host, but it was possible that cold storage/ food chain products or a direct transfer of the virus from an animal to humans were also possible ways through which the virus could have been introduced to humans. More extensive investigations would be needed to come to any conclusion.

The report noted that further investigation was needed with access to biological samples from Chinese authorities from September 2019.

COVID-19 was first detected in the city of Wuhan, China in late 2019. The virus has since been partially traced back to a large seafood and animal market in the city of Wuhan, after several people who had been to the market became sick with the illness we now know as COVID-19. Scientists were able to use genetic tests to confirm that the virus was first identified in people in the city of Wuhan. Tests on the genetics of viruses, much like genetics in humans, can reveal a lot about their origins. The majority of scientific studies now support the idea that the origin of the virus in animals was bats, specifically horseshoe bats, potentially from China or neighboring countries of Myanmar, Laos and Vietnam. Scientists also suggest that the virus may have been passed to humans through an intermediate host before spreading to humans, but are unsure about what animal the host might have been, though pangolins and civets have been suggested. The details about that event, which is called a zoonotic transfer, are still being investigated. World Health Organization experts will soon travel to China and work with Chinese health officials to identify the source of the virus. _This entry was updated with new information on July 16, 2020_

COVID-19 was first detected in the city of Wuhan, China in late 2019. The virus has since been partially traced back to a large seafood and animal market in the city of Wuhan, after several people who had been to the market became sick with the illness we now know as COVID-19. Scientists were able to use genetic tests to confirm that the virus was first identified in people in the city of Wuhan. Tests on the genetics of viruses, much like genetics in humans, can reveal a lot about their origins. The majority of scientific studies now support the idea that the origin of the virus in animals was bats, specifically horseshoe bats, potentially from China or neighboring countries of Myanmar, Laos and Vietnam. Scientists also suggest that the virus may have been passed to humans through an intermediate host before spreading to humans, but are unsure about what animal the host might have been, though pangolins and civets have been suggested. The details about that event, which is called a zoonotic transfer, are still being investigated. World Health Organization experts will soon travel to China and work with Chinese health officials to identify the source of the virus. _This entry was updated with new information on July 16, 2020_

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COVID-19 was first detected in the city of Wuhan, China in late 2019. The virus has since been partially traced back to a large seafood and animal market in the city of Wuhan, after several people who had been to the market became sick with the illness we now know as COVID-19. Scientists were able to use genetic tests to confirm that the virus was first identified in people in the city of Wuhan. Tests on the genetics of viruses, much like genetics in humans, can reveal a lot about their origins. The majority of scientific studies now support the idea that the origin of the virus in animals was bats, specifically horseshoe bats, potentially from China or neighboring countries of Myanmar, Laos and Vietnam. Scientists also suggest that the virus may have been passed to humans through an intermediate host before spreading to humans, but are unsure about what animal the host might have been, though pangolins and civets have been suggested. The details about that event, which is called a zoonotic transfer, are still being investigated. World Health Organization experts will soon travel to China and work with Chinese health officials to identify the source of the virus.

This entry was updated with new information on July 16, 2020

Context and background

Coronaviruses are a group of viruses that can cause a variety of different illnesses, but primarily upper-respiratory tract illnesses in humans. These illnesses include the common cold, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). Some viruses can originate in animals and later infect humans, and this can happen in a number of different ways, including: by eating meat or produce that has been contaminated by the virus, through the air or by touching a surface that was touched by an infected animal, through close contact with an infected animal, or through insect bites. Not all viruses transfer from animals to humans in all of these ways, it depends on the virus. The resources section contains more information about this.

Resources

  1. Viral and host factors related to the clinical outcome of COVID-19 (Nature)
  2. Genomic Study Points to Natural Origin of COVID-19 (NIH)
  3. Zoonotic diseases (U.S. CDC)
  4. Update and Interim Guidance on Outbreak of 2019 Novel Coronavirus (2019-nCoV) in Wuhan, China (U.S. CDC)
  5. Coronavirus Disease 2019 (COVID-19) (U.S. CDC)
  6. COVID-19: a novel zoonotic disease caused by a coronavirus from China: what we know and what we don’t (NCBI)
  7. Six months of coronavirus: the mysteries scientists are still racing to solve (Nature)
  8. The biggest mystery: what it will take to trace the coronavirus source (Nature)
  9. Emergence of SARS-CoV-2 through recombination and strong purifying selection (Science Advances)
  10. WHO experts to travel to China (WHO)
  11. COVID-19 origins report inconclusive: We must ‘leave no stone unturned’ – WHO chief (UN News)
  12. Origins of the SARS-CoV-2 virus (WHO)

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