The ABC of Pandemic: Animals, Bats and Coronavirus

ABC: Animals, Bats and Corona Virus

Lord Matt Ridley’s report in my words

This much we know that an animal was the source of the SARS-CoV-2 virus (the current novel coronavirus). However, was it a bat or a pangolin (a scaly anteater) or perhaps both? It’s not clear.

As I sat down to read the paper this past weekend, an article in the Wall Street Journal caught my eye. I thought to share it with my friends. So here it is a report by Lord Matt Ridley—in my words.

But before I do that, let me share what I have learnt so far about bats.

There are about 1,300 species of bats in the world. Some are tiny, as tiny as a bumble bee, while others such as fruit bats can weigh up to 4 pounds and flying foxes have a wingspan of 5 feet. Bats are mammals and can live up to 30 years. Some live solitary lives while others live in colonies of more than a million.

Bats have been the source of most of the dangerous new diseases of the past two decades. The natural reservoir of rabies is in bats. Ebola, Marburg and other highly dangerous viruses come from bats, mainly in Africa. The Hendra and Nipah viruses are caught from fruit bats and have caused lethal but small outbreaks in south Asia and Australia. And most coronaviruses seem to originate in bats, including SARS and MERS, a frequently fatal illness that people in the Middle East began catching from camels in 2012; the camels having picked it up from bats.

A group of Chinese scientists were looking for certain species of bats that carried viruses responsible for SARS epidemic. During that search, they collected a sample of the droppings of a horseshoe bat (Rhinolophus sinicus, tagged as RaTG13) from a cave in Yunnan province. The sample was stored in the Institute of Virology in Wuhan 2013 and forgotten. The feces from that bat contained the virus that causes COVID-19. Whether the virology lab or the wet market where bats are sold for meat, was the source of the COVID-19 virus, remains unknown and has spurred many conspiracy theories.

Research during the SARS epidemic had shown a relationship between the SARS virus and ACE2 receptors (special proteins) on the surface of human cells in the test tube. It was also discovered that the ACE2 receptors facilitate the viral entry into the human cells. Could it be possible that the bat coronaviruses were using ACE2 receptors to jump to humans and causing the infections? The answer was yes. The research showed that both SARS-CoV-2 (the current coronavirus) and the SARS-CoV (that causes SARS) use ACE2 receptor to facilitate viral entry into target cells.

Ralph Baric and colleagues at the University of North Carolina at Chapel Hill showed that the coronavirus virus could infect live mice that had been engineered to express the human ACE2 receptors. Dr. Baric reported in 2016 that the virus was “poised for human emergence”.

The literature shows that the research on the role of ACE2 inhibitors in the management of COVID-19 is ongoing.

The possibility of the novel coronavirus jumping species was reinforced in a paper published in February last year. Patrick Woo and colleagues at Hong Kong University surveyed the coronaviruses found in bats and came to the following conclusion:

“Bat–animal and bat–human interactions, such as the presence of live bats in wildlife wet markets and restaurants in Southern China, are important for interspecies transmission of [coronaviruses] and may lead to devastating global outbreaks.”

The Ebola, Hendra, Nipah, MERS and SARS epidemics gave us fair warning of the potential of future pandemics. When the Yunnan cave discovery was made in 2013, it should have sounded an alarm.

Since bats live for up to 30 years and don’t seem to suffer much in the way of symptoms from coronaviruses, it is possible that bat number RaTG13 may well still be alive. Even when this pandemic is over, new pandemics may not be far away.

The blog is based on the article by Mr. Ridley, a member of the House of Lords that was published on April 9, 2020 issue of the Wall Street Journal.