Aside from Covid-19, these viruses also go from bats to humans


  • Animals
  • Thursday, 13 Feb 2020

Bats appear to be able to co-exist with many viruses without falling ill themselves, These viruses sometimes make their way into humans, causing illness and death. — Filepic

I am confused. I read that the Wuhan Covid-19 coronavirus was initially thought to be spread by snakes. But now they say it is spread by bats. Which is it, snakes or bats?

The Wuhan virus is believed to have originated from a wildlife wet market in the city of Wuhan in the Hubei province of China, which sells both snakes and bats, as well as other exotic wildlife, for consumption.

These wildlife animals were for sale both dead and alive.

The market has been closed since Jan 1 (2020). But some time in December (2019), a coronavirus crossed over from one of these animals to humans for the first time.

A theory was published in a Chinese paper by a group of Chinese scientists, claiming that the coronavirus was spread by snakes.

Of course, the media picked this up and sensationally labelled it the “snake flu”.

Other scientists don’t believe this, however.

The new coronavirus, officially named Covid-19, is most closely related to a group of coronaviruses that typically infect bats.

Nevertheless, the story doesn’t end there. As it is winter in China and the bats are hibernating, some scientists believe that the virus passed from bats to another intermediate host.

An intermediate host? You mean, another possible animal that passes on the coronavirus to humans from bats?

Yes, that is what an intermediate host is.

So the “snake flu” group of scientists believe that bats transmitted the coronavirus to an intermediate host, snakes.

They claim that their theory is backed by genetic analysis.

They studied the genetic sequencing of 2019-nCoV and found an overlap between it and the Chinese cobra, as well as the many-banded krait.

But other scientists dispute this because coronaviruses usually infect mammals and not reptiles.

Still, it is early days yet and scientists are working around the clock to find out the exact host of 2019-nCoV, and any possible intermediate hosts.

What were other recent virus epidemics transmitted by?

The SARS (severe acute respiratory syndrome) virus was found to have been transmitted by civet cats, but it was a coronavirus that originated in bats.

It first appeared in Hong Kong in 2003 and caused a worldwide panic, if you remember. Here, the intermediate host was civet cats.

Let’s remember how the world snuffed out the SARS coronavirus, which was far deadlier than the Wuhan virus and killed at a higher rate.

When the SARS outbreak happened, the world reacted quickly.

They isolated infected patients.

China banned the eating of civet cats and implemented a mass slaughter of all civet cats in wet markets.

SARS died down in the population.

It still exists, but only in people working with it in labs.

After that, we had MERS-CoV.

Aha, MERS-CoV was a Middle Eastern flu. I remember it was transmitted by camels. Right?

Correct. MERS-CoV is also a coronavirus. It also originated in bats and camels were the intermediate hosts.

Once these viruses jump into humans, human-to-human transmission occurs very quickly.

Luckily, MERS-CoV was quite well contained. Most of the cases happened in Saudi Arabia.

Further back, I remember the Nipah virus. Was that transmitted by bats?

The Nipah virus originated in 1998 in Ipoh, Perak.

This virus is not a coronavirus, but a Henipavirus. It originated in fruit bats.

Here, the intermediate host was pigs, with the disease first appearing in pig farmers.

The Nipah virus was one of the deadliest viruses, causing death in 50% to 70% of patients infected by it.

Malaysia had to cull so many pigs at that time. The pig farmers were hit very hard, but the virus was contained.

The Nipah virus still exists and causes outbreaks now and then, especially in Bangladesh and India.

It is thought that bats are the direct cause because they infect palm sap and fruits.

When humans drink toddy made from the palm sap and eat the fruits, the virus jumps into them.

Are there any other viruses transmitted by bats?

Yes. Another virus is the Ebola virus, which causes haemorrhagic fever, and is mostly found in West Africa.

It is also very fatal, killing half of patients who catch it.

Ebola first appeared in 1976 and still causes sporadic outbreaks today.

The natural host is thought to be the fruit bat. It then jumps into intermediate hosts like monkeys, gorillas, chimpanzees or porcupines.

Thanks to deforestation and more humans coming into contact with wildlife and then with each other, these diseases tend to spread very rapidly, especially with air travel and human-to-human transmission.

This is the price we pay for technology.


Dr YLM graduated as a medical doctor, and has been writing for many years on various subjects such as medicine, health, computers and entertainment. For further information, email starhealth@thestar.com.my. The information contained in this column is for general educational purposes only. Neither The Star nor the author gives any warranty on accuracy, completeness, functionality, usefulness or other assurances as to such information. The Star and the author disclaim all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.


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