Why can bats transmit corona viruses without getting sick?

How bats prevent coronavirus disease

Bats can transmit coronaviruses without getting sick themselves. A current investigation was now trying to find possible reasons for this. The virus and the cells of bats seem to adapt to each other, which leads to a protective effect.

The current study by the University of Saskatchewan (Canada) investigated why bats can transmit coronaviruses without becoming ill themselves. The results of the study were published in the scientific reports published in English.

Bats do not contract corona viruses themselves

The researchers report that coronaviruses such as MERS, SARS and, more recently, the COVID19-causing coronavirus SARS-CoV-2 have their origin in bats. Although the above-mentioned viruses can cause serious and often even fatal diseases in humans, bats do not seem to become sick themselves for reasons that have not been well understood until now.

Immune responses from bats not turned off

The bats can't get rid of the virus, but they still don't get sick. The researchers therefore tried to find out why the MERS virus does not switch off the immune responses of the bats like in humans.

How do the animals protect themselves?

For the first time, the team has shown that cells of an insectivorous brown bat can be persistently infected with the MERS corona virus for months because important adaptations of both the bat and the virus work together. Instead of killing the bat's cells as the virus does with human cells, the MERS coronavirus enters into a long-term relationship with the bats, thanks to the unique Super immune system the bat is maintained, the researchers explain. It can be assumed that SARS-CoV-2 works in the same way.

Why does the virus spread to other species?

Habitat loss and various diseases could play a role in why the coronavirus spreads from bats to other species. When a bat experiences stress on its immune system, it disrupts the balance between the immune system and the virus and allows the virus to reproduce, the team reports. The MERS corona virus can also adapt very quickly to certain niches and can therefore be transmitted from species to species.

Bats cells adapt to the virus

When bat cells are exposed to the MERS virus, they adapt. It doesn't do this by producing inflammatory proteins that are key to disease, but by maintaining a natural antiviral response. This is turned off by the virus in other species, including humans, but not in bats. At the same time, the MERS virus also adapts to bat host cells by mutating a specific gene very quickly, the research group explains.

Adjustments make the virus harmless

When these adjustments work together, they result in the virus remaining in the bat for a long time, but being rendered harmless - until the delicate balance is disrupted, for example, by illness or other stress factors, reports the research team. Bats can therefore live with the virus without becoming acutely ill. (as)

Author and source information

This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.


  • Arinjay Banerjee, Sonu Subudhi, Noreen Rapin, Jocelyne Lew, Richa Jain et al .: Selection of viral variants during persistent infection of insectivorous bat cells with Middle East respiratory syndrome coronavirus, in Scientific Reports (published April 29, 2020), Scientific Reports

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