Corona viruses are a group of RNA viruses that are assumed to be carried by bats that cause diseases in mammals and birds. They can cause mild cold to even life threatening respiratory diseases. Deadly ones in this group can cause SARS, MERS, and COVID-19. For the MERS as well as SARS-CoV-2 (responsible for Covid-19) there is no vaccine till now and the rate of infection, as well as death, varies extremely for both, but bats are suspected to be the primordial carriers for both diseases. COVID is affecting 212 countries and territories infecting approximately 4 million people and killing 6.8 percent among the infected whereas the death rate, as well as infection rate, is low for MERS ( about 0.07 percent as that of COVID people were affected by it). The common host, as well as the mechanism of transmission, could help us to fight against the viruses.
Recently the scientists from the USask’s Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), one of the world’s largest containment level 3 research facilities, and a team of researchers from USask’s Western College of Veterinary Medicine and VIDO-InterVac had done research about the carriers of the Middle East respiratory syndrome (MERS) coronavirus. The bats which carry these viruses aren’t getting sick even though they are transmitting diseases exhibiting super immunity, the study which was focused on this may help us to identify how these corona viruses leap to humans.
The bats don’t get rid of the virus and yet don’t get sick. We wanted to understand why the MERS virus doesn’t shut down the bat immune responses as it does in humans
Vikram Misra, Microbiologist, USask
They had done the research focusing on Eptesicus fuscus (Big Brown Bat) commonly found throughout North America). The sample bat’s cells were infected using the MERS virus and were cultured for 126 days. They had done studies even focusing on the protein and transcripts rather than the cell itself. There were signs of coexistence and adaptation of the cells of the bats and the viruses due to mutations. The MERS virus enters into a long term harmonious relationship with the cells of the brown bat and is maintained by the ‘super immune system’ in bats contrasting to the imbalance of immunity in human cells. Misra also suggests that “SARS-CoV-2 is thought to operate in the same way and when a bat experiences stress to their immune system, it disrupts this immune system-virus balance and allows the virus to multiply”. The virus becomes a threat only when the delicate equilibrium between the virus and the host breaks. A 2017 USask University-led study showed that bat coronaviruses can persist in their natural bat host for at least four months of hibernation. Eventhough this could not explain how viruses transmit so easily among species this could demonstrate the adaptations that bats make to become the reservoir of these viruses.
MERS could easily mutate themselves and adapt to the situations in bats by modifying specific proteins, thereby not creating an antiviral response that is found in humans. VIDO-InterVac scientist Darryl Falzarano, who co-led the bat study, developed the first potential treatment for MERS-CoV and is leading VIDO-InterVac’s efforts to develop a vaccine against COVID-19. The upcoming task ahead of the team is to turn its focus to understanding how the bat-borne MERS virus adapts to infection and replication in camelid (a group of even-toed ungulates that includes camels) and human cells. “This information may be critical for predicting the next bat virus that will cause a pandemic,” said Misra.
Krupa V. Mathew
Journal credits: https://www.nature.com/articles/s41598-020-64264-1
READ MORE: “Initial infection points for Covid-19 coronavirus Identified“
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