Friday, May 15, 2020

Does a commensal relationship exist between coronaviruses and some human populations?

Nanjing Road, Shanghai (Wikicommons - Stephen Codrington). Populations with a long history of social crowding may have become more susceptible to coronavirus infection.

I've published a paper on coevolution between coronaviruses and "crowded" social environments. Comments are welcome. Here is the abstract:

Coronaviruses enter lung tissue via the ACE2 receptor, which varies structurally among human populations. In particular, the Chinese population has fewer variants that bind weakly to the coronavirus S-protein. This global variation suggests that the ACE2 receptor has coevolved with different environments, some of which have favored susceptibility to infection of lung tissue by coronaviruses. 

It has been argued that respiratory viruses boost the immune response of lung tissue and thereby prevent more serious pulmonary diseases, like tuberculosis, pneumonia, and pneumonic plague. This preventive effect has been shown with other viral pathogens, notably γherpesvirus 68 and cytomegalovirus. Some human populations may have therefore gained protection from severe respiratory infections by becoming more susceptible to mild respiratory infections, such as those normally caused by coronaviruses. 

This commensal virus-host relationship would have been especially adaptive wherever respiratory pathogens could easily propagate, i.e., in crowded environments, where many people live in proximity not only to each other but also to animal sources of infection. In regions that have long had crowded environments, natural selection may have favored susceptibility to infection by coronaviruses, which are normally mild in their effects, as a means to maintain a strong immune response to deadly pulmonary diseases.


Frost, P. (2020c). Does a commensal relationship exist between coronaviruses and some human populations? Journal of Molecular Genetics 3(2): 1-2.   


Luke Lea said...

Interesting. Would definitely explain a few things.

Santo said...

Northern Italy is densely populated since medievo.
I believe we can't draw any conclusive line based on populations with very different current lifestyle, just like compare apples with oranges. Chinese today, more fat than the older generations but still considerably thinner or healthier than black americans. The idea that different people have on avg different suscetibility to diseases is soundly logical but...