One of the prevailing and perhaps most comforting theories about the emergence of Covid, is that it was a coronavirus transmitted to humans by bats. But new research from scientists in Israel refute the theory which points to the opposite: bats have a highly effective immune system that enables them to deal relatively easily with viruses considered lethal for other mammals.
The Tel Aviv University study rejects the origin of the COVID-19 outbreak is in bats. The study was led by Maya Weinberg and Prof. Yossi Yovel who reviewed dozens of leading articles and studies in this field, and summed up their findings in iScience Journal. Israel has a long history studying the biology and ecology of bats.
The researchers explain that the infamous reputation of the bats is well known among both – the scientific community and the public at large, that they are often accused of being reservoirs of viruses including Covid-19, thus posing a threat to public health. In the present study, Weinberg sought to disprove this erroneous theory and show that bats play an important role in exterminating insects, replanting of deforested areas, and pollination of a number of crops.
Weinberg explains: “In general, bats are mistakenly conceived of as reservoirs of many contagious disease, only due to their being positive serologically positive; in other words, in possession of antibodies, which means that bats have survived the disease and developed an immune response.
“After that they overcame the virus altogether and disengaged from it; hence, they are no longer its carriers. Nevertheless, in many cases, a virus similar to a human pathogen is liable to be found in bats; however, it is not pathogenic to humans, and is not sufficient to use bats as a reservoir.”
In the study the researchers did a meta-analysis of the literature and checked the finding for over 100 viruses for which bats are considered potential reservoirs: Ebola, SARS, and COVID.
“We found that in a considerable number of cases (48%) this claim was based on the incidence of antibodies or PCR tests, rather than actual isolation of identical viruses. Moreover, many of the reported findings are not convincing,” the researchers say.
The mere isolation of a virus is not enough to see an animal as a reservoir, since a minimum number of index cases is required in which the virus is isolated in order to be considered a reservoir animal, as well as the existence of an established path of transmission, the researchers explain.
Anthropogenic conditions must exist in order for such an event to occur the scientists sum up.
After over 100 years of focus on viruses carried by bats, it appears that bats’ immune system is characterized by a restrained response during inflammatory processes. Bats have developed an excellent balance between resistance and tolerance: an increased defense response of the host, and immune tolerance through a number of different mechanisms.
To conclude, Weinberg adds: “the comprehensive study we’ve conducted raises serious doubts regarding the possibility of bats being the origin of the Covid19 outbreak.
“The findings give rise to the opposite perspective, according to which we must study in-depth the immunological anti-viral capabilities of bats, and thus obtain new and effective means of coping in humanity’s struggle against contagious disease, ageing and cancer.”
So how did Covid emerge? Is the jury still out? China meanwhile is pushing out Covid research papers to show it didn’t start there.
