COmprehending Microbiome of BATs: exploring the microbiome of bats to investigate virus diversity and One Health implications

OIE, WHO and FAO have long acknowledged the importance of a One Health vision. Almost 75% of human infectious diseases are derived from animals. Bats (Order Chiroptera) include more than 1100 species belonging to 17 families. Given their peculiar characteristics (global distribution, longevity, lifestyle, ecological role), bats are the ideal hosts for a large number of microorganisms and have been identified as reservoirs of emerging zoonotic agents important for animal and human health. In 2020, the novel coronavirus (CoV) SARS-CoV-2 emerged globally, giving rise to COVID-19 pandemic. Based on genetic analysis and comparisons with the sequences of other coronaviruses from several animal species, the virus appears to have originated from bats. As hypothesized for other hypervirulent human CoVs, SARS-CoV-1 and MERS-CoV, SARS-CoV-2 presumably spilled from bats to humans via adaptation in an intermediate animal host. CoVs similar to either SARS-CoV-1, SARS-CoV-2 or MERS-CoV have been identified in bat species in several countries, including Italy. However, there is concern that, unlike the other hypervirulent human CoVs, the massive environmental pressure generated by COVID-19 pandemic could also help SARS-CoV-2 bounce back into the wildlife. As the virus spread globally, infection with SARS-CoV-2 was reported in domestic cats, dogs, ferrets and farmed minks, as well as in large felids, hippopotamus, otters and gorillas in captivity. OIE’s risk analysis has addressed potential risk factors, such as the escape of susceptible farmed animals (i.e. minks). However, exposure of wildlife animals might have already occurred. Sustained circulation of the virus has been observed in white tail deer in North America and virus variants not present in human populations have been reported in waste waters. Other recent examples of zoonotic pathogens present in bats are Hendra virus, Nipah virus, Ebola virus, West Nile virus, Reoviruses and, importantly, Lyssaviruses (rabies). Changes in land use and increasing anthropization of wild areas have increased the possibilities of contact between humans and bat communities, increasing the transmission of pathogens. Some species of bats have adapted to the urban habitat. COMBAT project will explore virome diversity and population genetics in Italian bat species, assess novel biological and molecular diagnostic platforms, and promote training of young researchers and correct scientific information on bats. COMBAT project assembles the skills and expertise of researchers working in the field of animal infectious diseases, with long-term experience in diagnostics, epidemiology and virus discovery from Italian Universities, and public health bodies (Istituti Zooprofilattici Sperimentali, IZS). Also, to address a critical step of the project, i.e. the collection of biological samples from bats, the project will be supported by the Italian association of chiropterologists (GIRC).