Bats are considered a major source for future viral epidemics, as they are associated with several viruses with zoonotic potential. We herewith describe the high presence and biodiversity of bats associated to intensive pig farms for the production of heavy pigs in Northern Italy. Since chiropters or their signs of presence were not found within animal shelters in our study area, we investigated the circulation of fecal viruses with high environmental resistance, such as Mammalian Orthoreoviruses (MRVs), coronaviruses (CoVs) and astroviruses (AstVs) in both pigs and bats. Results of our preliminary study did not show any bat virus in pigs suggesting that spillover from these animals is rare. However, several AstVs, CoVs and MRVs circulated undetected. Among those, one MRV circulating in pigs was a reassortant strain with viral genes associated to bats.
On the other hand, we found a swine AstV and MRV genes associated to pigs in bat guano, indicating that viral exchange at the bat-pig interface might rather occur more frequently from pigs to bats than the other way around. Considering the indoor farming system as the most common system in the EU, preventive measures should be focused on biosecurity rather than displacement of bats, which are all protected in EU and provide critical ecosystem services for rural setting. Less...