Bats as hosts of zoonotic pathogens : potential conflicts between nature conservation and public health

Abstract: Bats belong to the order Chiroptera, one of the most species rich mammalian groups of Sweden, but it is also the most threatened one. Nineteen different bat species have been found in Sweden, of which 12 are red-listed. Globally rodents and bats are the animal groups known to host most zoonotic pathogens. Bats are known to carry rabies, even though there has been no discovery of cases in Sweden where humans have been infected. Bats in Sweden have previously been found to carry rabies specific antibodies, thus indicating that rabies is circulating among the Swedish bat populations. Various hantaviruses have been found in insectivorous bats, however in Sweden so far only rodents are identified hosts. In Sweden, the knowledge of pathogens hosted by bats is generally low. Thus, the aim of this study was to explore and answer the following three questions: (I) To which extent are Swedish bats, focusing on the Daubenton’s bat, reservoirs of zoonotic pathogens? (II) Do bats in Sweden host puumala orthohantavirus (PUUV)? (III) If bats host zoonotic pathogens, is there a conflict between nature conservation and public health? In this study, bats were trapped using mist nets mounted perpendicular to small streams in summer 2020. Blood, saliva and feces were sampled from 77 bats and tested for lyssavirus, flavivirus and Puumala orthohantavirus using PCR (polymerase chain reaction) techniques, sequencing, IFA and ELISA. Bats were found to host flavivirus and lyssavirus, but no hantaviruses. However, further tests are necessary to determine what kind of lyssavirus and flavivirus they carry. Furthermore, more tests are necessary to conclude if Swedish bats carry PUUV or not as the results were unclear. Conclusively, Bats living close to humans may bring some potential risks to human health. However, evicting, or culling bats may increase the transmission risk of the zoonotic disease’s bats host. Bats in Sweden are protected by law; thus, people should focus on measures to mitigate transmission risk without harming bats. Furthermore, bats provide ecosystem services benefiting human health, for example by preying on mosquitoes and hence suppressing other potential vector-borne diseases. Hence, bat conservation and public health may have a common goal.