Virus survey in populations of two subspecies of bent-winged bats (Miniopterus orianae bassanii and oceanensis) in south-eastern Australia reveals a high prevalence of diverse herpesviruses

Abstract

While bats are often viewed as carriers of infectious disease agents, little research has been conducted on the effects these potential pathogens may have on the bat populations themselves. The southern bent-winged bat (Miniopterus orianae bassanii) is a critically endangered subspecies endemic to south-eastern Australia. Population numbers of this bat have been declining for the past 50 years, but the reasons for this are unclear. As part of a larger study to determine if disease could be a contributing factor to this decline, 351 southern bent-winged bats from four locations were captured, and oral swabs were collected and tested for the presence of potentially pathogenic viruses. Results were compared with those obtained from 116 eastern bent-winged bats (Miniopterus orianae oceanensis) from three different locations. The eastern bent-winged bat is a related but more common and widespread subspecies whose geographical range overlaps partly with southern bent-winged bats. Herpesviruses were detected in bent-winged bats from all seven locations. At least six novel herpesviruses (five betaherpesviruses and one gammaherpesvirus) were identified. The prevalence of herpesvirus infection was higher in eastern bent-winged bats (44%, 51/116), compared to southern bent-winged bats (27%, 95/351), although this varied across the locations and sampling periods. Adenoviruses and a range of different RNA viruses (lyssaviruses, filoviruses, coronaviruses and henipaviruses) were also tested for but not detected. The detected herpesviruses did not appear to be associated with obvious ill health, and may thus not be playing a role in the population decline of the southern bent-winged bat. The detection of multiple novel herpesviruses at a high prevalence of infection is consistent with our understanding of bats as hosts to a rich diversity of viruses.

Viral Diversity of Microbats within the South West Botanical Province of Western Australia

“…This study shows that WA microbat populations host a variety of viral families and sustain multiple viral strains concurrently, in line with other studies [56][57][58][59][60][61]. Our results are in contrast to the only additional Australian initiative to date aiming at characterizing viral diversity in microbats, where only herpesviruses were detected [30]. Difference in the discovery rate between these two studies may be due to the number of species surveyed (two subspecies vs. 11 species) as well as sample type (oral swabs vs. faeces), with oral swabs likely to carry lower levels of viral RNA/DNA, thus decreasing the sensitivity of molecular assays.…”

Two subspecies of bent-winged bats (Miniopterus orianae bassanii and oceanensis) in southern Australia have diverse fungal skin flora but not Pseudogymnoascus destructans

“…destructans are present on bats towards the end of winter, thereby increasing the possibility of detecting the fungus at this time [ 4 , 28 , 29 ]. However, sampling of bats for other diseases [ 30 ] did occur in the middle of summer and early autumn. Therefore, samples collected in January, February and March were tested for dermatophytes and H .…”

“…As part of a larger study, oral swabs were also collected for examination for viruses [ 30 ], blood was collected for haematological and biochemical analyses, and ectoparasites were collected. Following sampling, all bats were released at the point of capture, typically within four to six hours.…”

A large-scale automated radio telemetry network for monitoring movements of terrestrial wildlife in Australia

“…Given the heavy focus of Australian wildlife research on ground-and tree-dwelling animals such as koalas, kangaroos and introduced mammalian herbivores (e.g. deer, pigs, goats) and predators (foxes, cats), and key importance of monitoring zoonotic disease spread (Haynes et al 2009, Vijaykrishna et al 2013, Enchéry & Horvat 2017, Holz et al 2018, Australia seems uniquely placed to drive the expansion of Motus into higher precision spatial estimates of land-bound animals, for example, with large-bodied ones that tend to roam in open habitats or high in tree tops. Detection parameters including station range and probability of detection within range could be estimated by double tagging land animals with GPS collars and coded tags.…”