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

Abstract

Bats are known reservoirs of a wide variety of viruses that rarely result in overt clinical disease in the bat host. However, anthropogenic influences on the landscape and climate can change species assemblages and interactions, as well as undermine host-resilience. The cumulative result is a disturbance of bat-pathogen dynamics, which facilitate spillover events to sympatric species, and may threaten bat communities already facing synergistic stressors through ecological change. Therefore, characterisation of viral pathogens in bat communities provides important basal information to monitor and predict the emergence of diseases relevant to conservation and public health. This study used targeted molecular techniques, serological assays and next generation sequencing to characterise adenoviruses, coronaviruses and paramyxoviruses from 11 species of insectivorous bats within the South West Botanical Province of Western Australia. Phylogenetic analysis indicated complex ecological interactions including virus-host associations, cross-species infections, and multiple viral strains circulating concurrently within selected bat populations. Additionally, we describe the entire coding sequences for five alphacoronaviruses (representing four putative new species), and one novel adenovirus. Results indicate that viral burden (both prevalence and richness) is not homogeneous among species, with Chalinolobus gouldii identified as a key epidemiological element within the studied communities.

Coronaviruses and Australian bats: a review in the midst of a pandemic

“…Similarly, cross-infections were also detected in south-west Western Australian bat communities, with tree hollows proposed as a source of transmission between sympatric bat species (Prada et al 2019). One alphacoronavirus strain detected in Chalinolobus gouldii had a spike protein with a higher sequence similarity to the coronavirus that causes Porcine Endemic Diarrhoea in pigs (Jung and Saif 2015) than to any other virus of bat origin (Prada et al 2019). Since the spike protein determines host tropism, the ability of the spike protein to enter mammalian cells other than bat cells is currently under investigation (Haynes et al, unpubl.…”

“…Coronavirus diversity and antibody prevalence in Australian bats is known from two cross-sectional studies on bat faeces or rectal swabs, encompassing 35 Australian bat species across 17 genera and 8 families (Smith et al 2016;Prada et al 2019) (Table 1, Fig. 2).…”

“…Based on PCR amplification and sequencing of a 396-440 bp fragment of the RNA-dependent RNA polymerase (RdRp) gene, Smith et al (2016) and Prada et al (2019) detected two betacoronaviruses (exclusively from pteropodiformes) and seven alphacoronaviruses (mainly from vespertilionid bats) across 15 Australian bat species. Full genome sequences from four of the seven alphaviruses amplified from host species have been subsequently obtained and made publicly available (Prada et al 2019). To date, there is no evidence of any SARS-like viruses (Sarbecoviruses) or MERS-like viruses (Merbecoviruses) in any Australian bat species, though cross-reactive antibodies have been detected (Smith et al 2016;W.…”

“…These data are indicative of a crossinfection event from the vespertilionid bat M. australis into the pteropodiforme R. megaphyllus and warrant further investigation. Similarly, cross-infections were also detected in south-west Western Australian bat communities, with tree hollows proposed as a source of transmission between sympatric bat species (Prada et al 2019). One alphacoronavirus strain detected in Chalinolobus gouldii had a spike protein with a higher sequence similarity to the coronavirus that causes Porcine Endemic Diarrhoea in pigs (Jung and Saif 2015) than to any other virus of bat origin (Prada et al 2019).…”

“…Moran et al 2009) are often overshadowed in public perception by their potential to act as reservoirs of zoonotic viruses, such as Hendra virus, Australian bat lyssavirus and Menangle virus. Most research on bat-borne viruses in Australia (~200 papers to date) has focussed on these pathogens, with only three coronavirus surveillance studies (Smith et al 2016;Holz et al 2018;Prada et al 2019). Even though none of Australia's bat species have distributions overlapping with species that are known hosts of SARS-related viruses, most of the chiropteran genera in which zoonoticrelated coronaviruses have been detected in China and elsewhere are represented in Australia (e.g.…”