Gammaretroviruses, novel viruses and pathogenic bacteria in Australian bats with neurological signs, pneumonia and skin lesions

Abstract

ABSTRACTMore than 70 bat species are found in mainland Australia, including five species of megabat from a single genus (family Pteropodidae) and more than 65 species representing six families of microbats. The conservation status of these animals varies from least concern to endangered. Research directed at evaluating the impact of microorganisms on bat health has been generally restricted to surveillance for specific pathogens. While most of the current bat virome studies focus on sampling apparently healthy individuals, little is known about the infectome of diseased bats. We performed traditional diagnostic techniques and metatranscriptomic sequencing on tissue samples from 43 individual bats, comprising three flying fox and two microbat species experiencing a range of disease syndromes, including mass mortality, neurological signs, pneumonia and skin lesions. We identified reads from four pathogenic bacteria and two pathogenic fungi, includingPseudomonas aeruginosain lung samples from flying foxes with peracute pneumonia, and with dermatitis. Of note, we identified the recently discovered Hervey pteropid gammaretrovirus, with evidence of replication consistent with an exogenous virus, in a bat with lymphoid leukemia. In addition, one novel picornavirus, at least three novel astroviruses and bat pegiviruses were identified. We suggest that the most likely cause of peracute lung disease wasPseudomonas aeruginosa, while we suspect Hervey pteropid gammaretrovirus was associated with lymphoid leukemia. It is possible that any of the novel astroviruses could have contributed to the presentation of skin lesions in individual microbats. This study highlights the importance of studying the role of microorganisms in bat health and conservation.IMPORTANCEBats have been implicated as reservoir hosts for zoonotic disease of concern, however, the burden of microorganism including viruses on bat health and disease is understudied. Here we incorporated veterinary diagnostics and RNA sequencing to identify the presence of microbes and viruses with possible pathogenic status in Australian bats with varying disease presentations. These techniques were able to effectively identify and describe several pathogenic species of bacteria and fungi in addition to known and novel viruses. This study emphasises the importance of screening pathogens in cases of bat mortality for the conservation of this diverse order.