Pulmonary lesions associated with the presence of adiaspores apparently produced by a novel Emmonsiellopsis genotype in wombats

Abstract

Australia is home to bare-nosed, northern hairy-nosed and southern hairy-nosed wombats. Adiaspores have been noted in the lungs of all 3 species and severe pneumonia has been characterized in 2 northern hairy-nosed wombats associated with intralesional adiaspores produced by a novel Emmonsiellopsis species. Similar organisms have been observed in the lungs of bare-nosed and southern hairy-nosed wombats. In the current report, DNA amplification and sequencing demonstrated that an adiaspore producing fungus in 3 bare-nosed wombats is a genetic variant or sister species to the Emmonsiellopsis sp. found in the northern hairy-nosed wombat. Thirty-two lung sections were evaluated for 7 histopathological parameters and adiaspores were counted in a 2.37 µm² randomly chosen area. Fisher’s exact tests, relative risk, and absolute risk were calculated to determine if there was a correlation between adiaspores and an inflammatory response. Adiaspores were observed in samples from most wild wombats and were rare in captive wombats. Wombats with adiaspores were 3.53 times more likely to have interstitial pneumonia compared to wombats without adiaspores. The severity of pneumonia varied from mild to marked. However, the impact of pneumonia appeared to be minimal, as wombats were in good condition, except for wombats with mange. Therefore, the presence of adiaspores in wombats and associated inflammatory responses are usually considered an incidental finding. Further studies to determine the pathogenicity and clinical significance of the Emmonsiellopsis spp. in wombats and their prevalence across a wider portion of wombats’ range may provide information on their impact on wombat populations.