Detection of Breinlia sp. (Nematoda) in the Leadbeater's possum (Gymnobelideus leadbeateri)

The Leadbeater's possum (Gymnobelideus leadbeateri) is a critically endangered marsupial in south-eastern Australia. Among other conservation efforts, free-ranging animals in the two remaining geographically separate populations (highland and lowland) have been extensively studied; however, little is known about their health and mortality. Although some wild populations are frequently monitored, cadavers are rarely recovered for post mortem examination. In June 2019, a recently deceased, wild, adult male lowland Leadbeater's possum was collected from a nest box and a comprehensive post mortem examination was conducted. Microfilariae of a filarioid nematode were observed in testes, liver, lung and skin samples in tissue impression smears and upon histopathological examination. No gross or histological changes were seen associated with the parasites, except for a focal area of tissue damage in the skin, suggesting that the possum is a natural host. Using a PCR-coupled sequencing method the filarioid was identified as a species of Breinlia. Species of Breinlia occur in other Australian marsupials and rodents.