The aetiology of wobbly possum disease: Reproduction of the disease with purified nidovirus

•Experimental reproduction of wobbly possum disease (WPD).•Three types of infectious inocula used, including the purified nidovirus isolate.•WPD diagnosed in 11/12 infected possums based on clinical signs and histopathology.•High levels of viral RNA in tissues of WPD-affected possums, but not in controls.•Our data support aetiological involvement of novel possum nidovirus in WPD.

The objective of this study was to investigate a role of a recently discovered marsupial nidovirus in the development of a neurological disease, termed wobbly possum disease (WPD), in the Australian brushtail possum (Trichosurus vulpecula). Four possums received 1 mL of a standard inoculum that had been prepared from tissues of WPD-affected possums, 4 possums received 1.8 mL (1×106 TCID50) of a cell lysate from inoculated cultures, and 4 possums received 1 mL (×107 TCID50) of a purified WPD isolate. All but one possum that received infectious inocula developed neurological disease and histopathological lesions characteristic for WPD. High levels of viral RNA were detected in livers from all possums that received infectious inocula, but not from control possums. Altogether, our data provide strong experimental evidence for the causative involvement of WPD virus in development of a neurological disease in infected animals.