PATHOLOGY AND MOLECULAR DETECTION OF RABIES VIRUS IN FERRET BADGERS ASSOCIATED WITH A RABIES OUTBREAK IN TAIWAN

Until Rabies virus (RABV) infection in Taiwan ferret badgers (TWFB; Melogale moschata subaurantiaca) was diagnosed in mid-June 2013, Taiwan had been considered rabies free for >50 yr. Although rabies has also been reported in ferret badgers in China, the pathologic changes and distribution of viral antigens of ferret badger–associated rabies have not been described. We performed a comprehensive pathologic study and molecular detection of rabies virus in three necropsied rabid TWFBs and evaluated archival paraffin-embedded tissue blocks of six other TWFBs necropsied during 2004 and 2012. As in other RABV-infected species, the characteristic pathologic changes in TWFBs were nonsuppurative meningoencephalomyelitis, ganglionitis, and the formation of typical intracytoplasmic Negri bodies, with the brain stem most affected. There was also variable spongiform degeneration, primarily in the perikaryon of neurons and neuropil, in the cerebral cortex, thalamus, and brain stem. In nonnervous system tissues, representative lesions included adrenal necrosis and lymphocytic interstitial sialadenitis. Immunohistochemical staining and fluorescent antibody test demonstrated viral antigens in the perikaryon of the neurons and axonal or dendritic processes throughout the nervous tissue and in the macrophages in various tissues. Similar to raccoons (Procyon lotor) and skunks (Mephitidae), the nervous tissue of rabid TWFBs displayed widely dispersed lesions, RABV antigens, and large numbers of Negri bodies. We traced the earliest rabid TWFB case back to 2004.