Porcine astrovirus 3 RNA in the central nervous system of weaned pigs with neurologic disease and polioencephalomyelitis in Brazil.

This report aims to describe the identification of porcine astrovirus 3 (PAstV3) RNA in the central nervous system (CNS) of weaned pigs with clinical signs of neurological disease associated with polioencephalomyelitis in southeastern Brazil. Three, 20 -35 days-old piglets that died after clinical manifestations of a neurological syndrome were submitted to post-mortem evaluations. Tissue samples were examined by histopathology, bacteriology, and molecular assays (RT-PCR, nested-PCR, RT-qPCR, and Sanger sequencing) to detect the primary infectious disease agents associated with neurological disease in pigs. The principal neuropathological alterations occurred in the grey matter of the spinal cord and brainstem resulting in nonsuppurative poliomyelitis and rhombencephalitis. PAstV3 RNA was detected in the CNS samples of all piglets with histopathological evidence of disease and was confirmed by nucleotide sequencing. Nucleic acids from pathogens commonly associated with neurological diseases in pigs, such as porcine teschovirus, porcine sapelovirus, porcine enterovirus G, atypical porcine pestivirus, senecavirus A, and encephalomyocarditis virus was not detected by molecular assays in the three piglets. This is the first report of PAstV3 in piglets with neurological disease and lesions consistent with polioencephalomyelitis in Brazil. This report highlights the importance of monitoring health events that could compromise pig farming productivity and animal welfare.