Feline panleukopenia is a serious and contagious disease of cats caused by a parvovirus (FPV). In neonatal kittens, it can attack part of the brain causing severe congenital abnormalities. In this study, the necropsy and histopathological analyses of a series of 28 cats that died from parvovirus infection in 2013 were performed. Infections were confirmed by real-time PCR and immunohistochemistry in several organs.

Strikingly, while none of these cats showed cerebellar atrophy or cerebellar positive immunostaining, some of them, including one adult, showed a bright positive immunostaining for viral antigens in cerebral neurons (diencephalon). Sequencing and PCR analyses showed that the virus infecting cat brains was FPV and presented a unique mutation in a viral protein important in the virus’ replication. Given the role played by this protein in the control of cell cycle and apoptosis in other parvoviral species, it is tempting to hypothesize that a cause-to-effect between this NS1 mutation and the capacity of this FPV strain to infect neurons in adult cats might exist. This study provides the first evidence of infection of cerebral neurons by feline panleukopenia virus in cats, including an adult. Further research is needed to clarify the impact of this capacity. (MK)