Suppurative Meningitis and Acute Necrotizing Pneumonia in a Japanese Black Calf Due to Mannheimia varigena Infection

Abstract

A normally born Japanese black calf showed astasia and subsequently died 4 days after birth. Mannheimia spp. were isolated from the brain, lungs, kidneys, and spleen by bacteriological examination. Although the isolate was initially classified as M. haemolytica, it was later classified as M. varigena (M.v) via 16S ribosomal RNA gene sequencing. Histopathological examination revealed suppurative meningitis, suppurative uveitis, and acute necrotizing pneumonia. M.v-immunopositive antigens were detected in the brain, eyeballs, and lungs via immunohistochemical analysis. M.v was isolated also from the dam of the dead calf and was considered the source of infection. Further investigations are needed to establish the virulence and carriers of M.v.