An outbreak of Fusobacterium necrophorum associated foot rot in a herd of four-horned antelope (Tetracerus quadricornis) in India

An outbreak of contagious foot rot due to Fusobacterium necrophorum infection was reported in a herd of four-horned antelopes (Tetracerus quadricornis) in a wildlife sanctuary at Goa, India. The infected animals showed signs of anorexia, limping and foot lesions, like erosions and sloughing of hooves. Mortality was recorded in two antelopes in which gross lesions, like generalized congestion of skeletal muscles and internal organs, and multi-focal to coalescing abscesses in lung, pleura, and diaphragm were observed. Histopathological evaluation of interdigital skin showed zones of coagulative necrosis, infiltration of mononuclear inflammatory cells, congestion, hemorrhage, and thrombosis in the dermis. Lung showed extensive areas of consolidation with alveolar edema, hyperemic alveolar capillaries, hemorrhage, and infiltration of inflammatory cells. The bacterial culture from heart blood, lung, liver, and kidney tissues revealed isolation of F. necrophorum being also confirmed by polymerase chain reaction (PCR) using amplification of lktA gene of F. necrophorum. In addition, the PCR also confirmed the presence of F. necrophorum DNA in the interdigital skin, lung, and liver tissues. Phylogenetic analysis showed that the F. necrophorum isolate from the present study grouped closely with isolates from Australia, China, Pakistan, and Iraq, as well as an Indian isolate from goat. The affected live animals were treated with oral antibiotics, anti-inflammatory medicines, and vitamin supplements for seven days, and recovered. This study confirmed the first outbreak of contagious foot rot and systemic infection with F. necrophorum in a herd of four-horned antelopes in India.