Signs and diagnosis challenges of rabies in a 40-day-old calf

Abstract

Rabies is a devastating zoonotic disease affecting all warm-blooded animals and humans. Although dogs are commonly recognized as primary transmitters of rabies in India, ruminants also significantly contribute as hosts within livestock populations. This study aimed to highlight the critical issues surrounding bovine rabies and propose practical strategies for documenting and managing it in resource-limited settings. A 40-day-old female Kangeyam calf presented with symptoms including aggressive behaviour, refusal to eat or drink and frequent bellowing. Clinical examination revealed hypersalivation, erected ears, extended neck, heightened alertness, hyperesthesia to sound, diarrhoea and straining. No external wounds were observed and there were no recent reports of dog bites. However, an epidemiological investigation indicated a semi-intensive rearing system and noted a previous history of dog bites on the farm. Based on history, clinical observation and epidemiological investigation, rabies was suspected. Saliva samples were collected from the suspected calf and its dam and subjected to real-time RT-PCR based on SYBR Green chemistry, confirming the presence of viral RNA in the calf and its absence in the cow. This farm investigation underscores the importance of timely bovine rabies diagnosis for safeguarding veterinarians and animal owners. It underscores the vital role of clinical diagnosis in resource-limited settings, where advanced diagnostic tools are often lacking, emphasizing the need for timely identification of rabies cases through clinical observations.