Post-mortem testing remains the gold standard for diagnosing rabies in dogs, as it provides definitive results by detecting the presence of the rabies virus in brain tissue.
The primary method for rabies diagnosis is the direct fluorescent antibody test (DFA), recognized by the World Health Organization (WHO) and the World Organisation for Animal Health (WOAH). DFA is highly sensitive and specific, enabling the detection of viral antigens in infected tissue. In addition to the DFA test, other confirmatory tests, such as reverse transcription polymerase chain reaction (RT-PCR) and histopathological examination, may be used. RT-PCR detects rabies virus RNA, providing rapid and accurate results, even in partially degraded samples. Histopathology can reveal the presence of Negri bodies—distinctive viral inclusions in neurons—though this method is less sensitive than DFA or molecular techniques.
Lateral flow assays (LFAs) have been developed in recent years to provide rabies testing potential at the time of necropsy. Low sensitivity and specificity and batch-to-batch variation have been identified as concerns in their use for rabies diagnosis, however many programs have found them to be a useful research tool in resource limited settings.
Proper sample collection and handling are critical for reliable diagnosis. The recommended tissues include the brainstem, hippocampus, and cerebellum. These should be collected aseptically and transported under appropriate conditions to ensure test accuracy.
Post-mortem rabies testing plays a vital role in protecting public health, confirming whether a potentially exposed person requires post-exposure prophylaxis (PEP). It also supports surveillance efforts, helping to monitor and control the spread of the disease in dog populations. Understanding the diagnostic process enhances awareness of the importance of timely and accurate rabies testing in safeguarding both animal and human health.