How can we Diagnose Rabies?
Diagnosis is made by rabies specific signs as there are no specific tests to detect the rabies virus before the actual onset of the clinical disease.
Diagnosis of rabies is generally made based on the presence of rabies-specific signs like hydrophobia and aerophobia. No specific tests are available to detect the rabies virus before the actual onset of the clinical disease.
The suspected rabid animal should be observed for a duration of up to 10 days following a bite. If the animal is alive till this time, then it is unlikely that it suffers from rabies.
The direct fluorescent antibody test (dfa) is most frequently used to diagnose rabies in animals. This test can be performed on brain tissue of dead animals suspected of being rabid. Specific collections of particles called Negri bodies are seen on microscopic examination of brain tissue.
This same test can be used to check for rabies infection in humans by using a piece of skin from the neck.
Isolation of the virus from saliva or spinal fluid of the patient can also be done. Specific antibodies produced by the body against the virus can be highlighted in the salivary secretions. However, these tests are not as sensitive and the diagnosis should be confirmed on a suspected animal by examining its brain a under microscope for changes related to rabies.