28.3 Diagnosis

Any patient having a history of animal bite should be suspected for rabies. Differential diagnosis with West Nile virus, herpesvirus, enterovirus is required. History and clinical symptoms like encephalitis, salivation, etc provide concrete support for rabies. Besides this, Negri bodies in the neurons of affected animals can be visualized using Seller's stain. RT-PCR assay can be conducted to test for the presence of viral RNA in the brain of suspected animal. RT-PCR of saliva can also be carried out. Immuno-histochemical staining can also be done from frozen sections of brain tissue. Fluorescent antibody test can also be done for the detection of viral antigens from the tissue samples.

 

28.4 Immunity, prevention and control

Rabies is a highly immunogenic disease and many vaccines are available for the same. In early stages of infection, infectious rabies virus is susceptible to antibody mediated neutralization and this efficacy has been proved in exposed humans of the classical Pasteurian post- exposure vaccination and it provides even better results when administered along with hyper-immune globulin.

Blood brain barrier shows promising results when its permeability is increased artificially as it helps in viral clearance and does not allow most immune cells across. Thus altering the permeability of blood brain barrier to contribute to viral clearance can also be exploited in case of Rabies.

Besides this, prophylactic measures should be taken like scheduled vaccination, washing the wounds with soap for 5 to 10 times while treating the infected cases and regular spaying of the animals can prevent the disease.