Serological Detection of Anti Rabies Virus Antibodies in Dogs and Its Implications to the Vaccination Schedules

This study was undertaken to determine the anti rabies virus antibody (ARVA) levels achieved by parenteral anti rabies vaccination in dogs. Quantitative detection of ARVA in the serum samples of vaccinated (n=102) and unvaccinated (n=14) dogs belonging to six age groups, viz., <3 months, 3-6 months, 6-12 months, 1-2 years, 2-3 years and >3 years was carried out by employing an indirect immunoenzymatic technique. Although, all the vaccinated dogs showed satisfactory levels (= 0.6 IU/ml) of ARVA (mean: 3.1 IU/ml, range: 0.6-13.6 IU/ml), the unvaccinated dogs did not possess adequate antibody levels (mean: 0.41 IU/ml, range: 0.13-0.59 IU/ml) to protect them from the disease. There was no significant (p>0.05) difference in the antibody responses between the male and female dogs. Antibodies which appear to be of maternal origin found in the unvaccinated puppies under 3 months of age were also inadequate (mean: 0.47 IU/ml, range: 0.3-0.59 IU/ml). On the contrary, puppies which had been vaccinated before 3 months possessed adequate levels (mean: 0.79 IU/ml, range: 0.66-1.2 IU/ml) of ARVA. However, their ARVA levels were significantly (p>0.05) lower than those of the dogs vaccinated after 3 months of age. The ARVA levels of the unvaccinated dogs of 3-6 months (mean: 0.16 IU/ml, range: 0.130.18 IU/ml) were significantly (p<0.05) lower than those of the unvaccinated puppies under 3 months. The adult dogs over 3 years and vaccinated = 3 times against rabies showed the highest levels (mean: 8.2 IU/ml, range: 3.5-13.6 IU/ml) of ARVA. The present findings indicate that although there is a high individual variation in the levels of humoral response, the pre-exposure parenteral vaccination is an effective prophylaxis against rabies in dogs. Furthermore, puppies below 3 months should also be included in vaccination schedules and they be given a booster vaccination at 3 months of age to achieve a long lasting protection from the disease.