Immune response in rabies vaccinated stray dogs of Kerala: A preliminary study

Background: The role of stray dogs in the persistence of domestic dog rabies and whether removal of such dog is beneficial remains contentious issues for control programs seeking to eliminate rabies. Though rabies immunization of stray dogs is an important component of government sponsored stray dog control programs, vaccine coverage and efficacy are largely unknown. Objective: This study aimed to determine herd immunity in vaccinated stray dogs of Kerala, a southern state of India by estimating the level of antibody in a random vaccinated population. Methodology: The study was conducted in stray dogs captured for government sponsored Animal Birth Control (ABC) program. Animals were vaccinated against rabies. Dogs selected randomly were bled after one month of vaccination. Rabies antibody level was measured by Indirect ELISA. Results: The study revealed that 70% of dogs showed minimum required protective titer (≥0.5IU/ml) at one month post vaccination. However, strong immune response could not be detected in a major proportion of vaccinated dogs even at one month post vaccination and hence unlikely that sufficient titre would be maintained for one year, a matter of concern in endemic areas.