Evaluation of Bait Acceptance and Immune Response in a Local Dog Population During an Oral Rabies Vaccination Field Study in Cambodia.

(1) Background: Dog-mediated human rabies remains a serious public health problem in Cambodia, partially due to the high abundance of dogs. As most dogs are free-roaming and cannot easily be handled and restrained, the rabies vaccination coverage is very low. Oral rabies vaccination (ORV) could increase the vaccination coverage to levels required for interrupting the transmission cycle. (2) Methods: In this study, the bait acceptance and immunogenicity of a commercially available vaccine bait were tested in local free-roaming dogs in the northern part of Takeo province in Cambodia. (3) Results: In total, 75.4% (515/683) of dogs initially showed interest when offered an egg-flavored bait containing the SPBN GASGAS rabies virus vaccine. Subsequently, 89.9% of these dogs consumed the bait, and almost all of them (98.3%) were considered successfully vaccinated. Blood samples were collected from 50 dogs prior to vaccination. Eight of these fifty dogs tested sero-positive for rabies antibodies (ELISA) and were excluded from follow-up samples. Thirty and ninety days post-vaccination, 91.4% and 68.2% of the relocated vaccinated dogs tested sero-positive, respectively. (4) Conclusions: Bait acceptance and immunogenicity showed similar results as observed in studies with the same vaccine bait conducted in other countries. Hence, ORV seems to be a very promising tool for dog rabies control in Cambodia, which has a large owned but free-roaming dog population.