The Role of the Gray Wolf in Rabies Transmission in Iran and Preliminary Assessment of an Oral Rabies Vaccine in this Animal

Introduction: In Iran, 95% of animal bites are attributed to domestic dogs and cats, while one-third of rabies victims are from wildlife. The wolf is one of the primary vectors of wildlife in the country. This study was aimed to assess the impact of wildlife on rabies transmission and to evaluate the efficacy of an oral rabies vaccine (ORV) in the gray wolf (Canis lupus pallipes). Methods: We studied the incidence of wolf attacks by analyzing a 10-year period of data (2000 to 2009) available in the Ministry of Health and Medical Education, the Veterinary Organization and Pasteur Institute of Iran. In the next step, five captive gray wolves were fed by Raboral V-RG® vaccine baits (Merial®, part of Boehringer Ingelheim, Germany) and monitored for rabies neutralizing antibodies over 20 months by rapid fluorescent focus inhibition test (RFFIT). Results: Our analysis showed that 55% of animal bites occurred in rural areas and the remaining in urban areas. The most rabid wolves were from Fars province in southern Iran. The vaccine baits were palatable for the hungry wolves. Seroconversion with antibodies titers ≥0.5 IU/ml occurred after 12 weeks and maintained for 78 weeks indicating potential protection against rabies after receiving a single ORV bait. Conclusion: Our results suggested that a single dose of vaccination with V-RG®, though initially designed for foxes and raccoons, can protect the gray wolf against rabies as well.