Scientists have found the first evidence of rabies infections in Indian bats highlighting the need for a bat-bite vaccine for humans. More than the third of all rabies deaths in the world occur in India, mostly from dog bites. About 20,000 people die of rabies in the country every year. Even though transmission of the disease and death is preventable, India has a dismal vaccine coverage rate of its canine population of just 15%.
Now, a new threat of rabies transmission might come from bats. Bats are known to by reservoirs of lyssaviruses, a group of RNA viruses that includes the rabies virus. There has been no evidence of lyssaviruses in Indian bats, until now.
Researchers from the National Centre for Biological Sciences and the National Institute of Mental Health and Neurosciences in Bengaluru carried out surveillance for the rabies virus among bats in Nagaland, s state which witnesses a lot of human-bat interaction especially during the harvest season. The team tested for evidence of infection by checking bat brain tissues for the rabies virus antigen and presence of the viral RNA and by checking bat blood sera for rabies-neutralising antibodies. Although the brain tissue showed no presence of the antigen or RNA, about five percent of blood samples showed the presence of antibodies against the rabies virus. This suggests that the bats had been exposed to the rabies virus or a related lyssavirus.
The researchers say that the findings are still preliminary and the focus of rabies interventions should still be on controlling its spread through dogs that account for 99% of cases. However, the study has important implications for disease transmission and rabies control measures and warrants more detailed surveillance of bat populations.
The study was published in the journal Epidemiology and Infection.