Is heartworm common among dogs in India, and is it necessary to get dogs vaccinated against it?
The only way dogs get heartworm is through an infected mosquito and India has a lot of mosquitos and you cannot tell if a mosquito is an infected carrier, same problem with mosquitos and dengue fever. So, as a general statement, the risk of heartworm would be quite high and the best way to deal with heartworm is to stop it before it happens, so vaccination would be a very good idea because curing after the fact is quite hard (and much more expensive).
1It's important for a dog to be on heartworm preventative like Sentinel or Trifexis year-round regardless of where you live, but even more important in areas with lots of mosquitos. There is currently no vaccine (like there is for rabies) according to the American Heartworm Society, but there are a variety of prevention methods. Jul 31, 2014 at 13:49