All 50 states have had confirmed cases of heartworm since the disease’s discovery back in 1856. However, since mosquitoes are responsible for transferring the parasite from dog to dog, some areas do pose a higher risk than others.
According to the American Heartworm Society, Mississippi, Louisiana, Arkansas, Texas and Tennessee are the top five worst states when it comes to heartworm diagnosis, in that order. In fact, in a 2016 AHS Incidence Survey, 10 percent of canines in Mississippi tested positive for the parasite. That’s…a lot.