The American Heartworm Society (AHS) has released a 2025 Heartworm Incidence Map, showing areas where heartworm rates are highest in the United States. The survey, conducted every three years, uses data submitted by shelters and veterinarians who ran heartworm antigen tests the previous year. Texas was the highest state with the highest number of heartworm cases, and this is the first time Texas has been at the top of the list for heartworm incidence. The highest heartworm rate was found in the southeast and Gulf Coast, which have been known as high rates in the past. The map is available online to compare it to previous years.