Can humans get Heartworm? Yes…and No.

Human pulmonary dirofilariasis is caused by the transmission of infective third stage larvae of the canine heartworm, Dirofilaria immitis, during blood-feeding by several species of infected mosquitoes.

One of the most common concerns pet owners have is whether they can contract heartworms directly from an infected dog. The answer is no. Heartworms are not contagious between pets and people. You cannot get heartworms through contact with your dog, their saliva, waste, or blood. The only way either a dog or a human can become infected is through the bite of a mosquito carrying infective larvae. This means that keeping your dog on heartworm prevention protects them from mosquito-transmitted infection, but it does not put you at risk of catching heartworms from them.

Since humans are not primary hosts and cannot support the parasite’s life cycle, infective larvae die after migrating to the pulmonary vascular bed, where an initial sub-clinical inflammatory reaction is typically followed by a single pulmonary granuloma.

The resulting nodular granuloma is described radiographically as a “coin lesion” that resembles a neoplastic lesion, which must be ruled out by invasive lung biopsy.

Dr. Sarah Kalivoda
Mountain View Animal Hospital & Holistic Pet Care
Reno, Nevada
775-853-6900