Dog heartworm disease is here to stay: The most important aspects of clinical relevance

Heartworm disease (HWD) is a clinically important parasitic disease of the cardiovascular system in dogs, and is caused by Dirofilaria immitis (D. immitis), which resides in pulmonary arteries. Infected domestic and wild canids as hosts, and mosquitoes as intermediate hosts, are the main reservoirs of D. immitis. Because D. immitis does not reach complete development in humans, HWD is considered to be a disease with zoonotic potential. In addition to its veterinary relevance and zoonotic potential, the disease is distributed worldwide, and thus, a multidisciplinary approach is necessary to control this disease on the global level. The life cycle of D. immitis explains the pathogenesis and clinical signs of HWD in dogs, and determines its diagnosis, therapy and prophylactic measures. In this review, the most important aspects of HWD in canine patients are emphasized: establishment of correct diagnosis of the disease, proper diagnostic procedures for monitoring the clinical condition of an infected dog, different therapeutic protocols and how efficient they are and finally, recommendations for adequate prophylactic measures. Dogs with and without clinical signs of HWD should be tested for both microfilariae and adults of D. immitis at appropriate times. If positive for heartworm, the pathological changes in relevant organs, mainly lungs and heart, should be assessed in the dog. Their extent and severity determine therapeutic protocol. For dogs cured from HWD and non-infected ones, adequate preventive measures should be applied.