Canine dirofilariosis caused by Dirofilaria immitis is a risk factor for the human population on the island of Gran Canaria, Canary Islands, Spain.

The aim of the present study was compare the prevalence of D. immitis in dogs and seroprevalence in humans of Gran Canaria (Canary Islands, Spain) taking into consideration the four isoclimatic areas of the island. A close relationship between the prevalence of Dirofilaria immitis in dogs and the seroprevalence in humans, in each isoclimatic area, was observed. The highest seroprevalence of infection in both canine and human hosts were found in a strip of mid-range altitude with 25.47% and 30.4% in dogs and 25.66% and 29.73% in humans, respectively. The coastal zone and the highest part of the island have prevalences significantly lower. These results demonstrate that the risk of infection by D. immitis in the human population in each area is tied to the prevalence in the canine population. Physicians should be alerted to the possibility of finding cases of human pulmonary dirofilariosis amongst the inhabitants of the island.