The prevalence of Dirofilaria immitis in Gran Canaria, Canary Islands, Spain (1994-1996).

Blood samples from 2034 dogs were tested to detect Dirofilaria immitis antigen during three consecutive years (from 1994 to 1996) in Gran Canaria Island, Canary Islands, Spain. The prevalence of heartworm infection was 67.02% in 1994, 58.92% in 1995 and 52.18% in 1996, with a mean prevalence of 58.89%. Heartworm infection was more common in males (56.19%) than in females (43.81 %), in dogs aged between 3 and 6 years old. The distribution of the disease in the different climatic zones was studied. Chronological changes in the dog's prevalence for heartworm infection in the three consecutive years and the role of the epidemiological factors in the changes of the positive rates were evaluated.