Dirofilaria Immitis: A Zoonoses Present on a Global Level

Abstract

The Dirofilaria immitis or heartworm is a worldwide distribution disease spread by mosquitoes of the Aedes, Anopheles, Culex and Taeniorhynchus kind; in humans, this filaria causes skin and lung lesions, though some cases of human dirofilariasis have already been reported with different locations, such as large mesenteric vessels, peritoneal vessels, the spermatic cord and even the right side of the heart. Unlike in dogs, there is no filaremia in humans. The most common symptoms are: retrosternal pain, coughing and hemoptysis. A fibrotic nodule (with a diameter from one to three centimeters) is often asymptomatic and can only be identified in chest X-rays as a coin-shaped lesion. Around fifty cases have been reported in humans in the United States, although cases have also been reported in Japan, Asia, Australia, Brazil and Argentina. A research was carried out at La Salle University in order to determine the frequency with which Dirofilaria immitis occurs in dogs in Bogotá D.C. (2600 meters over sea level) through the Elisa Petchek® enzyme test, which is specific and does not show any crossed reactions with other parasites, thus providing a quick and accurate diagnosis of the disease. A frequency of 1% was found of dogs that came out positive with Dirofilaria immitis. Considering that the dog population in this city is of approximately 8000 the possible number of animals that would come out positive for the parasite would be of around 8,000 dogs, which could potentially spread the disease to humans through a mosquito bite. The number of dogs exposed to the heartworm disease in the world is increasing, and due to the fact that dirofilaria is rarely seen in humans, its prevention depends largely on the reduction of the disease’s prevalence in dogs, since, even in Colombia specific antibodies were detected against the antigens of the adult Dirofilariaimmitis worms complex in individuals from an isolated Tikuna community in the Colombian Amazon.