Protect Your Family Heartworm Dogs, cats and even humans are susceptible to heartworm. Mosquitoes are present year-round in Flagler County, with a total of 48 species, 11 of which are capable of transmitting heartworm. To transmit heartworm the mosquito must first become infected itself, so mosquito control monitors the population of mosquitoes and applies pesticides as needed to keep the population low and break the transmission cycle of heartworm disease. Summary: Each year thousands of dogs become disabled or die from lung, heart, or circulatory problems caused by heartworm disease. The danger of infection is greatest during the summer when temperatures are favorable for mosquito breeding. In the southern United States, especially the Gulf Coast and Florida, where mosquitoes are present year-round, the threat of heartworm disease is constant. 48 species of mosquitoes call Flagler County Home, 11 of which are capable of transmitting heartworm. Infective larvae are concentrated in the proboscis, or mouthparts, of the mosquito. As the infected mosquito feeds on a dog, the infective larvae emerge from the tip of the proboscis and onto the skin of the animal. The mosquito must first be infected to transmit any disease. A drop of mosquito blood protects the larvae from drying prior to their entry into the host. Heartworm disease in cats is less frequent than in dogs. Cats are susceptible, but appear to be more resistant than dogs. Heartworm is also an occasional parasite of humans. The parasite is usually found in the lung (pulmonary dirofilariasis), and less often in the heart. Although the worm forms a “coin lesion” in the lung, which may be confused with other diseases on x-rays, such as carcinoma, its clinical significance in man has not been fully determined. During the last 40 years about 100 cases of human pulmonary dirofilariasis have been reported from Florida. Mosquito control in residential areas where dogs and cats live can break the transmission cycle of heartworm disease by monitoring the population of mosquitoes and applying pesticides as needed to keep the population low.