Heartworm (Dirofiliaria immitis) is a parasite, spread by mosquitoes. Infected dogs have microfilariae, an immature form of heartworm, circulating in their bloodstream. Microfilariae are sucked up by mosquitoes when feeding on the blood of infected dogs. The parasites develop into heartworm larva inside the mosquito and a single bite from a carrier mosquito can infect … Continue reading Heartworm