PATHOLOGY

Detailed explanation-1: -The microfilariae develop further for 10 to 30 days in the mosquito’s gut and then enter its mouthparts. At this stage, they are infective larvae and can complete their maturation when they enter a dog. The infective larvae enter the dog’s body when the mosquito bites the dog.

Detailed explanation-2: -Inside your pet’s pulmonary artery, the female heartworms give birth to tiny larvae (L1) called microfilariae. How long does it take heartworm larvae to reach adulthood? Once inside a pet, the L3 larvae molt into L4 larvae in seven to 14 days, then to L5 larvae in 45 to 60 days.

Detailed explanation-3: -Heartworm microfilariae are first stage larvae: L1s. Note: Ivermectin, and milbemycin based heartworm preventives will kill microfilariae after prolonged use. Dogs on these heartworm preventives, even if infected with adult heartworms, will not test positive for microfilariae.

Detailed explanation-4: -The heartworm life cycle has five larval stages (L1 through L5; FIGURE 2 ). Adult heartworms typically live in the pulmonary arteries but may invade the right ventricle, right atrium, and caudal vena cava in heavy infections.