Heartworm disease is becoming more prevalent in the Sarnia-Lambton area and especially near the water. Heartworm is a parasite which lives in the blood of a dog’s heart and adjacent blood vessels. The adult heartworm produce offspring, called microfilariae, which circulate in the infected dogs’ blood.

When a mosquito “bites” an infected dog, it sucks out blood containing the microfilariae. After about two weeks in the mosquito, the microfilariae become infective larvae. This step is necessary for the transmission of heartworm. When the mosquito bites another dog, the infective larvae are transmitted.

The infective larvae migrate through the tissues of the dog’s body and reach the heart in about 2 to 3 months. In the heart the larvae develop into adult heartworms. It takes about six months from the time the dog is bitten by an infected mosquito until adult heartworms produce microfilariae.

Heartworm Symptoms

Some dogs in the early stages of heartworm infection may not show any signs at all. As the disease progresses dogs may show difficulty breathing, coughing, listlessness, weight loss and rough hair coat. If not detected and controlled with proper treatment, heartworm can lead to congestive heart failure and death. Testing for the presence of heartworm disease and appropriate treatment in the early stages can help prevent symptoms from occurring.

Prevention of heartworm is key. If treatment is needed for a dog that is heartworm positive, there is only one medication that is available to treat for heartworm disease effectively. The treatment of heartworm disease is a long and difficult course of treatment.