Heartworm disease is a common condition that strikes a variety of animals, including the family dog.

Mosquitoes transmit heartworm from animal to animal. When an infected mosquito bites an animal, the heartworm microfilaria develop into larvae. As larvae mature, they moves through the dog's body and eventually into the heart and blood vessels. Over time, the worms injure the lungs and heart, leading to lung disease, heart disease or damage to other organs. Heartworms may survive five to seven years in dogs.

A dog infected with heartworms may initially show no signs of disease. As the disease progresses though, the dog may cough, become lethargic, lose its appetite or have difficulty breathing. If not treated, the condition can become fatal.

A veterinarian can test a dog's blood for heartworms. Additional tests, such as chest x-rays and an echocardiogram, can help confirm the diagnosis and determine the severity of the infection. Heartworm treatment is designed to kill adult worms present in a dog's body and may require hospitalization; other medications help limit inflammatory reaction as the worms die.

Heartworm disease in dogs is highly preventable. Several FDA-approved heartworm preventives are available to reduce the risk. A blood test for existing heartworm should be done before starting a prevention regime. Serious complications are rare among dogs in good health, and if the disease is detected early.

Source: American Veterinary Medical Association