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What Can I Do to Prevent Heartworm?

Veterinary care for heartworm includes prevention and treatment. Before starting preventative treatment, a veterinarian may test the animal for adult heartworm. Veterinarians most commonly use a blood antigen test that can detect one or more female heartworms that are at least seven to eight months old.

If you have concerns, make an appointment to speak to your veterinarian about heartworm prevention and treatment. Your veterinarian is a local expert at preventing and treating heartworm transmission in your community, as heartworm is more common in some places than others.

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Heartworm Disease

Heartworm is a small, thread-like parasitic worm that scientists refer to as Dirofilaria immitis. Heartworm earns its common name by living in the host’s heart, lungs, and blood vessels. Heartworm can cause severe lung disease, heart failure, organ damage, and death. Often, mosquitoes transmit heartworms to dogs, cats, ferrets, wolves, foxes, ferrets, sea lions, and in rare instances, humans. Heartworm can affect any breed of dogs or cats.

Heartworm infects animals all over the world. Once inside an animal, a heartworm can live up to five to seven years. Male heartworms can grow to up to four to six inches in length. Females are even larger, growing as long as 12 inches. Adult heartworms look like strands of

Heartworm is a small, thread-like parasitic worm that scientists refer to as Dirofilaria immitis. Heartworm earns its common name by living in the host’s heart, lungs, and blood vessels. Heartworm can cause severe lung disease, heart failure, organ damage, and death. Often, mosquitoes transmit heartworms to dogs, cats, ferrets, wolves, foxes, ferrets, sea lions, and in rare instances, humans. Heartworm can affect any breed of dogs or cats.

Heartworm infects animals all over the world. Once inside an animal, a heartworm can live up to five to seven years. Male heartworms can grow to up to four to six inches in length. Females are even larger, growing as long as 12 inches. Adult heartworms look like strands of cooked spaghetti.

Veterinarians refer to the number of worms inside an animal as the “worm burden.” Research shows that the average worm burden for a dog is 15 worms but that a dog’s worm burden can range from 1 – 250 worms. Worm burdens vary for other animals depending on size and other factors.

There are four stages, or classes, of heartworm disease; the higher the class, the more severe the disease has become. In the first class, the animal may not have any symptoms, or may have a mild cough. Animals in the second stage may have a cough and seem fatigued after moderate exercise. During the third stage, the animal suffers a general loss of body condition, has a persistent cough, and tires after mild activity. In the fourth class, also called laval syndrome, the worm burden blocks blood flow to the heart; surgical removal of the heartworms is the only option, and this surgery is risky.

Heartworm Infection

Mosquitoes spread heartworm to the animals they bite. When a mosquito bites an animal, it transmits infected larvae through the bite wound. Once inside an animal, it takes six or seven months for the larvae to mature into adult heartworms. These adult heartworms mate and the females release the offspring, called microfilariae, into the host animal’s bloodstream. Mosquitoes then ingest these microfilariae when they bite the infected animal, completing the lifecycle of heartworm.

Worms live inside mosquitoes only long enough to become infective larvae, about 10 to 14 days. Microfilariae cannot become infective larvae without first passing through a mosquito. This means heartworm is only spread through mosquito bites and not by casual contact.

Sources:

American Heartworm Society

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