Phone: 614-292-5274 Fax: 614-292-9783
e-mail: extento@postoffice.ag.ohio-state.edu
William F. Lyon
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| Dog Hearworm |
Canine or Dog Heartworm disease is a serious and potentially fatal disease of dogs. Long white worms, nematodes, Dirofilaria immitis, are the cause. Adult worms, which reach a length of 6 to 14 inches, live in the right side of the heart and in the adjacent blood vessels. A dog may have several hundred of them in its system, although the number usually is less.
Large accumulations of adult worms impair circulation of the blood, which can result in serious damage to a dog's heart, lungs, liver and kidneys. Advanced stages of the disease may cause its victim to have difficulty breathing, cough, tire easily, become listless, lose weight or faint. If not detected and controlled with proper treatment, the disease can lead to heart failure and death.
Heartworm infection is spread by mosquitoes. When a mosquito bites an infected dog, it takes up blood which may contain immature forms of heartworms. Then when the mosquito bites another dog, the heartworm larvae are passed into the second dog, infecting it. The larvae migrate through the tissues of the body for about three months, then enter the heart where they reach adult size in another three months.
Most dogs can be successfully treated for heartworms if the disease is detected early. The adult worms are killed with an organic arsenical drug given through a series of carefully administered injections. A few days after treatment, the worms die and are carried by the bloodstream to the lungs where they lodge in small vessels. There they decompose and are absorbed by the body over a period of several months.
Although no vaccine is available for heartworm disease, veterinarians have developed a method of preventing infection.
Many veterinarians recommend a daily dose of diethylcarbamazine (Filaribits, Pet-Doc) or a monthly dose of ivermectin (Heartgard) to prevent heartworms. Both dogs and cats can be easily treated with Heartgard by feeding meat-based chewable doses by hand, in pieces or mixed with food.