Heartworm Facts

Animals are infected with heartworm disease by the bite of a mosquito. Cats, ferrets and dogs are most susceptible to this disease. Animals infected with heartworm often suffer heart failure, severe lung problems, and damage to their other organs which may cause death.

Heartworms in dogs

When a dog is infected with heartworms, the females reproduce baby heartworms that are known as microfilariae. These are released into the bloodstream of the dog. Later a mosquito bites the dog, and some of the microfilariae enter the mosquito.

It takes the microfilariae 10 to 14 days to become infective larvae within the mosquito. Then the mosquito bites another dog, and that dog becomes infected with the larvae. Within six to seven months the larvae will become adult heartworms, and the process begins all over again.

Heartworms live in a dog for five to seven years. The males are shorter than the females, measuring 4 to 6 inches. The females measure between ten to twelve inches. They look like cooked spaghetti. The average dog can have approximately 15 heartworms, but may have as many as 250.

If dogs are not very active, they may have only a few heartworms or if they have just recently become infected, they may not show any symptoms. Symptoms often begin with a cough that only happens on occasion. The owner may notice that the dog has a more frequent cough, and that it gets tired after moderate activity.

If the heartworm infection continues, the cough and the tiredness will become more persistent. Signs that the dog has problems breathing and signs of heart failure become noticeable. The worst case scenario is called caval syndrome. With this syndrome, the dog has so many heartworms that the blood cannot flow back to the heart because it is blocked by the worms.

Heartworms in cats

Cats can also become infected with heartworms. Their bodies are more resistant to the infection, and the heartworms do not live as well or as long in a cat's body. Fewer mature into adults. It is common for cats to only have between one and three worms in their body.

Seldom are microfilariae found in a cat's bloodstream. If they do enter the bloodstream, they only live a short time. The larvae take a month longer to mature in a cat's body than they do in a dog.

Cats are less apt to show symptoms of heartworm disease. A cat may die from heartworms before the owner even knows it is sick. The most common symptom in cats is a respiratory problem. Cats seldom show signs of heart failure, but they may have symptoms such as weight loss, vomiting, decreased activity and decreased appetite.

Heartworms in ferrets

Ferrets are infected with heartworms by a mosquito bite. Interestingly, the ferret has some of the same characteristics that are found in dogs and some of the same ones found in cats. Their symptoms are more like those of a cat, but they have the same susceptibility to heartworms as a dog.

They do not have as many heartworms as a dog, but not as few as a cat. Microfilariae can only be found in the bloodstream of 50 to 60 percent of the infected ferrets. Their main symptoms are coughing, overall weakness, breathing problems and becoming less active.

People need to have their pets checked by a vet for heartworms at least twice a year. Prevention is the best way to deal with this specific problem. It is very possible that this pet disease could be done away with if owners would take prevention seriously.
