Heartworms, spread by Nature's vampires: mosquitoes

Q: How do dogs get heartworms?

A: Only by the bite of an infected mosquito. There's no other way dogs get heartworms. And there's no way to tell if a mosquito is infected. That's why prevention is so important.

Heartworm disease has been reported in all 50 states. And the bite of just one mosquito infected with the heartworm larvae will give your dog heartworm disease.

Heartworm disease has not only spread throughout the United States, but it's also now found in areas where veterinarians used to say, "Oh, we don't have heartworm disease." Areas like Oregon, California, Arizona, and desert areas--where irrigation and building are allowing mosquitoes to survive. And if you have mosquitoes and you have animals, you're going to have heartworms. It's just that simple.

It takes about seven months, once a dog is bitten by an infected mosquito, for the larvae to mature into adult heartworms. They then lodge in the heart, lungs, and surrounding blood vessels and begin reproducing. Adult worms can grow up to 12 inches in length, can live 5-7 years, and a dog can have as many as 250 worms in its system.

Q: Can people get heartworms from their dogs?

A: It can only be passed on by mosquitoes. It's a specific parasite that only affects dogs, cats, ferrets, and other mammals. In rare cases, heartworms have infected people, but it does not complete its life cycle. The heartworm will migrate to the lung and cause a round lesion that looks like a tumor. But these are very rare cases.

Q: If one of my dogs has heartworms, can he give it to my other dogs?

A: No. Again, the only way heartworms are transmitted is through the bite of an infected mosquito. And even if an uninfected mosquito bit your infected dog, and then bit your uninfected dog the same night, he wouldn't transmit the parasite from one dog to the other. That's because when a mosquito bites an infected animal, the heartworm needs to undergo an incubation period of two weeks in the mosquito before the mosquito can infect other animals.

Q: How can I prevent my dogs from getting heartworms?

A: For less than the cost of going to Starbucks for a weekly coffee, you can prevent heartworm disease in your dog. There are monthly pills, monthly topicals that you put on the skin, and there's also a six-month injectable product. The damage that's done to the dog and the cost of the treatment is way more than the cost to prevent heartworm disease. A year's supply of heartworm preventative will cost about $35 to $80, depending on a dog's weight.

Q: What are the symptoms of heartworm infestations in dogs?

A: Initially, there are no symptoms. But as more and more worms crowd the heart and lungs, most dogs will develop a cough. As it progresses, they won't be able to exercise as much as before; they'll become winded easier. With severe heartworm disease, we can hear abnormal lung sounds, dogs can pass out from the loss of blood to the brain, and they can retain fluids. Eventually, most dogs will die if the worms are not treated.

Q: Once my dog has heartworms, what's the treatment? How much will it cost?

A: The drug that you treat with is called Immiticide. It's an injectable, arsenic-based product. The dog is given two or three injections that will kill the adult heartworms in the blood vessels of the heart.

The safest way to treat heartworms includes an extensive pre-treatment workup, including X-rays, blood work, and all the tests needed to establish how serious the infection is. Then the dog is given the injections. With all the prep work, it can run up to $1,000. Treatment costs vary between veterinary clinics.

The best prevention is to test and protect your pet by putting on heartworm prevention all year long for the entire length of the pet's life.

If you have questions about heartworms, please contact Dr. Norette L. Underwood of Trumann Animal Clinic and Best Friends Vet Mobile at catdoc56@gmail.com or on facebook at Trumann Animal Clinic.