Heartworm disease affects dogs and cats and is spread by mosquitoes. It is one of those diseases that is easy to prevent, but difficult to cure. A worm called Dirofilaria immitis causes the disease. Part of its life cycle involves living in a mosquito. The infective larvae of the worm are injected into the animal when an infected mosquito bites the dog or cat. Heartworm is most common in tropical areas where the most mosquitoes live, but it is present in almost all areas of the United States and parts of Canada. If you’ve seen mosquitoes, you should talk to your vet about heartworm.
Although both cats and dogs can get heartworm, it’s most common in dogs. The worm lives in the blood vessels of the infected animal so heartworm is diagnosed using a blood screening test. In the early stages, a dog may not show any symptoms of the disease. As it progresses, the heart becomes more and more stressed. Dogs start to experience problems with breathing and have an unwillingness to exercise. They may also cough, lose weight, and become listless and depressed.
Treatment for cats is difficult and often can be fatal, however dogs with heartworm often recover. The most important part of the treatment happens at home. Basically a vet gives the dog drugs to kill the worm. As the worms die, they travel through the blood stream. If blockages occur, they can kill the dog. So a dog undergoing heartworm treatment absolutely has to avoid any form of exercise, or even may need to be confined to a kennel for about a month. The dog must be kept quiet so the body can break down and absorb the dying worms.
Although heartworm is a terrible disease, preventing it is quite simple. Your veterinarian can recommend different types of preventatives. Preventatives can be given monthly, daily, or as an injection that is done by your vet once every 6 months. It is important to discuss the type of chemicals that are contained in the pills or injection because certain breeds of dogs react to certain types of heartworm medications. Before you get a preventative, the vet also will need to do a blood test to determine if heartworms are already present. Dogs never should be given preventative without determining whether or not heartworm is already present.
Heartworm preventatives have changed a lot over the years and continue to evolve. These days, some preventatives also work against other internal or external parasites as well. Your veterinarian can explain all the different options when you bring in your pet for the heartworm test.