Heartworms in the dog’s heart can cause heart damage and/or clots in the body that can cause death. Preventing heartworm disease is much easier than having to treat heartworm disease. Cats can get heartworms too but it is not as common, it is still hard to diagnose, and there is no current treatment for cats.
Where You Live Will Depend on How Likely it is Your Dog or Cat Will Get Heartworms
Do you live in an area where there are a lot of heartworms? Most of the continental United States has heartworm disease and certain areas have a higher instance of the infection. Click here for the most recent case numbers of heartworm reported to veterinary clinics in the United States. As shown on the map, more humid areas are more prevalent for dogs and cats getting heartworm.
Heartworms Come from Mosquitoes
Dogs and cats get infected with heartworms from mosquitoes. The heartworm infects a dog’s heart and a cat’s lungs. Both dogs and cats will cough if the worms are impacting the heart or lungs. Keeping the mosquitoes under control in your yard will help decrease the likelihood of your dog getting heartworm.
Signs of Heartworm Infestation
Typically, once your dog or cat shows signs of coughing, exercise intolerance (hard time excreting any energy), lethargy (sleeps or lays around more than normal), weight loss, decreased appetite, and/or difficulty breathing can mean the heartworms have already caused damage to the heart.
Treating Heartworm Infestation in Dogs
The treatment of heartworm infestation is very hard on the dog’s body, contains arsenic, and there is no treatment for cats at this time. This is why prevention is so important.
Prior to getting the heartworm treatment medication the dog has to be sedated to administer an injection intramuscularly (into the muscle) on the back. The dog’s back has to be shaved and sanitized and they have to stay at the hospital for the day to be monitored. The veterinary staff will apply ice to the injection site after the injection is given. Normally, large dogs get three injections and small dogs get two injections. Click here for the recommendations of the Heartworm Society on what should be given and when. Your veterinarian may have different protocols depending on what they have seen in your area, their experiences, and your pet’s symptoms. Prior to the injections, or any treatment, the majority of dogs require multiple blood tests and x-rays. They will also be started on multiple medications including antibiotics, steroids, and monthly heartworm preventatives.
The dog’s activity must be restricted until after the last injection. The dog should be kept in a crate except when on a leash, which includes walks to use the bathroom or with you in the house. This is the preferred method of the Heartworm Society and the method that I have seen used in multiple clinics. Always talk to your veterinarian about what is best for you and your pet. Click here for dog crates and here for dog leashes. You do not want the dog to run after something they see in the yard, even if it’s only a few feet or seconds. If the dog’s heart rate gets high it can cause the dying worm to leave the heart and cause an embolism (obstruction in the blood vessels) that can cause a stroke or death. Preventing this at all costs is best.
Costs of Heartworm Treatments
Heartworm treatment usually costs well over $1,000 for all of the medication, injections, hospital stays, blood work, and x-rays. The larger the dog, the more it costs due to the medications needed and the amount of the injection given. The injection is dosed by the weight of the dog and is normally charged per bottle.
Preventing Heartworm Infestations
How can you prevent heartworm infections? Give a heartworm preventative. Most preventatives are chewable tablets, however, there are also topical and injectable options.
The topical and chewable ones need to be given monthly at home normally. There are also, injections that can be given at the veterinary hospital and can last up to a year. This may be ideal if the monthly preventative is hard for you to remember or your dog will not eat the chewable preventative. Since heartworms come from mosquitoes, your veterinarian will have the best information on what type of preventative is best for your pet. This will depend on your area and how prevalent heartworm disease is where you live. Also, if your pet travels with you and you don’t know about the heartworm instances in that area make sure to have them on a preventative. Heartworm infestations are much easier to prevent than to treat and even with treatment there is still permanent damage to the heart, the dog could get it again, and the dog could die from the treatment.
See How the Worms Affect the Heart
If you like pictures, the Heartworm Society has some great pictures of the heart being permanently damaged by heartworms or to see what a heartworm looks like. (https://heartgardclinic.com/sites/default/files/2020-07/HGD_Flipbook.pdf).
Check out my article on Flea Infestations in Dogs and Cats to find out how to prevent these pests too.