Heartworm in dogs: how to prevent, diagnose, and treat

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Heartworms are a common parasite that can infect any dog at just about any time. The heartworm, sometimes called dog heartworm, is a type of roundworm that is spread by mosquitos. It’s impossible to tell if a mosquito is carrying a heartworm. But it’s not impossible to prevent the spread of heartworm to your dog.

How heartworms infect and kill dogs

Heartworm doesn’t always kill, but if left untreated, it can prove fatal. Mosquitos deposit larvae on the skin of a host dog. The larvae then enter the dog through the mosquito’s bite. Over the next six months, these larvae will mature into adult heartworms. Heartworms, once mature, can live for five to seven years inside of a dog. If no preventative methods are used, your dog can become the host to new larvae every year, increasing the number of heartworms living inside of them.Adult heartworms can be up to a foot long. They live inside of a host’s heart, lungs, and the associated blood vessels of these two organs. Heartworms can cause lasting damage to these two organs, as well as the dog’s kidneys and liver. Heartworm disease can lead to death by pulmonary thrombosis and heart failure. Even if you kill all the heartworms in your dog’s body, they can still suffer from symptoms of heartworm disease.

Preventing heartworm

Luckily, preventing heartworm is relatively easy. There are many prescription medications that your dog can take that will kill heartworms before they mature into adults. Because heartworm larvae can molt into their adult stage in as few as fifty-one days, it’s important to administer your chosen heartworm medication on a strict schedule. Most medications are administered monthly.Heartworm medications come in all shapes and sizes: some are pills, others are topical skin treatments, and some are even chewable. Medications typically cover other types of parasites as well, such as hookworms, tapeworms, and flea eggs. Talk to your vet about the best prescription for your dog.No matter what state you live in, you need to administer preventative heartworm medication year-round. Some believe that dog owners in colder states can stop giving the medication during the winter, but this is untrue. Mosquitos are constantly changing and adapting to colder climates. Heartworm has been diagnosed in every state in America, including desert states like Arizona, where mosquitos breed on golf courses and in irrigated fields. Plus, it’s important to build the habit of administering preventative heartworm treatment every month.

Diagnosing heartworm

Early on in the disease, dogs can be completely asymptomatic. Early signs of heartworm disease include shortness of breath, tiring easily, or coughing. Active dogs often show signs of the disease before less active dogs.If you or your vet suspects heartworm disease, your vet may order a blood test. Blood tests can detect adult heartworms older than seven months.Your vet may order a blood test every year as part of your annual vet visit. This is done to make sure that you catch heartworm early. Even if you administer your dog’s heartworm medication on a strict schedule, it’s still a good idea to get an annual test.

Treating heartworm disease

While heartworm disease is a serious diagnosis, it doesn’t spell the end of your dog’s life. In fact, it is a very treatable disease.If your dog tests positive for heartworms, your vet will likely want to test your dog with an additional (and different) test. Treating a dog for heartworm disease is expensive, and it’s a good idea to make sure that’s completely necessary.Your vet will also immediately tell you to restrict exercise. Exercise can exacerbate damage done by heartworms. Restricting exercise can be hard for dogs used to high levels of activity, but it’s extremely important that you keep them on doggy bed rest.Typically, there is a therapy treatment your dog must undergo to stabilize the disease before the actual heartworm treatment can begin. Depending on your dog’s condition, therapy can last for just a few weeks or for many months.After your dog is stabilized, your vet will administer the treatment. The actual heartworm treatment requires multiple steps. Your vet will develop a plan of attack and go over the treatment schedule with you. The treatment is usually administered at an animal hospital. Your dog may need to be crated during the treatment process.The more severe your dog’s disease is, the more likely it is that complications will develop after the heartworms are successfully killed.During this entire period, you’ll want to either start or continue your preventative medication routine. Six months after the heartworm treatment is complete, your vet will administer another test to confirm that the treatment worked.

If you can't afford the treatment

If you can’t afford to treat your dog’s heartworm, you should still either begin or continue a strict regimen of preventative care. If you can’t kill the heartworms that are already using your dog as a host, you can at least prevent more heartworms from infecting your dog and worsening the disease. Some dogs can live a normal lifespan even after becoming infected with heartworms, though typically complications from heartworm disease will lead to a shorter lifespan.While pet insurance typically won’t cover the cost of preventative care, it will cover the costs of treating heartworm disease. Preventative medication can cost as little as five to ten dollars every month – combined with a pet insurance policy for around thirty dollars every month, you can fully protect your dog from heartworm disease for a relatively affordable monthly price.

Image: Sofia Bergstrom