Heartworm in Dogs

Three Minutes
Apr 12, 2023

Heartworm is a serious disease in dogs that may cause irreparable damage to the heart and lungs. However, it is preventable with the proper preventative and testing schedule.

Still, canine heartworms can be a real problem for many dogs and have been for years, since they were first discovered in 1856.1

A heartworm infection can be life-threatening, since the worms could clog up a dog’s arteries, heart, and lungs. This can reduce blood flow and oxygen circulation to a dog’s major organs along with the rest of the body. Dogs with heartworm may be at risk for heart failure, organ failure, and even death.

Here’s everything you need to know about heartworm disease in your dog.

How Do Dogs Get Heartworms?

Heartworm disease is caused by a parasite that’s transmitted through mosquito bites. When a mosquito bites a dog, the heartworm larvae travel into the dog’s bloodstream. These larvae then travel to your pet’s pulmonary vessels and lungs. The larvae then mature into adult heartworms, and reproduce to create microfilariae.2

Mosquitos are the only way your pet can get heartworm. Even if just one infected mosquito bites your dog, they’ll become infected, too. Since there’s no way to tell if a mosquito is infected, prevention becomes even more important.

Which Pets Are Most at Risk?

Heartworm disease has been found in all 50 states, even in areas where vets used to think it wasn’t an issue. According to PetMeds, heartworm disease tends to be most common in the eastern United States, the southern United States, and near Midwestern river valleys such as the Mississippi and Ohio Rivers.3

Pets that live outdoors or spend a lot of time outdoors are logically at a higher risk for heartworm disease. But that doesn’t mean indoor pets are completely safe. Think about those humid summer nights when mosquitoes seem to follow you indoors. Mosquitoes can easily get inside your house and target your dog.

Many shelter animals are also at a high risk for heartworm. If you adopt a dog from a shelter, be sure to have them tested for the parasite. You’ll also want to get them on a prevention plan as soon as possible. If you adopt a dog with heartworm, be prepared to give them the treatment they need.

On a side note, if you’re concerned that you might be at risk,  don’t worry. Humans can’t get heartworm from their pets.

Preventing Heartworm in Dogs

The good news is that heartworm is entirely preventable. Preventative treatment options range from monthly pills to monthly topical ointments to 6-month injections. The American Heartworm Society advises pet owners to get their pets tested for heartworms every 12 months and give them a heartworm preventative each month of the year.4

Heartworm prevention and testing usually costs dog owners a few hundred dollars per year, depending on which preventative option they go with. This is definitely one of those expenses you probably don’t want to skimp on. It’s best to ask your vet which heartworm prevention they recommend for your dog and get started as soon as possible.

Heartworm Symptoms in Dogs

Heartworm disease doesn’t present symptoms at first. However, there are some signs of heartworm in dogs you can watch out for. You may notice your dog beginning to cough and becoming very short of breath when running. A decreased appetite and weight loss might also be possible.

There are four stages of a heartworm infestation. The severity of your infected dog’s heartworm symptoms will depend on which stage they’re in.

Stage 1 symptoms

Stage one is virtually undetectable. This is the time between the initial infection and the worms reproducing. The worms are making their way through the blood vessels and to the heart and lungs. Dogs in the first stage don’t have visible symptoms.

Stage 2 symptoms

The heartworms have started reproducing, and your dog may have heartworm larvae and adult worms in their system. Generally, the symptoms in this stage are mild, and may include coughing and exhaustion.

Stage 3 symptoms

This is when the heartworms are starting to clog up your dog’s body, such as their blood vessels, heart, and lungs. They may cough up blood or have difficulty breathing.

Stage 4 symptoms

This stage can be dangerous for dogs, and happens when the abundance of worms causes organ failure. When worms clog up the heart, this blockage is called caval syndrome. Symptoms include labored breathing, pale gums, and dark urine.4

How To Treat Heartworm in Dogs

Heartworm disease in dogs is treatable. Vets can use a blood test to check for heartworm disease.5 The treatment for heartworm in dogs is a series of injections that require several tests prior to the shots. Because of the tests needed, heartworm treatment can get expensive. According to PetCareRx, the cost of treating a dog with heartworm can range from $400 to $1,000.6

During treatment, dogs have to be kept quiet, calm, and still. The worms start to die after the treatment, and if your dog is too active, the dead worms might block their pulmonary vessels.

Pet Insurance Could Help You Prevent Heartworm

Heartworm prevention may seem pricey, but it’s minimal when compared to the high cost of treatment and recovery from this dangerous parasite. Protecting your dog also saves them from having to go through the trauma and pain of extensive treatment. However, dog insurance can help you cover these expenses. 7

MetLife Pet Insurance offers a Preventative Care plan add-on that covers parasite prevention and treatment.8

At MetLife Pet, we take heartworm disease prevention seriously. There’s no better time to test your dog for heartworm and get them started on heartworm prevention than the present. Get a free quote today to get up to 100% reimbursement on covered expenses.

Protect your Pets

Coverage in 3 Easy Steps

1 “HEARTWORM UPDATE,” Ceva Animal Health and AAHA

2  “Heartworm Disease in Dogs,” VCA Animal Hospitals

3 “Heartworm in Dogs and Cats,” PetMeds

4 “Heartworm in Dogs,” American Heartworm Society

5 “Keep the Worms Out of Your Pet’s Heart! The Facts about Heartworm Disease,” U.S. Food & Drug Administration

6 “What’s the Cost of Heartworm Treatment?,” PetCareRX

Provided all terms of the policy are met. Application is subject to underwriting review and approval. Like most insurance policies, insurance policies issued by IAIC and MetGen contain certain deductibles, co-insurance, exclusions, exceptions, reductions, limitations, and terms for keeping them in force. For costs, complete details of coverage and exclusions, and a listing of approved states, please contact MetLife Pet Insurance Solutions LLC.

8 Available at an additional cost.

Coverage underwritten and issued by Independence American Insurance Company (“IAIC”), a Delaware insurance company, headquartered at 11333 N Scottsdale Rd, Ste 160, Scottsdale, AZ 85254 or Metropolitan General Insurance Company (“MetGen”), a Rhode Island insurance company, headquartered at 700 Quaker Lane, Warwick, RI 02886. Coverage subject to restrictions, exclusions and limitations. Application is subject to underwriting review. See policy or contact MetLife Pet Insurance Solutions LLC for details. MetLife Pet Insurance Solutions LLC is the policy administrator for this coverage. The entity may operate under an alternate, assumed, and/or fictitious name in certain jurisdictions as approved, including MetLife Pet Insurance Services LLC (New York and Minnesota), MetLife Pet Insurance Solutions Agency LLC (Illinois).

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