The cost of heartworm prevention vs. treatment in dogs

Disclaimer: This article, its content, and its related references do not constitute veterinary advice and should not be considered a substitute for veterinary care. If your pet is showing any symptoms that could indicate a medical emergency, please seek immediate emergency care.

Heartworm disease is a common and potentially fatal parasitic infection spread by the bite of an infected mosquito. Some dog owners are hesitant to use year-round heartworm prevention due to its cost. However, the cost of a single round of treatment for heartworm is roughly ten times the amount of a year’s supply of prevention. Additionally, heartworm infection carries a potential for serious long-term health consequences. If you have a dog, read on to learn:

• How dogs get heartworms and why heartworms are dangerous
• The cost of heartworm prevention
• The financial and health costs of canine heartworm disease

In addition to being expensive, heartworm treatment is difficult for the dog and their owner. The disease and its treatment carry potentially life-threatening risks, and heartworms can cause permanent damage to a dog’s heart, lungs, and blood vessels, leading to lifelong health issues and diminished quality of life. Treatment for heartworm disease kills the adult heartworms, but it causes additional side effects and doesn’t reverse the damage done by the heartworms. Overall, it’s much cheaper and safer to use year-round heartworm prevention medication rather than risk an infection.

Heartworm disease is a parasitic infection caused by Dirofilaria immitis, a parasitic worm that’s spread through the bites of infected mosquitos. When an infected mosquito bites, microscopic heartworm larvae are injected into a dog’s bloodstream. From there, they migrate to the large blood vessels in and around the heart and lungs. After several months, the larvae mature into adult heartworms.

Dogs are the natural host for heartworms, meaning the immature heartworms that are injected are more likely to successfully mature into adult worms and reproduce.

Canine heartworm infections are common and have been diagnosed in all 50 US states and across Canada. It’s especially common in the southeastern United States, where there are large numbers of infected mosquitos that remain active year-round. However, heartworm disease is also a concern for dogs in colder climates.

The American Heartworm Society recommends all dogs receive year-round prevention regardless of their geographical region. Heartworm preventives do not kill adult heartworms; they’re only effective against the immature larvae. Because it’s difficult to predict when mosquitos are going to become active in colder climates, it’s best to always be protected. Additionally, preventives must be used at the right time following exposure in order to be effective, so it can be difficult to administer them at the correct time if they’re not given every 30 days throughout the year.

Heartworm disease in dogs is a potentially fatal condition and can cause long-term damage to the heart and lungs even after it’s been treated. Treatment kills the adult heartworms, but it doesn’t do anything to repair the damage they caused. The process of killing the adult heartworms also causes additional damage. Veterinarian-recommended heartworm prevention is the only proven way to prevent heartworm disease in dogs. Various natural remedies and prevention methods may become popular but have no scientific evidence to support that they work and are safe.

Why heartworm infections are dangerous

Adult heartworms live in the vessels in and around the heart and lungs. They can reach up to a foot in length (30.5 cm), roughly the size and shape of a spaghetti noodle. Because they’re so large, their presence in blood vessels interferes with blood flow through the heart. Over time, permanent heart and lung damage can develop as a result. In severe cases, living and dead adult worms can block blood vessels. This is more likely to occur in smaller dogs due to their smaller blood vessels.

“Compared to the major health risks associated with heartworm disease, heartworm preventives are much safer than risking infection,” explains Dr. Jo Myers, a veterinarian on the Vetster platform. “Side effects from preventatives are rare, and products are convenient, easy to use, and effective when used properly.”

The cost of heartworm preventative medication can vary depending on the size of your dog and what product you choose. Products are available as both chewables and topicals, and the active ingredients vary, as does their activity against other parasites, such as fleas, ticks, intestinal worms, lice, and mites. Larger dogs require higher doses, making it more expensive. The average cost of heartworm preventives for a 40lb dog is between $70 and $200 for a year’s worth of prevention. Broad-spectrum parasite prevention is an important part of preventative care for all dogs.

Some pet care insurance plans may help offset some of the costs associated with heartworm prevention. Be sure to thoroughly read the policy. In addition, ask your veterinarian about other cost-saving opportunities. Some brands offer discounts or rebates for purchasing a full year’s supply of prevention. In addition, some veterinary clinics may offer in-house wellness plans that include heartworm prevention.

One round of treatment for a heartworm infection is roughly ten times more expensive than prevention — between $1,200 and $1,800 on average. This means dog owners can get about 10 years’ worth of prevention for the price of one round of heartworm treatment, and affected dogs usually require at least two rounds of treatment to ensure all the adult heartworms are killed. It’s difficult to give an exact cost of treatment because the cost of treatment varies depending on:

• Size of the dog
• Severity of disease
• Location of the vet practice

If your dog has tested positive for heartworms, the usual next step is for the veterinarian to go through a much more precise cost estimate as you decide on the treatment plan. Severe infections often cost more to treat than those that are caught early. Because the dog is sicker, they typically require more care before, during, and after treatment. It’s typical for a dog to need at least two rounds of treatment, and the likelihood of needing more than that increases with the severity of the infection. The entire process takes anywhere from six months to more than two years. The costs of treatment involve:

• Laboratory testing
• Chest X-rays
• Medication
• Hospitalization and monitoring

Different medications are used to kill the adult heartworms, prevent future infections, reduce inflammation, and treat symptoms as they develop. Melarsomine injections are used to kill adult heartworms, and preventives are also used to kill larvae and stop new adults from developing. Doxycycline is an important medication used in treating heartworm infections by reducing Wolbachia, a bacteria that’s released by dying heartworms. Administering doxycycline before the adulticide medication reduces the risk of a widespread inflammatory response in the heart, lungs, and blood vessels during treatment. In severe cases where the worms are preventing adequate blood flow through the heart, surgical removal of adult worms may be recommended.

The treatment for heartworm disease isn’t just hard on an infected dog’s body, it’s also difficult because of how much it costs, how long it takes, and how hard it is on both the dog and owner to go through. In addition to the financial cost of treatment, dogs being treated for heartworm disease require strict exercise restrictions for multiple weeks to months. This can be especially difficult for a dog who doesn’t feel ill, which is the case for many infected dogs.

Other secondary health issues that result from a heartworm infection can have additional potential costs. Most pet insurance plans do not cover heartworm disease treatment or any secondary conditions because it’s considered a preventable disease.

The long-term health costs of heartworm disease in dogs

In addition to being somewhat harmful itself, heartworm treatment also doesn’t do anything to reverse the damage caused by the worms. Even if the adult worms are successfully eliminated, they can leave lasting health complications, such as:

• Heart failure
• Lung disease
• Kidney disease

Dogs with heartworms are at risk for blood clots that can cause additional severe health problems, such as stroke or pulmonary thromboembolism. Long-term medical care for these conditions can also be costly and life-threatening as well as affect a dog’s quality of life.

The American Heartworm Society and Companion Animal Parasite Council recommend that all dogs receive heartworm prevention year-round.

Dogs in endemic areas are constantly exposed to mosquitos that can carry heartworm larvae, and it only takes a single bite from an infected mosquito to result in a heartworm infection. A single missed dose or skipping doses over the winter months can result in an infection. Mosquitos can become periodically active during bouts of warmer weather in the winter, and it’s difficult to know when mosquitos are active, even for brief periods of time.

Additionally, prevention must be given at the appropriate time following an infected bite, since it’s only active against certain larval stages, which is hard to predict. With all these complicating factors, giving a preventive every 30 days all year round is the best way to ensure your dog is protected.

If you would like to talk to a veterinary professional about the best heartworm prevention for your dog, virtual vet appointments are available every day through the Vetster platform for your convenience.

How much does it cost to treat a dog with heartworms?

Heartworm treatment costs vary widely for each case and include heartworm medications, antibiotics, laboratory testing, X-rays, and other veterinary care. On average, one round of treatment costs between $1,200 and $1,800, which is roughly ten times the yearly cost of prevention. Most dogs with heartworm disease will need at least two rounds of treatment. Heartworm prevention is not only better for your dog, it’s safer and less costly than risking an infection.

How much is heartworm prevention vs. treatment?

Heartworm prevention costs vary depending on the size of your dog and which product you’re using. On average, a year’s worth of preventative for a 40lb dog is between $70 and $200. The cost of one round of heartworm treatment is roughly ten times the cost of a year’s supply of prevention, ranging between $1,200 and $1,800 on average. Many dogs need at least two rounds of treatment, making year-round prevention a safer and more cost-effective option.

Does pet insurance cover the cost of heartworm prevention or treatment?

Some pet insurance policies may cover all or part of the cost of heartworm prevention for dogs. It’s important to read the policy closely to know what’s covered. Most pet insurance policies will not cover any part of heartworm disease treatment, as it’s considered a preventable disease.