Heartworm Prevention for Our Furry Friends

In Northeast Texas, warm temperatures, high humidity, and plentiful rainfall create the perfect environment for mosquitoes. While these pests are often just a nuisance to people, they pose a serious and potentially deadly threat to pets. Mosquitoes are the sole transmitters of heartworms, a parasite that can cause severe damage to the heart, lungs, and blood vessels of dogs, cats, and other animals. Mosquitoes are active for much of the year in our region; therefore, heartworm prevention is not just seasonal. It is a year-round necessity.

Dirofilaria immitis. The scientific name for heartworms. When a mosquito bites an infected animal, it ingests microscopic heartworm larvae, similar to a seed. When that same mosquito later bites another pet, it implants the larvae (seed) into the bloodstream of your pet. Over the next several months, the larvae mature and migrate to the heart and lungs, where they grow into long, spaghetti-like worms that live inside the pulmonary arteries, right atrium, and right ventricle. As adults, heartworms interfere with blood flow, strain the heart, and damage the lungs, often leading to serious illness or death if left untreated. From what I’ve found, Lamar County has one of the highest heartworm burdens in the country. At Animal Health Center, we diagnose over 100 cases each year. This is 3-4x the national average. Dogs are the most common hosts for heartworms, but cats, ferrets, and even wildlife can also be infected.  This disease can cause coughing, exercise intolerance, weight loss, labored breathing, heart failure, and fluid buildup in the abdomen of your pet.

This December/January has not helped our mosquito burden. Our long mosquito season typically extends from early spring through late fall, but this year, mosquitoes will remain active through the winter. Standing water from rainfall, lakes, creeks, and even backyard containers provides ideal breeding grounds. Because it takes only one bite from an infected mosquito to transmit heartworm disease, even pets that spend most of their time indoors are not fully protected. Mosquitoes can easily enter homes through open doors, windows, and small gaps, putting indoor cats and dogs at risk as well.

Heartworm prevention is one of the simplest and most effective ways to protect pets from this dangerous disease. Preventive medications work by killing the immature heartworm larvae and kill them before they become juveniles and adults. At our office, we lean towards using ProHeart12 (moxidectin), which, with a single injection, will protect your pet for 12 months. Moxidectin is very similar to ivermectin, but this formulation is bound in a fat of liposome which allows for slow release of the medication and reduces the need to remember a monthly tablet. No guesswork, just constant coverage.

The most important aspect of heartworm prevention is consistency. Missing even one dose can allow surviving larvae to mature and establish an infection. Because heartworms take several months to grow into adults, pets may appear healthy for a long time while the disease silently progresses. By the time symptoms become noticeable, the damage to the heart and lungs can already be significant. That is why veterinarians recommend year-round prevention in our region.

Annual heartworm testing is also a key part of a responsible prevention plan. Even pets that are on preventives should be tested once a year to ensure the medication is working and that no infection has occurred. Testing is quick and requires only a drop of blood. Early detection allows for earlier treatment, which improves the chances of a successful outcome and reduces the risk of complications.

Heartworm disease is treatable, but it is far more difficult and expensive. Treatment involves a long period of antibiotic treatment, and then a series of injections to kill the adult worms. During this time, your pet will be required to maintain strict exercise restrictions. If the heart rate gets too high (during exercise), the worm can break apart and cause dangerous blockages in the blood vessels of the lungs, making the recovery period critical and stressful for both pets and their owners. In severe cases, surgery may be required, and in some pets, the damage caused by heartworms is permanent.

The good news is that heartworm disease is entirely preventable. By keeping up with heartworm prevention and working with your veterinarian, pet owners in Northeast Texas can protect their dogs and cats from this threat. Preventive care is not only safer for pets, but it is also far more affordable than treating an established infection.

In a region where mosquitoes are a constant presence, heartworm prevention is essential. Whether your pet spends its days running in the backyard, lounging on the couch, or curling up by your side at night, we recommend protection from a disease that is both dangerous and avoidable. With simple, consistent care, you can help ensure your pets enjoy a long, healthy life free from heartworm disease.