Houston Pet Owners: Why Heartworm Prevention Can't Wait
If you live in Houston and your pet isn't on heartworm prevention, this is the most important article you'll read today. Houston consistently ranks as one of the highest-risk cities in the entire United States for heartworm disease. Our warm, humid climate and year-round mosquito season create the perfect conditions for this potentially fatal disease to spread — and it affects far more pets here than in most other parts of the country. At CAWLM Veterinary Hospital + Spa, we see heartworm-positive pets regularly. Here's everything Houston pet owners need to know.
What Is Heartworm Disease?
Heartworm disease is a serious and potentially fatal condition caused by a parasitic worm (Dirofilaria immitis) that lives in the heart, lungs, and surrounding blood vessels of affected animals. It is transmitted exclusively through the bite of an infected mosquito — which means any pet that spends time outdoors (or lives with someone who does) is at risk.
Dogs are the primary host, but cats can be infected too — and heartworm disease in cats is often more difficult to detect and treat.
Why Houston Is Different
Most of the United States has a defined mosquito season. Houston does not. Our mild winters mean mosquitoes are active virtually year-round, which means your pet's exposure window never truly closes. Combined with our high humidity and dense mosquito population, Houston pets face a significantly higher risk than pets in most other American cities. Year-round prevention isn't just recommended here — it is essential.
Signs of Heartworm Disease
Early heartworm infection often has no visible symptoms, which is why annual testing is so important. As the disease progresses, signs can include:
Persistent cough
Fatigue after moderate activity
Reluctance to exercise
Decreased appetite and weight loss
Swollen belly (in advanced cases, due to fluid accumulation)
In cats: coughing, wheezing, vomiting, or sudden collapse
Prevention Is Simple — and Life-Saving
Heartworm prevention is inexpensive, easy to administer, and highly effective. Options include monthly chewable tablets, topical treatments, and an injectable prevention administered every 12 months by your veterinarian. The cost of a year's worth of prevention is a fraction of the cost of heartworm treatment — which is lengthy, expensive, and hard on your pet's body.
What If My Pet Tests Positive?
If your pet tests positive for heartworm disease, don't panic — but do act quickly. Treatment is available for dogs, though it requires a period of strict rest and multiple veterinary visits. Cats unfortunately have no approved treatment, making prevention even more critical for feline members of your household. Our Houston veterinary team at CAWLM will walk you through every step of the diagnosis and treatment process with honesty and compassion.
The Bottom Line for Houston Pet Owners
Test annually — even pets on prevention should be tested every year
Prevent year-round — Houston's climate means there is no "safe" season to skip
Start early — puppies and kittens can begin prevention as young as 8 weeks old
Don't assume indoor pets are safe — mosquitoes come inside
Book a wellness visit at CAWLM to get your pet tested and started on the right prevention plan for Houston's unique climate. It's one of the most important things you can do for your pet this year.
Located at 4902 San Jacinto Street in Houston's Museum District. Serving pet families across Houston, Pearland, Katy, Sugar Land, The Woodlands, and beyond.