Pawliday Inn
Ask any Houstonian about mosquitoes and you'll get a groan. Between the heat, the humidity, the bayous and all the standing water after a storm, our area gives mosquitoes plenty of places to breed. For dog owners, that's more than an annoyance. Mosquitoes spread heartworm, a serious disease that's common along the Gulf Coast. This guide covers how heartworm works, why prevention matters in Houston, and how to reduce mosquito exposure around your home.
What heartworm is
Heartworm disease is caused by a parasitic worm that lives in the heart, lungs and nearby blood vessels of infected animals. Left untreated, it can cause lasting damage to the heart and lungs, and it can be fatal.
How dogs get it
Dogs don't catch heartworm directly from other dogs. It spreads through mosquitoes:
- A mosquito bites an infected animal and picks up tiny immature worms.
- Those larvae develop inside the mosquito.
- When the mosquito bites your dog, it can pass larvae into your dog's body.
- Over a period of months, the larvae grow into adult worms.
Because one bite can be enough, even mostly indoor dogs are at risk. Mosquitoes get inside, and most dogs go out to potty several times a day.
Why Houston is a high-risk area
Heartworm is found across the United States, but it's especially common in warm, humid regions with lots of mosquitoes, and the Gulf Coast fits that description. In Houston:
- Mosquito season is long, and mild winters don't reliably end it.
- Bayous, retention ponds, drainage ditches and low spots hold water.
- Heavy rain and tropical storms leave standing water all over neighborhoods.
- Many animals, including stray dogs, coyotes and other wildlife, can carry heartworm.
That's why many vets in our area recommend year-round heartworm prevention and regular testing. Ask your vet what they recommend for your dog.
Signs of heartworm disease
Early heartworm disease often has no signs at all. That's what makes testing important. As the disease progresses, dogs may show:
- A mild, persistent cough
- Getting tired quickly during exercise or play
- Reduced appetite and weight loss
- Trouble breathing
- A swollen belly in advanced cases
These signs can have other causes too. If you notice any of them, see your vet.
Prevention is much easier than treatment
Heartworm prevention for dogs is available in several forms, including monthly chewables, topical products and longer-lasting injections given by a vet. Your vet will help you pick the right option.
Treating a dog who already has heartworm disease is possible, but it's typically a longer, harder process that requires strict rest and close veterinary care. Preventing infection in the first place is far simpler.
Testing matters, even on prevention
Your vet will usually test your dog before starting prevention and at regular intervals afterward. Testing catches infections from missed doses, a product that didn't absorb, or a gap when switching products. Ask your vet how often your dog should be tested.
Don't skip doses
Missing a dose, or giving one late, can leave a gap in protection. Set a phone reminder, and talk to your vet about what to do if you're late.
Reducing mosquitoes at home
Prevention medicine is the main defense, but cutting down mosquitoes helps your whole household.
- Dump standing water weekly. Check flowerpot saucers, kids' toys, buckets, tarps, clogged gutters and dog water bowls left outside.
- Change outdoor water bowls daily.
- Keep grass trimmed and clear brush where mosquitoes rest.
- Repair window and door screens.
- Limit outdoor time at dawn and dusk when many mosquitoes are most active.
- Ask your vet about repellents. Some insect repellents made for people are not safe for dogs. Use only products labeled for dogs.
After a big storm, walk your yard once the water drains and empty anything that's still holding water. Our hurricane season plan for dogs in Houston covers more on storm prep.
Heartworm, fleas and ticks: one routine
Many Houston owners pair heartworm prevention with flea and tick prevention, and some products combine them. Your vet can help you decide what makes sense. Our guide to flea and tick prevention in Houston covers that side.
If your dog stays with us
At Pawliday Inn, every daycare and boarding dog needs current Rabies, DHPP and Bordetella vaccinations, plus regular flea, tick and intestinal parasite prevention. If your dog takes a monthly heartworm preventive and it's due during a boarding stay, bring it with clear written instructions. Our packing list for dog boarding can help you remember the rest. For more on overnight stays, see current rates and details on our homepage.
Frequently asked questions
Can my indoor dog get heartworm?
Yes. Mosquitoes get indoors, and most dogs go outside at least to potty. Many vets recommend prevention for indoor dogs too.
Do I need heartworm prevention in winter in Houston?
Many vets in our area recommend year-round prevention because winters here are mild and mosquitoes can stay active. Follow your vet's advice.
Can heartworm spread from dog to dog at daycare?
Not directly. Heartworm spreads through mosquito bites, not through contact between dogs.
How do I know if my dog has heartworm?
Your vet can test for it with a blood test. Early disease often has no symptoms, so regular testing is the best way to find out.