Yes, Mosquitoes Are Dangerous to Your Pets
While mosquito bites on dogs and cats are usually minor, the disease they transmit—heartworm—is anything but. Heartworm disease kills thousands of dogs each year and is found in all 50 states, with the highest rates in the Gulf Coast region where Romex operates.
Here's the short version: a single mosquito bite can transmit heartworm larvae to your dog or cat. Those larvae grow into foot-long worms that live in the heart and lungs. Untreated, heartworm disease is fatal.
How Mosquitoes Transmit Heartworm
- An infected dog or coyote carries adult heartworms that produce microscopic larvae (microfilariae) in the bloodstream
- A mosquito bites the infected animal and picks up the larvae
- The larvae develop inside the mosquito for 10–14 days
- The mosquito bites your dog or cat, depositing larvae through the bite wound
- Larvae migrate through tissue for 6 months, eventually reaching the heart and lungs as adult worms
Adult heartworms can grow up to 12 inches long. A heavily infected dog may harbor 30+ worms. The worms damage the heart, lungs, and blood vessels, leading to heart failure.
Heartworm Symptoms in Dogs
Heartworm disease develops silently for months before symptoms appear:
- Early stage: Mild cough, especially after exercise
- Moderate stage: Persistent cough, fatigue, reluctance to exercise, decreased appetite
- Advanced stage: Swollen belly (fluid accumulation), labored breathing, pale gums
- Caval syndrome: Life-threatening blockage of blood flow; requires emergency surgery
By the time symptoms appear, significant damage has already occurred. That's why prevention is far more effective—and far less expensive—than treatment.
Can Cats Get Heartworm?
Yes, but it presents differently. Cats are not natural hosts, so most larvae don't survive to adulthood. However, even immature worms cause a condition called Heartworm Associated Respiratory Disease (HARD) with symptoms including:
- Coughing and asthma-like attacks
- Vomiting (not related to eating)
- Weight loss and decreased appetite
- Difficulty walking or sudden collapse
There is no approved treatment for heartworm in cats—only supportive care. Prevention is the only option.
Year-Round Prevention Is Essential
In Texas, Oklahoma, Louisiana, and Mississippi, mosquitoes are active 10+ months per year. The American Heartworm Society recommends year-round prevention for all dogs and cats in our region. Options include:
- Monthly oral chewables (Heartgard Plus, Interceptor Plus, Simparica Trio)
- Monthly topical treatments (Revolution, Advantage Multi)
- Injectable prevention (ProHeart 6 or ProHeart 12—lasts 6–12 months)
Cost ranges from $5–$15 per month for prevention. Heartworm treatment for an infected dog costs $1,000–$3,000+ and involves months of restricted activity. Prevention is clearly the better investment.
Protecting Pets from Mosquito Bites
Beyond heartworm prevention, you can reduce your pet's mosquito exposure:
- Keep dogs indoors during peak biting hours (dawn and dusk)
- Use pet-safe mosquito repellents—never apply human DEET products to pets
- Eliminate standing water in your yard (see our prevention checklist)
- Ensure window and door screens are intact
- Consider professional mosquito yard treatment to reduce the population around your home
Professional barrier spray is safe for pets once dry (typically 30 minutes after application). We always advise keeping pets indoors during treatment and for 30 minutes afterward.
The Bigger Picture: Protect Your Whole Family
Mosquito control protects everyone under your roof—two-legged and four-legged. Between heartworm risk for pets and West Nile virus risk for humans, reducing mosquito populations around your home is a family safety issue.
Read our complete mosquito control guide for the full prevention strategy, or request a quote for professional yard treatment.