Bayou Hot Zones: Louisiana Pets Face High Risk of Heartworm Disease

BATON ROUGE, Louisiana (April 2, 2025) – Louisiana pets are under attack from parasites. Thrive Pet Healthcare reminds pet owners that even indoor pets are at risk of heartworm and other parasite-related illnesses—especially in Louisiana, where mosquitoes thrive year-round.

“We often see dogs and cats dealing with parasite-related illnesses, even when the pet is kept indoors,” said Dr. Chris Slay, a veterinarian at South Baton Rouge Animal Hospital in Baton Rouge, a member of Thrive Pet Healthcare’s community of veterinary hospitals. “If your pet is not protected, all it takes is one little mosquito slipping in through an open door or window for your furry friend to end up with more than just an itch.”

According to 2024 data from the Companion Animal Parasite Council, several parishes in and around Baton Rouge report some of the highest heartworm rates in the country:

Statewide, the highest heartworm-positive rate was reported in St. Mary Parish, where 80% of dogs tested positive. Other high-prevalence areas include Webster Parish (50%) and Plaquemines Parish (25%).

Carried by mosquitoes, heartworm can affect a dog’s heart and lungs. Some dogs show signs such as coughing, shortness of breath, fatigue after moderate activity, or weight loss, but many show no symptoms until the disease is more advanced. Fortunately, it’s very preventable with veterinarian-prescribed preventatives.

While heartworm is more common in dogs, cats in Louisiana are also vulnerable. Even indoor-only cats can be infected by mosquitoes entering the home. Symptoms may include coughing, vomiting or difficulty breathing, but some cats show no signs at all.

Approximately 1 in 500 cats nationwide test positive for heartworm disease annually, but the rate is significantly higher in Louisiana, where 1 in 200 cats test positive.

“One in 7 dogs and 1 in 4 cats have fleas, which can cause itchy skin, tapeworms, or other infections,” said Dr. Lindsey Carr, veterinarian at Dodge City Veterinary Hospital in Denham Springs, also a member of Thrive Pet Healthcare’s community of veterinary hospitals. “Fleas can quickly multiply in your home, and ticks can survive for over 200 days without food or water. This is why providing your pet with year-round protection is critical—it really makes a big difference.”

Veterinarian-prescribed preventatives are the most effective way to protect pets from parasites and the diseases they carry. Until June 30, 2025, participating Thrive Pet Healthcare hospitals are offering 15% off in-hospital purchases of popular parasite preventatives, including:

With a Thrive Plus membership, year-round protection is more accessible and affordable for pet parents. Member pets receive unlimited free exams,* $5 basic nail trims, and 10% off services like bloodwork, dental cleanings and spay/neuter—making it easier to stay on top of health concerns before they become serious.

Visit thrivepetcare.com to find a location near you that offers primary, specialty, emergency, and urgent veterinary care services, as well as participating Thrive Plus membership hospitals.