If you've spent any time outdoors in West Texas during the warmer months, you already know that mosquitoes are a persistent nuisance. But beyond the itchy bites and the swatting, these insects carry a genuine threat to the animals we love. A single mosquito bite is all it takes to transmit heartworm disease, a condition that can cause lasting damage to a pet's heart, lungs, and blood vessels, and in severe cases, it can be fatal.
The encouraging news is that heartworm disease is largely preventable. With the right medication and a consistent routine, you can give your dog or cat strong, reliable protection against this parasite. At Andrews Veterinary Clinic, we work with pet owners throughout the Andrews area to build prevention plans that fit their animals' needs and their own schedules.
This article covers everything you need to know about protecting your pet, including:
Why heartworm is a concern for both dogs and cats
What prevention products are available and how they work
Whether year-round prevention is truly necessary in Texas
How safe these medications are and what to watch for
The Heartworm Threat in West Texas
West Texas has a climate that many people find appealing, with plenty of sunshine, warm summers, and mild winters compared to much of the country. But that same environment creates conditions where mosquito populations can remain active for a surprisingly long stretch of the year. In the Permian Basin region, temperatures can stay warm well into the fall, and even a brief warm spell in winter can bring mosquitoes back out. That extended season of mosquito activity means pets in this part of Texas face a longer window of potential exposure than animals living in colder northern states.
Heartworm disease is caused by a parasitic worm called Dirofilaria immitis. When a mosquito carrying heartworm larvae bites your pet, those larvae enter the bloodstream and eventually mature into worms that take up residence in the heart, lungs, and surrounding blood vessels. The resulting damage can be severe. Dogs are the more common host, but cats are absolutely vulnerable as well, and the disease often presents differently in felines, sometimes with few outward signs until the condition has advanced significantly.
It is worth noting that heartworm has been confirmed in all 50 U.S. states. Living in a dry or semi-arid region does not eliminate the risk. Mosquitoes find ways to breed wherever standing water exists, even briefly, and the animals and birds that carry infected mosquitoes travel widely. For pet owners in Andrews and the surrounding communities, this is not a theoretical concern but a genuine, year-round consideration.
The American Heartworm Society publishes regularly updated guidelines for pet owners and veterinarians. Familiarizing yourself with those recommendations is a good starting point for understanding the scope of the issue and the best ways to address it.
Why Cat Owners Cannot Afford to Skip Prevention
Many cat owners assume heartworm is a dog problem. This is a common and understandable misconception, but it can put cats at real risk. While cats do not serve as the ideal host for heartworm and typically carry fewer worms than dogs, the consequences of infection can actually be more severe in felines. Even a small number of worms can trigger a serious inflammatory response in a cat's respiratory system, sometimes referred to as heartworm-associated respiratory disease.
Compounding the problem is the fact that treatment options for cats are far more limited than those available for dogs. There is currently no approved drug therapy to eliminate adult heartworms in cats, which means veterinarians are largely limited to managing symptoms and supporting the animal through the illness. Prevention, therefore, is not just the better option for cats, it is essentially the only reliable strategy.
Even cats that live exclusively indoors are not fully protected. Mosquitoes routinely enter homes through open doors, windows, and small gaps, and they do not distinguish between indoor and outdoor animals when seeking a blood meal.
Heartworm Prevention Options for Dogs and Cats
Pet owners today have more choices than ever when it comes to parasite prevention. The right product for your animal depends on factors like species, weight, lifestyle, any other health conditions, and honestly, what format is easiest for you to administer consistently. Here is an overview of the main categories:
1. Monthly Oral Medications
Chewable tablets are among the most widely used heartworm prevention products for dogs. Many are flavored to mimic treats, which makes the monthly routine relatively straightforward for most pet owners. These medications are typically given once every 30 days and work by eliminating larvae that may have been transmitted during the previous month. Many oral products also include coverage for intestinal parasites such as roundworms and hookworms, which are common in the Texas soil and can affect both pets and, in some cases, people.
2. Topical Spot-On Treatments
Applied directly to the skin, usually between the shoulder blades, topical treatments are a practical solution for pets that resist swallowing pills or tablets. These products are absorbed through the skin and provide systemic protection. They are available for both dogs and cats, and many formulas also address fleas, ticks, and other external parasites. In a region where ticks are also a concern for outdoor animals, a broad-spectrum topical product can offer meaningful convenience.
3. Injectable Prevention (Dogs Only)
For dog owners who struggle to maintain a monthly schedule, injectable heartworm prevention offers a compelling alternative. These products are administered by a veterinarian and remain effective for six to twelve months depending on the specific formulation. This option is particularly useful for working dogs, hunting dogs, or owners who travel frequently and may find it difficult to track a monthly dosing calendar.
Does Year-Round Prevention Make Sense in Texas?
Some pet owners wonder whether they can safely skip heartworm prevention during the cooler months. In many parts of Texas, including the Andrews area, the answer is a clear no, and here is why.
First, the West Texas climate does not deliver the kind of sustained freezing temperatures that reliably eliminate mosquito populations. Winters here tend to be mild and variable, with warm stretches that allow mosquitoes to survive and remain active even in January or February. Second, heartworm prevention medications work retroactively, eliminating larvae from the previous 30-day window. If you stop the medication and then restart it after a gap, you may be leaving a period of potential infection unaddressed. Third, every major veterinary organization with a stake in this issue, including the American Heartworm Society, the Companion Animal Parasite Council, and the American Veterinary Medical Association, recommends that pets receive year-round prevention regardless of geographic location or season.
The cost of consistent prevention is modest compared to the expense and difficulty of treating an active heartworm infection. Treatment for dogs involves a multi-month protocol that includes injectable medications, strict activity restriction, and close veterinary monitoring. The process is hard on the animal and significantly more expensive than a year's supply of preventive medication. For cats, as mentioned earlier, treatment options are even more limited.
Safety of Heartworm Preventatives
A question we hear regularly from caring pet owners is whether these medications are safe. The short answer is yes, with appropriate care and guidance. All FDA-approved heartworm prevention products go through rigorous testing before reaching the market, and decades of widespread use have demonstrated a strong safety profile across the vast majority of animals.
That said, responsible use matters. Dosing is based on body weight, and using the correct product for your pet's size is essential. Certain dog breeds, particularly those with a genetic mutation affecting drug sensitivity (such as some herding breeds including Collies and Australian Shepherds), may require special consideration when selecting a prevention product. Your veterinarian can help you navigate those nuances.
Side effects from heartworm preventatives are uncommon, but they can occur. Signs to watch for include vomiting, lethargy, loss of coordination, or skin irritation at the application site for topical products. If you notice anything unusual after administering a prevention product, contact your veterinarian promptly. In most cases, reactions are mild and resolve quickly, but it is always better to check.
One more important point: most heartworm prevention products require a veterinary prescription, and many also require a recent negative heartworm test before they can be dispensed. This is because giving a prevention product to a dog that already has an active heartworm infection can cause a serious reaction. Testing first is a straightforward step that protects your pet. We also want to address the topic of so-called natural alternatives such as garlic supplements or essential oil preparations. There is no scientific evidence that any of these products prevent heartworm, and some can be harmful to pets. We recommend sticking with products that have been tested and approved.
Heartworm and the Broader Parasite Picture in West Texas
Heartworm prevention rarely exists in isolation. West Texas pet owners also contend with fleas, ticks, and intestinal parasites that thrive in the region's warm, dry landscape. Many of the same mosquito-active months also correspond to peak flea and tick season. Ticks in particular are a concern for dogs that spend time outdoors, whether hiking in the Guadalupe Mountains, hunting on ranchland, or simply exploring the open spaces that define life in this part of the state.
Choosing a heartworm prevention product that also addresses these other parasites can simplify your pet care routine and provide more comprehensive protection. During your pet's annual wellness exam, your veterinarian can help you evaluate which combination of products makes the most sense based on your animal's lifestyle and local risk factors.
Frequently Asked Questions
My cat stays inside all the time. Does she still need heartworm prevention?
Yes. Mosquitoes can and do enter homes, and indoor cats are not immune to infection. Because treatment options for heartworm in cats are so limited, prevention is strongly recommended for all cats, regardless of whether they go outdoors.
What is the most affordable way to prevent heartworm?
Monthly oral medications tend to be the most budget-friendly option, though prices vary based on your pet's weight and the specific brand. Your veterinarian can help you find a product that fits your budget without compromising on effectiveness.
Is the injectable option better than a monthly chewable?
Both are effective when used correctly. The injectable option offers a convenience advantage for owners who find monthly dosing difficult to maintain, while oral medications are often less expensive. The best choice depends on your pet's individual situation and your own preferences.
What should I do if I miss a dose?
Contact your veterinarian as soon as you realize you have missed a dose. They can advise you on the safest way to get back on schedule and whether any additional steps, such as retesting, are warranted based on how long the gap was.
Does my dog need a heartworm test before starting prevention?
Yes, in most cases. Testing before starting or restarting a prevention product is an important safety measure. Administering certain preventatives to a dog with an existing infection can trigger a harmful reaction.
Take the Next Step for Your Pet's Health
Protecting your dog or cat from heartworm disease is one of the most straightforward and impactful things you can do for their long-term wellbeing. In a region like West Texas, where mosquito season stretches well beyond the summer months, staying consistent with prevention is especially important.
If you have questions about which product is right for your pet, need to schedule a heartworm test, or want to establish a complete parasite prevention plan, the team at Andrews Veterinary Clinic is here to help. We invite you to call us at (432) 523-4355 or schedule a wellness exam to discuss heartworm prevention, vaccination schedules, and the other services we offer to keep your pets healthy throughout every season. Serving Andrews and the surrounding West Texas communities, we are committed to being a trusted partner in your pet's care.