If you live in West Texas, you already know that mosquitoes are a fact of life, especially during the warmer months when standing water collects after storms and the evenings stay warm well into fall. What you may not know is that those mosquitoes can carry a potentially deadly parasite that puts your dog at serious risk. That parasite is heartworm, and it is one of the most serious preventable diseases affecting dogs across Texas and the rest of the country.
The good news is that with the right information and a solid prevention plan, you can protect your dog before the problem ever starts. This article covers everything you need to know, including how heartworm spreads, what warning signs to watch for at each stage of infection, why prevention is far better than treatment, and when to seek urgent veterinary care.
Here is a quick look at what we will cover:
How dogs contract heartworm and why Texas dogs are especially vulnerable
The four stages of heartworm disease and their symptoms
Early warning signs that should prompt a vet visit
Why prevention is the smartest strategy for your pet
How Dogs Get Heartworm
Heartworm disease is caused by a parasitic worm known scientifically as Dirofilaria immitis. Dogs become infected when a mosquito that has previously fed on an infected animal bites them and deposits microscopic larvae into the skin. Those larvae travel through the dog's body and eventually settle in the heart, lungs, and surrounding blood vessels, where they mature into adult worms that can grow up to a foot in length.
According to the American Veterinary Medical Association, heartworm has been confirmed in all 50 states, so no region is entirely off the hook. That said, the climate in West Texas creates particular conditions worth noting. The area experiences long, hot summers with temperatures that regularly climb above 100 degrees Fahrenheit, and mosquito populations tend to surge after any significant rainfall. Even in the drier months, irrigation systems, livestock water troughs, and low-lying areas near the Permian Basin can provide enough standing water to support mosquito breeding. Dogs that spend time outdoors, whether on a ranch, a farm, or just a backyard, face ongoing exposure throughout much of the year.
Andrews, Texas sits in a region where agricultural and outdoor lifestyles are common, meaning many dogs here have regular access to open land and are potentially exposed to infected mosquitoes more frequently than pets in urban settings. That makes awareness and prevention especially important for local pet owners.
The Four Stages of Heartworm Disease
Heartworm infection does not announce itself right away. The disease progresses through four recognized stages, and the earlier it is caught, the better the outcome for your dog.
Stage 1: Mild or Early Infection
During the first stage, most dogs show no outward signs of illness at all. If anything is noticeable, it might be an occasional soft cough or a slightly lower energy level after play or exercise. Because these signs are easy to dismiss as normal tiredness or a minor respiratory irritation, many owners do not realize anything is wrong. This is precisely why routine testing matters so much, even when your dog appears perfectly healthy.
Stage 2: Moderate Disease
As the infection advances into the second stage, symptoms become a bit more consistent, though still easy to overlook. A dog in this stage may develop a cough that lingers, show less enthusiasm for walks or playtime, and tire more quickly than usual. Physical activity that once seemed effortless may now leave your dog winded or reluctant to continue.
Stage 3: Severe Disease
By the third stage, heartworm disease has caused significant damage to the pulmonary arteries and surrounding tissue. Dogs at this point typically show obvious fatigue, noticeable weight loss, and labored breathing even at rest. One of the most telling signs at this stage is a distended abdomen, which results from fluid accumulating in the belly due to compromised circulation. At this point, the disease has progressed considerably, and treatment becomes more complicated and risky.
Stage 4: Caval Syndrome (Emergency)
The fourth and final stage is a life-threatening emergency. At this point, the worm burden is so severe that blood flow through the heart is physically obstructed. Dogs may collapse suddenly without warning. Other urgent signs include pale or white gums and urine that appears dark brown, almost the color of coffee. This condition requires immediate veterinary intervention, and even with prompt treatment, the prognosis is guarded.
Early Warning Signs Every Dog Owner Should Know
Because heartworm disease can be silent for months, or even longer, staying attuned to subtle changes in your dog's behavior and physical condition is one of the most valuable things you can do. Some of the earliest indicators that something may be wrong include:
A mild cough that does not seem connected to a cold or allergy
Unusual tiredness after routine activity like a short walk or backyard play
A reduced interest in food
Gradual, unexplained weight loss
Breathing that seems slightly more labored than normal
None of these symptoms on their own is definitive proof of heartworm, but any of them warrants a conversation with your veterinarian. A simple blood test can confirm or rule out infection, and catching the disease early dramatically improves your dog's chances of a full recovery.
When to Seek Emergency Care
Some symptoms signal that your dog needs veterinary attention right away, without waiting for a scheduled appointment. Contact your vet immediately if your dog experiences any of the following:
Sudden difficulty breathing or respiratory distress
A visibly swollen or bloated abdomen
Fainting or collapsing
Gums that look pale, gray, or white instead of a healthy pink
Urine that is dark or discolored
These are signs of advanced heartworm disease, and time is critical. The sooner a dog in this condition receives care, the better the chances of stabilizing them and preventing further harm.
It is also worth remembering that even dogs on preventive medication should be tested annually. No medication is 100 percent effective if a dose is missed or given late, and annual screening gives your vet the chance to catch any infection before it has time to progress. A routine blood panel during your dog's yearly wellness visit is usually all it takes.
The West Texas Factor: Why Local Conditions Matter
West Texas may not be the first place that comes to mind when people think about mosquito-borne illness, but the region's climate and landscape create real risks for pets. The area around Andrews sees hot, dry conditions for much of the year, but summer thunderstorms can leave behind pockets of standing water that become mosquito breeding grounds almost overnight. Oil field operations, agricultural irrigation, and livestock facilities throughout the Permian Basin also create environments where mosquitoes thrive.
Dogs in this part of Texas often live active, outdoor lifestyles. Many accompany their owners on ranch work, hunting trips, or long hikes across the wide-open terrain that defines the region. That kind of exposure to the outdoors is one of the things that makes life here special, but it also means dogs may encounter infected mosquitoes far more often than pets that spend most of their time indoors.
Additionally, Texas is home to a wide range of wildlife, including coyotes and foxes, that can serve as natural reservoirs for heartworm. These animals can carry the parasite and, when bitten by mosquitoes, pass it along. In a rural region like this one, domestic dogs may come into closer proximity to wildlife than in more densely populated areas, which adds another layer of risk worth considering when building your pet's prevention plan.
Prevention Is Always the Better Choice
The American Heartworm Society recommends year-round preventive medication for all dogs, regardless of where they live. In a state like Texas, where mosquito season can stretch across most of the calendar year, this recommendation carries even more weight.
Preventive products come in several forms. Monthly oral chewables are popular because most dogs accept them readily and they are easy to administer on a regular schedule. Topical spot-on treatments applied to the skin are another option, and for pet owners who want a longer-term solution, injectable preventives administered by a veterinarian can provide protection for up to six months or a year at a time.
All of these options are significantly safer and far less costly than treating an active heartworm infection. Treatment for established heartworm disease involves a series of injections with a powerful medication, strict exercise restriction for weeks to months, and the risk of serious complications including permanent damage to the heart and lungs. Even a dog that survives treatment may never fully recover the level of health it had before infection.
Preventive medications, by contrast, work by eliminating immature larvae before they can develop into adult worms. When given consistently and on schedule, they are highly effective. Some products also protect against other common parasites such as roundworms, hookworms, and fleas, making them a practical part of a broader wellness routine for your dog.
It is worth addressing one common question: can heartworm be prevented through natural remedies? The short answer is no. Garlic, herbal supplements, essential oils, and similar home remedies have not been shown in scientific studies to prevent heartworm transmission or kill larvae. Some of these substances are actually toxic to dogs. The only reliably effective prevention comes from FDA-approved veterinary medications, and your vet can help you choose the right product for your dog's size, lifestyle, and health history.
One more point worth making: indoor dogs are not automatically safe. Mosquitoes find their way into homes regularly, and a single bite from an infected mosquito is all it takes. Every dog, regardless of how much time it spends outside, benefits from consistent heartworm prevention.
Frequently Asked Questions About Heartworm in Dogs
How soon after infection do symptoms appear?
Heartworm larvae take several months to mature into adult worms, and dogs can carry an infection for months or even years before showing any visible signs. This long silent phase is one of the reasons routine annual testing is so important.
Is heartworm disease painful for dogs?
In the later stages, yes. As worms accumulate in the heart and lungs, they cause significant physical damage that leads to breathing difficulty and considerable discomfort. Preventing infection is the kindest thing you can do for your pet.
Can my dog spread heartworm to other dogs or to people?
Heartworm is not transmitted directly from dog to dog or from dogs to humans. A mosquito must first bite an infected animal and then bite another host to spread the parasite. However, infected dogs in the community do increase the risk for other pets by providing a source of larvae for mosquitoes to pick up.
How often should my dog be tested?
Annual testing is the standard recommendation, even for dogs that take preventive medication without interruption. Testing is quick, requires only a small blood sample, and gives you and your vet a clear picture of your dog's health.
Take the Next Step for Your Dog's Health
Protecting your dog from heartworm does not have to be complicated. With the right preventive medication, annual testing, and a veterinarian you trust, you can keep this serious disease from ever becoming a problem for your pet. Dogs in Andrews and across the surrounding region face real mosquito exposure, and the best time to build a prevention plan is before any symptoms appear.
The team at Andrews Veterinary Clinic is here to help. Whether you are looking to start your dog on a heartworm preventive, schedule an annual wellness exam that includes parasite screening, or simply have questions about your pet's health, we welcome the chance to partner with you. Give us a call at (432) 523-4355 to schedule an appointment with Andrews Veterinary Clinic and give your dog the protection it deserves.