Heartworm disease is one of those conditions that’s far easier to prevent than to treat, and that’s exactly why we talk about it so much at Skaer Veterinary Clinic. It’s a serious, potentially fatal disease in dogs and cats, caused by a blood-borne parasite called Dirofilaria immitis. The good news? With safe, affordable prevention available today, no pet should ever have to go through it.
Here’s what every Wichita pet owner should understand about how heartworm works, why our Kansas mosquito seasons matter, and how to keep your dog or cat protected.
What heartworms actually do
Adult heartworms live in the heart and the large blood vessels nearby. They’re not small, the female can reach 6 to 14 inches long, and a single dog can carry as many as 300 worms. They live up to five years, and during that time the females release millions of tiny offspring called microfilariae into the bloodstream.
The damage comes from clogging. Adult worms interfere with the heart’s valves and block major blood vessels, which reduces blood supply to the lungs, liver, and kidneys and slowly causes those organs to malfunction. The microfilariae cause their own trouble in the small vessels of the lungs and liver. It’s a whole-body disease that often does its damage quietly.
How a mosquito spreads it
Heartworm doesn’t pass directly from pet to pet. It needs a middleman: the mosquito. When a mosquito bites an infected animal, it picks up microfilariae during the blood meal. Over the next 10 to 30 days, those develop inside the mosquito into infective larvae. The next time that mosquito bites a dog or cat, it deposits the larvae, which then migrate to the heart, mature over two to three months, and start the cycle again.
This is why heartworm risk lines up so closely with mosquito season, and why it matters here. As many as 30 species of mosquitoes can transmit heartworm. Long hair offers no protection, since mosquitoes simply bite where the coat is thinnest.
Heartworm in Kansas
Heartworm was once thought of as a southern problem, mostly limited to the south and southeast. That’s no longer the case. The disease has spread across nearly all of the United States and into Canada, and it’s now found anywhere mosquitoes are common, which certainly includes Kansas. With our warm, humid summers and healthy mosquito populations, dogs and cats here are genuinely at risk.
Because the worms take five to seven months to mature, heartworm is rarely diagnosed in dogs under a year old. It’s most often found in dogs between four and eight years of age, after the infection has had time to build, which is part of what makes year-round prevention so important.
The signs are easy to miss
This is the hard truth about heartworm: dogs and cats may show no signs at all for as long as two years, and by the time symptoms appear, the disease is often well advanced. When signs do show up, the most common are:
- A soft, dry cough
- Shortness of breath
- Weakness, listlessness, and loss of stamina
- Tiring quickly or even fainting after exercise
In advanced cases, we may see weight loss, anemia, and fluid buildup in the abdomen and legs from congestive heart failure. Severely infected pets can die suddenly during exercise or excitement. Because the early disease is so silent, waiting for symptoms is not a safe strategy.
How we diagnose it
In most cases, heartworm is diagnosed with a simple blood test. The most widely used one detects proteins produced by adult female worms, and it’s accurate enough to catch the great majority of infections. Depending on what we find, we may recommend additional steps, such as a second blood test for microfilariae, bloodwork to check organ function, X-rays, or in some cases an EKG or ultrasound of the heart. These help us understand how far the disease has progressed and whether a pet can safely tolerate treatment. Many of these tests we can run right here using our in-house diagnostics, digital X-ray, and ultrasound.
Treatment is possible, but it’s hard on your pet
There’s real progress to share here. Older heartworm treatments relied on arsenic-based drugs with frequent toxic reactions. The newer medication is far safer, and we can now successfully treat more than 95% of dogs with heartworm.
That said, treatment isn’t simple. It involves a series of injections to kill the adult worms, usually given a month apart. As the worms die and break down, they travel to the lungs, and this is a genuinely delicate period. Complete rest is essential, the dog must be kept quiet with no exercise for about a month after treatment. A cough is common for several weeks. We watch closely for any reaction and treat promptly if one occurs.
Cats are a different and trickier story. There is no drug approved to treat heartworm in cats, and when the worms die they can pass to the lungs and cause sudden death. For cats, we often manage symptoms supportively and aim to keep them stable. It’s a real dilemma, and the clearest takeaway is that prevention matters even more for our feline patients.
Prevention is the whole point
After reading all of that, here’s the part we most want you to hold onto: heartworm is almost entirely preventable. Safe, affordable, easy-to-give preventives stop the disease before it can ever take hold, and they’re a tiny fraction of the cost and stress of treatment.
For dogs and cats in Wichita and the surrounding communities, we generally recommend year-round prevention paired with regular testing. If your pet isn’t on a preventive yet, or you’re not sure they’re up to date, give us a call or bring it up at your next wellness exam. It’s one of the simplest, highest-value things you can do to protect your pet.
The Skaer Veterinary Clinic Team
