Heartworms are an important parasite that infects the pulmonary (lung) vessels going into the heart. Ultimately, the parasites migrate and set up shop in these vessels and act almost like a clog to a pipe. When the heart pumps and tries to get blood to the body, the worms make this process harder and place a strain on the heart
In severe cases with a high load of worms, the parasite can even fall into the heart creating a more severe problem. Additionally, the lungs can get very sensitive to the presence of this invader and become inflamed and cause a dry cough.
Heartworms present slightly differently in cats versus dogs, but in both cases the worms live in the same place and are preventable using monthly heartworm prevention.
Heartworm infection in cats:
Because if a cat’s smaller size, felines usually have a single or 2-worm infection. The end result is standard testing for the parasite detection in dogs isn’t nearly as accurate in cats due to a much smaller presence. In cats, testing is available but the accuracy of detection is much lower even in infected (heartworm positive) individuals.
1. Testing: from blood / serum
- Looking for a protein called the antigen
- Looking for an antibody to the heartworm
There are laboratory tests that look for both the antigen and the antibody. A positive result from either should be taken seriously. A negative result doesn’t always mean a cat is negative; it may just be too low of a load to be detected.
2. Radiographs (X-rays)
- X-rays of the chest don’t give an exact answer as to whether a cat is positive or negative for heartworms, but they do show the size and shape of the heart and the characteristics of the lungs, such as whether they look normal or inflamed. They can also show the pulmonary vessels and whether they are distended, suggesting structural changes due to harboring a parasite.
- Echocardiogram – this is an ultrasound of the heart and can sometimes show the worms in the pulmonary vessel leading to the heart. It can also show if the heart is contracting properly against the extra workload the heartworms place on it and if any part of the heart is enlarged.
3. Treatment for felines
Unlike dogs there isn’t a clear-cut way to kill heartworms. They tend to not last very long in the cat but they can have a dramatic impact to your cat’s life. Often the first signs of infection that you see are respiratory distress and death from a clot.
In some instances though, if your cat is coughing, lives in a high prevalence area (like Texas or anywhere mosquitos thrive) and isn’t on prevention, your veterinarian may test you cat for heartworm disease and even if negative since detection is so challenging may try to treat or rather manage the infection
Management of feline heartworm disease includes medicating with doxycycline, steroids like prednisolone if coughing or inflammation is present AND placing your cat companion on a monthly heartworm prevention so no new infection can occur.
Heartworm infection in dogs:
Because dogs often have a higher worm burden, testing for an infection is often easier and is common practice on an annual exam. If heartworms are present, there are outlined true treatment protocols that have high success rates of ridding your dog of the parasite.
X-rays are often indicated to see how severe the infection is – has the heart changed size? Is there significant lung inflammation and more?
from heartworm disease
After a month of the antibiotic doxycycline a 3-injection protocol is administered in a particular way. The 1st injection that kills adults is done 30 days prior to the next injection with the final a day later. The goal is to space out the killing of the parasite so the dog doesn’t have the full worm burden dying off all at once which can lead to severe lung inflammation and blood clots to the lungs (pulmonary thromboembolisms).
Prevention:
Whether we are talking about a cat or a dog, untreated heartworm disease can lead to right-sided heart failure, clots and death. What’s so heartbreaking in these cases is knowing that we can prevent heartworm disease with monthly readily available heartworm medications that can be prescribed and often dispensed from your family veterinarian.
While many people believe that their pet is safe since he or she lives mostly indoors, that’s not really the case. The infection is transmitted by mosquitoes and these blood-thirsty buggers quickly fly into our homes through cracked windows or even a door that’s open for a few seconds.
Heartworms are found throughout the United States and other countries. While they have a higher infection rate in wet, warm, humid places such as Texas, Louisiana, Mississippi and Florida, they are found everywhere, which is why dogs and cats should be on monthly prevention year round.
Talk to your veterinarian to protect your animal companions. Monthly prevention can save your pet’s life and save you a significant amount of expense resulting from diagnostic, treatment / management protocols.
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