Heartworms. Just the name sounds dire. The truth is, heartworm disease is a serious condition for dogs, and a growing concern for cats. Spread by mosquitoes, the disease is particularly prevalent in tropical and temperate areas of the United States.
Roscoe, a 7-year-old male dachshund mix, is the “poster dog” for what can happen if your pet becomes infected with heartworms. When little Roscoe was rescued from an animal control shelter by Angels Among Us, a rescue organization in Atlanta, GA, his initial veterinary exam indicated possible advanced heartworm disease.
He was referred to BluePearl Georgia Veterinary Specialists where board-certified cardiologist Nicole Piscitelli confirmed through a diagnostic echocardiogram that the heartworms had infiltrated into important blood vessels affecting blood flow to his heart and lungs. Heartworm disease at this stage, called caval syndrome, will ultimately lead to death if left untreated. The treatment for caval syndrome requires surgical extraction, which is more complicated than treatment of less advanced stages of heartworm disease. Dr. Piscitelli used ultrasound guidance to successfully remove Roscoe’s bundle of heartworms from his heart.
There is a medication that will eradicate the heartworms in infected dogs, however, it is time consuming, costly and sometimes dangerous. Currently for cats, there is no medication available to eradicate the heartworms. Instead, supportive therapy for the symptoms of the disease can be offered and/or surgical extraction if the disease progresses to caval syndrome in felines.Therefore, prevention is critical. Without prevention, your pet’s summer mosquito bites can lead to a heart writhing with worms by early winter.
The Ugly Truth
Dirofilaria immitis is the parasite that we know as heartworms. At maturity, these heartworms can be nearly a foot in length. Clustered together they look like ugly spaghetti noodles (as shown in the picture). It only takes approximately 6 months for the larvae to grow this big inside the host animal. Heartworms also have a long lifespan – 5 to 7 years – which means with each mosquito season, an increasing number of worms can infect an individual pet.
Initially, an infected dog may not show any signs of illness. Multiple factors affect the onset of symptoms, including the overall lifestyle of the pet, other health issues, and the number of adult worms in the dog’s heart and major blood vessels. A mild persistent cough, reluctance to exercise, fatigue after moderate activity, decreased appetite and weight loss are among the early signs of heartworm disease in dogs. In cats, the symptoms can appear as respiratory problems – wheezing and shortness of breath. Just one or two worms can lead to severe respiratory symptoms and even death, and because there is no approved treatment for cats, prevention is equally important in cats as it is in dogs.
“The good news for Roscoe is that he is expected to make a full recovery, but it’s important to remember that heartworms are entirely preventable,” said Dr. Piscitelli.
All approved heartworm medications work by eliminating the immature (larval) stages of the parasite. Once the heartworm larvae molt into the adult stage (a time frame of about 2 months), preventive medication is not effective in eliminating the worms.
“Please remember to seek proper preventive medicine from your family veterinarian and be diligent about following the recommended schedule,” Dr. Piscitelli urges. “Maintaining monthly heartworm prevention will not only protect your pet from these parasites, but it is also a much more effective and cheaper alternative than treating existing heartworms.”