How to Prevent Heartworm Infection in Dogs
📝 Summary
Heartworm in dogs is spread mainly by mosquito bites and, less often, from an infected mother to her puppies. Signs such as coughing, tiredness, and poor appetite appear only after worms mature in the heart and lungs, so prevention — regular checkups, monthly preventives, and mosquito avoidance — is far safer than treatment.
1 How Dogs Get Heartworm
Dogs are mainly infected with heartworm (Dirofilaria immitis) through mosquito bites. When a mosquito carrying heartworm larvae bites a dog, infection readily occurs. The larvae enter the bloodstream and travel to the heart and lungs, where they slowly mature into adult worms. Pregnancy is another route: if a mother dog is infected during pregnancy, the larvae can cross the placenta and infect the fetuses.
2 Symptoms of Heartworm Infection
Early infection often shows no obvious signs, especially when only a few worms are present. As the number grows or adult worms lodge in the heart or lungs, symptoms begin to appear: coughing, exercise intolerance, and lethargy, along with a gradual drop in the dog’s spirits and appetite. Without treatment, later complications can include anemia, ascites (fluid in the abdomen), heart and lung failure, jaundice, pulmonary edema, and liver or kidney failure. On X-ray, an enlarged right ventricle or thickened pulmonary artery may be seen; echocardiography or a blood smear then confirms the diagnosis.
3 How to Prevent Heartworm
To keep your dog from getting heartworm, follow these steps:
1. Take your dog for regular veterinary checkups to catch and treat heartworm early.
2. Give preventive medication on a set schedule to lower the chance of infection.
3. During mosquito season, use mosquito repellents at home, dress the dog in protective clothing, and apply a pet-safe repellent. Avoid taking the dog to areas with heavy mosquito activity.
Overall, preventing mosquito bites is the single most important step in reducing the risk of heartworm.
4 Treatment
If you suspect heartworm symptoms, take the dog to a veterinary hospital promptly. Treatment depends on severity: adult worms are usually treated with an injection of sodium arsenamide or thiacetarsamide, while larvae may be treated orally with levamisole, combined with supportive care for the symptoms that appear. During treatment, limit the dog’s exercise to avoid dead worms blocking blood vessels and causing discomfort.
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