Heartworm Disease in Dogs: Heartworms are parasitic worms that live in the heart and blood vessels of dogs. They are transmitted through the bite of an infected mosquito. As the mosquito feeds on the blood of an infected dog, it picks up tiny heartworm larvae, which then develop into infective larvae. When the mosquito bites another dog, the infective larvae enter through the bite wound.
Once inside the dog, the larvae mature into adult worms over several months. The adults then mate and produce offspring called microfilariae, which circulate in the bloodstream. This process repeats when other mosquitoes feed on infected dogs and transmit the microfilariae to new hosts.
- An infected dog may show no symptoms for months or years. However, as the number of adult heartworms increases, symptoms start to appear.
- Coughing, tiring easily, decreased appetite, and weight loss are common signs. The dog may cough up blood or have nosebleeds.
- In severe cases, the worms can block blood flow, causing heart failure, lung disease, organ damage, and even death.
- Heartworm disease is diagnosed through blood tests that check for the presence of heartworm antigens and antibodies. Additional tests like chest x-rays can confirm the diagnosis and determine the severity of the infection.
- The good news is heartworm disease is preventable through medications that kill the larvae before they mature. However, treatment for adult heartworm infections can be difficult and expensive. Prevention is definitely the best way to protect your dog from this potentially deadly disease.
Early Signs And Symptoms of Heartworms in Dogs
If your dog is showing any of these symptoms, heartworm disease could be the culprit. Get your pup to the vet right away for testing and treatment.
- Coughing: One of the earliest signs of heartworms is a cough, especially one that gets worse with exercise or at night when lying down. Heartworms invade the heart and lungs, causing irritation that leads to coughing.
- Lethargy or decreased activity: As heartworms multiply in the heart and lungs, less oxygen is able to circulate in the blood. This can make your dog tired and less active.
- Difficulty breathing: If the heartworm infection is severe enough, it can cause fluid buildup in the lungs and make it hard for your dog to breathe. This is a medical emergency.
- Weight loss: Heartworms feed on blood and nutrients in the body, depriving your dog. Unexplained weight loss could signal heartworm disease.
- Swollen abdomen: Fluid buildup in the abdomen, known as ascites, can occur with advanced heartworm disease. The abdomen will look swollen and distended.
- Heart murmur or abnormal pulse: Heartworms can damage heart valves and alter heart rhythms, leading to abnormal heart sounds when listening with a stethoscope. An abnormal pulse may also be detected.
The good news is heartworm disease is completely preventable. Give your dog monthly heartworm medication and have them tested annually. Early detection and treatment can help get your faithful friend back to full health and activity. Don’t ignore the signs—your dog’s life depends on it!
Advanced Heartworm Symptoms in Dogs
Advanced heartworm disease can be life-threatening for dogs. As the disease progresses, the damage to your dog’s heart and lungs becomes severe. Watch for these advanced heartworm symptoms in your dog and get them to the vet right away if noticed:
1. Coughing And Respiratory Distress
Heartworms clog up and inflame the arteries in the lungs, making it difficult for a dog to breathe. You may notice your dog coughing frequently, especially at night or after exercise. Their breathing may become labored or wheezy. In severe cases, the coughing and difficulty breathing can lead to respiratory failure if left untreated.
2. Lethargy And Weakness
As heartworms damage the heart, it has to work harder to pump blood through the body. This can leave a dog feeling fatigued, less active, or weak. Your usually energetic dog may tire easily after normal activity or seem generally lethargic.
3. Swollen Abdomen
When the heart has to work extra hard against the heartworms, it can lead to fluid buildup in the abdomen known as ascites. The abdomen will look swollen or distended, and you may see visible rippling under the skin when the dog moves. The ascites can become severe enough to cause nausea or discomfort in some dogs.
4. Pale Gums
Check your dog’s gums if they look pale or bluish in color, that is a sign that their circulation and oxygen levels have been compromised by the heartworms. Pale gums warrant an emergency vet visit right away.
The damage from advanced heartworm disease can be irreversible, so early detection and treatment is critical. Be vigilant in watching for these serious symptoms in your dog and schedule regular vet checkups and heartworm testing to diagnose and treat the disease before it becomes this advanced. With prompt and appropriate care, most dogs can recover well and live normal lives, but the sooner treatment starts the better the outcome will be.
How do dogs get heartworms?
Heartworms are transmitted by mosquitoes. When an infected mosquito bites a dog, it deposits baby heartworms called microfilariae into the dog’s bloodstream. These microfilariae then mature into adult heartworms that lodge in the heart and arteries, causing damage and even death.
What are the symptoms of heartworm disease?
Early signs of heartworm disease are often subtle and easy to miss. As the infection progresses, symptoms may include:
- Coughing, difficulty breathing or tiring easily
- Lethargy or lack of appetite
- Swollen abdomen or visible heartworms under the skin
- Anemia, pale gums or blood in the urine
If left untreated, heartworm disease can lead to heart failure and death. That’s why prevention and early diagnosis are so critical.
How can I prevent heartworm disease in my dog?
The only way to prevent heartworm disease is through a monthly heartworm preventative medication prescribed by your vet. These come as chewable tablets, topical drops or injections. Whichever form you choose, it’s important to give them year-round as directed by your vet.
Do heartworm preventatives also treat other parasites?
Many heartworm preventatives are broad-spectrum, meaning they also protect against other common internal parasites like hookworms, roundworms and whipworms. Some also treat external parasites such as fleas. Check with your vet about which product is right for your dog based on their risk factors.
What’s the treatment for heartworm disease?
If diagnosed early, heartworm disease can be treated with a series of injections to kill the adult heartworms. However, treatment does come with risks, so prevention is always better. Talk to your vet about the best options for your dog if heartworms are detected.
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