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9 Things to Know About Heartworms In Dogs

Heartworms In Dogs
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Dogs & pets have been inspirational signs of love and loyalty. Nothing lights up a home brighter than the affection and admiration of pets. The best indication or depiction of love from a pet parent to their dogs is safeguarding them against various diseases and conditions. 

Many people bring a dog to their home without knowing the basics of different illnesses they might be vulnerable to. One such common disease found in them is heartworms. Studies show that one out of every 200 dogs gets affected by this disease.

Failing to diagnose and treat the disease at the right time could lead to fatal consequences. Even if your dog survives, it might have to live with long-term organ damage.

The good news is that the success rate of the treatment is impressive, with over 95% of dogs surviving the disease. With timely treatment and proper care, most dogs can continue to lead happy and healthy lives.

Technology and medicine have proven to be highly effective in these cases. While Heartgard for dogs is used to prevent heartworms by killing the larvae in the bloodstream, medicines like melarsomine are used for treating this disease.

These medications are formulated to eliminate adult heartworms and kill any bacteria associated with the worms. 

In this article, we will outline a few crucial details about heartworm disease in dogs to help pet parents gain a better understanding of the condition. Let’s get started.

There are many things a pet parent should know about heartworms in dogs. Therefore, the following section will provide a detailed overview of a few vital points on “9 Most Important Things To Understand Heartworms Disease in Dogs.

Heartworms In Dogs Causes

Most of the diseases in pets are caused by consuming bad or rotten food items. But dogs are exposed to heartworms through mosquitoes. These mosquitoes act as blood carriers from another animal that is infected. 

The larvae transfer when the host mosquito feeds on the dog. In this carrying stage, the immature larvae are known as microfilaria. Research states that there are approximately 30 mosquito breeds capable of transferring heartworms. 

It’s worth mentioning here that heartworm disease isn’t contagious. That means the parasite can’t be transmitted from an infected dog to a healthy dog or any other animal.

Size Of The Heartworm

Dogs encounter various kinds of worms on streets, water bodies, etc. and their sizes differ. Heartworms can be extremely long compared to most other worms.

Their breadth is around 5 mm, while their length varies in males and females. While males are 6 inches long, females can grow up to 12 inches or longer, resembling the shape of noodles. 

The sheer size of heartworms makes them more dangerous than other parasites. Also, if left untreated, heartworms can survive and reproduce in a dog’s body for up to seven years. Dogs can have nearly 250 living worms inside their bodies. The condition is known as worm burden.

How Heartworms Are Transmitted?

Many research studies have tried to ascertain a relationship between the topography of a region and the spread of heartworm disease. Some people highlight that the condition is commonly found in high-temperature zones.

Heartworms are transmitted through the bite of infected mosquitoes. When a mosquito bites an infected animal, it picks up baby worms (microfilariae) which mature into larvae.

Later, the infected mosquito bites another animal, transmitting the larvae. These larvae mature into adult heartworms in the host’s heart and lungs.

While prevalent in many parts globally, heartworm disease is especially common in tropical and subtropical regions, with localized outbreaks in temperate zones.

It isn’t surprising considering that mosquitoes tend to thrive better in hot and humid weather.

However, there is no conclusive determination of any geographical limits of the illness. Research conducted in the US found that the disease was present in dogs in all 50 states of the country, regardless of their climate or weather system.

Therefore, pet parents should avoid carelessness, even if they reside with their dog in cold temperatures.  It’s just as important to take precautionary measures when people travel with their dogs.

End Stage Heartworms In Dogs

The host larva matures into an adult in around six months. In this duration, the infection travels through the bloodstream and reaches different organs in a dog’s body, including their lungs, hearts, blood vessels, etc. It is better to get the diagnosis at the early stages to avoid any severity.

Heartworms In Dogs Symptoms

Most of the diseases in dogs are difficult to identify at early stages. That’s because dogs are fairly adept at masking their weaknesses. They’d rather suffer in silence than let their human companions know that they’re in pain.

That’s why even a thorough diagnosis can also fail to detect heartworms. However, it’s important to monitor the symptoms and administer the right treatment early on.

The symptoms of heartworm disease take around six months to be clearly seen in the dog. These signs include:

  • Lack of energy or enthusiasm
  • Exercise intolerance
  • Continuous dry cough
  • Weight loss
  • Breathing problem 
  • Post-exercise symptoms like coughing or fainting
  • Loss of appetite
  • Degrading coat quality
  • Lethargy

Advanced stages of heartworm disease are characterized by syncope, i.e. fainting due to restricted blood flow. Your dog could also develop a swollen belly caused by heart failure. The condition is known as ascites.

Pet parents should make it a point to immediately consult a licensed veterinarian when their dogs start showing any of the aforementioned symptoms.

Heartworm In Dogs X-Ray

Considering the slow and silent maturation process of heartworm larvae, it can take up to a year before a dog starts exhibiting characteristic symptoms. That emphasizes the importance of taking your dog to the vet for regular screenings to rule out heartworm disease. 

X-rays of dogs with heartworms reveal distinct changes. The heart often appears enlarged, particularly the right side, and the pulmonary arteries, especially those leading to the lungs, can show a tortuous, enlarged appearance.

A characteristic “reverse D” or “pulmonary artery bulge” may be observed, indicating advanced heartworm disease. These radiographic changes reflect the obstruction and inflammation caused by the presence of adult worms.

Routine heartworm screening helps detect and treat the condition at its early stages. Puppies as young as six months of age should be screened for the parasite. Even if your dog is on preventive medication, make sure you get tested for the parasite at least once a year.

Testing is just as important for dogs who have previously undergone treatment for heartworm disease.

Prevention Of Heartworm In Dogs

It is necessary to prevent the condition rather than wait for the treatment. That’s because the cost of treating heartworm disease in dogs is 15 times higher than that of preventing the condition.

Pet owners can use various measures to prevent this ailment. These include eye inspection, oral pills, chewable tablets, annual injections, etc. Topical treatments are also available for the prevention of heartworm disease.

However, before using these measures, people should make sure that they have a valid prescription from a licensed veterinarian. They’ll also help you identify the most effective preventive technique based on your pet’s lifestyle and medical history.

Heartworms Vaccine

Most preventive treatments for heartworm disease must be administered for a pre-defined duration, at specific times of the day. It’s important for pet parents to follow these instructions to the ‘T’. 

While the duration of treatment varies from 30 days to six months, it’s up to a veterinarian to determine how long your dog will need to take the medication.

Make sure you administer each dose at the right time. Otherwise, you could end up jeopardizing your dog’s health, and leave them susceptible to infection.

there is no vaccine available to prevent heartworm disease in dogs. The primary method of prevention involves monthly prophylactic medications, which can be in the form of tablets, chewables, topicals, or injections.

These medicines effectively prevent heartworm larvae, transmitted by infected mosquitoes, from maturing into adult worms within the dog’s heart and lungs.

Regular testing and a consistent administration of preventatives, as prescribed by a veterinarian, are vital to ensure a dog remains heartworm-free.

Risks Involved In Heartworms Treatment In Dogs

There are numerous constraints in the treatment of heartworms in dogs. While treating the disease, a dog can face different conditions, including blood clots and fatal consequences.

Also, your dog can experience adverse reactions due to the presence of dead heartworms in its body. The dying parasites could accumulate in your dog’s lungs, causing respiratory distress and even death.

That emphasizes the importance of monitoring your dog’s health and constantly staying in touch with your veterinarian. Apart from the health risk, the treatment is also costly and can reach up to $1000, depending on the severity and spread of the disease.

Heartworm In Dogs After Treatment

If you don’t give your dogs a timely heartworm treatment, it may result in severe conditions, including caval syndrome. In this situation, there is a blockage in blood flow due to the accumulation of an extensive number of worms.

Typical symptoms of caval syndrome include:

  • Breathing difficulties
  • Pale gums
  • Dark-colored urine

It is a critical scenario where surgery is needed to extract these worms from the dog’s body. Once the dog is affected by this problem, survival becomes tricky. It has around 14 to 42% death risks. Even if they survive the surgery, their main body parts, like lungs, liver, etc., will not be healthy. 

Other long-term consequences of heartworm disease include lung damage and congestive heart failure. The inflammatory response to the parasite can also cause severe damage to lung tissue.


The points mentioned above give adequate information about the severe disease found in dogs worldwide. Many people ignore such conditions and take them as a mere climatic reaction. Dog parents should be responsive to these changes and approach a licensed professional immediately. 

Take adequate preventive measures, such as eye inspection and oral pills, to protect your dog from the parasite. Also, keep an eye out for common symptoms of heartworm disease, including weight loss, dry cough, and degrading coat quality. Don’t forget to take your dog to the vet for regular heartworm screenings as well.

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