Warning Signs: Heartworm Symptoms In Dogs

Kate Barrington
by Kate Barrington
Pet parents need to know the heartworm symptoms in dogs in order to catch and treat this potentially fatal disease in time.

Heartworm is a disease caused by a parasitic worm that lives in the tissues and arteries of the heart in infected dogs. This disease is incredibly dangerous and, unfortunately, it is still fairly common even though preventive measures are inexpensive and simple to implement. It is also the case that dogs infected with heartworm typically do not exhibit symptoms until the disease has progressed and the heartworm has begun reproducing. At this point, treatment can be expensive and the condition itself will likely be painful for the dog. To protect your dog from the pain and suffering from these disease, take the time to learn the basics about heartworm symptoms in dogs.

Related: Heartworm Treatment: What Are Your Options?

Transmission of Heartworm

A dog infected with heartworm cannot pass the disease directly to another dog – heartworm can only be transmitted by mosquitoes. When a mosquito bites a dog that is infected with heartworm, it takes in some of the microfilariae – the baby heartworms – and they develop inside the body of the mosquito over a period of 14 days into infective larvae. Then, when the mosquito bites another dog, it transmits some of those larvae into the dog’s bloodstream. What many pet owners do not realize is that when an infected mosquito bites an unprotected dog, the dog doesn’t immediately become infected with heartworm. It takes about six months for the infective larvae to develop into adults and to start reproducing. It is only when the adult heartworms take up residence in the heart and lungs then begin producing when the dog is likely to exhibit symptoms.

Related: How Do Dogs Get Heartworm?

Heartworm Symptoms in Dogs

Heartworm symptoms in dogs can be easy to confuse with the symptoms of other diseases, which is part of what makes these disease so dangerous. It is also possible for some dogs to not show any symptoms at all until the disease has progressed into the final stages where it will be difficult to treat. Some symptoms of heartworm may include labored breathing, vomiting, coughing, unexplained weight loss, lethargy, and exercise intolerance. Dogs that are highly active and those with other medical problems are more likely to show symptoms than dogs that are otherwise healthy.

As the disease progresses, infected dogs may develop more severe symptoms such as abdominal swelling due to fluid accumulation or heart failure. Some dogs even develop a condition called caval syndrome caused by a blockage of blood flow to the heart. If surgery isn’t performed to correct the blockage, the dog has a low chance of survival at this point. Symptoms of caval syndrome include the sudden onset of labored breathing, bloody or coffee-colored urine, and pale gums.

Prevention of Heartworm

By now you should understand the seriousness of this deadly disease. Though heartworm is incredibly deadly, it is actually easy to prevent. All you have to do is get your vet to prescribe a monthly heartworm preventive that you give your dog every 30 days. In order to be started on a preventive program your dog will first need to be tested for heartworm. Only puppies under six months of age can be started on a preventive program without testing but they must be tested within another 6 months of starting the program.

Heartworm is a dangerous disease but it is also highly preventable. At the first signs of heartworm symptoms in dogs, take him to the vet immediately to be treated. And to keep your dog healthy, be sure to speak to your vet about a heartworm preventive program.

Kate Barrington
Kate Barrington

Kate Barrington is the loving owner of two cats (Bagel and Munchkin) and a noisy herd of guinea pigs. Having grown up with golden retrievers, Kate has a great deal of experience with dogs but labels herself a lover of all pets. Having received a Bachelor's degree in English, Kate has combined her love for pets and her passion for writing to create her own freelance writing business, specializing in the pet niche.

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