Heartworm in Dogs: Symptoms and Treatment
Heartworm disease is a very serious parasitic infection that directly affects your dog’s heart. In the veterinary community, we strongly promote prevention over treatment. This is because prevention is easy to provide and infection and treatment can be very difficult for dogs.
Your veterinarian will help you decide on the best course of prevention for your dog, and you should always obtain prescription products directly from your veterinary team. Find a trusted local veterinarian to learn more about why regular heartworm treatment is imperative to optimal dog health.
What is heartworm disease?
The worm-like parasites that infect your dog’s heart can grow up to a foot in length. The disease is transmitted by mosquitoes. When an infected mosquito bites your dog, that mosquito can directly infect your dog’s bloodstream with the parasite. It takes 4-6 weeks for the parasite to grow into adult heartworms. It doesn’t take long for these worms to reproduce and further infect and populate your dog’s heart. Adult heartworms in dogs can look like a ball of spaghetti and occlude valves, leading to heart failure.
What are the stages of heartworm disease?
The beginning of heartworm disease starts when an infected mosquito bites your dog and injects microfilaria directly into the bloodstream. From there, microfilaria develops into adult worms, taking over your dog’s heart as their home after a couple of molting stages. At this point, the adult heartworms lodge themselves in the heart and reproduce until their host becomes very ill. It can take up to two years for your dog to develop heart failure if infected with heartworm disease. However, it doesn’t take long after the heartworms occupy the heart to make your dog feel less than healthy.
What are heartworm symptoms and how is heartworm disease in dogs diagnosed?
Heartworm symptoms can include the following:
- A mild but persistent cough
- Fatigue after moderate activity
- A reluctance to exercise
- Decreased appetite
- Weight loss
- Swollen belly due to excess fluid in the abdomen
If you noticed any of these heartworm symptoms, you should take your dog to your veterinarian to have him or her tested immediately. Heartworm disease is diagnosed by a blood test. You should have your dog tested yearly for heartworm disease during their wellness and vaccine appointment. This screening test is quick but, if a result is positive, your veterinarian will want to conduct additional testing to confirm the result.
Is heartworm disease in dogs treatable?
Heartworm disease is treatable, but it depends on what stage of heartworm disease your dog has and if they are in heart failure. Heartworm treatment in dogs is lengthy and expensive but usually has a good prognosis.
Can you heartworm disease in dogs be prevented?
Heartworm prevention for dogs is easy and well worth it. Have your dog tested yearly for heartworm disease, even if monthly prevention is given? The reason for the annual heartworm test is it’s possible that your dog did not swallow an oral dose. Monthly heartworm prevention treatments should be started during puppyhood and continued throughout their life year-round, no matter the climate in which you live. Most heartworm prevention brands also protect against other internal parasites, such as roundworms and hookworms. These are also zoonotic, meaning you can catch them from your dog.
Heartworm is across the United States and more prevalent in southern states such as Florida and Alabama where there are more mosquitos. However, cases have been reported in northern, colder climate states such as Montana. This disease is extremely harmful to your dog but preventable with routine prevention year-round and yearly screenings during your dog’s wellness exam.
Because early detection and heartworm treatment greatly benefit your dog, we highly recommend you contact a veterinarian near you - especially if you suspect your dog may be suffering from parasites.