Heartworms cause serious problems for dogs. Many pet owners have dogs with early stages of heartworm disease and don’t know it. Heartworm disease can be prevented and often cured in dogs but is fatal if left untreated. Pet owners should have their dogs tested for heartworm disease annually whether or not they are already on preventative medication.

What is heartworm disease?

Heartworms are a parasitic worm transferred to mammals through mosquitos. Although several mammals can contract the parasitic worm, dogs, wolves, coyotes and foxes are ideal hosts for the disease as the worm can mature into adulthood and reproduce inside their bodies. Ferrets are also susceptible to a fatal case of heartworm disease. Cats, and in rare cases even humans can contract heartworm disease, but most of the worms die before reaching adulthood making them less of a threat to the heart, lungs and other internal organs.  

How does heartworm disease spread?

Mosquitos are the only known transferring hosts of heartworms. While a mosquito is feeding on the blood of an infected animal with advanced stages of the disease, it ingests baby worms, or microfilaria living in the infected animal’s blood stream. After about two weeks, these baby worms have reached a level of maturity where they are infectious. Once a mosquito bites a susceptible host; it transmits the infectious larvae onto the skin of the animals which makes its way into the puncture wound left from the mosquitos bite and infects the animal. If your dog is on heartworm prevention medication, the larva typically dies quickly without causing harm. If your pet is not on heartworm preventative medication, the heartworm can live years without being detected. Then, as the worm grows and reaches adulthood, it starts causing serious complications.

What are heartworm symptoms?

Because heartworms can live up to 7 years, the symptoms are dependent on the stage of infection and the amount of worms an animal has.

    Stage 1 – No symptoms present other than the occasional cough

    Stage 2 – Occasional cough and abnormal tiredness

    Stage 3 – A cough, tiredness, and some trouble breathing. Signs of heart and or lung damage are usually seen on a chest x-ray at this stage.

    Stage 4 – Heartworms have caused severe damage to the animals heart, lungs, liver, and kidneys. In this stage, Caval syndrome is likely. Caval syndrome is when there is such a large amount of worms blocking blood flow to the heart that it creates a sudden life-threatening problem in need of quick surgical intervention. At this point, most dogs do not live long enough to receive the life-saving surgery.

Can you treat heartworm disease?

Heartworm treatment for dogs is possible, but treatment is costly and hard on your pet’s body. It typically requires many vet visits, blood work, x-rays, hospital stays and multiple medications. There is no drug approved to treat heartworm in cats. That said, cats that test positive for heartworm have a better prognosis as they are not ideal hosts for the parasite. The best thing for you to do for your pet is to prevent heartworms from ever developing.

Heartworm prevention is the best treatment

Dogs and cats should get on heartworm prevention medication starting as young as possible and no later than two months old. Dosage is based on body weight so most puppies and kittens can receive heartworm preventives as early as their first check-up. Every US state has reported heartworm infections, so every dog and cat in the US is at risk of coming into contact with the disease. There are three types of preventive options, but a veterinarian must prescribe them all. Heartworm prevention can be received through:

1.    Monthly heartworm prevention pills

2.    Monthly topical solution

3.    Bi-annual preventative injections   


Next steps for a healthier pet:

If your pet is not currently on a heartworm prevention regimen or you are more than two weeks late on administering your monthly heartworm preventative, than consult with your veterinarian or make an appointment today.  




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