Spring is here, and so is the annual resurgence of heartworm disease-carrying mosquitoes. And while warmer weather certainly creates an insect population boom, dismissing heartworm disease as only a fair weather threat puts your pet in serious danger. 

This parasitic disease is now more prevalent than ever, affecting more than one million pets every year, and driving the need for year-round heartworm prevention in dogs and cats. If that’s not enough, Town and Country Animal Hospital has compiled 12 reasons why your pet needs 12 months of heartworm prevention.   

#1: Deadly heartworm disease affects dogs, cats, and ferrets

Heartworm disease is caused by a parasite that is transmitted through an infected mosquito’s bite. Heartworm larvae migrate to the pet’s heart and lung vessels, where they mature into long spaghetti-like worms, creating vascular inflammation, restricting blood flow, and compromising circulation. Pets with heartworm disease often experience progressive signs that include heart failure, blood vessel obstructions, and sudden death.

#2: Heartworm disease has been diagnosed in all 50 states

There’s no hiding from heartworm disease. Mosquitoes and infected pets have carried this deadly parasite, formally known as Dirofilaria immitis, all across the country, as well as to Hawaii and Alaska. 

While the warming climate and altered wildlife migration patterns have contributed to this change, increased stray and rescue pet transport—many of which were likely carrying heartworm disease—has also played a role.

#3: Mosquitoes don’t stop at the door—indoor pets need protection

Mosquitoes don’t respect boundaries. So, while your indoor-only pet may never set a paw outside, heartworm-carrying mosquitoes can slip through an open door or window screen, or hitch a ride on another pet, or your clothes. If your indoor pet—including cats and ferrets—isn’t on preventives, they’re vulnerable to heartworm disease.

#4: One missed dose and your pet can be infected

Monthly heartworm prevention works by preventing immature heartworms (i.e., microfilariae) from reaching the damaging adult stage. Each month, the medication kills off any circulating microfilariae. But, when your pet misses a dose, or you pause their preventive during the winter, the immature heartworms have a chance to grow. By the time you restart your pet’s preventives, the medication is no longer effective against the maturing worms and the infection they cause.

#5: Affected pets may show no signs until infection is severe

You often have no way of knowing that your pet is heartworm positive until the disease is in the late stages, or your pet is tested during their annual wellness appointment. Infected cats may not show any clinical signs at all—but may pass away unexpectedly. 

Assuming you will know when your pet is sick and only then pursuing treatment is gambling with their health—especially when prevention is easy and effective.

#6: Heartworm disease treatment isn’t available for cats or ferrets

Dogs can undergo treatment to kill existing adult heartworms but, unfortunately, no safe heartworm treatment is available for cats or ferrets, who can only be given supportive care. Heartworm positive cats can be treated symptomatically to manage their pain and clinical signs, in hopes that they may outlive their heartworm infection—however, many cats do not survive. Ferrets may be treated off-label with dog medication, but those with severe disease face high fatality risks.

#7: Pet heartworm prevention is more economical than treatment or management

The average price of heartworm prevention is between $5 to $15 per month, while heartworm treatment in dogs can cost up to $1,200. Additional costs, such as emergency stabilization for heart failure or respiratory distress, may be necessary for dogs.

#8: Heartworm treatment for dogs is painful, lengthy, and not risk-free

Canine heartworm treatment involves killing off the adult worms—which can range in number from 20 to 200—without triggering a life-threatening blockage as the dead worms leave general circulation. The process involves a series of painful, deep intramuscular injections, followed by six weeks of strict crate rest to minimize the risk for a traumatic obstruction. 

#9: Prevention protects other pets, too

When your pet receives a heartworm preventive, they are no longer a reservoir host for Dirofilaria immitis—meaning the heartworm cycle stops with them, and they cannot be infected or pass on the infection through the mosquito’s blood meal. This in turn can reduce the chances of other area pets—including stray or immunocompromised animals not receiving preventives—being infected.

#10: Monthly heartworm prevention for pets includes a dewormer

When you give your pet monthly heartworm prevention year-round, you’re also protecting them from roundworms and hookworms. Most monthly chewable and topical treatments include a dewormer, while others may include flea and tick prevention.

#11: Heartworm prevention for pets is safe, easy, and effective

There is no reason not to protect your pet with heartworm prevention. Heartworm preventives are proven safe and effective, and the only sure way to protect your pet from heartworm disease. Preventives come in every formulation—including topical, oral chews, and 6- or 12-month injections—making ensuring your pet’s health and safety more convenient than ever.

#12: Your pet’s annual heartworm test is an automatic reminder to refill your prescription

We recommend that your pet have their heartworm screening test and their heartworm medication refilled at their yearly visit. This simple blood test ensures that your pet’s prevention program is working properly, and that no doses have been missed during the previous year. 

Heartworm disease doesn’t take a holiday—and neither should your pet’s prevention protocol. To schedule your pet’s annual heartworm test, or to ask about prevention product recommendations, contact Town and Country Animal Hospital.