Heartworm disease is a potentially fatal but preventable condition. When your veterinarian examines your pet—regardless of the reason—they will likely ask you whether you are consistently administering your four-legged friend’s heartworm preventives and when they had their last heartworm test. Unfortunately, some pet owners underestimate this disease’s seriousness and prevalence, and fail to administer their four-legged friend’s year-round preventives, which safeguard their pet against the disease. Read our Palm City Animal Medical Center team’s eight facts about heartworm disease and prevention to help maintain your precious pet’s health.
#1: A parasitic worm causes heartworm disease in pets
A parasitic worm (i.e., Dirofilaria immitis) causes heartworm disease, which is a serious condition most commonly affecting dogs, cats, and ferrets. Heartworms can lead to severe lung disease, heart failure, and other organ damage. If left untreated, heartworm disease is usually fatal.
#2: Mosquitoes transmit heartworms to pets
The heartworm life cycle begins when a female mosquito bites an infected dog and ingests the microfilariae during a blood meal. Within 10 to 30 days, the microfilariae develop inside the mosquito. When an infected mosquito feeds on your pet, they transmit the infective larvae to your four-legged friend’s body.
#3: Adult heartworms live in your pet’s heart and lung blood vessels
Once the infective larvae enter your pet’s body, they move through the tissues and slowly migrate toward their final destination—your pet’s lungs and heart—where they mature into adult worms and begin reproducing microfilariae during the next six months. Female adult heartworms can grow to 14 inches in length. Adult heartworms clog the heart and its major blood vessels, including the pulmonary artery. When the worms clog the main blood vessels, they reduce the blood supply to the body’s other organs, particularly to the lungs, liver, and kidneys. Decreased blood flow and oxygen delivery can cause these organs to fail.
#4: Adult heartworms reproduce in an infected pet’s body
Adult worms reproduce microfilariae, which circulate throughout an infected pet’s body, but remain primarily in the small blood vessels. These immature heartworms are nearly the same width as the small vessels, and can block blood flow. Microfilariae primarily injure an infected pet’s lungs and liver. They may also affect a pet’s kidneys, causing toxins to accumulate in their body.
#5: Heartworm disease can affect cats, dogs, and ferrets
Most people believe heartworm disease affects only dogs, but cats and ferrets can also contract the disease. Although cats are not this parasite’s preferred host, your feline friend can still suffer significant, potentially life-threatening health complications if they are infected. Only one to two adult worms are necessary to sicken a cat, but unfortunately, their subtle disease signs are commonly misdiagnosed as more common feline respiratory conditions. Ferrets are also highly susceptible to heartworm disease, and one or two adult worms can affect them similarly to cats.
#6: Heartworm signs develop slowly in pets
Heartworm disease is sometimes referred to as a silent killer because the condition can take months before an infected pet exhibits signs. As the heartworm larvae mature and the infection progresses, signs may include:
- Decreased appetite
- Weight loss
- Difficulty breathing
- Abdominal swelling
In severe cases, heartworm disease can lead to heart failure, and a pet may collapse, have pale gums, and experience seizures. Heartworm-positive cats may be asymptomatic, exhibit respiratory difficulties that mirror asthma or bronchitis, or experience a catastrophic blockage that results in sudden death.
#7: Heartworm disease treatment is available only for dogs
Unfortunately, no safe treatment is available for heartworm-positive cats, although medical management can help keep an infected cat comfortable for as long as possible. Canine heartworm treatment is available, but is expensive, lengthy, and risky. The earlier a dog’s infection is diagnosed and treatment begins, the better their prognosis. Treatment involves a series of injections to kill the adult heartworms, which poses risks, as the dead and dying worms can form a life-threatening blood vessel blockage. During and after treatment, an infected dog’s owner must restrict their four-legged friend’s activity and carefully monitor their signs to prevent additional heart and lung damage.
#8: Heartworm prevention protects your pet
The best way—and the only way for cats—to ensure your pet is protected against this devastating disease is through year-round consistent administration of veterinarian-prescribed heartworm preventive medication. Preventives are available in monthly oral or topical treatments for dogs and cats, and in 6- or 12-month injections for dogs. Heartworm preventives eliminate the circulating microfilariae but do not kill adult heartworms, making heartworm disease testing essential before starting a prevention protocol.
If your pet does not currently have a year-round heartworm prevention plan, schedule an appointment with our Palm City Animal Medical Center team, and rest easier knowing you’re doing all you can to protect your pet from this life-threatening infection.