Heartworm disease is a life-threatening condition that has been diagnosed in pets living in all 50 states. Many factors, such as climate, wildlife populations, and mosquito species, contribute to heartworms’ prevalence across the United States. Although the mosquito population peaks when temperatures and humidity are at their highest, the population never completely dissipates, and pets—including dogs, cats, and ferrets—are at risk for contracting this condition throughout the year. Fortunately, you can safeguard your pet against heartworm disease by ensuring they receive monthly medication administered year-round. Learn how to protect your pet by reading our Juanita Hills Animal Hospital team’s information about heartworm disease transmission, effects, and treatment options.
Infected mosquitoes can transfer heartworms to pets
More than a nuisance, mosquitos are key players in heartworm transmission. When a mosquito bites an infected animal—usually an infected pet or wild animal, such as a fox, wolf, or coyote—young heartworms (i.e., microfilariae) enter the bug’s system. Within two weeks, the microfilariae develop into larvae inside the mosquito, who can then transmit the parasite to another animal they bite. If an infected mosquito bites your pet, the immature heartworms migrate into your four-legged friend’s bloodstream, traveling to the blood vessels surrounding their heart and lungs. Once inside your pet, larvae spend about 6 months maturing into adult heartworms. Adult worms reproduce, and inflame and irritate an infected pet’s heart and lung lining, leading to vessel thickening. In addition, as the worms die at various developmental stages, their remains spread to smaller arteries, causing dangerous blockages. Adult heartworms can live for 5 to 7 years in a dog and 2 to 3 years in a cat.
Early heartworm signs in pets can be challenging to identify
Depending on the infection’s severity, heartworm disease signs vary. In the early stages, a pet may show no signs. Heartworm-positive cats may be asymptomatic, exhibit respiratory difficulty that mirrors asthma or bronchitis, or experience a catastrophic arterial blockage resulting in sudden death. Ferrets’ heartworm infection signs are similar to those of cats, and also include decreased activity, cough, and weakness. Dogs do not usually show signs until the heartworm larvae have matured, causing vascular inflammation. At that time, an infected dog may begin to show the following signs:
- Exercise intolerance
- Appetite loss
- Pot-bellied appearance
- Respiratory distress
- Sudden death
Test your pet for heartworm annually
The American Heartworm Society recommends pets be tested for heartworms every 12 months, including pets who are on heartworm prevention year-round—to ensure that the preventives are effective. Keep in mind that if you inadvertently miss providing even one dose of your pet’s preventive or administer the medication late, your four-legged friend may not have complete protection. To diagnose heartworm disease, your veterinarian can use one or both of two available blood tests. Five months after infecting your pet, the adult female heartworm begins producing certain proteins that can be detected through an antigen test. Another test detects microfilariae in your pet’s bloodstream. The earlier your veterinarian detects heartworm disease, the sooner they can provide treatment, and the better your furry pal’s prognosis.
Heartworm treatment is only available for dogs
Cats are not typical heartworm hosts, and most worms do not survive to the adult stage within a cat’s body. However, only one to two adult worms can be dangerous, and immature worms can cause a cat to develop heartworm-associated respiratory disease (HARD). Currently, no treatment is available for feline heartworm disease, making monthly prevention and annual testing vital for cats.
If your dog tests positive for heartworm disease, treatment is available—but this comes at a cost. Canine heartworm treatment is expensive, the recovery process is lengthy—requiring four to six months’ strict crate rest—and serious side effects can occur as the worms die.
Heartworm preventives protect pets
Heartworm preventives don’t prevent transmission. However, these medications prevent disease progression by killing the larval heartworms in your pet’s blood before they mature into adult worms inside your pet’s lungs and heart. Inconsistently administering your pet’s heartworm preventive enables microfilariae to mature, reaching a stage in which the medication is ineffective. Heartworm disease can develop in dogs, cats, and ferrets several months after an infected mosquito bites your pet, transmitting the immature worms. Only a two- or three-month lapse in preventive administration allows infection to take hold.
Heartworm disease prevention is the best treatment for all pets. Several products are available, which make protecting your pet convenient to your lifestyle. If you would like to discuss heartworm prevention methods or your pet should be tested, schedule an appointment with our Juanita Hills Animal Hospital team.