The heartworm, or diofilaria immitis, is a parasitic worm that can cause infection in animals. The Merck Veterinary Manual states at least 70 species of mosquitoes can serve as intermediate hosts for the filarial organism. Heartworm infections generally are diagnosed in dogs, but also can occur in cats and even ferrets. Any breed or size can become infected. However, “most infections are diagnosed in medium- to large-sized, 3- to 8-year-old dogs,” reports the Merck manual.
Signs of heartworm infection. Unfortunately, early detection of heartworm infection can be difficult, as signs may not be noticed easily. A dog infected with heartworms may have a mild yet persistent cough after the worm infestation grows. The American Society for the Prevention of Cruelty to Animals (ASPCA) states some animals may show signs that include:
- Labored breathing
- Fatigue and listlessness
- Vomiting and weight loss
Cats and heartworm infection. The American Heartworm Society cautions that cats can have non-specific symptoms when infected with heartworms. These signs of heartworms often mimic other feline diseases and, as a result, the heartworm infection may not be detected. Signs can include breathing difficulties, gagging/vomiting, lethargy and weight loss. While these symptoms are similar to those that present with feline allergic bronchitis or feline asthma, the American Heartworm Society states the symptoms are due to a condition called Heartworm Associated Respiratory Disease or HARD. If you suspect your pet has heartworm symptoms, contact your veterinarian immediately.
How pets are infected with heartworms. Pets, both indoor and outdoor animals, may be infected by heartworms through mosquito bites. The heartworm enters your pet’s bloodstream as microscopic larvae. It takes about six months for the larvae to mature into worms that make their way through the bloodstream and into the heart chambers. Along the way, the heartworms can damage arteries and blood vessels. Heartworms can live in dogs for as many as seven years.
Heartworm prevention. The ASPCA and the American Heartworm Society recommend giving your pet heartworm medication year round, as this will help prevent not only heartworm infection but also can provide protection against other intestinal parasites. Medication typically comes in pill form, but topical products applied to your pet’s skin are another option. Consult with your veterinarian on the best heartworm preventative treatment for your pet.