Heartworm disease is a widespread condition that threatens the lives of dogs and cats every year. The disease is caused by a parasite that can grow up to a foot long in the heart and lungs of infected hosts and is transmitted between individuals by mosquitos. Left unmanaged, the disease can be severe and, in some cases, fatal.


Medication in the form of pills, topical ointments, and injections should be administered year-round to prevent infection. A prescription by a veterinarian is required to purchase any preventative medication and many websites have been caught selling fake or unapproved preventatives, so be sure to consult with your veterinarian about which brands to trust.


In both cats and dogs, a heartworm infection is most commonly accompanied by a mild cough. Dogs may also experience fatigue, decreased appetite and weight loss. Cats may exhibit asthma-like attacks, vomiting, decreased appetite, weight loss, difficulty walking, fainting, seizures, or fluid accumulation in the abdomen. If your cat or dog displays any of these symptoms, a veterinarian can perform a test to check for heartworm infection. Additionally, it is recommended that both cats and dogs are tested every twelve months in order to detect new infections before symptoms develop.


Symptoms of heartworm can quickly progress and lead to life-threatening conditions for your dog, so early detection is key to treating this disease. Your veterinarian may prescribe medication to treat the infection and lessen the severity of symptoms. In addition, it is important to limit your dog’s exercise, as physical activity can worsen the damage that heartworm causes to the lung and heart.

Unfortunately, there is no approved medication to treat heartworm in cats, so prevention is critical. If your cat does test positive, a veterinarian may recommend hospitalization to manage symptoms and stabilize your cat. Continued administration of preventative medications is essential to ensure that your cat does not develop new infections that worsen the severity of the disease.


With temperatures warming up for the summer, mosquitos will become increasingly abundant leading to more transmission of this disease. If you do not use heartworm preventatives for your cat or dog already, now is a great time to start. It may just save their life!