Bites That Bring Disease: Protecting Your Dog from Heartworms & Lyme Disease
April is both National Heartworm Awareness Month and Prevention of Lyme Disease in Dogs Month, making it the perfect time to focus on protecting pets from these serious yet preventable diseases. Understanding how these infections are transmitted and taking proactive steps can help ensure your dog stays safe and healthy.
Mosquitoes and Heartworms
Heartworm disease, caused by Dirofilaria immitis, is transmitted through mosquito bites. Once in the bloodstream, the larvae travel to the heart and lungs, where they grow into foot-long worms. These worms cause significant damage to the heart and lungs, obstruct blood flow, and can ultimately lead to heart failure or death.
In many cases, there are no symptoms until the disease has progressed, and at this point, pets may develop coughing, fatigue, labored breathing, or even collapse. Treatment for adult heartworm infections is both costly and physically demanding, requiring a series of injections containing arsenic-based medication. Unfortunately, there is no safe treatment for heartworm disease in cats.
The good news is that heartworm disease is entirely preventable. Monthly year-round preventatives, available as chewable tablets, topicals, or injections, kill the immature larvae before they can develop into adult worms. An added bonus: many heartworm preventatives also protect against common intestinal parasites.
Ticks and Lyme Disease
Lyme disease is caused by the bacterium Borrelia burgdorferi, which is transmitted through the bite of an infected deer tick (Ixodes scapularis). Unlike heartworm disease, Lyme disease affects both dogs and humans, making prevention especially important.
In dogs, Lyme disease presents differently than in humans. The classic bullseye rash seen in people does not typically appear on dogs, and many infected dogs show no symptoms at all. Some, however, develop fever, lethargy, joint pain, swelling, and lameness that shifts from one leg to another, often weeks to months after infection. Treatment with antibiotics at this stage is generally effective, but if left untreated, Lyme disease can progress to acute kidney failure, which is difficult to treat and often fatal.
Fortunately, Lyme disease is easily preventable. Effective strategies include:
Use a monthly, year-round flea and tick preventative (oral or topical)
Avoid tall grass and wooded areas where ticks are prevalent
Perform daily tick checks (on both pets and humans!)
Discuss Lyme disease vaccination with your veterinarian to determine if it is appropriate for your dog
The Importance of Testing
Annual screening for heartworm and Lyme disease is highly recommended and is done with a simple blood test. A positive heartworm test detects an adult heartworm (infection), while a positive Lyme test detects antibodies to Borrelia burgdorferi (indicating exposure). After a positive Lyme test, further testing may be necessary to determine whether treatment is needed.
This April, ensure your pet is up to date on heartworm and Lyme disease testing, and talk to your veterinarian about the best multi-layered prevention plan for your pet. Prevention is always easier than treatment—stay proactive and keep your pets happy, healthy, and safe from heartworm and Lyme disease!
For more information:
American Heartworm Society Website (https://www.heartwormsociety.org/)
American Veterinary Medical Association’s information on Lyme Disease (https://www.avma.org/resources-tools/pet-owners/petcare/lyme-disease-dogs)