Treating and Preventing Heartworm

Heartworm (Dirofilaria immitis) is a serious and potentially fatal disease in dogs.

Heartworm is a blood-borne parasite, transmitted via mosquitoes. Mosquitoes bite dogs, and the infective larvae enter the bloodstream moving into the heart and adjacent vessels.  The young larvae mature over six months after infection.

Heartworms can clog the heart and major blood vessels in your dog, interfering with normal heart valve function, and the blood supply to all bodily organs, leading to disease and death. Young heartworms (microfilariae) circulate throughout the body in small blood vessels and may block blood flow depriving organs of nutrients and oxygen. This occurs in the lungs and liver.

Symptoms of heartworm that you may see in your pet are:

• Soft dry coughing
• Shortness of breath
• Weakness
• Reduced exercise tolerance
• Restlessness
• Death

Heartworm is diagnosed with blood tests and in cases showing symptoms, may require further tests including:

• Serological blood tests to detect adult heartworms
• Blood smears to detect microfilaria
• Complete Clinical Blood Test to assess organ damage
• X-rays to detect heart enlargement and disease secondary to heartworm
• Electrocardiograms and Echocardiography may be required to assess heart function

Heartworm is readily preventable with a range of products, including Proheart annual preventative injections. Starting injections at ten weeks of age, then repeated at six months, then annually with vaccinations.

In adult dogs, we recommend testing for heartworm before giving heartworm preventative medications. As giving preventative medications can kill the adult worms, allowing them to clog large blood vessels with catastrophic results.