Most dogs with heartworm infection have no clinical signs, regardless of worm burden and duration of infection. In these animals, infection is often an incidental finding on routine screening. Only dogs with very high worm burdens or complications of heartworm infection present to the hospital with clinical signs of heartworm disease. Heartworm disease is the clinicopathologic manifestation of heartworm infestation of the pulmonary arteries, right side of the heart, and vena cava and may cause several cardiovascular life-threatening conditions.
The observed clinical signs depend on the severity of disease and the duration of infection. They often reflect the effects of the parasites' presence in the pulmonary arteries and lungs. The history may include weight loss, diminished exercise tolerance, lethargy, poor body condition, cough, dyspnea, syncope, and abdominal distention/ascites. If severe heartworm disease with pulmonary hypertension is present, physical examination may reveal a split second heart sound, a right-sided heart murmur (tricuspid insufficiency), and a cardiac gallop.
Heartworm infection can be diagnosed on routine screening before the development of clinical signs by directly examining the blood for microfilariae or by testing for the presence of circulating antigens in the blood, serum, or plasma.
Nowadays there is a wide number of veterinary products used in the prevention and control of the disease. You may be able to choose the schedule that works better for you and your pet: one tablet once a month (Tri-Heart, Heartgard) or one injection every 6-12 months (Pro-Heart). No matter what product you will decide Heartworm disease prevention will be achieved, your fur baby will be happy and healthy.