Heartworm Information


Lowndes County has a very high incidence of heartworms in dogs. Please consider having your dog checked for heartworms at your local veterinarians during their annual rabies vaccination and check-up. Placing your dog on a monthly heartworm preventative will destroy the microfilaria that causes Heartworm disease to begin. Symptoms are not visible until, in many cases, it is too late to save your pet.

Effects of Heartworms

Arteries fail with worms living inside them. The lining of the artery becomes damaged within days of the worm's arrival. Cells of the immune system are called into the area but the worm is far too big for these tiny cells to destroy. The resulting inflammation continues to damage the artery. The arteries swell. Abnormal blood clotting (embolism) results. Blood is redistributed to other arteries that are not plugged by worms and fluid begins to build up in the lung around the worm-filled arteries.

The blood sent to the lungs is not well oxygenated and as areas of the lungs become damaged they are unable to provide oxygen to the blood. A form of non-infectious pneumonia (pulmonary eosinophilic granulomatosis) can result from excessive infiltration of inflammatory cells into the lung in response to the parasite.


  • Coughing and exercise intolerance result as areas of the lung are lost to the blood oxygenation process.
  • Nose bleeds may occur due to abnormal blood clotting in the lung.

Heart Failure

Blood normally is pumped with ease through the arteries of the lung.

  • If worms begin backing up into the heart, there will be less space in the pumping chamber for blood to be pumped.
  • In order to meet the body's oxygen demand, the heart must pump faster and stronger still.
  • This condition is called Pulmonary Hypertension and the right side of the heart must drastically increase its ability to work.
  • When the arteries are plugged with worms, the heart must pump harder against the pressure of the plugged arteries.
  • When the heart muscle begins to thicken due to overworking. It may not conduct electrical impulses normally. This means that the pumping / filling rhythm can be disrupted and an Arrhythmia may result.