Heartworms are now common in pets and stray dogs across the United States. The warmer the climate and the more mosquitoes present, the more likely it is that your pet will catch them.
Some facts about heartworms Heartworms are transferred from dog to dog through the bite of an infected mosquito. In areas where heartworms are common, a few summers of repeated mosquito bites to dogs not receiving preventative medications can result in enormous numbers of adult worms in the petís heart. The more mosquito bites your pet gets, the more the chance it will get infected. So dogs that spend a lot of time outside or in unscreened areas are much more likely to have heartworms than indoor pooches.
What are the signs of heartworms in my dog? Most dogs do not show any signs early in infection. The first sign of heartworm disease is premature aging. Dogs with heartworms often gray prematurely about the muzzle and forelegs. Their coat lacks luster and with time, their activity level decreases. Owners donít notice this because it occurs so gradually and many write it off as ďjust getting old.Ē
With time, a persistent, dry cough begins. This cough is most noticeable at night when the house is quite and the dog is resting or in a sitting position. This cough is due to three things: bronchitis that develops as pieces of dying worms become trapped in the lungs, fluid that accumulates in the lungs as the heart fails and the enlarged damaged heart pressing on the petís wind pipe.
Later, the dogís tummy assumes a pear-shaped, pot-bellied look as the dogís liver enlarges and fluid accumulates in the abdomen. While these events are occurring, the dogís heart and pulmonary arteries are enlarging due to mechanical obstruction of the worms, inflammation and damage to the heart valves.
How do heartworms injure my petís heart? Not only do mature heartworms clog up the arteries leading to the lungs, as the heartworms grow, they irritate the lining of the network of blood vessels that lead from the heart to the lungs. This irritation partially blocks these arteries and makes the heart work harder to pump blood through the lungs to receive oxygen. The more heartworms are present, the harder the work becomes. Eventually, the heart begins to enlarge and fail due to the overwork.
How will my veterinarian check if my pet has heartworms? Most veterinarians check their patientís blood for heartworms every year. The most accurate test checks for products that heartworms release in your petís blood stream. All heartworm tests rely on finding substances that only mature heartworms produce or finding baby heartworms (microfilaria) in your pet. It takes five to seven months from the day your pet was bitten by an infected mosquito for these substances to appear. So there is no point in asking for these tests if your pet is less than 5-7 months old.
How do I keep my dog from getting heartworms? Ordinary worm medicines do not kill heartworms. To prevent your pet from catching heartworms, you must give them a special preventive medication. It is important to protect your pet from heartworm disease. Prevention is much easier than treatment. Most common preventative medications are taken once monthly in the form of oral pills, chewable tablets or a topical ointment. The newest form of prevention is the six-month injectable.
Joann Hager, founder of Tri-County Animal Rescue, writes a weekly pet advice column for The Gazette. For more information, visit www.tcar.us.