Some Facts About Heartworms
Male heartworms are a few inches long and look like angel hair spaghetti. The female worms are much larger and cause most of the damage. 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 pet's heart.
After a mosquito sucks larva heartworms up with blood from an infected dog; it rests for a period of time before these larva become infective. When that mosquito then bites another dog or the same dog, it transfers these microscopic larva as it bites. That is the only way a pet gets a new heartworm. During the next 6-7 months, the larval heartworms migrate slowly through the dogs body and arrive at the heart . There they mature into adult worms.
Heartworm disease is worst in warm areas of the World where mosquitoes are active all year long. 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 don't notice this because it occurs so gradually and many write it off as "just getting old". They just don't have that old "bounce in their step". This occurs much slower or not at all when a dog only has a few heartworms. 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 pet's wind pipe.
Later, the dog’s tummy assumes a pear-shaped, pot-bellied look as the dog’s liver enlarges and fluid accumulates in the abdomen. While these events are occurring, the dog’s 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 Pet's 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 patient's blood for heartworms every year. The most accurate test checks for products that heartworms release in your pet's blood stream. All heartworm tests rely on finding substances that only mature heartworms produce or finding baby heartworms (microfilaria) in your pet. It takes 5-7 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.