Heartworm Disease

This disease is very prevalent in tropical zones and along the Gulf Coast. All 50 states have heartworm disease. It can affect any pet older than 6 months old, but is most common in 3-8 years olds. It is reported dogs have a 100% chance of getting heartworm disease if they are not on monthly prevention and live in a high incidence area.

Mosquitoes carry the microscopic worm and transmit it to dogs through a bite. The worms grow over a period of months and eventually lodge in the heart and the lung vessels. Heartworms can grow to be 30 cm long.

Most animals are diagnosed in Stage I or Stage II heartworm disease. Stage I is not symptomatic and these animals are usually diagnosed through a routine heartworm test. Stage II animals exhibit coughing and exercise intolerance and have already suffered some lung damage. Stage III patients are very ill and usually in congestive heart failure.

There is currently very effective treatment for heartworm disease. It involves injections in the back 3 times over a period of a month. This treatment eradicates the adult worms but does not kill the "baby worms" called microfilaria. Pets will need to take heartworm prevention to kill the baby worms so they can not grow to be adults. This treatment is almost 100% effective at curing a pet of heartworm disease.Even though there is a very effective treatment for heartworm disease, prevention is always recommended. The treatment can be painful and is expensive for bigger dogs. It is less expensive to give a pet heartworm prevention monthly for their entire life than to pay for the treatment in some cases! Most drug manufacturers guarantee their product and will pay for treatment if your pet has been on prevention without fail. It is important to realize if your pet has missed only one month of prevention they can contract this disease. However, it is almost impossible for the pet to develop heartworms if they receive a form of prevention every 30 days. If there are no "baby worms", there can be no adults. Please see Heartworms, Fleas, and Ticks to compare the common heartworm preventions.For information on feline heartworm disease, please see Feline Heartworms.