by Sally Uhrich

It’s that time again; April is national heartworm month. Pet owners need to begin treatment for the prevention of heartworm disease in dogs.

To jog the concern of clients, veterinary clinics often display a preserved heart infected with heartworm in a jar and hang posters about heartworm life cycles in examining rooms. However, seeing is not necessarily believing. Although clients can view the infested heart loaded with long, spaghetti-like worms every time they visit, many gamble that their dogs will never be bitten by an infected mosquito.

Heartworm prevention is simple. It involves a blood draw to determine whether the parasite is present and regular dosing with preventive medication. Heartworm infestation is dangerous; untreated dogs die and treated dogs go through weeks of discomfort, while the worms are killed and expelled from their bodies.

Mosquitoes ingest larva when biting an infected dog and deposit the cargo in uninfected dogs. The microfilariae burrow into the dog and eventually travel to the right side of the heart through a vein and await the opportunity to reproduce. The worms can also lodge in the veins of the liver. Adult heartworms can reach 12 inches in length and can remain in a dog’s heart for several years.

The progression of the disease is traumatic. Symptoms include a listless dog with a worsening cough. Breathing becomes more difficult as the disease may progress into congestive heart failure.Treatment for the disease is possible and successful, if the disease has not progressed too far. Dogs must first be evaluated for any secondary problems of heart, liver or kidney problems, to determine if it can endure treatment.

Medication is administered each day for two days, followed by several weeks of inactivity to give the dog’s system a chance to absorb the dead worms. Exertion can cause the dead worms to dislodge, travel to the lungs, and possibly cause death.

Further treatment is needed at least three-to-four weeks after the administration of the drug to kill the adult worms. The dog is dosed daily for a week, then the blood test is repeated. If microfilariae are still present, the dose can be increased. Follow-up studies should be done in a year. Surgical removal of the adult heartworms may be indicated in advanced cases with heart involvement.

Preventive medications come in oral and topical versions and are only available from a veterinarian. Some of these drugs also kill other parasitic worms, as well as fleas, ticks and mites. Some veterinarians recommend a year-round heartworm prevention program to guard against the occasional mosquito flying about in areas with mild winters. Talk to your veterinarian as to whether year-round or seasonal treatment is best for your dog.

The treatment of heartworm disease involves time and money for the pet owner, not to mention the anguish involved with watching one’s pet endure agonizing treatments. The possibility of loosing the dog is a real concern. This is one situation where an ounce of prevention is definitely worth a pound of cure!

Castle Pines veterinarian Dr. John Vickers is offering a 10 percent discount on heartworm testing through the month of April. To schedule an appointment, call 303-688-8665.