By Dwight D. Bowman, MS, and PhD for Veterinary Practice News
Heartworm disease is a horrible disease that consists of foot long worms that live in the pulmonary arteries and the heart of infected dogs. This disease is 100 percent preventable using safe products that can be conveniently administered to dogs on a regular basis. These products also have activities against other internal and external parasites.
So, why bother to have all dogs on year round prevention? The best answer is: Why not? The drugs are remarkably safe. The safety information and years of field use have revealed no significant secondary disease due to these products. We now have several generations of dogs who have received these products their entire lives, and they appear completely happy and healthy.
Heartworm is a brutal disease. Treatment is not a good alternative to prevention!
All mosquitoes do not sleep all winter long, so it is hard to predict when in a year mosquitoes will be present in any number. If a mosquito goes to sleep in the winter with a heartworm in its tissues, will it still be infective in the spring? We do not know, but some agents, such as West Nile virus, over winter in mosquitoes and are infectious as soon as they get warm enough to awaken and feed.
If heartworm starts cycling in an area, it tends to stay there, and we have not pushed heartworms out of any community.
The year round treatment of dogs for heartworms also prevents infections with common intestinal parasites. Most of the heartworm preventives on the market also remove adult intestinal parasites. Roundworms and whipworms can occur in the middle of winter; eggs in backyards, under a foot of snow remain infectious. Hookworms are constantly migrating to the dog's intestine from the deeper tissues where they cannot be reached by concentrations of drugs in the preventives. Thus, a dog can develop a patent (active) hookworm infection in February from an infection acquired last June.
Every dog should be on heartworm preventives until things are different than today. It is time to maximize the protection of dogs to minimize the numbers with disease. If we could make all dogs live and play only in screened enclosures and defecate in toilets, this would be unnecessary. The logical approach is year round heartworm prevention. |
