Here's a question from Randar...
Hey, I got a dog question. Is it necessary to keep my dogs on heart worm and flea stuff during the winter or do they just say that to keep up sales.
The short answer is "it depends". And since I've discovered that my readership is international, let me forewarn that my answer is mainly based on northern hemisphere, especially North American, pattern.
Fleas require warm, humid environments in order to thrive. The lower the temperature and the dryer the environment, the worse the conditions for them. This means that in desert climates or areas that have strong winters there isn't as much of a flea problem. In the American southeast, flea prevention is needed pretty much year-round. The further north or west you go, the less the concern. For example, in the winter in the Daktoas, fleas definitely won't survive. However, you need to keep in mind that this is mainly talking about fleas surviving outside. We keep our homes very climate controlled, with temperatures in the upper 60s to low 70s (Fahrenheit), and often humidity control. Under these conditions fleas can survive year-round. Even in the US southeast, I have never seen a month go by, even in Winter, that I haven't seen at least a few clients with fleas on their pets. Take these guidelines and make the decision about whether or not to use flea prevention during the winter. Or better yet, ask your vet about local flea prevelance.
Heartworm prevention is a different issue. It is transmitted by mosquitoes, so conditions in which these insects would survive will increase the risk of heartwom disease. If the conditions are too cold or dry (since mosquitoes need water to lay their eggs), they the mosquitoes won't live and therefore heartworm risks are lower. However, the disease you are risking is much greater. Fleas can cause allergy problems, skin disorders, tapeworms, and even anemia in small pets. However, heartworm disease can cause death. Currently only about 50% of American dogs are given heartworm prevention regularly. Since the potential disease is so severe, it is recommended to keep dogs on prevention year-round.
The recommendations of veterinarians are based on the best health care for your pets. Yes, we would like to be profitable and support our familes. But most of us don't try to deliberately make recommendations or manipulate clients in order to make money. We really are trying to look out for our patients.