Cats and dogs—even those living indoors—need parasite prevention all year long. While the infection rate decreases in cold weather, pets are still at risk. One reason is that outdoor parasites tend to move inside during winter months. Another thing to keep in mind is that the cost of treatment far outweighs the cost of prevention.
What you need to know: Times, they are a-changing. Pets travel now more than ever, families relocate more often, and climates are less predictable. All this means that parasites are increasingly showing up in so-called atypical areas. Take heartworm infection. Cases have been recorded in every state except Alaska. Even in the northernmost sections of Maine and Washington, veterinary clinics reported one to five cases of heartworm infection in 2007, according the American Heartworm Society. That's not a high number, but for the one to five clients whose pets became infected, the low risk didn't matter.
Fleas and ticks are hearty creatures, and they can survive inhospitable conditions including cold weather. This is especially true if they manage to find their way into homes or crawl spaces or other areas that are sheltered from winter elements. Bottom line: Pets aren't safe even when the temperatures dip.
If I keep my pet on parasite prevention, why do I need to test for heartworms each year?
Even though today's preventive medications are highly effective, like with any medicine, none are 100 percent effective, especially if your pet inadvertently misses a dose. Testing is the only way to ensure we catch infection early.