For a variety of reasons, even in regions of the country where winters are cold or the climate is dry, the American Heartworm Society recommends year-round Heartworm prevention.
Heartworms (Dirofilaria immitis) are fairly large worms (can grow up to 14 inches long) that, in adulthood, live in the heart and pulmonary arteries of an infected animal. Pets acquire these worms through mosquito bites as mosquitoes readily pick up larval heartworms from infected animals and carry them to new animals.
Heartworm has been found in all 50 states. Most states have “hot spots” where the heartworm infection rate is very high compared with other areas in the same state, however the incidence of heartworm disease in a particular area is not always predictable from year to year. Factors affecting the level of risk of heartworm infection include the climate (temperature, humidity), the species of mosquitoes in the area, presence of mosquito breeding areas, and presence of animal reservoirs (infected dogs, foxes, coyotes).
Mosquito species constantly change and adapt to various climates, and many vectors are expanding their viable season and range as weather patterns change. Some mosquito species successfully overwinter indoors creating a potential year-round risk to pets. Moist micro-climates (irrigated fields, backyard ponds, man-made golf courses) perpetuate mosquito populations, and affect the severity and duration of the mosquito season. Heartworm infection in wildlife with large ranges (eg. coyotes) adds to the spread of this parasite in domestic pets.
VIP Petcare follows the guidance of The American Heartworm Society, and recommends year-round prevention for all areas of the US to help keep pets happy, healthy, and safe.