Even if you don't have the joy of a cat in your home you're still hosting their fur and dander, according to the National Institutes of Health!

"Scientists at the National Institute of Environmental Health Sciences (NIEHS), one of the National Institutes of Health, and the U.S. Department of Housing and Urban Development have found that detectable levels of dog and cat allergens are universally present in U.S. homes. Although allergen levels were considerably higher in homes with an indoor dog or cat, levels previously associated with an increased risk of allergic sensitization were common even in homes without the pets."

For more information, please see http://www.nih.gov/news/pr/jul2004/niehs-06.htm