At least one usual argument among cat lovers is now over: Whiskers, Lucy and Tigger are most definitely better off staying indoors, scientists reported Wednesday.
Pet cats allowed outdoors, truthfully, are nearly three times as likely to become infected with pathogens or parasites than those which are confined to quarters, they reported in the Royal Society journal Biology Letters. Two-legged house-mates should also our cats—a.k.a. Felis catus—can transmit some of those diseases to humans, the authors said.
Intriguingly, the farther domesticated felines are from the equator, the much more likely they are to be afflicted by some kind of bug or virus, if they spend time outdoors.
“Each degree in absolute latitude increased infection likelihood by four percent,” explained lead author Kayleigh Chalkowski, a researcher at the School of Forestry and Wildlife Sciences at Auburn University in Alabama.
“You think of tropical regions as just having more wildlife, more parasites,” she said to AFP. “But it turned out that latitude had the opposite effect.”
To settle the indoor-vs-outdoor argument once and for all, Chalkowski and colleagues combed through just about two dozen earlier studies in which the prevalence of one or more diseases was compared across interior and exterior environments. In the end, the new study focused on 19 different cat pathogens in more than a dozen countries which include Spain, Canada, Australia, Switzerland, Germany, Pakistan, Brazil, the Netherlands and St. Kitts.
‘Keep your kitty indoors’
“This is the first time outdoor access as a risk factor for infection in cats has been quantified across a wide range of geographic locales and types of pathogens,” Chalkowski stated.
The effects were actually consistent for almost all of the diseases, including feline roundworm and the single-cell parasite which causes toxoplasmosis, both of which can affect humans. This held true regardless of how they were transmitted—whether from soil, other cats, or prey like mice and birds.
“Basically, no matter where you are in the world, keeping your cat indoors is a great way to keep them healthy from infectious diseases,” Chalkowski stated by way of summary.
This is especially good advice, she went on to say, “considering that many of the pathogens cats carry can actually be spread to humans”. Other domesticated animals can transmit disease to their caretakers—dogs, for example, spread rabies, and cattle can carry Cryptosporidium parvum, a parasitic disease that attacks the intestinal tract.
Wild cats were likely first drawn to human communities in search of rodents, and were domesticated in upwards of 5,000 years ago. In ancient Egypt, they were associated with the gods and prominently showcased in hieroglyphics.
There are about 90 million pet cats in the United States, and an estimated 500 million worldwide.