A new study published by the UK Royal Society’s Biology Letters examined the relationship between rates of parasitic infection in cats and whether they have an indoor or outdoor lifestyle.
Cats are an ideal way to study parasite risk because there has been a lot of research on the subject. There’s “a useful dichotomy in cat ownership between indoor-only cats and those with outdoor access.” The researchers used meta-analysis to determine whether outdoor access is a significant risk factor for parasitic infection in pet cats. They looked at 19 different pathogens including many relevant to human, pet and wildlife health.
Twenty-one studies of the pathogens were evaluated, including FIV, Bartonella henslae (which causes the infamous and rarely-but-potentially-serious cat-scratch disease) and Toxoplasma Gondii (pictured). Research from 16 different countries was included, from Chile to Canada to Pakistan.
Many parasites that infect cats have life cycles involving transmission from soil, prey such as mice, or other cats, so the authors hypothesized that infection rates would be higher in outdoor cats. And indeed, thosecats were 2.77 times more likely to be infected with parasites than indoor-only cats.
(Some of these parasites are zoonotic, i.e. they can be passed to humans, a health concern for pet owners, particularly pregnant women and the immune-suppressed. Dogs can also contract some of these as well as other parasites, so outdoor cats are not the only risk of of human exposure.)
Wildlife and cats also pass parasites back and forth. Toxoplasma Gondii, a parasite that reproduces only in the intestines of domestic cats, has been found in Beluga Whales in the St Lawrence as well as many other wild mammals.
Interestingly, there was also a correlation between latitude and infection risk, with each degree farther north increasing risk by 4%.
The study demonstrates that restricting outdoor access reduces the risk of parasitic infection in cats. Reason # 752 to keep your cat safe from roaming!
To read the full study, click here.