One out of every two pet cats in Europe is infested with some sort of parasite, according to research published last week in the journal Parasites and Vectors. Ear mites and fleas were the most prevalent bugs found outside of the body, while intestinal worms and lung worms were most common inside.

In all, 1,519 cats were examined at veterinary hospitals in France (Maisons-Alfort and Nantes), Italy (Bari and Naples), Austria (Vienna), Belgium (Liège), Hungary (Budapest), Romania (Cluj-Napoca), and Spain (Madrid).

29.6% of cats had parasites on the outside of their bodies (ectoparasites) and 35.1% tested positive for parasites inside the body (endoparasites). 14% were infested with both.

Italian cats were the most flea-bitten. Pet felines in Bari and Naples were 2.5 and 5 times as likely as cats in Budapest, the reference city, to be infested with feline roundworm.

The biggest risk factors for parasitic infection among pet cats were access to the outdoors, number of cats in a household, and the frequency of parasite treatments. So Italy has a large population of crazy cat ladies who allow their pets to run rampant outdoors. Makes sense.

Precise data for cat parasites in the U.S. are scarce, but localized studies in major cities indicate that the rates are lower. If you're wondering about American dogs, their rate of parasitic infestation is between 35 and 55%, with canines in the southeastern states faring the most poorly.

The study highlights the importance of proper hygiene practices for pets. Millions of people become infected with parasites from their cat or dog every ear in the U.S. Already, around one out of every ten people in the U.S. plays host to Toxoplasma gondii, a mind-altering parasite transmitted to humans through cat feces.

Avoid infestation by de-worming your dog or cat on a regular basis, washing your hands frequently, and giving your pet a bath every once and a while. If you have a cat, clean its litter box every day and consider restricting its access to the outdoors.

Source: Beugnet et. al. "Parasites of domestic owned cats in Europe: co-infestations and risk factors." Parasites & Vectors 2014, 7:291 doi:10.1186/1756-3305-7-291