Cats are cute, playful and when it’s on their terms, excellent snugglers. Behind dogs, they’re the most popular pet in America. According to a recent pet owner’s survey by the Humane Society, 86 million households have at least one cat and up to four million felines per year find their way to a shelter. That’s a lot of poop to scoop and it’s not always in the confines of a litter box. People who tend to gardens, parents who let their children play in public sandboxes and even pet owners need to be aware of a potential health hazard involving cat feces.

Cat Poop Parasite

For years, pregnant women and those with compromised immune systems have been warned about the dangers of mishandling Fluffy’s litter box due to the infectious parasite, Toxoplasma gondii (T. gondii) which can cause congenital problems and serious illness. Cats acquire this parasite when they eat infected prey such as mice or birds and then shed the eggs (oocysts) in their waste. New research suggests, that the number of oocysts per square mile may be larger than previously known.

In a recent CNN interview,  Robert H. Yolken, director of the Stanley Neurovirology Laboratory at Johns Hopkins School of Medicine, and E. Fuller Torrey, executive director of the Stanley Medical Research Institute in Chevy Chase, MD explained the cause for their concern. “Based on studies done in California, it is estimated that cats deposit 1.2 million tons of cat poop into the environment each year. At any given time, approximately 1% of cats are infected with Toxoplasma gondii. A single infected cat can deposit millions of oocysts, each of which may survive in moist soil for 18 months or longer. It’s thought that it only takes one oocyst to infect a human, which is concerning.”

The resulting infection from an oocyst is called Toxoplasmosis. Symptoms of toxoplasmosis may mimic the flu, but has also been known to cause encephalitis, neurological diseases, and affect the heart, liver, ears and eyes. Smaller research studies have linked toxoplasmosis to obsessive compulsive disorder (OCD) attention deficit hyperactivity disorder (ADHD) and schizophrenia.

Despite the study, veterinarians are coming to kitty’s defense. “Cat feces can harbor parasites, but if people take precautions, the possibility of transmitting parasites to humans can be eliminated,” said Kimberly May, Doctor of Veterinary Medicine in Denver, Colorado. “T. gondii infects cats when they hunt and ingest rodents or birds that harbor it. Keeping cats indoors greatly minimizes feline hunting behavior. The parasite can also be transmitted to cats by feeding them raw foods. Do not feed cats raw food.”

For Doctor May, the issue comes down to basic hygiene and taking reasonable precautions.  “Washing your hands after scooping the box is important,” she advised. “Most human infections of T. gondii do not come from cat ownership. They are a result of consuming raw or undercooked food, poor food handling practices, or gardening without proper gloves/hand washing. Yes, cats can harbor parasites, but so can humans. Human pinworm infections are transmitted without animals, usually between children. To put it into perspective, I haven’t heard anyone use that as a reason to not have toddlers.”