Everyone loves cuddling with kittens. But there can be a little-known danger lurking behind that furry little face and that innocent-sounding meow: a parasite called Toxoplasma gondii (T. gondii).

T. gondii is the most common parasite in developed nations, according to Schizophrenia Bulletin. The cat-taken parasite can infect any warm blooded species, and the Centers for Disease Control and Prevention estimates more than 60 million people in the U.S. may have it.

Many people never endure any symptoms at all. But in those with weaker immune systems, infection with T. gondii can cause an illness called toxoplasmosis, which can result in miscarriages, fetal development illnesses, weeks of flu-like illness, blindness and even death. It's also been associated with mental disorders including bipolar disorder and schizophrenia. Now two more studies investigate the mental health problems in greater detail.

Their latest study, published in Schizophrenia Research, together with research worker Wendy Simmons, compared two preceding studies that found a connection between childhood cat ownership and also the development of schizophrenia later in life with an unpublished survey on mental health from 1982, 10 years before any data on cat possession and mental illness had been published. Results of the evaluation suggested that cat exposure in youth may be a risk factor for developing mental disorders.

The research was published in the journal Acta Psychiatrica Scandinavica.

Results showed that an individual infected with T. gondii was almost twice as likely to develop schizophrenia. In addition they discovered an organization with addiction and obsessive-compulsive disorder, but say the findings should be approached with caution.

“In schizophrenia, the signs of an organization with T. gondii is overwhelming,” the authors say in a press release. “These findings may give further hints about how T. gondii infection can maybe [change] the danger of specific psychiatric illnesses.”

The Humane Society estimates there are 75 to 80 million pet cats and another 30 to 40 million stray or feral cats roaming the USA. Outside cats have an elevated probability of infection with T. gondii. Cats excrete millions of eggs that are contaminated, or oocysts, in their feces, which can remain for years in water or soil.

Fortunately, there are precautions that cat lovers can take — you don't have to limit your feline contact to seeing cat videos on YouTube.

Children may be protected by keeping their cat alone inside and always covering the sandbox when not in use,” Torrey told CBS News in an e-mail. The CDC also recommends changing the cat's litter box daily, since T. gondii does not become infectious until 1 to 5 days after it is shed in feces. Additionally, avoid feeding cats undercooked or uncooked meat.