According to an article in the March issue of The Atlantic on Jaroslav Flegr, evolutionary biologist at Charles University in Prague, and his decades-long research on Toxoplasma gondii (T. gondii or Toxo), these two girls are possibly the cause of all the crazy in my house:


Amelie (left), a tuna addict with weight issues
and an inability to do much of anything
except lie around. And, Sophie (right), a meowing mess of insanity, who wants you to pet her without actually touching her and will invade your space anytime you open up a laptop or book.

T. gondii is a parasite excreted by cats in their feces and it is the cause of toxoplasmosis, a parasitic disease that infects warm-blooded animals. To think my two lazy house cats could be so diabolical and energetic to distribute a disease, let alone even carry it in their bodies is laughable. Yet, cats are the primary source of infection. I sleuthed around the Center for Disease Control (CDC) website and discovered the CDC considers toxoplasmosis to belong to a group called Neglected Parasitic Infections as “more than 60 million men, women, and children in the U.S. carry the Toxoplasma parasite, but very few have symptoms because the immune system usually keeps the parasite from causing illness.” Toxoplasmosis can present with flu-like symptoms, but in most healthy adults, the disease will not progress any further. People with weakened immune systems are at greater risk of becoming seriously ill. In some cases, toxoplasmosis can be fatal.

Flegr started his research on T. gondii in the 1990s when he suspected his behavioral changes could be due to an infection from the parasite. Flegr found himself engaging in reckless behavior and turning more introverted than normal for him. His research found that this behavior was common for men infected with the parasite. In women the opposite occurred; infected women became more extroverted, trusting and rule-abiding. Flegr (who was confirmed through diagnosis to be infected with T. gondii) discovered these findings after several students – both infected and non-infected – participated in personality studies using standardized personality tests and computer-based tests. Flegr repeated these tests on both civilian and military groups with the same results. Flegr notes the effects on personality are subtle, but still, the little bugger is getting into our brain. But where in the brain?

Joanne Webster, a parasitologist at Imperial College London, studying Toxo-infected rodents, not only confirmed previous research findings that infected rats behaved less cautious around predators, but she was also able to prove that cysts from T. gondii were most abundant in the gray matter of the brain. Webster tagged the parasite with fluorescent markers and followed its movement through the rat’s body into the brain. The parasite was amping up production of dopamine (I’ve talked about this in many a post! This is the pleasure zone of the brain) in the host brain, creating what Webster calls, “fatal feline attraction,” an effect where the rodent is actually attracted to the cat’s urine. The rat is attracted to its own predator! Webster teamed up with Glenn McConkey and his team at University of Leeds to confirm the data and with great interest from the scientific community, reported their findings last year.

T. gondii is being studied as a possible culprit in several other diseases and behaviors including car crashes, suicides, the dementia that many AIDS patients experienced before antiretroviral drugs were developed, and schizophrenia (where patients exhibit a high level of dopamine). A wow moment for me reading the article is when E. Fuller Torrey, a psychiatrist at the Treatment Advocacy Center who has spent decades researching the causes of schizophrenia, said, “schizophrenia did not rise in prevalence until the latter half of the 18th century, when for the first time people in Paris and London started keeping cats as pets. The so-called cat craze began among poets and left-wing, avant-garde Greenwich Village types.” And as the trend rapidly spread, the incidence of schizophrenia soared. According to Torrey, 70 epidemiology studies since the 1950s have researched the link between schizophrenia and T. gondii. Recent studies found schizophrenia patients infected with T-gondii to have an almost exclusively more pronounced reduced gray matter than other patients. Dr. Jiri Horacek, co-author on a recent paper, said, “the parasite may trigger schizophrenia in genetically susceptible people.” As in, not everyone with cats turns into the crazy cat lady, unless of course, your genes are ready set for schizophrenia.

I’m not worried so much that Amelie and Sophie have caused any of the humans in my household to have dormant toxoplasmosis in our system. I’m more of the mind to think they seem a little infected in the head as they spend ridiculous amounts of time being startled by nothing and attacking the empty air. But, if you are really worried about being infected, maybe you should skip getting a house cat and just stick with Internet sensation LOL Cats. After all, isn’t cats what the internet is for?