Toxoplasmosis is a disease caused by the Toxoplasma gondii parasite. Most often associated with cats, pregnant women and new parents who also have a cat have no doubt heard about this disease. In fact, toxoplasmosis can infect nearly all warm-blooded animals and some estimates have one-third of the world’s human population carrying the parasite. While the cat is the primary host of Toxoplasma gondii health professionals warn that it most likely through contact with undercooked meat, specifically pork, lamb, or venison.
Surprisingly, toxoplasmosis is more common than you would think. Fortunately, most healthy humans are able to fight the infection and usually show no symptoms of disease. People with compromised immune systems, for example people with HIV/AIDS, those undergoing chemotherapy, and recent organ-transplant recipients, are especially at risk of developing more severe symptoms. Usually, few people are unaware that they have toxoplasmosis as their immune system prevents the parasite from causing illness. But in immune-compromised individuals, flu like symptoms including swollen lymph nodes, muscle pain, and fever may be experienced. In more severe cases of toxoplasmosis, people may suffer damage to the eye, brain, or other organs.
Recent research about toxoplasmosis suggests that the disease can cause behavioral changes in infected rats, mice, and possibly even humans. After becoming infected, researchers have noticed that rats and mice actually become attracted to the scent of cats, an advantageous change for the parasite. Toxoplasma gondii only reproduces when a cat is host, and this change in behavior makes it much more likely that the rat will be eaten by a cat so the cat can serve as host. Interestingly, behavioral changes in hosts have also been noticed in humans. Slower reaction times, an increased risk of schizophrenia, and an increased risk of traffic accidents are just two of the reported behavioral changes. Women may be more outgoing and show signs of increased intelligence; while men show increased aggression and jealousy.