Mark Thomas, an associate professor at University of Auckland, said the disease begins with an acute phase lasting typically for six to eight weeks and continues as a chronic infection, normally without obvious symptoms that cannot be cured and last for life.
"While chronic toxoplasmosis has been shown to have a strong association with conditions affecting the brain such as schizophrenia, and with suicide and self-harming behavior, the disease in its acute phase has usually been seen as a benign, trivial and self-healing illness," Thomas said in a statement.
"We were surprised, when the results came in, to discover how common it was for patients to report significant and prolonged symptoms such as impaired memory and concentration, headaches and extreme fatigue."
The study, conducted with assistance from Dr. Arlo Upton, a microbiologist at Labtests Auckland, and Weng Kit Wong, a third-year medical student at The University of Auckland, was based on a questionnaire completed by adults diagnosed by their physicians with acute toxoplasmosis in Auckland in 2011.
Of 31 patients who completed the questionnaire, 90 percent reported fatigue, 74 percent reported headaches, 52 percent said they had difficulty concentrating, 16 had muscle aches and 12 had fever.
"Most respondents reported that these effects had a significant impact on their overall physical and mental health," Thomas said. "There has not been any previous similar study, and so these findings are new."
The paper was published in the Scandinavian Journal of Infectious Diseases.