Toxoplasma gondii is a single-celled parasite that causes toxoplasmosis. The parasite can be found throughout the world and infects more than 60 million people in the United States alone. It is estimated that 11% of the population 6 years and older have been infected in the US and up to 95% of the population in other parts of the world. Infection rates are higher in areas of the world where climates are hot, humid, and at lower altitudes.
A Toxoplasma infection can occur through the ingestion of contaminated meat, contaminated water, or handling of contaminated animal feces or soil. Credit: Fra-Dor
Symptoms of a toxoplasmosis infection are self-limiting although most healthy individuals will not develop symptoms at all. In mild cases, some individuals will experience flu like symptoms that last for a month or more. In severe cases, toxoplasmosis can cause damage to organs including the brain or the eyes. Ocular toxoplasmosis is more common with symptoms including reduced vision, blurred vision, pain with bright light, redness of the eye, and sometimes watery eyes.
Infection can also be passed from the mother to the infant in the womb. Some newborns will not develop toxoplasmosis symptoms until later in life while others will experience serious brain or eye damage at birth.
There are three principal routes of T. gondii infection including (1) through the ingestion of contaminated food or water, (2) animal to human or (3) mother to child. In rare instances, transmission can occur when people receive infected blood through transfusions or receive an organ from an infected donor.
Researchers from Shenyang Agricultural University in Shenyang, China performed a study to investigate the potential impact of T. gondii infection on the health of young students as well as associated risk factors for infection. Researchers collected 3,569 whole blood samples from newly enrolled undergraduate and postgraduate students from Shenyang Agricultural University in September 2016 and samples were screened for the presence of T. gondii antibodies. A questionnaire was also distributed to participants requesting basic demographic information, educational background, and place of residence prior to attending the University. Participants were also asked if they had ever drank unboiled water, consumed raw meat or vegetables, had contact with dogs or cats, participated in gardening or other agricultural activities, or received a blood transfusion.
Of the 3,569 participants, 1.82% (65) were found to be seropositive for T. gondii antibodies. Although there was no difference in seroprevalence between undergraduates or postgraduates or males or females, seroprevalence tended to be higher in older participants. Statistical analyses revealed that variables found to be associated with infection included living in rural areas, participating in gardening or agriculture activities, and drinking unboiled water. Further analysis revealed that participation in gardening or other agricultural activities had the greatest association with T. gondii infection.
To prevent transmission of T. gondii, the Centers for Disease Control and Prevention recommends using a thermometer to ensure meat is cooked to the appropriate temperature, avoid drinking untreated water, and wear gloves while gardening to prevent contact with animal feces. Cats and kittens are known to carry and shed T. gondii oocysts in their feces so particular attention should be paid when cleaning litterboxes. Always practice proper handwashing technique after handling raw meat or vegetables, gardening, or coming in contact with animals or animal feces.
Sources: Frontiers in Microbiology, CDC