Toxoplasma gondii is a protozoan parasite which can be transmitted by fecal-oral contamination. Cats are the original hosts for this protozoa. They excrete microscopic in active forms of this protozoa in their feces. Farm animals (notably sheep and pigs) become infected by consuming feed and water contaminated by barn cats’ fecal material.
Active forms of this parasite then multiply with the farm animals and encyst themselves in the brain, heart muscle, other skeletal muscle, and liver. The cysts are microscopic and can exists as long as the farm animal lives.
When these animals are slaughtered to provide meat, the raw meat contains the cysts which can then infected humans if it is eaten raw or not heated sufficiently to inactive various forms of this parasite. About 30% of all fresh pork is infected and is the main meat source of Toxoplasma gondii in the United Sates.
If cutting and grinding equipment is not thoroughly washed and sanitized, other raw meats such as ground beef can also become contaminated. About 5% of the ground beef sold in supermarket contains some pork because the grinding equipment is not properly cleaned between grinding operations. Cysts of this protozoa are also found in wild game meats such as elk, moose, and venison.
Symptoms of the disease in humans are fever, muscle aches, headaches, loss of appetite and sore throat. Other symptoms will appear, depending upon the internal organs involved. In pregnant women, these parasites can be carried by way of the placenta to fetal tissue. If fetuses are infected, spontaneous abortions may occur. Most infected infants show no obvious symptoms at birth, but will show signs of eye damage and mental retardation later in life.
It is estimated that there are over 3,300 cases of congenital Toxoplasmosis each year resulting in 450 deaths of infants and young children. Other surviving infected children are mentally retarded as a result of this parasitic infection.
Toxoplasma gondii
