lol - no more cat poo for me.

Toxoplasma is an intracellular parasite that lives in many tissues including muscle but has a particular fancy for brain tissue. Sexual reproduction occurs inside the cells in the intestinal lining of felines. Immature oocysts (kinda like eggs) are release into the intestine of the cats and excreted in their faeces. They mature and if ingested by a domestic animal or human things called tachyzoites penetrate the lining of the small intestine and lodge in tissues. When they are found in large enough numbers they form small cysts. The development of cysts also allows immunity to new infection to be developed. Thus if you are infected prior to pregancy you will not pick up a new infection and your baby wont be at risk. The risk to the featus comes if an infection occurs during pregnancy and the cysts develop in tissues being formed - e.g the brain. The parasite is able to cross the placental barrier from the mothers blood to the featus's.

In terms of how you get it - you need to ingest the oocyst so if you get cat faeces on your hands and then on your mouth you may pick it up. You can also get it from eating the cysts if they are in meat that hasn't been cooked properly as a cow or sheep etc may have eaten the oocyst and have cysts in their muscle tissue.

Basically it's not a problem in adults unless the infection becomes chronic, in which case you can see blindness, heart damage and pneumonia depending on where the cysts are located, but these cases are really really rare.

Hope that answers your question sarah without being too technical.