If you have a normal immune system, you're not likely to experience complications of toxoplasmosis, although otherwise healthy people sometimes develop eye infections. Untreated, these infections can lead to blindness.
But if your immune system is weakened, especially as a result of HIV/AIDS, toxoplasmosis can lead to seizures and life-threatening illnesses such as encephalitis — a serious brain infection.
In people with AIDS, untreated encephalitis from toxoplasmosis is fatal. Relapse is a constant concern for people with toxoplasmosis who also have a weakened immune system.
Children with congenital toxoplasmosis may develop disabling complications, including hearing loss, mental disability and blindness.