few people with toxoplasmosis develop symptoms because the immune system usually keeps the parasite from causing illness. however anyone with a compromised immune system is at risk for serious problems from toxo. these individuals include those undergoing chemotherapy people with hiv/aids or other immune disorders and recent organ-transplant recipients. in these people an infection that occurred anytime during life can reactivate and cause the severe symptoms of toxoplasmosis such as damage to the eye brain or other organs. ocular toxoplasmosis which damages the eyes can lead to reduced vision blurred vision pain (often with bright light) redness of the eye and sometimes tearing according to the cdc.
why do some people develop severe problems from toxoplasmosis?