Toxoplasmosis is a disease caused by a protozoan parasite known as toxoplasma. There are various forms of toxoplasmosis. Acute toxoplasmosis breaks out 1–3 weeks after the infection and its course tends to be asymptomatic. Its symptoms may sometimes resemble common viral diseases. Many patients experience swollen lymph nodes on their neck and under their jaw. In people with severe immunodeficiency, such as AIDS patients or those with organ transplants, an old latent infection may reactivate and take on a fatal brain form of the disease /it is more often the result of the reactivation of latent toxoplasmosis rather than of acute/recent infection/. In other people, acute infection subsides spontaneously in a matter of months and the disease changes into its most common form, the so called latent toxoplasmosis. Patients with latent toxoplasmosis have IgG toxoplasma antibodies in their blood (which is why they can’t become infected again) and dormant parasites in organs like brain, muscles or testicles. The most dangerous form of toxoplasmosis is called congenial toxoplasmosis. It occurs when a woman becomes infected during her pregnancy (which doesn’t happen very often) and the infection is transmitted through the placenta to the developing foetus. In the first trimester, the chances of transmission from a recently infected mother to her baby are approximately 15%, but the consequences can be grave (miscarriage, the child may be born with a serious developmental disability, including hydrocephalus or microcephaly). If the mother becomes infected in the third trimester, the risk of mother‑to‑child transmission is of up to 70%, but the consequences tend to be less serious and mostly functional, such as retinitis. The probability of transmitting the infection to the foetus as well as subsequent damage to the child can be reduced by administering medicine against acute toxoplasmosis both the pregnant mother and her new‑born child. Finally, the last form of toxoplasmosis is ocular toxoplasmosis with retinal damage mostly, but not exclusively, in consequence of congenial infection. The infection may cause repeated inflammation of the retina, leading to the loss of sight in the affected eye.