November 2012

Since Channel 7’s recent story on toxoplasmosis many patients have asked me about this condition.

Toxoplasma gondii is a protozoan parasite that can infect most mammals and birds, but which only undergoes sexual reproduction in cats. People can acquire the infection by eating undercooked meat (especially pork and kangaroo, but also beef, lamb and chicken), through contact with cat faeces (for example in sandboxes), through contaminated drinking water, or from pregnant mother to unborn child through the placenta (congenital toxoplasmosis).

In adults with a healthy immune system the parasite usually causes a self-limited, flu-like illness (although the eyes may be affected). In babies the result of infection depends on when during pregnancy the infection occurs. In the first trimester the infection may result in miscarriage, but when the baby survives it may have congenital toxoplasmosis syndrome, which can include retinal damage and visual loss, liver and spleen enlargement, small head (microcephaly), raised pressure in the brain, seizures and anemia. Because infections later in pregnancy are less likely to result in miscarriage, retinal effects are more commonly seen but changes are generally less severe.

It is very important that in order to avoid toxoplasmosis pregnant women avoid eating undercooked meat and eggs. You should avoid contact with cats and kitty litter. Infection with toxo before pregnancy doesn’t cause congenital toxoplasmosis syndrome, only infections during pregnancy.