Toxoplasms (Toxoplasma gondii) are unicellular organisms and occur in a wide range of mammals, but also birds. Cats are the natural final host and excrete after multiplication in the intestines the parasite eggs, the so-called oocysts through faeces. These are spread by wind, rain and surface water and can survive for a very long time in the environment. They remain infectious for a period of up to 18 months in humid soil and sand. Intermediate hosts can absorb them through drinking water or diet, whereby carnivores and omnivores can also mutually infect themselves. This is for instance the case if a pig eats an infected rat.
Humans are infected through the uptake of oocysts or the consumption of meat of infected animals such as pigs or sheep. The consumption of the following foods has to be considered as a risk factor in view of an infection with toxoplasms:
- Raw meat, mainly from pigs, sheep and goats, but also from game;
- Raw meat products, such as minced meat and raw sausage;
- Raw, non-washed fruit and vegetables.
In healthy adults an infection with toxoplasms develops as a rule without symptoms.
Severe cases of toxoplasmosis occur if women are infected for the first time during pregnancy and the development of the foetus in the womb is disturbed. In Germany the congenital form of toxoplasmosis, i.e. if a child is already infected during pregnancy with toxoplasms is reportable. Between 2001 and 2010 an average of 18 cases of congenital toxoplasmosis was reported. The focus of prophylaxis is on preventive check-ups during pregnancy.