Toxoplasmosis: Underestimated risk

A new leaflet published by the Federal Institute for Risk Assessment (BfR) provides information on protection against infections with toxoplasmins. The unborn children of women who become infected with this parasite for the first time during pregnancy may suffer severe damage or even die. Infants under the age of five and people with an immune system weakened by previous illnesses or medication are particularly at risk. "These groups of individuals should know which foods constitute a special risk and how they can protect themselves from an infection with toxoplasmins", says Professor Dr. Dr. Andreas Hensel, President of BfR. Toxoplasmins may be particularly prevalent in raw meat. Furthermore, the surface of fruit and vegetables may also be contaminated with this pathogen.

Infection with toxoplasmins (toxoplasmosis) is one of the most frequent parasitic infections in the world. However, in most cases it goes undetected. The pathogen Toxoplasma gondii can attack all warm-blooded animals, including birds. Once the pathogen has reached the host organism, it normally remains throughout its host’s lifetime in the tissue of muscles and the nervous system. Hence, toxoplasmins may be found in raw foods of animal origin like minced meat and raw sausage products. Infectious pathogen stages (oocysts) are also excreted in the faeces of infected cats. They can be widely distributed by rain and surface water and survive for a long time in the environment. This is how these oocysts can also reach fruit, vegetables and drinking water.

Heating, i.e. boiling, roasting, frying or pasteurising, reliably kills all development stages of the parasite. By contrast, it can survive for several weeks at fridge temperatures. Toxoplasmins may still even be infectious under certain circumstances at deep-frozen temperatures.

Roughly half of the population in Germany has antibodies to these parasites. Acute toxoplasmosis only occurs rarely and generally manifests flu-like symptoms such as fatigue, muscle pain and swollen glands particularly in the neck area. However, individuals with a weakened immune system may experience severe courses of the disease involving various organs, for instance the lungs and the brain. If a pregnant woman is not immune to toxoplasmins, an infection during pregnancy can lead, in some cases, to severe deformations like hydrocephalus, mental handicap or blindness in the unborn child. Miscarriages and stillbirths may occur, too. The acute phase of toxoplasmosis can be effectively treated with antibiotics. However, medication has little impact on the permanent stages in tissue.

For the purposes of avoiding infection with toxoplasmins, BfR, therefore, makes the following recommendations especially to individuals with a weakened immune system and pregnant women who have no antibodies to toxoplasmins:

• Do not eat any raw sausage or meat products (minced meat, carpaccio, smoked sausage, smooth textured sausage, salami); thoroughly cook meat dishes.
• Carefully rinse, peel and/or cook raw fruit and vegetables prior to consumption.
• Store food with clumps of earth attached, like potatoes and carrots, separately from other foods.
• Avoid contact with cat faeces.
• Wash hands frequently.

The leaflet “Protection against Toxoplasmosis” is intended for consumers and multipliers. It is available (in german) free-of-charge from BfR (publikationen@bfr.bund.de or fax 030-18412-4970). It can also be downloaded from the Internet on www.bfr.bund.de.