Toxoplasmosis is an infection caused by a common, single-celled parasite known as toxoplasma gondii (T. gondii). It can infect humans and other warm-blooded animals. It can’t be spread person-to-person and is usually only passed on by entering the food chain.
However, if a woman contracts toxoplasmosis just before, or during pregnancy, she can pass on the infection to her unborn child. This can result in congenital toxoplasmosis which can cause serious health problems for the baby, including brain damage or partial blindness.
T. gondii infection is rarely reported in the UK. This may be because, in generally healthy people, the symptoms can be very mild and go unnoticed. Only about 10 to 15% of people develop symptoms. They may be similar to flu or glandular fever and include:
The risk of contracting toxoplasmosis during pregnancy is also low. A study in 2008 found that only about 5 in 1,000 at-risk women contracted the infection. These numbers refer to women who had not been exposed to the infection before. If you have had the infection once, you usually develop immunity and don’t get infected again. However, if you contract toxoplasmosis shortly before conceiving, as well as during pregnancy itself, you are at risk of passing it on to your baby. The infection cannot however, be passed on by breastfeeding. Bear in mind you may not experience any symptoms yourself but, if you are infected, it increases your risk of:
Miscarriage (losing the baby before the 23rd week of pregnancy)
Stillbirth (when the baby is born with no signs of life after the 24th week of pregnancy)
Causes of toxoplasmosis in pregnancy
The T. gondii parasite is found in the faeces of infected cats and the meat of other infected animals. The infection can be passed on in one of four main ways:
Eating food contaminated by cat faeces, such as fruits or veg
Using knives or chopping boards which have been used to prepare infected, undercooked or raw meat
Eating or handling infected, undercooked or raw meat
Eating or drinking infected unpasteurised animal products such as goats' milk or certain cheeses
Very rarely, the infection can be transmitted from an infected blood transfusion or organ transplant.
Diagnosing toxoplasmosis in pregnancy
Tests for the T. gondii infection usually involve a blood test for antibodies. Bear in mind early testing can sometimes produce a false positive result, so tests are often repeated, 2 - 3 weeks after the first.
If you are pregnant and tests confirm that you've had a recent toxoplasmosis infection, your GP will arrange further tests to determine if your baby is also infected. This usually involves an amniocentesis. This test has a very small (1%) risk of causing a miscarriage. It’s carried out anytime after 15 weeks of pregnancy and involves inserting a fine needle into the mother's abdomen to gather a sample of amniotic fluid that surrounds the foetus in the womb. The sample will be tested for toxoplasmosis. The results can confirm if the baby has the infection but cannot establish the extent of any damage to the baby.
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