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Toxoplasmosis

What is toxoplasmosis?

Toxoplasmosis is an infection caused by a parasite called toxoplasma gondii, which is a microscopic organism.

How is it caught?

It can be caught by eating anything infected with the parasite. This includes directly eating anything with infected cat faeces in it (for example soil), or eating raw and undercooked meat, or eating unwashed fruit and vegetables, or consuming unpasteurised goats milk and goats milk products.

It can also be caught from receiving blood or organ transplants.

The organism may also enter the body through cuts or abrasions in the skin. This is a possible risk when handling newborn lambs or for farmers lambing.

For the baby, toxoplasmosis can be caught from its mother whilst still in the womb. This is referred to as transplacental transmission.

How long does it take to become infected?

In the case of transplacental transmission, it can take between 4 and 8 weeks after the mother's infection for the baby to become infected.

The incubation period is 5-23 days after eating something infected with the parasite.

How do you know if you have become infected?

Toxoplasmosis does not usually have any symptoms. Most pregnant women may never know they were infected. Some women may have mild flu like symptoms. Very rarely, some people may experience a more long term illness similar to glandular fever.

The only conclusive method of detecting if you have become infected is to have a blood test.

How common is toxoplasmosis?

Studies have shown that 30% of 30-year-olds and 50% of 70-year-olds have had a toxoplasmosis infection. It is accepted that once you have had an infection you are then immune for life, you cannot catch the infection again.

It is estimated that only 15% of women booking in for antenatal care are already immune. This leaves 85% of pregnant women still at risk of contracting the infection.

The blood test

If a pregnant woman feels there is a risk that she may have been infected during her pregnancy or would like to know if she has already had the infection before her pregnancy (and is therefore immune) then a blood test can be carried out.

The toxoplasmosis blood test involves taking a sample of blood from the mother to look for antibodies to the infection. Antibodies are part of the body's response to an infection. It may take three weeks for these antibodies to be present following an infection, so the blood test must be done three weeks after any incident which may put someone at risk.

The results may come back in a week, but if they have been passed on to a Toxoplasma Reference Laboratory they may take longer.

The result may state that no antibodies were found and therefore no infection has taken place (negative blood test). Alternatively, it may state that antibodies were found and the toxoplasmosis infection has been caught (positive test). However, it is then important to determine when the infection was caught.

If the infection occurred before the pregnancy then the woman is immune and there is no risk to the baby.

If the infection has occurred recently or is currently active then there is a risk that the baby will become infected. It can take between 4 and 8 weeks for the infection to pass to the baby.

What can you do to reduce the risks of catching toxoplasmosis?

To avoid catching toxoplasmosis you can take the following precautions:

• Only eat meat that has been thoroughly cooked through. Do not eat rare meat with any pinkness or blood in it (eating raw or undercooked meat is the most common cause of getting toxoplasmosis).
• Wash your hands and all cooking utensils and surfaces after preparing raw meat.
• Wash all fruit and vegetables thoroughly to remove all traces of soil.
• Always wear gloves when gardening. Take care not to put hands or gloves to your mouth and wash your hands and gloves when finished to remove all traces of soil.
• Wear rubber gloves when handling dirty cat litter. Take care not to put hands or gloves to your mouth and wash your hands and gloves when finished. If possible get someone else to do this job.
• Avoid cured meats, such as parma ham and salami.
• Avoid unpasteurised goat's milk and products made from it.
• Take care when visiting farms and wash hands thoroughly after any contact with sheep. Avoid handling new born lambs.
• Cover children's sandboxes to prevent cats from using them as litter boxes.

How likely is it to catch toxoplasmosis in pregnancy?

It is estimated that 1 in 500 women catch toxoplasmosis in pregnancy. There are currently 1 million pregnancies a year in the UK, so about 2,000 women a year will catch toxoplasmosis during their pregnancy.

How likely is the baby to get toxoplasmosis?

It has been estimated that only 40% of pregnant women with toxoplasmosis will pass the infection on to their unborn child. This means that about 800 babies each year are infected with toxoplasmosis. The actual risks to the baby vary and are related to the stage of pregnancy the woman is in when the infection was acquired.

If the infection is caught in early pregnancy (first trimester), only 15% of babies are thought to be infected. If the infection is caught by the mother in the middle three months of her pregnancy (second trimester), then the risk of the baby being infected is 25%. The risk of transmission to the baby is 65% in the third trimester, which is the last three months of pregnancy.

How will the infection affect the baby?

If toxoplasmosis is caught in early pregnancy and is transmitted to the baby then there is a high risk of miscarriage. Babies infected during that first trimester or the second trimester may be born with severe abnormalities such as hydrocephalus (water on the brain), brain damage, or epilepsy. They may also suffer with deafness, blindness or growth problems. These may be so severe that the baby is stillborn.

If toxoplasmosis is caught in the third trimester of pregnancy and transmitted to the baby then babies may not suffer such severe and obvious problems. Although most of these babies may appear normal at birth, a large proportion will develop problems later in life. These are usually eye problems.

How can toxoplasmosis be treated in pregnancy?

If a woman has been confirmed as having a current infection of toxoplasmosis in pregnancy then she may be offered an antibiotic, called spiramycin, which is thought to reduce the risk of transmission to the baby.

If there is concern that the baby may already be infected, and the woman is more than 15 weeks pregnant, then she may be offered amniocentesis. Amniocentesis is the removal of a sample of amniotic fluid from around the baby through a special needle, and this fluid may be tested for toxoplasmosis. If the baby is infected then the use of certain antibiotics may reduce the severity of the infection.

At 20 weeks of pregnancy an ultrasound scan may also highlight any obvious physical abnormalities in the baby. Termination of pregnancy is also an option for some women, when an infected baby with severe abnormalities has been confirmed.

All babies born to women with confirmed toxoplasmosis in pregnancy will then be monitored closely by paediatricians. These women can breastfeed their babies as toxoplasmosis is not transmitted in breastmilk.

What is Tommy's doing to help?

Tommy's has taken over the work of The Toxoplasmosis Trust, an organisation set up to provide information about toxoplasmosis. We have various leaflets available on toxoplasmosis. These are available to download from this website in pdf format (see above) or from Tommy's. If you would like to receive copies of any of these leaflets, please contact Tommy's on 0870 777 30 60 or email info@tommys.org with your postal address and details of the leaflets you require.

Tommy's runs a toxoplasmosis support network to enable people affected by toxoplasmosis to contact others who have been through similar experiences. The network contains details of those people willing to discuss their experiences with toxoplasmosis and to help support others. If you are interested in being put in contact with someone in this network or in joining the network yourself, please contact Tommy's on 0870 777 30 60 to discuss this in more detail.

What is current UK Government policy on toxoplasmosis screening?

The UK National Screening Committee recently reported that screening for toxoplasmosis in pregnancy should not be offered routinely. There is a lack of evidence that antenatal screening and treatment reduces mother-to-child transmission or the complications associated with toxoplasma infection. There are also important and common adverse effects associated with antenatal screening, treatment and follow-up for mother and child. Antenatal screening based on monthly or 3-monthly re-testing of susceptible women would be labour intensive and would require substantial investment without any proven benefit. Primary prevention of toxoplasmosis through avoidance of undercooked or cured meat may prove a good alternative to antenatal screening, which cannot currently be recommended.

Pregnant women should be informed of primary prevention measures to avoid toxoplasmosis infection such as:

• washing hands before handling food
• thoroughly washing all fruit and vegetables, including ready-prepared salads, before eating
• thoroughly cooking raw meats and ready-prepared chilled meals
• wearing gloves and thoroughly washing hands after handling soil and gardening
• avoiding cat faeces in cat litter or in soil

What are the latest research findings in toxoplasmosis?

Risk factors for toxoplasmosis in pregnant women in Kent, United Kingdom

Published in June 2005 in the medical journal Epidemiology and Infection, this study aimed to establish which risk factors for toxoplasmosis seemed to be the most important risks. To find this out, the researchers Dr J Q Nash, S Chissel, J Jones, F Warburton and N Q Verlander, asked pregnant women attending antenatal clinics in the Ashford, Folkestone and Dover areas of East Kent between October 1999 and November 2001 to have a toxoplasmosis blood test and complete a questionnaire about dietary and environmental exposure to toxoplasmosis. A significantly higher rate of toxoplasmosis was associated with the woman’s childhood home being in a rural location, the childhood home being in Europe excluding the UK, feeding a dog meat and increased age.

This seemed rather alarming to us as we’d always believed that dogs were not a risk to humans regarding toxoplasmosis, as they do not shed infected faeces. On discussing this with Dr Nash, he explained that he felt the risk was not from contact with the dogs but the handling of raw meat. We shall therefore continue to recommend that women wash there hands thoroughly after handling raw meat.

Risk factors for Toxoplasma gondii infection in mothers of infants with congenital toxoplasmosis: Implications for prenatal management and screening

Published in February 2005 in the American Journal of Obstetrics and Gynaecology by Kenneth M. Boyer et al. Research was carried out to determine whether most mothers of infants with congenital toxoplasmosis could be identified by certain demographic characteristics, a history of exposure to the recognised risk factors for toxo or by experiencing illness similar to the symptoms of acute acquired toxoplasmosis during pregnancy. The mothers of 131 infants with congenital toxo at a clinic in North America were characterised demographically and questioned concerning exposure to recognised risk factors or illness. The results showed that no broad demographic features identified populations that were at risk. Only 48% of mothers recognised having put themselves at risk of toxo (for example by exposure to cat faeces or undercooked meat) or remembered experiencing illness in pregnancy compatible with acute acquired toxo. They concluded that whilst education programmes may be preventing acquisition of toxo cases, only routine screening of all pregnant women or all newborn infants at birth would prevent or detect a higher proportion of congenital infections.

Prevention of toxoplasmosis during pregnancy - an epidemiologic survey over 22 consecutive years

A study published in 2004, carried out in Brussels, Belgium, assessed the effectiveness of two different methods of prevention of toxoplasmosis during pregnancy, over a 22 year period. During the first study period (1979-1982) the natural incidence of toxoplasmosis in pregnancy was studied in 2986 pregnant women. In the second study period (1983-1990) the incidence of toxoplasmosis was studied in 8300 women. During this period, women who were negative to toxoplasmosis at the beginning of their pregnancies received a written list of recommendations on how to avoid a toxoplasma infection during pregnancy. In the third study period (1991-2001) the incidence of toxoplasmosis was studied in 16,541 women. During this period, the prevention campaign consisted of a leaflet explaining a) toxoplasmosis as a disease and b) what measures should be taken to avoid toxoplasmosis during pregnancy. The third part of the campaign involved a reiteration of these recommendations during antenatal classes held around mid-gestation. The impact of the two prevention programs was studied by measuring the number of women who went from being negative to positive for toxoplasmosis during their pregnancy. The results showed that twenty of 1403 negative women in the first period (1.43%), 19 of 3605 women in the second period (0.53%) and 8 of 8492 in the third period (0.09%) became positive during pregnancy. The first prevention campaign reduced the number of women becoming positive by 63%. The second prevention program resulted in a reduction rate of 92%. They concluded from the study that promotion of simple measures is very effective in the prevention of toxoplasmosis during pregnancy. Primary prevention should not only be based on education about preventive measures given by physicians, but these guidelines should be reiterated during antenatal classes and leaflets distributed containing written recommendations on the nature of the disease and its avoidance.