Toxoplasmosis
In this section you can read about toxoplasmosis and its effects, how it can be identified and treated, as well as information on how to reduce the risk of infection. If you have, or someone you know has, suffered the loss of a baby due to toxoplasmosis, and would like additional support, please visit our In Memory section. |
 | Toxoplasmosis is a fairly common parasitic infection. In non-pregnant women it doesn't have many symptoms. In fact a large percentage of people will never know they have been infected by the toxoplasmosis parasite.
However, if you are pregnant and become infected, toxoplasmosis may have serious effects on your baby’s development. It might also cause a miscarriage or a stillbirth.
What is toxoplasmosis?
Toxoplasmosis (or toxoplasma infection) is caused by a parasite, a microscopic organism, called toxoplasma gondii.
Toxoplasmosis does not usually have any obvious symptoms. Some people 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 finding out if you have become infected is to have a blood test.
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How common is toxoplasmosis?
While as many as half the population may have had it at some point in their lives, around 2,000 UK women per year contract toxoplasmosis during pregnancy. In about 800 of these cases the infection will pass from mother to baby and around 80 babies per year are severely affected.
Once you have had the infection you are then immune for life, you cannot catch the infection again.
Most pregnant women may never know they have been infected unless they experience problems during their pregnancy that necessitate tests.
If a pregnant woman feels there is a risk that she may have become infected 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.
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How could someone get toxoplasmosis?
Ongoing research is giving us more and more insight into how the parasite is transmitted, but here we list the main ways that someone might get infected.
You could catch the infection by:
- eating anything infected with the parasite. This includes eating raw and undercooked meat (the most common cause), eating unwashed fruit and vegetables, or consuming unpasteurised goat’s milk and
 goat’s milk products. It also includes eating anything with infected cat faeces in it (for example, soil left on vegetables) - receiving blood or organ transplants infected with the parasite
- handling cat litter or newborn lambs. If you have cuts or abrasions on your skin, the parasite could, for example, enter the body through a cut when cleaning out cat litter or handling newborn lambs.
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How can someone find out if they are infected?
The incubation period is 5–23 days after coming into contact with the parasite. However, toxoplasmosis does not usually have any obvious symptoms and many people do not know they are infected. The only conclusive method of detecting if you have become infected is to have a blood test.
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The toxoplasmosis blood test
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 the event that caused the possibility of infection.
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 toxoplasma 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 four and eight weeks for the infection to pass to the baby.
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How does a baby get infected with toxoplasmosis?
The baby can catch toxoplasmosis while in the womb. This is referred to as transplacental transmission.
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What is the risk of a baby getting toxoplasmosis?
It has been estimated that 40% of pregnant women with toxoplasmosis will pass the infection on to their baby in the womb. This means that about 800 babies each year are infected with toxoplasmosis.
The percentage risk of the baby getting toxoplasmosis becomes higher if the infection is caught by the woman further on during her pregnancy.
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How can toxoplasmosis affect the baby?
If toxoplasmosis is caught in early pregnancy and is transmitted to the baby then there is a high risk of miscarriage.
If infected during the first or second trimester the baby may be born with: hydrocephalus (water on the brain), brain damage, epilepsy, deafness, blindness or growth problems.
The developmental problems may be so severe that the pregnancy ends in a stillbirth.
If toxoplasmosis is caught in the third trimester of pregnancy and is transmitted to the baby then there may not be such severe and obvious problems. However, although things may appear to be fine at birth, health problems may develop, particularly with vision, later in life.
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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, 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 an 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 problems in the baby. Termination of pregnancy is also an option for some women, when an infected baby with severe developmental problems has been confirmed.
All babies born to women with confirmed toxoplasmosis in pregnancy will be monitored closely by paediatricians. These babies can be breastfed as toxoplasmosis is not transmitted in breastmilk.
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What can I do to try to reduce the risk of catching toxoplasmosis?
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.
Do not eat cured meats, such as Parma ham and salami.
Only eat meat and ready-prepared chilled meals that have been thoroughly cooked through.
Wash your hands and all cooking utensils and surfaces after preparing raw meat.
Wash all fruit and vegetables, including ready-prepared salads, thoroughly to remove all traces of soil.
Do not eat unpasteurised goat's milk and products made from it.
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.
Always 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. Better still, get someone else to do this job.
Cover children's sandboxes to prevent cats from using them as litter boxes.
Take care when visiting farms and wash hands thoroughly after any contact with sheep. Avoid handling newborn lambs.
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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 three-monthly re-testing of susceptible women would be labour intensive and would require substantial investment without any proven benefit.
It advocates primary prevention of toxoplasmosis through avoidance of undercooked or cured meat rather than antenatal screening.
It also says that pregnant women should be informed of primary prevention measures to avoid toxoplasma 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 and avoiding cat faeces in cat litter or in soil.
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What are the latest research findings on toxoplasmosis?
Ongoing research is giving us more and more insight into how the parasite is transmitted and how infection can be prevented. We have included details of some of the main studies here for your further information.
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. 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, older age of the mother and feeding a dog raw meat.
This seemed rather alarming to us at Tommy’s 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 therefore continue to recommend that women wash their 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
Kenneth M Boyer and his colleagues undertook research 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 toxoplasmosis or by experiencing illness similar to the symptoms of acute acquired toxoplasmosis during pregnancy.
The mothers of 131 infants with congenital toxoplasmosis 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 infection (for example, through exposure to cat faeces or undercooked meat) or remembered experiencing illness in pregnancy compatible with acute acquired toxoplasmosis.
The research concluded that whilst education programmes may be preventing acquisition of toxoplasmosis, 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
Published in 2004 in the Journal of Perinatal Medicine, Volume 32
A long-term study 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 2,986 pregnant women.
In the second study period (1983–1990) the incidence of toxoplasmosis was studied in 8,300 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 programmes was studied by measuring the number of women who went from being negative to positive for toxoplasmosis during their pregnancy. The results showed that 20 of 1,403 negative women in the first period (1.43%), 19 of 3,605 women in the second period (0.53%) and 8 of 8,492 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 programme resulted in a reduction rate of 92%.
The research concluded 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; these guidelines should be reiterated during antenatal classes and leaflets distributed containing written recommendations on the nature of the disease and its avoidance.
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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. You can order copies of our main leaflet Toxoplasmosis and pregnancy online at Tommy's shop.
Tommy's also 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 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 call Tommy's on 020 7398 3483 so that we can discuss this with you in more detail.
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