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Pregnancy Care Guidelines

43 Toxoplasmosis

There is limited evidence to support testing for toxoplasmosis during pregnancy. As infection may be transmitted to the baby during pregnancy, the focus is on providing women with advice about how to avoid sources of toxoplasmosis.

43.1 Background

Toxoplasmosis, which is caused by the parasite Toxoplasma gondii, is usually asymptomatic and self-limiting. Symptoms when they occur include swollen lymph nodes, muscle aches and pains and fever.

When women who have not previously been exposed to the parasite (eg are non-immune) become infected during pregnancy, the infection can be transmitted to the baby (Di Mario et al 2009). The likelihood of a woman acquiring a primary infection during pregnancy varies, depending on local prevalence (Pappas et al 2009):

  • low prevalence: the potential for a woman to become infected is low but if she is infected during pregnancy it will most likely be a primary infection
  • high prevalence: primary infection during pregnancy is unlikely due to previous exposure.

Toxoplasmosis infection can be acquired by (Di Mario et al 2009):

  • eating raw or insufficiently cooked meat
  • not washing hands thoroughly after handling raw meat or gardening
  • contact with cat faeces (directly or indirectly through the soil or cat litter); or
  • contact with contaminated raw vegetables or fruits.

43.1.1 Prevalence and incidence

In Australia, primary infection with toxoplasmosis during pregnancy is rare (Gilbert 2002) although it is estimated that between 60% and 80% of Australians are non-immune (Pappas et al 2009).

  • Country of origin: The prevalence of immunity to toxoplasmosis is high in Latin America, parts of Eastern/ Central Europe, the Middle East, parts of South-East Asia and Africa. There is a trend towards lower prevalence of immunity in many European countries and the United States (Pappas et al 2009).
  • Congenital toxoplasmosis: The incidence of congenital toxoplasmosis has been reported to range from 0.03/1,000 live births in England and Wales (Gilbert et al 2006) to 0.3/1,000 live births in south-eastern Brazil (Carvalheiro et al 2005).

43.1.2 Risks associated with toxoplasmosis during pregnancy

Mother-to-child transmission rates have been reported to range from 11.3% (Ricci et al 2003) to 18.5% (Varella et al 2009). The risk of transmission increases with gestational age (from 5% at 12 weeks to 80% just before birth) (Dunn et al 1999). However, babies infected early in pregnancy have a greater risk of congenital anomalies (Di Mario et al 2009).

Congenital toxoplasmosis has been associated with stillbirth, intracranial anomalies and/or developmental delay, ocular inflammation (Gilbert et al 2006) and impaired hearing (Andrade et al 2008; Brown et al 2009). In a prospective cohort study (n=620), babies with congenital toxoplasmosis had lower gestational age but there was no significant association with low birth weight or small for gestational age (Freeman et al 2005).

43.2 Testing for toxoplasmosis

The evidence on the benefits to women and babies of testing for toxoplasmosis is limited and inconclusive. Routine testing for toxoplasmosis during pregnancy is not recommended in the United Kingdom (NICE 2008).

43.2.1 Diagnostic accuracy of tests

Tests for toxoplasmosis aim to identify whether maternal infection is acute or chronic. Studies have compared a range of tests for IgG and IgM antibodies and IgG avidity (Petersen et al 2005; Thalib et al 2005; Flori et al 2008; Bobic et al 2009; Kasper et al 2009; Lachaud et al 2009; Elyasi et al 2010; Wallon et al 2010; Jost et al 2011; Lesle et al 2011; Robert-Gangneux et al 2011; Yamada et al 2011). There is great heterogeneity between the studies, making it difficult to comment on the predictive and diagnostic accuracy of one test over another. Studies into the timing of testing are limited and inconclusive (Gilbert & Gras 2003).

No evidence on the cost-effectiveness of testing for toxoplasmosis was identified. 

43.2.2 Harms and benefits of testing

No high-level evidence on the harms and benefits of testing for toxoplasmosis was identified. A narrative review found that psychological consequences of testing included parental anxiety due to false positive results and uncertainties related to prognosis of children with a diagnosis of congenital toxoplasmosis (Khoshnood et al 2007).

Recommendation

  • Grade C
  • 49

Do not routinely offer testing for toxoplasmosis to pregnant women. 

Approved by NHMRC in June 2014; expires June 2019

43.2.3 Availability of safe and effective treatments

Spiramycin and sulphonamide medications have been used to treat toxoplasmosis with the aim of reducing mother-to-child transmission and the severity of fetal infection (Peyron et al 1999).

A systematic review (Thiébaut et al 2007) found weak evidence for an association between early maternal treatment and reduced risk of congenital toxoplasmosis. A subsequent review (Peyron et al 1999) concluded that despite the large number of studies performed, it is still not known whether treatment of pregnant women with presumed toxoplasmosis reduces the transmission of T. gondii.

While some studies have reported a lack of symptoms among babies whose mothers were treated during pregnancy (Berrébi et al 2007; Berrébi et al 2010; Cortina-Borja et al 2010), current research is inadequate to assess whether the possible benefits outweigh the potential harm to the baby from treatment (Peyron et al 1999).

43.3 Discussing toxoplasmosis

There is suggestive evidence that women may have low levels of knowledge about the risks associated with T. gondii (Ferguson et al 2011) and that health education approaches may help reduce risk of congenital toxoplasmosis (Gollub et al 2008).

Recommendation

  • Grade C
  • 50

Advise pregnant women about 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 meat 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. 

Approved by NHMRC in June 2014; expires June 2019

43.4 Practice summary: toxoplasmosis

When

Early in pregnancy.

Who

  • Midwife
  • GP
  • obstetrician
  • Aboriginal and Torres Strait Islander Health Practitioner
  • Aboriginal and Torres Strait Islander Health Worker
  • multicultural health worker.

What

  • Discuss sources of toxoplasmosis
    Explain that becoming infected with toxoplasmosis during pregnancy can lead to the infection being transmitted to the baby so it is important to take measures to avoid infection.
  • Take a holistic approach
    Women who are originally from an area of low prevalence are at risk of primary infection if they travel to countries where toxoplasmosis is highly prevalent.
  • Document and follow-up
    If a woman is tested for toxoplasmosis, tell her the results and note them in her antenatal record. Have a system in place so that women who become infected with toxoplasmosis during pregnancy are given ongoing follow-up and information.

43.5 Resources

  • SA Perinatal Practice Guidelines Workgroup (2015) Toxoplasmosis in pregnancy. In: South Australian Perinatal Practice Guidelines. Adelaide: SA Health.

References

  • Andrade GM, Resende LM, Goulart EM et al (2008) Hearing loss in congenital toxoplasmosis detected by newborn screening. Braz J Otorhinolaryngol 74(1): 21–28.
  • Berrébi A, Assouline C, Bessières MH et al (2010) Long-term outcome of children with congenital toxoplasmosis. Am J Obstet Gynecol 203(552): e1–6.
  • Berrébi A, Bardou M, Bessières MH et al (2007) Outcome for children infected with congenital toxoplasmosis in the first trimester and with normal ultrasound findings: a study of 36 cases. Eur J Obstet Gynecol Reprod Biol 135: 53–57.
  • Bobic B, Klun I, Vujanic M et al (2009) Comparative evaluation of three commercial Toxoplasma-specific IgG antibody avidity tests and significance in different clinical settings. J Med Microbiol 58(Pt 3): 358–64.
  • Brown ED, Chau JK, Atashband S et al (2009) A systematic review of neonatal toxoplasmosis exposure and sensorineural hearing loss. Int J Pediatr Otorhinolaryngol 73(5): 707–11.
  • Carvalheiro CG, Mussi-Pinhata MM, Yamamoto AY et al (2005) Incidence of congenital toxoplasmosis estimated by neonatal screening: relevance of diagnostic confirmation in asymptomatic newborn infants. Epidemiol Infect 133(3): 485–91.
  • Cortina-Borja, M, Tan, H. K, Wallon, M et al (2010) Prenatal treatment for serious neurological sequelae of congenital toxoplasmosis: An observational prospective cohort study. PLoS Med 7(10): e1000351.
  • Di Mario S, Basevi V, Gagliotti C et al (2009) Prenatal education for congenital toxoplasmosis. Cochrane Database Syst Rev 2009, Issue 1. Art. No.: CD006171. DOI: 10.1002/14651858.CD006171.pub2.
  • Dunn D, Wallon M, Peyron F et al (1999) Mother-to-child transmission of toxoplasmosis: risk estimates for clinical counselling. Lancet 353(9167): 1829–33.
  • Elyasi H, Babaie J, Fricker-Hidalgo H et al (2010) Use of dense granule antigen GRA6 in an immunoglobulin G avidity test to exclude acute Toxoplasma gondii infection during pregnancy. Clin Vaccine Immunol 17(9): 1349–5
  • Ferguson W, Mayne P, Cafferkey M et al (2011) Lack of awareness of risk factors for primary toxoplasmosis in pregnancy. Irish J Med Sci 180(4): 807–11.
  • Flori P, Bellete B, Crampe C et al (2008) A technique for dating toxoplasmosis in pregnancy and comparison with the Vidas anti-toxoplasma IgG avidity test. Clin Microbiol Infect 14(3): 242–49.
  • Freeman K, Oakley L, Pollak A et al (2005) Association between congenital toxoplasmosis and preterm birth, low birthweight and small for gestational age birth. BJOG 112(1): 31–37.
  • Gilbert R & Gras L (2003) Effect of timing and type of treatment on the risk of mother to child transmission of Toxoplasma gondii. BJOG 110(2): 112–20.
  • Gilbert R, Tan HK, Cliffe S et al (2006) Symptomatic toxoplasma infection due to congenital and postnatally acquired infection. Arch Dis Childhood 91(6): 495–98.
  • Gilbert GL (2002) 1. Infections in pregnant women. Med J Aust 176: 229–36.
  • Gollub EL, Leroy V, Gilbert R et al (2008) Effectiveness of health education on Toxoplasma-related knowledge, behaviour, and risk of seroconversion in pregnancy. Eur J Obstet Gynecol Reprod Biol 136(2): 137–45.
  • Jost C, Touafek F, Fekkar A et al (2011) Utility of immunoblotting for early diagnosis of toxoplasmosis seroconversion in pregnant women. Clin Vaccine Immunol 18(11): 1908–12.
  • Kasper DC, Prusa AR, Hayde M et al (2009) Evaluation of the Vitros ECiQ immunodiagnostic system for detection of anti- Toxoplasma immunoglobulin G and immunoglobulin M antibodies for confirmatory testing for acute Toxoplasma gondii infection in pregnant women. J Clin Microbiol 47(1): 164–67.
  • Khoshnood B, De Vigan C, Goffinet F et al (2007) Prenatal screening and diagnosis of congenital toxoplasmosis: a review of safety issues and psychological consequences for women who undergo screening. Prenatal Diag 27(5): 395–403.
  • Lachaud L, Calas O, Picot MC et al (2009) Value of 2 IgG avidity commercial tests used alone or in association to date toxoplasmosis contamination. Diag Microbiol Infect Dis 64(3): 267–74.
  • Lesle F, Touafek F, Fekkar A et al (2011) Discrepancies between a new highly sensitive Toxoplasma gondii ELISA assay and other reagents: Interest of Toxo IgG Western blot. Eur J Clin Microbiol Infect Dis 30(10): 1207–12.
  • NICE (2008) Antenatal Care. Routine Care for the Healthy Pregnant Woman. National Collaborating Centre for Women’s and Children’s Health. Commissioned by the National Institute for Health and Clinical Excellence. London: RCOG Press
  • Pappas G, Roussos N, Falagas ME (2009) Toxoplasmosis snapshots: global status of Toxoplasma gondii seroprevalence and implications for pregnancy and congenital toxoplasmosis. Int J Parasitol 39(12): 1385–94.
  • Petersen E, Borobio MV, Guy E et al (2005) European multicenter study of the LIAISON automated diagnostic system for determination of Toxoplasma gondii-specific immunoglobulin G (IgG) and IgM and the IgG avidity index. J Clin Microbiol 43(4): 1570–74.
  • Peyron F, Wallon M, Liou C et al (1999) [2006] Treatments for toxoplasmosis in pregnancy. Cochrane Database Syst Rev 1999, Issue 3. Art. No.: CD001684. DOI: 10.1002/14651858.CD001684.
  • Ricci M, Pentimalli H, Thaller R et al (2003) Screening and prevention of congenital toxoplasmosis: an effectiveness study in a population with a high infection rate. J Matern-Fetal Neonat Med 14(6): 398–403.
  • Robert-Gangneux F, Gangneux JP, Vu N et al (2011) High level of soluble HLA-G in amniotic fluid is correlated with congenital transmission of Toxoplasma gondii. Clin Immun 138(2): 129–34.
  • Thalib L, Gras L, Romand S et al (2005) Prediction of congenital toxoplasmosis by polymerase chain reaction analysis of amniotic fluid. BJOG 112(5): 567–74.
  • Thiébaut R, Leproust S, Chêne G et al (2007) Effectiveness of prenatal treatment for congenital toxoplasmosis: a meta-analysis of individual patients’ data. Lancet 369(9556): 115–22.
  • Varella IS, Canti ICT, Santos BR et al (2009) Prevalence of acute toxoplasmosis infection among 41,112 pregnant women and the mother-to-child transmission rate in a public hospital in South Brazil. Mem Inst Oswaldo Cruz 104(2): 383–88.
  • Wallon M, Franck J, Thulliez P et al (2010) Accuracy of real-time polymerase chain reaction for toxoplasma gondii in amniotic fluid. Obstet Gynecol 115(4): 727–33.
  • Yamada H, Nishikawa A, Yamamoto T et al (2011) Prospective study of congenital toxoplasmosis screening with use of IgG avidity and multiplex nested PCR methods. J Clin Microbiol 49(7): 2552–56.
Last updated: 
21 November 2018