Differential Diagnosis and fetal diagnosis.
At the beginning of pregnancy among the routine serological screening of the pregnant woman, the anti-toxoplasma IgM and IgG antibodies are usually checked (3). In case both anti-toxoplasma (anti-toxo) IgM and IgG antibodies results are negative there is a follow up serological examination of them every 1, 2 or 3 months. Since on follow up, they remain negative while fetal ultrasounds have no detectable abnormalities, no more actions are required. In case anti-toxo IgM antibodies are negative and IgG antibodies are positive, most probably the pregnant woman was infected in the distant past and before conception, which means no treatment is required (unless the pregnant woman is immunosuppressed). If anti-toxo IgM are positive, while anti-toxo IgG antibodies are negative, additional serological tests should be repeated in 1-3 weeks. In this case, since the after coming results are the same, the outcome is considered to be clinically insignificant, which means no treatment is required and a routine serological testing follow up is enough. However in case both anti-toxo IgM and IgG are positive after the follow up or even both of them are positive in the first test, an early infection of toxoplasma gondii is more likely to have occurred. In this case more serological tests should be performed in order to differentiate an early from a past infection and to find out whether the fetus has been infected too (11).  To detect an early infection the main additional serological tests used are IgG avidity, anti-toxo IgA and IgE antibodies detection by the ELISA method.
Avidity is called the binding force of an antigen to its antibody. In the initial stages of antigenicity avidity is low, while after a few months it is increased by creating B cell antigens (12). The antigenic contact causes B cell maturation, while antibodies and antigens are binding stronger. In this way avidity will rise. High avidity can reject the possibility of acute infection. However, It seems that the combination of IgM and IgE anti-toxo antibody detection by ELISA is the most reliable method for acute infection diagnosis (13).
The main benefits of the anti toxo IgE antibody detection by ELISA, which make it an excellent supplementary method to diagnose acute toxoplasmosis, are its high specificity and positive predictive value with a sufficient sensitivity (14).
Finally, Toxoplasma gondii IgA antibody detection has been used in screening of pregnant women since they significantly increase the possibility of acute T. gondii infection in contrast to patients without them (15-17). However, some authors have found IgA either too insensitive or reactive for too long suggesting that, IgA testing is controversial and not a dependable marker for T. gondii acute infection detection (18).
For fetal toxoplasmosis infection, it is the amniotic fluid PCR analysis rather than the umbilical cord blood sample, the leading method for prenatal diagnosis. Despite the fact that this method provides fast results for parasite detection, it is also independent of a patient’s immunological status and it has a broad spectrum of application in different biological samples. In addition, the protocol provides qualitative results (19).
Moreover, amniotic fluid PCR analysis should be done when primary infection is detected in pregnant women or even when serological tests are inconclusive whether an acute infection has occurred. Finally, PCR analysis is used in case of abnormal fetal ultrasound features have been detected, such as microcephaly, ascites, hepatosplenomegaly, hydrocephalus and severe IUGR (intrauterine growth restriction). Furthermore, in order to reduce the false negative results, amniotic fluid PCR should be performed 4 weeks after the suspected primary infection of the pregnant, but never before the 18th week of gestation. In case primary infection of the mother is confirmed while embryo infection is not, spiramycin has to be used for embryo protection, in order to avoid T.gondii transmission to the fetus across the placenta. Finally, when embryo infection is confirmed or highly suspected (in most cases by a positive amniotic fluid PCR analysis) pregnant women should receive pyrimethamine sulfadiazine and folic acid as a treatment (20).
Overall, this is one of the few cases reported based on the literature of a 19-year-old girl detected with toxoplasmosis during her pregnancy, managed successfully leading to a successful pregnancy. Early detection and medical intervention are necessary either to prevent embryo infection or treat embryos when infection is confirmed or suspected. Not only her young age but also her successful pregnancy as well, contributes to its interest for publication.