High performance of a novel point-of-care blood test for Toxoplasma infection in women from diverse regions of Morocco.

Point-of-care (POC) testing for Toxoplasma infection has the potential to revolutionize diagnosis and management of toxoplasmosis, especially in high-risk populations in areas with significant environmental contamination and poor health infrastructure precluding appropriate follow-up and preventing access to medical care. Toxoplasmosis is a significant public health challenge in Morocco, with a relatively heavy burden of infection and, to this point, minimal investment nationally to address this infection. Herein, we analyse the performance of a novel, low-cost rapid test using fingerstick-derived whole blood from 632 women (82 of whom were pregnant) from slums, educational centres, and from nomad groups across different geographical regions (i.e. oceanic, mountainous) of Morocco. The POC test was highly sensitive and specific from all settings. In the first group of 283 women, sera were tested by Platelia ELISA IgG and IgM along with fingerstick whole blood test. Then a matrix study with 349 women was performed in which fingerstick - POC test results and serum obtained by venipuncture contemporaneously were compared. These results show high POC test performance (Sensitivity: 96.4% [IC95 90.6-98.9%]; Specificity: 99.6% [IC95 97.3-99.9%]) and high prevalence of Toxoplasma infection among women living in rural and mountainous areas, and in urban areas with lower educational levels. The high performance of POC test confirms that it can reduce the need for venipuncture and clinical infrastructure in a low-resource setting. It can be used to efficiently perform seroprevalence determinations in large group settings across a range of demographics, and potentially expands healthcare access, thereby preventing human suffering.

Congenital toxoplasmosis: evaluation of molecular and serological methods for achieving economic and early diagnosis among Egyptian preterm infants.

BACKGROUND: Early diagnosis of congenital toxoplasmosis (CT) is difficult when specific immunoglobulin M (IgM) antibodies are absent, or if persist for months, in the newborn infant's blood. OBJECTIVES: To study the risk factors of neonatal toxoplasmosis and to compare different immunologic profiles (Toxoplasma-specific IgM, IgA antibodies and the avidity of IgG antibodies) with polymerase chain reaction (PCR) for reaching economic and early postnatal diagnosis. MATERIALS AND METHODS: We prospectively studied 80 preterm neonates, recruited from neonatal intensive care units (NICUs) of Cairo University hospitals. Whose gestational age ≤ 34 weeks with (n = 60) or without (n = 20) CT risk. Serum samples for specific IgA, IgM antibodies and avidity of IgG toxoplasma antibodies were measured by ELISA then compared to PCR. RESULTS: Of the 60 studied cases, 16 (26.7%) were positive for toxoplasmosis by PCR, of which 15 (25%) had low avidity of IgG antibodies (positive), 14 (23.3%) were positive for IgA and 10 (16.7%) were positive for IgM, with sensitivity for avidity of IgG, IgA and IgM: 93.2%, 87.5% and 62.5%, respectively. CONCLUSION: Determination of avidity of IgG toxoplasma antibodies and/or serological detection of specific IgA for toxoplasmosis offer, simple tests for diagnosis of congenital toxoplasmosis with (better sensitivity) than IgM.

Clinical validation of a western blot assay for congenital toxoplasmosis and newborn screening in a hospital in Armenia (Quindio) Colombia.

Congenital Toxoplasma infection can only be discovered or prevented by the appropriate serological screening and subsequent treatment of the mother and her offspring. In Colombia, there is no obligatory Toxoplasma screening for pregnant women and both the reporting and follow-up of congenital toxoplasmosis cases is limited, thereby is a public health problem that have no been addressed by health authorities. The aim of this study was to investigate the occurrence of congenital toxoplasmosis in a public hospital from Armenia, Colombia. A total of 200 serum samples of cord blood were collected. We applied a western blot assay (ID Blot DPC Diagnostics, US) for Toxoplasma IgG, IgM and IgA antibodies that was validated in a cohort of children with confirmed presence or absence of congenital infection. The sensitivity of western blot assay was 91 per cent and the specificity was 100 per cent. In the cord blood samples, we found one infected child that died at day 4 of life and his infection was confirmed by PCR of the B1 specific Toxoplasma gene on brain biopsy. This results show a high prevalence (0.5 per cent, IC95 per cent 0.2-0.8) of Toxoplasma infection in Colombian newborns. Thus, we recommend additional studies to determine the cost-effectiveness of a newborn screening program for congenital toxoplasmosis in other settings in Colombia.

[Usefulness of quantitative assessment of Toxoplasma gondii genome using PCR-TaqMan in amniotic fluid, maternal and neonatal blood in selected complications in pregnancy]. / Przydatnosc ilosciowej oceny genomu Toxoplasma gondii przy uzyciu metody PCR TaqMan w plynie owodniowym, krwi matki oraz krwi noworodków w wybranych przypadkach patologii ciazy.

UNLABELLED: Routine serological diagnosis of Toxoplasmosis provides high sensitivity, but not high specificity. The high sensitivity combined with high specificity offered by PCR-TaqMan as well as the degree of infection led us to investigate the presence and levels of Toxoplasma gondii genome in amniotic fluid, maternal and neonatal blood in cases of pregnancy where infection with this agent was suspected. MATERIALS AND METHODS: Samples of amniotic fluid and blood were taken from 28 women between the 16th and 40th week of gestational age. Postnatal blood samples were also taken from their infants. Included in the study group were women with IUGR, PROM, preterm delivery imminent, Toxoplasmosis in previous pregnancies, raised IgG or IgM anti-Toxoplasma antibody titers and with amniotic fluid disturbances (oligohydramnios and polyhydramnios). Presence and levels of Toxoplasma genome was investigated using PCR-TaqMan. PCR products were detected by electrophoresis on polyacrylamide gel. RESULTS: Toxoplasma gondii genome was detected in blood from 13 women, 3 newborns and in amniotic fluid from one other women. Toxoplasma genome was detected in blood from one newborn, but was not detected in sample from its mother. CONCLUSIONS: The PCR-TaqMan test is highly sensitive and specific method allowing detection of the parasite genome and assessment of its level. Limitations of this method are its relatively high cost and poor access to ABI PRISM 7700 (TaqMan) sequence detector. The PCR TaqMan is useful in cases, where serological tests for the presence of infections are ambiguous.

What is known about the prevention of congenital toxoplasmosis?

The French programme for the prevention of congenital toxoplasmosis consists of the diagnosis and treatment with spiramycin of acute infections during pregnancy and monthly follow-up of all identified seronegative women. The major flaw is that the efficacy of spiramycin in preventing contamination of the fetus, or at least in reducing the extent of the infection, has never been evaluated in a randomised placebo-controlled clinical trial. Its evaluation would require the follow-up of children born to mothers contaminated during pregnancy for more than 6 months, a goal that is difficult to obtain in current practice. The cost of the programme depends largely on the proportion of non-immune women of childbearing age. Since the modes of contamination are known and are linked to living habits, it should be possible to reduce the risk of infection during pregnancy by adequate health education. This approach is still to be evaluated.