IgG Avidity in Samples Collected on Filter Paper: Importance of The Early Diagnosis of Congenital Toxoplasmosis

Objective The purpose of the present study is to standardize and evaluate the use of the immunoglobulin G (IgG) antibody avidity test on blood samples from newborns collected on filter paper to perform the heel test aiming at its implementation in ongoing programs. Methods Blood samples from newborns were collected on filter paper simultaneously with the heel prick test. All samples were subjected to immunoglobulin M IgM and IgG enzyme-linked immunosorbent assays (ELISA). Peripheral blood was collected again in the traditional way and on filter paper from newborns with high IgG levels (33). Three types of techniques were performed, the standard for measuring IgG in serum, adapted for filter paper and the technique of IgG avidity in serum and on filter paper. The results of the avidity test were classified according to the Rahbari protocol. Results Among the 177 samples, 17 were collected in duplicate from the same child, 1 of peripheral blood and 1 on filter paper. In this analysis, 1 (5.88%) of the 17 samples collected in duplicate also exhibited low IgG avidity, suggesting congenital infection. In addition, the results obtained from serum and filter paper were in agreement, that is, 16 (94.12%) samples presented high avidity, with 100% agreement between the results obtained from serum and from filter paper. Conclusion The results of the present study indicate that the avidity test may be another valuable method for the diagnosis of congenital toxoplasmosis in newborns.

Detection of Acute and Chronic Toxoplasma gondii Infection among Women with History of Abortion in the Southwest of Iran

Background. Toxoplasma gondii (T. gondii) is one of the most common intracellular protozoan parasites, which can infect humans and a wide range of mammals and birds. The current study is aimed at investigating the occurrence of T. gondii infection in women with a history of abortion in Khuzestan, Iran. Materials and Methods. A total of 480 women with an abortion history, as well as 200 pregnant women with a normal delivery, were examined in this study. The blood, placenta, and umbilical cord blood samples were assessed by the enzyme-linked immunosorbent assay (ELISA) and nested-polymerase chain reaction (PCR) assay. Results. Based on the results of ELISA assay, the prevalence of toxoplasmosis was 30.83% in women with a history of abortion (25.62% with T. gondii IgG and 5.20% with T. gondii IgM). According to the IgG avidity test, 60.16% of IgG-positive samples showed high avidity, while 27.64% showed low avidity. On the other hand, the prevalence of toxoplasmosis in women with a normal delivery was 23% (21.5% with T. gondii IgG and 1.5% with T. gondii IgM). According to the IgG avidity test, 81.39% of these women showed high avidity, while only 4.65% showed low avidity. Based on the nested-PCR method, T. gondii DNA was detected in 14.18% of blood samples, 4.69% of placental samples, and 1.34% of umbilical cord samples, collected from 148 seropositive women with a history of abortion. Besides, using this method, the parasite DNA was identified in 4.34% of blood samples, collected from 46 seropositive women with a normal delivery, but not in any of the umbilical cord or placenta samples. Conclusion. The present results showed that T. gondii infection contributes to abortion in Khuzestan Province, Iran. Therefore, it is essential to investigate toxoplasmosis in pregnant women, especially in those who are seronegative, using molecular and serological methods and inform them about their disease and the associated risks.

Tubulointerstitial nephritis and uveitis syndrome following meningitis and systemic lymphadenopathy with persistent Toxoplasma immunoglobulin M: a case report

Background Tubulointerstitial nephritis and uveitis syndrome is a rare lymphocyte-related oculorenal inflammatory disease presumed to be associated with drug use and infectious agents. Toxoplasma gondii is one of such pathogens that could exhibit encephalitis, meningitis, and uveitis in immunocompromised or in some immunocompetent individuals. If the immunoglobulin M of Toxoplasma is positive on screening, the interpretation of the result is not simple, especially when immunoglobulin M stays positive persistently. Case presentation A 34-year-old Asian male developed fever, headache, and lymphadenopathy with tenderness, which was initially diagnosed as meningitis. Antibiotics were started, and diclofenac sodium was used for the fever. Although his symptoms were alleviated in a week by the treatment, gradual decline in renal function was noted, prompting a renal biopsy that indicated acute granulomatous interstitial nephritis. A week later, tenderness in both eyes with blurred vision appeared and revealed iritis and keratic precipitations in both eyes; hence, the diagnosis of acute tubulointerstitial nephritis and bilateral uveitis syndrome was made. Toxoplasma gondii-specific immunoglobulin G and immunoglobulin M titers were both positive. Although we could not rule out recent infection of Toxoplasma gondii, which may cause uveitis initially, Toxoplasma immunoglobulin G avidity test indicated a distant infection, which allowed us to rule out meningitis and uveitis as responsible for the complication of recent Toxoplasma gondii infection. Drug-induced lymphocyte stimulation test, or lymphocyte transformation test of diclofenac sodium, was solely positive among the tested drugs. Uveitis was alleviated only with ophthalmic steroid, and renal function returned to normal without administration of systemic steroid. Conclusions We experienced a case of diclofenac-induced tubulointerstitial nephritis and uveitis syndrome. In ruling out infections, Toxoplasma immunoglobulin M was persistently positive, and Toxoplasma immunoglobulin G avidity test indicated a “distant” infection. From these two results, we ruled out recent infection. However, it should be noted that “distant” infection indicated by commercial immunoglobulin G avidity is still a multiplex profile consisting of reinfection, reactivation, and latent infection. Narrowing down the infection profile of Toxoplasma is challenging in some cases. Therefore, careful diagnosis and extended follow-up of such patients are needed.

Serodiagnosis of Toxoplasmosis by Using ELISA and IgG Avidity Test in Relation to Some Risk Factors among Women at Childbearing Age in Zakho City, Duhok Province/ Iraq.

This study intended to evaluate the seroprevalence of anti-Toxoplasma IgG and IgM antibodies in the sera of 630 women at childbearing age, and to link the outcomes with some risk factors. The enrolled women visited Zakho Maternity Hospital from July 2018 to July 2019. Their ages ranged from 15 to 45 years. All samples were examined using ELISA to detect immunoglobulin G and M, in addition to performing IgG Avidity test for seropositive pregnant women. The differences between seropositivity and age was significant (p<0.05), the highest rate (20.43%) for anti-Toxoplasma IgG antibodies in the age group 33-38 years. Women who had more contact with cats showed higher IgG and IgM seropositivity rates (16.45% and 1.26%, respectively). Married women had higher IgG Abs seropositivity than single ones (12.52% vs 6.31%, respectively), moreover, only married women were seropositive for IgM Abs. Pregnant women presented higher IgG Abs seropositivity than non-pregnant (15.21% versus 10.49%), with almost equal seropositivity for IgM Abs (0.65% and 0.86%, respectively). Anti-Toxoplasma IgG Abs seropositivity was higher in women underwent miscarriages than those with normal pregnancies (18.44 vs. 8.81%), however IgM Abs was only found among women who had miscarriages (0.97%). Women with triple miscarriages presented the highest IgG Abs seropositivity (37.03%). Chronic infection was found in 68.75% of pregnant women, whereas acute infection was found in 31.25 %. Following up the pregnancy resulted in 15 healthy births, 9 miscarriages, and 10 women did not show up. The findings of this study demonstrate the relationship between toxoplasmosis and risk factors in women at childbearing age, with the aim of decreasing infection rates through the health education and application of hygienic measures.

Assessment of an in-house ELISA and IgG avidity test based on SAG1 and GRA7 proteins for discriminating between acute and chronic toxoplasmosis in humans

To improve serodiagnostic methods for diagnosis of acute from chronic toxoplasmosis, an economical in-house ELISA for measuring Toxoplasma -specific IgG, IgM and IgG avidity has been developed and assessed based on use of various T. gondii antigens, including SAG1, GRA7 and a combination of SAG1 and GRA7 (SAG1+GRA7) as well as Toxoplasma lysate antigens (TLAs). Performances of in-house IgM, IgG and IgG avidity assays were compared to those of ELISA commercial kits and VIDAS Toxo IgG avidity. A set of 138 sera from patients with acquired T. gondii infection and seronegative people were assessed. Receiver operating characteristic (ROC) analysis revealed an area under curve (AUC) of 0.98, 0.97, 0.99 and 0.99 for IgM-TLAs, IgM-SAG1, IgM-GRA7, and IgM-SAG1+GRA7, respectively. Furthermore, AUC was calculated as 0.99, 0.99, 0.98 and 0.99 for IgG-TLAs, IgG-SAG1, IgG-GRA7 and IgG-SAG1+GRA7, respectively. The current study showed that GRA7 included 100% sensitivity for the detection of Toxo IgM, while SAG1 included 89.7% sensitivity. Furthermore, the highest specificity (97.2%) to detect Toxo IgM was achieved using SAG1+GRA7 antigen. For the detection of Toxo IgG, the highest sensitivity (100%) was recorded for SAG1+GRA7 followed by TLAs (97.9%). The SAG1+GRA7 showed the greatest potential for assessing avidity of IgG antibodies with 97.1% of sensitivity and 96.6% of specificity, compared to VIDAS Toxo IgG avidity. The preliminary results have promised better discriminations between acute and chronic infections using a combination of SAG1 and GRA7 recombinant antigens, compared to TLAs.

EVALUATION OF Toxoplasma gondii SEROPREVALENCE AND IGG AVIDITY TEST RESULTS AMONG CHILDBEARING-AGE WOMEN IN KARABUK PROVINCE

Toxoplasmosis is a zoonotic infectious disease that is common worldwide and caused by the Toxoplasma gondii. Congenital toxoplasmosis is one of the major complications of this infection. The present study aimed to investigate T.gondii seroprevalence and evaluate the IgG avidity test results among childbearing- age women retrospectively. A total of 9401 samples obtained from childbearing -age (15-49 years of age) women who attended Karabuk University Training and Research Hospital between February 2016- January 2020, over the four-year, were included in the study.The Toxoplasma-IgM, Toxoplasma-IgG antibody, and Toxoplasma IgG avidity tests were analyzed chemiluminescent method by using ARCHITECT I 2000 SR immunoassay device (Abbott Laboratories, USA). Toxoplasma-IgM and Toxoplasma-IgG seropositivity were detected as 0.7% (67/9401) and 15.7% (1415/9005) respectively. A high percentage of Toxoplasma-IgM and Toxoplasma-IgG seropositivity were detected among 31-35 years of age group. The Toxoplasma seropositivity increased by age, but no statistically difference was found (P >0.05).The Toxoplasma IgG avidity was high in 45 patients (69.4%), low avidity was detected in 16 patients (22.6%) and from the remaining 6 patients were borderline (8%). The Toxoplasma IgM and IgG seropositivity rate decreased 2016 to 2020. The highest Toxoplasma IgM and IgG seropositivity were in 2016 with 1.2% and 16.8%, respectively. The T. gondi seropositivity rate was decreased from 2016 to 2020; it is probably a result of increasing awareness of the disease among patients. We think our results will contribute to the epidemiological data in our province and country and raise awareness.

Toxoplasma gondii seroprevalence among pregnant women in Rabat, Morocco

Background Toxoplasmosis is an infectious disease caused by a protozoan parasite named Toxoplasma gondii (T.gondii). Pregnant women are considered one of the risk groups. The objective of this retrospective study is to provide an updated estimate of the seroprevalence of anti-T. gondii antibodies among a group of Moroccan pregnant women monitored at the Parasitology Laboratory of the National Institute of Hygiene in Rabat in Morocco. Methods Serum samples were tested for the presence of specific anti-T. gondii immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies using indirect enzyme-linked immunosorbent assay (ELISA). Anti-Toxoplasma IgM- and IgG-positive cases were also evaluated with the anti-Toxoplasma IgG avidity test. All cases were evaluated according to the age, parity, and historical of abortion. Results Among 677 pregnant women, 94.1% (637/677) were serologically screened for the first time and therefore had no knowledge of their serological status, and only 5.9% (40/677) were screened for the second or third time. The overall anti-T. gondii IgG and IgM seropositivity among the 637 pregnant women included in the study analysis was 43% (274/637) and 3.9% (25/637), respectively. The use of the IgG avidity test allowed excluding recent infection among 83% of cases with IgG and IgM positive sera. The mean age was 29.4 ± 6.3 years. The result of the bivariate analysis revealed that the age influenced significantly the seroprevalence rate, while the parity and the existence of previous spontaneous abortion did not have any significant statistical correlation with seropositivity to T. gondii. Conclusion This study shows that 43% of pregnant women were positive and 57% of them had no antibody against the T. gondii infection. However, the pregnancy follow-up and the counseling of pregnant women remain essential for the prevention of congenital toxoplasmosis.

Results of the Toxoplasmosis Screening in 9311 Pregnant Women in a Tertiary Center in Turkey

Introduction: Toxoplasma gondii is an important parasite that can cause permanent sequelae to the fetus when infected during pregnancy in humans. Although the frequency of this parasite varies widely between countries, it is known that it is common in our country. The aim of this study was to determine the seroprevalence of toxoplasma in pregnant women admitted to a tertiary hospital in central Anatolia and to evaluate the pregnancy outcomes together with seroprevalence. Materials and Methods: A total of 9311 patients admitted to a tertiary hospital between January 2016 and December 2018 were included into the study. After serological examination, avidity test was performed in cases suggestive of acute infection. Amniocentesis was recommended to be performed by Polimeraze Chain Reaction (PCR) in patients with low avidity. Results: The frequency of Toxoplasma immunoglobulin (Ig) G and M seropositivity rates were 20.3% and 0.28%, respectively. Low avidity was found in approximately 27% of the patients with IgM positivity, and only 15.4% had low avidity by confirmatory test. One patient could not be reached during follow-up. PCR was performed in 4 patients whose low avidity value was confirmed by re-tests and all of their PCR results were reported negative. No cases of congenital toxoplasmosis were detected during the 3 years in our clinic. Conclusion: The inclusion of toxoplasma in routine screening programme is still controversial and differs between countries. Screening in areas with a high rate of toxoplasma, such as in our country, may be rational. If infection is detected, treatment may be recommended because it may reduce the transmission to the fetus.