Avidity Test Research Articles

Pitfalls in the Serological Evaluation of Maternal Cytomegalovirus Infection as a Potential Cause of Fetal and Neonatal Involvements: A Narrative Literature Review.

Cytomegalovirus (CMV) is the most common cause of intrauterine infection and serological assays are the primary tools for assessing CMV infections during pregnancy. CMV-specific immunoglobulin M (IgM) antibodies have been used as a diagnostic marker for primary CMV infection in pregnant women, although CMV-IgM has been detected in non-primary CMV infections. IgG avidity testing may aid the distinguishing of primary from non-primary CMV infection; however, there is no standardized assay for detecting this difference. Moreover, when maternal serology shows positive CMV-IgG with negative CMV-IgM findings, vertical transmission probability following primary CMV infection is often excluded. However, symptomatic congenital CMV infections in the context of negative findings for maternal CMV-IgM have been reported recently. The absence of CMV-IgM is recognized in both primary and non-primary CMV infections. Furthermore, maternal non-primary CMV infections during pregnancy may yield a greater proportion of symptomatic congenital CMV infections than previously thought. If universal prenatal screening is performed, ultrasonography for abnormal fetal findings should be conducted regardless of CMV-IgM antibody status. If not universally screened, CMV antibody screening should be performed whenever routine fetal ultrasound reveals abnormal findings. For suspected fetal CMV infection, amniotic fluid or postnatal infant urine CMV-DNA testing is required.

IgG Avidity Test as a Tool for Discrimination between Recent and Distant Toxoplasma gondii Infection-Current Status of Studies.

Toxoplasma gondii, an obligate intracellular protozoan parasite, is the causative agent of one of the most prevalent zoonoses worldwide. T. gondii infection is extremely important from a medical point of view, especially for pregnant women, newborns with congenital infections, and immunocompromised individuals. Thus, an accurate and proper diagnosis of this infection is essential. Among the available diagnostic tests, serology is commonly used. However, traditional serological techniques have certain limitations in evaluating the duration of T. gondii infection, which is problematic, especially for pregnant women. Avidity of T. gondii-specific IgG antibodies seems to be a significant tool for discrimination between recent and distant infections. This article describes the problem of diagnosis of T. gondii infection, with regard to IgG avidity tests. The IgG avidity test is a useful serological indicator of toxoplasmosis, which in many cases can confirm or exclude the active form of the disease. IgG antibodies produced in the recent primary T. gondii infection are of low avidity while IgG antibodies with high avidity are detected in the chronic phase of infection. Furthermore, this paper presents important topics of current research that concern the usage of parasite recombinant antigens that may improve the performance of IgG avidity tests.

Prevalence and genotypic characterization of human parvovirus B19 in hemophilia patients.

Parvovirus B19 (B19V) is usually transmitted through respiratory tract, but can also be received through blood transfusion. This study evaluated the seroprevalence, DNA existence, and circulating genotypes of B19V in hemophilia patients. Serum samples of cases and controls were analyzed for B19V using ELISA and real-time PCR. Finally, obtained sequences were used for genotyping. Among cases, 3% were anti-B19V IgM positive and 47% were anti-B19V IgG positive and B19V DNA was detected in 16% of them. However, among controls, 38% were anti-B19V IgG positive (P>0.05) and 5% were B19V DNA positive (P= 0.019). Also ∼13% of cases were positive and all of controls were negative for IgG avidity test (P= 0.029). Viral load in case group was higher than control group (P = 0.037). Since hemophilia patients receive large amounts of blood factors, prevalence of B19V in these patients might be higher than normal subjects.

Differential avidity determination of IgG directed towards the receptor-binding domain (RBD) of SARS-CoV-2 wild-type and its variants in one assay: Rational tool for the assessment of protective immunity.

The avidity (binding strength) of IgG directed towards the receptor‐binding domain (RBD) of spike protein has been recognized as a central marker in severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) serology. It seems to be linked to increased infection‐neutralization potential and therefore might indicate protective immunity. Using a prototype line assay based on the established recomLine SARS‐CoV‐2 assay, supplemented with RBD of the delta and the omicron variant, differential avidity determination of IgG directed towards RBD of wild‐type (WT) SARS‐CoV‐2 and distinct variants was possible within one assay. Our data confirm that natural SARS‐CoV‐2 infection or one vaccination step lead to low avidity IgG, whereas further vaccination steps gradually increase avidity to high values. High avidity is not reached by infection alone. After infection with WT SARS‐CoV‐2 or vaccination based on mRNA WT, the avidity of cross‐reacting IgG directed towards RBD of the delta variant only showed marginal differences compared to IgG directed towards RBD WT. In contrast, the avidity of IgG cross‐reacting with RBD of the omicron variant was always much lower than for IgG RBD WT, except after the third vaccination step. Therefore, parallel avidity testing of RBD WT and omicron seems to be mandatory for a significant assessment of protective immunity towards SARS‐CoV‐2.

Concordance between Anti-CMV IgM ELISA and IgG Avidity testing of serum immunoglobulin in FUO patients

Concordance between Anti-CMV IgM ELISA and IgG Avidity testing of serum immunoglobulin in FUO patients

Characterizing Kinetics and Avidity of SARS-CoV-2 Antibody Responses in COVID-19 Greek Patients.

In-depth understanding of the immune response provoked by SARS-CoV-2 infection is necessary, as there is a great risk of reinfection and a difficulty in achieving herd immunity due to a decline in both antibody concentration and avidity. Avidity testing, however, could overcome variability in the immune response associated with sex or clinical symptoms, and thus differentiate between recent and past infections. In this context, here, we analyzed SARS-CoV-2 antibody kinetics and avidity in Greek hospitalized (26%) and non-hospitalized (74%) COVID-19 patients (N = 71) in the course of up to 15 months after their infection to improve the accuracy of the serological diagnosis in dating the onset of the infection. The results showed that IgG-S1 levels decline significantly at four months (p = 0.0239) in both groups of patients and are higher in hospitalized ones (up to 2.1-fold, p < 0.001). Additionally, hospitalized patients’ titers drop greatly and are equalized to non-hospitalized ones only at a time-point of twelve to fifteen months. Antibody levels of women in total remain more stable months after infection, compared to men. Furthermore, we examined the differential maturation of IgG avidity after SARS-CoV-2 infection, showing an incomplete maturation of avidity that results in a plateau at four months after infection. We also defined 38.2% avidity (sensitivity: 58.9%, specificity: 90.91%) as an appropriate “cut-off” that could be used to determine the stage of infection before avidity reaches a plateau.

Seroprevalence and associated risk factors of Toxoplasma gondii and Neospora caninum infections in cattle in Central India.

Toxoplasma gondii and Neospora caninum are closely related cyst-forming parasites identified as important causes of reproductive failures in ruminants. While these parasites have been reported worldwide, seroprevalence and associated risk factors for cattle infections have not been determined in India. A total of 576 serum samples of cattle were analyzed for antibodies to T. gondii and N. caninum using enzyme-linked immunosorbent assay (ELISA), modified/Neospora agglutination test (MAT/NAT), and an indirect fluorescent antibody test (IFAT-tachyzoite and bradyzoite). Additionally, general information about cattle, movement of cats and dogs, the menace of rodents, management, and reproductive disorders were assessed to identify the potential risk factors. Overall, 32.9% (190/576) serum samples reacted positively to T. gondii and 24.8% (143/576) to N. caninum. The performance of the diagnostic tests showed excellent agreement between IFAT and ELISA (kappa [κ]=0.98) and between MAT/NAT and ELISA (κ=0.97). Combining both infections on avidity test, 94% sera had high-IgG avidity, and 3% had low-IgG avidity antibodies, indicating chronic infection in the majority of the cases. The identified risk factors (p<0.05) for exposure to T. gondii were: increasing age (Odds Ratio [OR]: 2.02), movement of cat (OR: 4.8) and rodents (OR: 1.57) in the farm; and for N. caninum: increasing age (OR: 1.6), movement of dogs in the farm (OR: 2.07), drinking pond water (OR: 1.64) and abortion (OR: 1.82). These findings revealed that T. gondii and N. caninum infections are widespread in the study area and suggest conducting nationwide epidemiological studies owing to their economic importance.

Seroprevalence and risk factors for cytomegalovirus infection among pregnant women in southern Taiwan, 2014–2015

ObjectiveTo investigate the seroprevalence of and risk factors for cytomegalovirus (CMV) infection among pregnant women in southern Taiwan. Materials and methodsFrom 2014 to 2015, pregnant women undergoing their first prenatal care visit participated in this study at Kaohsiung Chang Gung Memorial Hospital and Chiayi Chang Gung Memorial Hospital. A serologic test was performed for anti-CMV IgG/IgM. Transabdominal amniocentesis was scheduled for those with seropositive anti-CMV IgM. Extraction of CMV DNA was performed via real-time polymerase chain reaction (PCR). Maternal sociodemographic characteristics and risk factors for CMV seropositivity were analyzed. ResultsA total of 539 pregnant women undergoing their first prenatal visit were included. Eighty-three pregnant women were excluded for delivering at other hospitals. The overall seroprevalence rate of anti-CMV IgG in the remaining 456 cases was 87.28%. The seroprevalence rates of anti-CMV IgG(+)/IgM(+) and IgG(+)/IgM(−) were 1.32% and 85.96%, respectively. According to the anti-CMV IgG avidity test, only 3 pregnant women (0.65%) had primary CMV infection. Two of them underwent amniocentesis, and the results for both were negative for CMV DNA. According to the logistic regression analysis, the seropositivity of anti-CMV IgG was significantly associated with maternal age ≥30 (adjusted OR = 2.08, 95% CI: 1.10–3.94, p = 0.025) and the seropositivity of anti-CMV IgM was significantly associated with gestational weeks ≥37 when delivery (adjusted OR = 7.81, 95% CI: 1.23–49.58, p = 0.029). ConclusionIn southern Taiwan, among pregnant women, the CMV seroprevalence was high (87.28%), but the rate of primary CMV infection was very low (0.65%). Pregnant women aged more than 30 years had a significant risk of CMV seropositivity.

Rubella immunity in native Turkish and Syrian immigrant pregnant women between 2010-2018

Objectives: The study has aimed to investigate the rubella immunity in native-Turkish and Syrian-immigrant pregnant women in Turkey. Methods: Between September 2010 and December 2018, the hospital records of pregnant patients were evaluated retrospectively. For each year, for the number of patients who were screened for rubella IgG and/or IgM antibodies, IgG avidity (if any), and PCR tests (if any) were investigated, and subjects were categorized by nationality. Results: During the study period, a total of 80,302 pregnant were tested with at least one of the rubella IgM or IgG antibodies. Of these, 22,962 pregnant women were screened for both IgG and IgM, 24,684 were screened for IgG, and 78,580 pregnant women were screened for IgM rubella antibodies. The seropositivity rate of IgG rubella antibodies in native and Syrian pregnant groups was 93.8% and 95.9%, respectively. In both groups, the IgM rubella antibodies were found as 0.5%. IgG avidity was investigated in 252 patients, whose test results were positive for IgM and IgG; and a low IgG avidity was detected in 5 native patients, while none was detected in the Syrian group. Conclusions: In the Syrian immigrant group, the susceptibility to Rubella is low, and it does not differ from the native Turkish population.

Determination of Low IgG Class Antibody Avidity Percentage by IgM Levels Specific to Toxoplasma Gondii.

Ig (Immunglobulin) M detection and low avidity index are markers of recent infection in differentiating acute and chronic stages of Toxoplasma gondii (T. gondii) infections. In this study, we aimed to evaluate whether the anti-T. gondii IgM antibody index threshold value could be a predictive factor in the estimation of low avidity and its use in improving the diagnosis of early toxoplasma infection. Anti-T. gondii IgM, IgG antibody and IgG avidity results were analyzed. Anti-T. gondii IgG and IgM antibodies in blood samples were studied with chemiluminescent microparticle immunoassay (CMIA), and IgG avidity test was performed with Enzyme Linked Fluorescent Assay (ELFA) technique. The overall seroprevalence of anti-T. gondii antibodies (IgG and/or IgM) was 19.4%. Of the 64 patients whose avidity tests were studied, 47 (73.4%) were female. Twenty seven (57.4%) of the women were pregnant. In the IgG avidity test, 7.8% low avidity was detected. Low avidity was detected in only 4 (15.4%) of 26 IgM positive cases. IgM analysis of a case (6-month-old baby) with low avidity was found to be negative. In the prediction of low avidity, the assay's IgM positivity cutoff value was ≥ 0.6, its sensitivity, specificity, positive predictive value, and negative predictive value were 80%, 62.7%, 2.3%, and 99.7%, respectively. With Architect, 37.3% of samples were false positive. Determining the IgM index cutoff value was unsuccessful in distinguishing low avidity. The area under the ROC curve was 0.574 (p = 0.60). In our study, the positive predictive value of the IgM test kit in estimating low avidity was low and the false positivity rate was 37.3%. It is thought that the index cutoff value of the anti-T. gondii IgM antibody test kit cannot be considered as a good predictor of recent infection. Studies with larger patient groups are needed.

Antibody response to SARS-CoV-2 for more than one year-kinetics and persistence of detection are predominantly determined by avidity progression and test design.

BackgroundAntibody detection of SARS-CoV-2 requires an understanding of its variation, course, and duration.MethodsAntibody response to SARS-CoV-2 was evaluated over 5–430 days on 828 samples across COVID-19 severity levels, for total antibody (TAb), IgG, IgA, IgM, neutralizing antibody (NAb), antibody avidity, and for receptor-binding-domain (RBD), spike (S), or nucleoprotein (N). Specificity was determined on 676 pre-pandemic samples.ResultsSensitivity at 30–60 days post symptom onset (pso) for TAb-S/RBD, TAb-N, IgG-S, IgG-N, IgA-S, IgM-RBD, and NAb was 96.6%, 99.5%, 89.7%, 94.3%, 80.9%, 76.9% and 92.8%, respectively. Follow-up 430 days pso revealed: TAb-S/RBD increased slightly (100.0%); TAb-N decreased slightly (97.1%); IgG-S and IgA-S decreased moderately (81.4%, 65.7%); NAb remained positive (94.3%), slightly decreasing in activity after 300 days; there was correlation with IgG-S (Rs = 0.88) and IgA-S (Rs = 0.71); IgG-N decreased significantly from day 120 (15.7%); IgM-RBD dropped after 30–60 days (22.9%). High antibody avidity developed against S/RBD steadily with time in 94.3% of patients after 430 days. This correlated with persistent antibody detection depending on antibody-binding efficiency of the test design. Severe COVID-19 correlated with earlier and higher antibody response, mild COVID-19 was heterogeneous with a wide range of antibody reactivities. Specificity of the tests was ≥99%, except for IgA (96%).ConclusionSensitivity of anti-SARS-CoV-2 assays was determined by test design, target antigen, antibody avidity, and COVID-19 severity. Sustained antibody detection was mainly determined by avidity progression for RBD and S. Testing by TAb and for S/RBD provided the highest sensitivity and longest detection duration of 14 months so far.

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

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. 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. 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. 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.

Prevalence and Recurrence Rates of Cytomegalovirus Infection Among Patients With Hematological Diseases in the Western Brazilian Amazon: A Cross-Sectional Study.

Cytomegalovirus (CMV) is a worldwide distributed pathogen that may cause serious complications in patients with hematological diseases. This study aimed to serologically characterize CMV infection in patients suffering from hematological diseases in Amazonas state, Brazil. Serum samples from 323 patients were tested for the presence of anti-CMV IgM or IgG antibodies using an enzyme-linked immunosorbent assay. Positive samples for IgM were submitted to the IgG avidity test to differentiate primary infection from recurrent infection. An epidemiological questionnaire was administered to collect the sociodemographic information of the study population. The overall prevalence of CMV infection verified in this study was 91.3%. The highest rates were found in patients suffering from platelet disorders (94.5%), anemia (93.3%), or leukemia (91%). The study population was predominantly composed of individuals with low socioeconomic status. Blood transfusions were more common in patients with anemia or leukemia, but this variable was not correlated with the seropositivity for CMV infection. Measurement of IgG avidity in patients positive for anti-CMV IgM demonstrated a recurrent infection rate of 5.2% (17/323). Over 80% of recurrent infections occurred in patients with acute lymphocytic leukemia (ALL) or anemia. Our findings indicated that CMV infection is highly prevalent in patients from the western Brazilian Amazon who have hematological diseases. The prevalence observed progressively rose with increasing age, whereas anemia or ALL figured as risk factors for the recurrence of CMV infection.

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

BackgroundTubulointerstitial 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 presentationA 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.ConclusionsWe 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.

Evaluation of Seropositivity of Toxoplasmosis Suspected Patients Admitted to the National Parasitology Reference Laboratory Between 2009 and 2019

Toxoplasmosis caused by Toxoplasma gondii (T. gondii), which is an obligatory intracellular parasite, is a worldwide zoonotic parasitic disease. In this study, results of T. gondii test conducted between January 2009 and May 2019 were analysed. This study aimed to evaluate the results of T. gondii test of patients who were admitted to the General Directorate of Public Health, National Parasitology Reference Laboratory between 2009 and 2019. The results of anti-T. gondii IgG, IgM, IgG avidity and Sabin-Feldman dye tests (SFDT), which are used to detect the presence of T. gondii, were examined. ELISA was used for anti-T. gondii IgG, IgM and IgG avidity tests. SFDT, which is the reference test in the diagnosis of T. gondii, is still the gold standard. In addition to laboratory analyses, information on gender, age, city of origin, year distribution of all cases and type of sample sent was also collected. Of the 2.778 patients evaluated, 25.4% were males and 74.6% were females. Moreover, 47.1% and 10.2% of the patients were positive for anti-T. gondii IgG and anti-T. gondii IgM antibodies, respectively. In SFDT, 1.228 (52%) patients were found to be positive, including 319 (59.4%) of 537 men and 909 (49.8%) of 1.824 women. In this 10-year study, the most common seropositivity titre of SFDT was at the level of 1/64. In our study, IgG levels were found to be positive in all cases in which IgG avidity was studied when all the cases in which all three of the anti-T. gondii IgG, IgM and IgG avidity tests were studied together in one patient were evaluated. In addition, of the 293 patients with positive anti-T. gondii IgG, 62.8% had high avidity, 24.2% had a limit value and 13% had a low avidity. In cases involving both mother and baby, anti-T. gondii IgG and IgM seropositivity rates were 80% and 5% for both, respectively. These high rates support the transfer of antibodies from the mother to the baby. Regarding the distribution of provinces from which the samples originated, the highest number of cases came from Ankara (80.7%). Blood is the most predominant sample, followed by cerebrospinal fluid. T. gondii maintains its importance in public health, owing to its high positivity rates. This study, in which 10-year data were collected, showed that despite an increase in awareness, high seropositivity still continues. Therefore, systematic collection and evaluation of laboratory analysis results for toxoplasmosis diagnosis will contribute in taking control measures.

Measurement of the IgG Avidity Index in the Diagnosis of Clinical Toxocariasis Patients

Toxocara spp. are parasitic nematodes responsible for human toxocariasis, a common zoonotic helminth infection. The five main features of human toxocariasis are the classical ocular toxocariasis and visceral larva migrans syndrome, followed by covert toxocariasis, common toxocariasis and neurotoxocariasis. The diagnosis of toxocariasis is feasible by considering clinical symptoms, anamnestic history and serology laboratory results; however, serological criteria cannot be used to distinguish active Toxocara infection from past exposure, which is an area of much discussion in clinical practice. In this context, we developed avidity tests (ELISA and immunoblotting) and evaluated their clinical usefulness in distinguishing past from active toxocariasis. Our study involved 46 patients divided into two groups: “active toxocariasis” (n = 14) and “chronic toxocariasis” (n = 32). According to the avidity indices obtained for both the chronic and active toxocariasis groups, we proposed two thresholds: first, an AI lower than 32% supports an active infection; secondly, a threshold above 42% can exclude an active infection. In order to use this assay in routine clinical practice, however, is still requires standardisation with regards to the method and threshold values, which can be established through studies involving larger populations.

Serodiagnosis Of Toxoplasmosis By Using ELISA And IgG Avidity Test In Relation To Some Risk Factors Among Women at Childbearing Agein 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. &#x0D; The differences between seropositivity and age was significant (p&lt;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). &#x0D; 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. &#x0D; 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.

Undisclosed HIV status and antiretroviral therapy use among South African blood donors.

Undisclosed antiretroviral drug (ARV) use among blood donors who tested HIV antibody positive, but RNA negative, was previously described by our group. Undisclosed ARV use represents a risk to blood transfusion safety. We assessed the prevalence of and associations with undisclosed ARV use among HIV-positive donors who donated during 2017. South African National Blood Service (SANBS) blood donors are screened by self-administered questionnaire, semi-structured interview, and individual donation nucleic acid amplification testing for HIV. Stored samples from HIV-positive donations were tested for ARV and characterized as recent/longstanding using lag avidity testing. Of the 1462 HIV-positive donations in 2017, 1250 had plasma availability for testing of which 122 (9.8%) tested positive for ARV. Undisclosed ARV use did not differ by gender (p= .205) or ethnicity (p= .505) but did differ by age category (p< .0001), donor (p< .0001), clinic type (p= .012), home province (p= .01), and recency (p< .0001). Multivariable logistic regression found older age (adjusted odds ratio [aOR] 3.73, 95% confidence interval [CI] 1.98-7.04 for donors >40 compared with those <21), first-time donation (aOR 5.24; 95% CI 2.48-11.11), and donation in a high HIV-prevalence province (aOR 9.10; 95% CI 2.70-30.72) compared with Northern Rural provinces to be independently associated with undisclosed ARV use. Almost 1 in 10 HIV-positive blood donors neglected to disclose their HIV status and ARV use. Demographic characteristics of donors with undisclosed ARV use differed from those noted in other study. Underlying motivations for nondisclosure among blood donors remain unclear and may differ from those in other populations with significant undisclosed ARV use.

Frequency, timing and risk factors for primary maternal cytomegalovirus infection during pregnancy in Quebec.

Maternal Cytomegalovirus (CMV) infection in the first trimester (T1) of pregnancy is a public health concern, as it increases the risk of severe neurodevelopmental outcomes associated with congenital infection compared to infections occurring later during pregnancy. To determine CMV seroprevalence in T1 of pregnancy, its trend, risk factors and the incidence rate of primary infection during pregnancy. Using the biobank of the prospective cohort "Grossesse en Santé de Québec" collected between April 2005 and March 2010 at the Québec-Laval Hospital, Québec, Canada, maternal CMV serology was determined using Abbott Architect Chemiluminescence microparticle immunoassays for immunoglobulin G(IgG), immunoglobulin M(IgM) titration and IgG avidity testing. Changepoint detection analysis was used to assess temporal trends. Risk factors associated with seropositivity were determined by multivariable logistic regression. CMV seroprevalence in T1 of pregnancy was 23.4% (965/4111, 95% CI, 22.1-24.7%). The incidence rate for CMV primary infection during pregnancy was 1.8 (95% CI, 1.2-2.6) per 100 person-years. No changepoint was identified in the maternal CMV-seroprevalence trend. Multivariable analyses showed that T1 maternal CMV seropositivity was associated with having one child OR 1.3 (95% CI, 1.10-1.73) or two or more children OR 1.5 (95%CI, 1.1-2.1), ethnicity other than Caucasian OR 2.1 (95% CI, 1.1-3.8) and country of birth other than Canada and the USA OR 2.8 (95% CI, 1.5-4.9). In this cohort, maternal seroprevalence in T1 of pregnancy and seroconversion rate were low. This information and identified risk factors could help guide the development and implementation of preventive actions and evidence-based health policies to prevent CMV infection during pregnancy.