Abstract Objective To determine the laboratory-based performance and operational characteristics of three dual rapid diagnostic tests (RDTs) for testing HIV and syphilis. Methods Three dual RDTs (SD ...Bioline, Chembio, and MedMira) were evaluated using 1514 serum specimens archived at laboratories or collected from clinics in China and Nigeria to determine sensitivity and specificity, with 95% confidence intervals. Concordance of testing results read by two technicians, stability of testing results read at two time points, and test operation characteristics were also assessed. Results All three of the evaluated RDTs gave excellent performance with a combined sensitivity ranging from 99.0%–99.6% for HIV and 98.3%–99.0% for syphilis, and a combined specificity ranging from 97.9%–99.0% for HIV and 97.2%–99.6% for syphilis. Concordance of testing results between two technicians and stability of testing results read within and one hour past the recommended reading period showed excellent agreement, with Kappa greater than or equal to 0.98. Conclusions All the tests were found to be very or fairly easy to use and easy to interpret the results. Further evaluations of these dual RDTs with whole blood in field settings, and more studies on the implication of introduction of these tests in HIV and syphilis control programs are needed.
This paper evaluates an experiment in which individuals in rural Malawi were randomly assigned monetary incentives to learn their HIV results after being tested. Distance to the HIV results centers ...was also randomly assigned. Without any incentive, 34 percent of the participants learned their HIV results. However, even the smallest incentive doubled that share. Using the randomly assigned incentives and distance from results centers as instruments for the knowledge of HIV status, sexually active HIV-positive individuals who learned their results are three times more likely to purchase condoms two months later than sexually active HIV-positive individuals who did not learn their results; however, HIV-positive individuals who learned their results purchase only two additional condoms than those who did not. There is no significant effect of learning HIV-negative status on the purchase of condoms.
Abstract
Background
Treponemal immunoassays are increasingly used for syphilis screening with the reverse sequence algorithm. There are few data describing performance of treponemal immunoassays ...compared to traditional treponemal tests in patients with and without syphilis.
Methods
We calculated sensitivity and specificity of 7 treponemal assays: (1) ADVIA Centaur (chemiluminescence immunoassay CIA); (2) Bioplex 2200 (microbead immunoassay); (3) fluorescent treponemal antibody absorption test (FTA-ABS); (4) INNO-LIA (line immunoassay); (5) LIAISON CIA; (6) Treponema pallidum particle agglutination assay (TPPA); and (7) Trep-Sure (enzyme immunoassay EIA), using a reference standard combining clinical diagnosis and serology results. Sera were collected between May 2012-January 2013. Cases were characterized as: (1) current clinical diagnosis of syphilis: primary, secondary, early latent, late latent; (2) prior treated syphilis only; (3) no evidence of current syphilis, no prior history of syphilis, and at least 4 of 7 treponemal tests negative.
Results
Among 959 participants, 262 had current syphilis, 294 had prior syphilis, and 403 did not have syphilis. FTA-ABS was less sensitive for primary syphilis (78.2%) than the immunoassays or TPPA (94.5%-96.4%) (all P ≤ .01). All immunoassays were 100% sensitive for secondary syphilis, 95.2%-100% sensitive for early latent disease, and 86.8%-98.5% sensitive in late latent disease. TPPA had 100% specificity.
Conclusions
Treponemal immunoassays demonstrated excellent sensitivity for secondary, early latent, and seropositive primary syphilis. Sensitivity of FTA-ABS in primary syphilis was poor. Given its high specificity and superior sensitivity, TPPA is preferred to adjudicate discordant results with the reverse sequence algorithm over the FTA-ABS.
We compared performance of 5 treponemal immunoassays, the Treponema pallidum particle agglutination assay (TPPA), and the fluorescent treponemal antibody absorption test (FTA-ABS). FTA-ABS was less sensitive for primary syphilis (78%) than the immunoassays or TPPA (94%-96% sensitivity). TPPA was 100% specific.
Comparative validation data and clinical performance data are essential for the reliable interpretation of SARS-CoV-2 antibody test results. This study aimed to assess the performance of six ...SARS-CoV-2 IgG immunoassays in different disease severity settings. Four automated chemiluminescence immunoassays Access (Beckman Coulter), Architect (Abbott), Atellica-IM (Siemens) and Elecsys (Roche) and two ELISA assays (SARS-CoV-2 IgG-S1-based and NCP IgG, Euroimmun) were evaluated in 143 patients and 50 pre-pandemic control sera. Accuracy and precision tests were performed for validation. Overall sensitivity differed between 73.38-88.65%, being higher in spike protein-based assays. Specificity was ≥ 98% in all immunoassays. IgG response was lower for the samples taken <20 days post-symptom onset (87.30%) than for the samples taken ≥20 days post-symptom onset (94.80%). Higher rate of antibody was detected in the clinically moderate disease group. In the asymptomatic and mild group more antibody positivity was detected with spike protein-based assays. Clinical performance of the immunoassays differs according to disease severity and antigen targeted; moderate disease leading to highest rate of IgG response. All the assays tested were eligible for the detection of SARS-CoV-2 IgG however, spike-based assays revealed relatively higher sensitivity than the nucleoprotein-based assays particularly in the asymptomatic and mild disease severity.
Background. Algorithms for the diagnosis of syphilis continue to be a source of great controversy, and numerous test interpretations have perplexed many clinicians. Methods. We conducted a ...cross-sectional study of 24 124 subjects to analyze 3 syphilis testing algorithms: traditional algorithm, reverse algorithm, and the European Centre for Disease Prevention and Control (ECDC) algorithm. Every serum sample was simultaneously evaluated using the rapid plasma reagin, Treponema pallidum particle agglutination, and chemiluminescence immunoassay tests. With the results of clinical diagnoses of syphilis as a gold standard, we evaluated the diagnostic accuracy of the 3 syphilis testing algorithms. The κ coefficient was used to compare the concordance between the reverse algorithm and the ECDC algorithm. Results. Overall, 2749 patients in our cohort were diagnosed with syphilis. The traditional algorithm had the highest negative likelihood ratio (0.24), a missed diagnosis rate of 24.2%, and only 75.81% sensitivity. However, both the reverse and ECDC algorithms had higher diagnostic efficacy than the traditional algorithm. Their sensitivity, specificity, and accuracy were 99.38%–99.85%, 99.98%–100.00%, and 99.93%–99.96%, respectively. Moreover, the overall percentage of agreement and κ value between the reverse and the ECDC algorithms were 99.9% and 0.996, respectively. Conclusions. Our research supported use of the ECDC algorithm, in which syphilis screening begins with a treponemal immunoassay that is followed by a second, different treponemal assay as a confirmatory test in high-prevalence populations. In addition, our results indicated that nontreponemal assay is unnecessary for syphilis diagnosis but can be recommended for determining serological activity and the effect of syphilis treatment.
How serologic antibody tests should be used during the COVID-19 pandemic is outlined. Aside from being used to screen donor blood for antibodies, the tests could address the unintended consequence of ...receiving convalescent plasma or hyperimmune globulin. The tests, however, tend to report false-negatives and miss infections among people who are immunocompromised and do not produce antibodies.
•This study identified a notable prevalence of Treponema pallidum infection among vulnerable populations.•Individuals living with HIV (PLHIV) exhibited a remarkably high seroprevalence rate of ...Treponema pallidum infection, reaching 41.81 %.•The findings underscore the necessity for implementing public health policies specifically designed to reduce Treponema pallidum transmission and enhance health outcomes for diverse and at-risk populations.
Syphilis is a significant public health concern worldwide. According to the 2020 estimates, nearly 7.1 million new cases of syphilis have been reported globally, with over 30 % of these cases reported from American nations, particularly Brazil. Concerns have been raised regarding the susceptibility of specific groups to syphilis due to challenges and vulnerabilities that place these groups at a higher risk of infections or complications in the treatment outcomes. The present study aimed to compare the seroprevalence and the factors associated with syphilis among such high-risk groups. The study was designed as a cross-sectional one and was conducted with pregnant women, people living with HIV (PLHIV), people living with tuberculosis (PLTB), indigenous and healthy populations in Mato Grosso do Sul, Brazil. The study was conducted between June 2019 and August 2022, during which the included patients were subjected to treponemal and non-treponemal serological assays. The study also included a survey conducted through a self-reported questionnaire to collect information regarding the participants' demographics and sexual behaviors. A total of 550 samples were collected, with 110 participants in each of the five groups. The results of the study revealed that the seroprevalence of Treponema pallidum infection in pregnant women, PLHIV, PLTB, indigenous and healthy populations of the study region was 10 % (n = 11/110), 41.81 % (n = 46/110), 17.27 % (n = 19/110), 5.45 % (n = 6/110), and 8.18 % (n = 9/110), respectively. Homosexual orientation (p = 0.04) and a history of sexually transmitted infection (STI) (p = 0.01) were associated with the seroprevalence of T. pallidum infection in PLHIV. However, no such associations were noted in the remaining four groups. The seroprevalence of T. pallidum infection was observed to vary significantly among the different high-risk groups, which highlighted the persistent concern of syphilis, particularly among vulnerable populations. These findings underscore the significance of focused interventions and public health strategies customized to the specific requirements of each of the groups evaluated in the present study to decrease the number of cases of syphilis and thereby prevent future complications in patients with other serious infections.
Expression and immunolocalization of a Trichinella spiralis 31 kDa protein at different developmental stages.
•Trichinella spiralis 31kDa protein (Ts31) was expressed and purified.•Ts31 gene was ...expressed at all developmental stages of the parasite.•Ts31 was located in the cuticle and stichocytes of the parasite.•Sensitivity and specificity of rTs31-ELISA was 97.83% and 99.13%, respectively.•T. spiralis rTs31 protein is a potential diagnostic antigen for human trichinellosis.
The Trichinella spiralis 31kDa protein (Ts31) was screened from the excretory-secretory (ES) proteins of muscle larvae (ML) by immunoproteomics using serum from mice infected with T. spiralis at 18 days post infection (dpi). The aim of this study was to characterize the Ts31 protein and to evaluate the potential of the recombinant Ts31 protein (rTs31) for serodiagnosis of human trichinellosis. Ts31 gene was cloned and rTs31 was produced in an E. coli expression system. An anti-rTs31serum recognized the native protein migrating in a 25–55kDa range by Western blotting of ML crude or ES antigens. Expression of Ts31 gene was observed at all developmental stages of T. spiralis (adult worms, newborn larvae, pre-encapsulated larvae and ML). An immunolocalization analysis identified Ts31 in the cuticle and stichocytes of the parasite. The sensitivity of rTs31-ELISA and ES antigen ELISA for detecting anti-Trichinella IgG antibodies in sera of patients with trichinellosis was 97.83% (45/46) and 86.78% (39/46), respectively (P>0.05); The specificity of rTs31-ELISA was 99.13% (114/115), which was significantly higher than 85.22% (98/115) of ES antigen ELISA (P<0.01). The rTs31 protein of T. spiralis could be considered as a potential diagnostic antigen for trichinellosis.
Tuberculosis is a highly contagious zoonotic disease caused by Mycobacterium spp. A study was conducted to detect the presence of Mycobacterium in captive elephants. A total of 15 captive elephants ...were screened from various regions in Maharashtra. The blood and serum samples collected were subjected to rapid test kit, BacT/ALERT 3D system, Ziehl-Neelsen (ZN) staining and PCR. All the samples were found seronegative using rapid test kit and whole blood PCR. Whereas, all samples were signalled culture positive in BacT/ALERT 3D system which were further subjected to PCR, only one amplicon was produced of 176bp of RD4 gene (Mycobacterium bovis) and no acid-fast organism was detected upon ZN. Due to the atypical nature of this organism, diagnosis of this disease in elephants using various tests is complicated unlike the diagnostic tests that are validated in domestic animals. Therefore, many tests have sub-optimal sensitivity and specificity in elephants. As TB is a zoonotic disease, transmission can occur between human-livestock-elephants interface. Therefore, the zoos and state forest authority should inculcate a protocol of periodic TB screening for Mahouts and elephants in captivity along with protocol of elephant-visitor interaction, thus helping in conservation of this endangered species in India.
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