IgG ELISA Research Articles

Post COVID-19 condition after delta infection and omicron reinfection in children and adolescents.

The burden of COVID-19 in children and adolescents has increased during the delta and omicron waves, necessitating studies of long-term symptoms such as fatigue, dyspnoea and cognitive problems. Furthermore, immune responses in relation to persisting symptoms in younger people have not been well characterised. In this cohort study, we investigated the role of antibodies, vaccination and omicron reinfection upon persisting and long-term symptoms up to 8 months post-delta infection. SARS-CoV-2 RT-PCR positive participants (n=276, aged 10-20 years) were prospectively recruited in August 2021. We recorded the major symptoms of post COVID-19 condition and collected serum samples 3- and 8-months post delta infection. Binding antibodies were measured by spike IgG ELISA, and surrogate neutralising antibodies against Wuhan and delta variants by the hemagglutination test (HAT). After delta infection, persisting symptoms at 3 months were significantly associated with higher delta antibody titres (OR 2.97, 95% CI 1.57-6.04, p=0.001). Asymptomatic acute infection compared to symptomatic infection lowered the risk of persisting (OR 0.13, 95% CI 0.02-0.55, p=0.013) and long-term (OR 0.28 95% CI 0.11-0.66, p=0.005) symptoms at 3 and 8 months, respectively. Adolescents (16-20 years) were more likely to have long-term symptoms compared to children (10-15 years) (OR 2.44, 95% CI 1.37-4.41, p=0.003). This clinical and serological study compares long-term symptoms after delta infection between children and adolescents. The association between high antibody titres and persisting symptoms suggest the involvement of an immune mechanism. Similarly to adults, the dominant long-term symptoms in children are fatigue, dyspnoea and cognitive problems. This work was funded by the Ministry of Health and Care Services, Norway, the University of Bergen, Norway and Helse Vest, Norway (F-12621).

Mapping the risk of Rift Valley fever in Uganda using national seroprevalence data from cattle, sheep and goats.

Uganda has had repeated outbreaks of Rift Valley fever (RVF) since March 2016 when human and livestock cases were reported in Kabale after a long interval. The disease has a complex and poorly described transmission patterns which involves several mosquito vectors and mammalian hosts (including humans). We conducted a national serosurvey in livestock to determine RVF virus (RVFV) seroprevalence, risk factors, and to develop a risk map that could be used to guide risk-based surveillance and control measures. A total of 3,253 animals from 175 herds were sampled. Serum samples collected were screened at the National Animal Disease Diagnostics and Epidemiology Centre (NADDEC) using a competition multispecies anti-RVF IgG ELISA kit. Data obtained were analyzed using a Bayesian model that utilizes integrated nested Laplace approximation (INLA) and stochastic partial differential equation (SPDE) approaches to estimate posterior distributions of model parameters, and account for spatial autocorrelation. Variables considered included animal level factors (age, sex, species) and multiple environmental data including meteorological factors, soil types, and altitude. A risk map was generated by projecting fitted (mean) values, from a final model that had environmental factors onto a spatial grid that covered the entire domain. The overall RVFV seroprevalence was 11.3% (95% confidence interval: 10.2-12.3%). Higher RVFV seroprevalences were observed in older animals compared to the young, and cattle compared to sheep and goats. RVFV seroprevalence was also higher in areas that had (i) lower precipitation seasonality, (ii) haplic planosols, and (iii) lower cattle density. The risk map generated demonstrated that RVF virus was endemic in several regions including those that have not reported clinical outbreaks in the northeastern part of the country. This work has improved our understanding on spatial distribution of RVFV risk in the country as well as the expected burden of the disease in livestock.

Detection of SARS-CoV-2 in Terrestrial Animals in Southern Nigeria: Potential Cases of Reverse Zoonosis.

Since SARS-CoV-2 caused the COVID-19 pandemic, records have suggested the occurrence of reverse zoonosis of pets and farm animals in contact with SARS-CoV-2-positive humans in the Occident. However, there is little information on the spread of the virus among animals in contact with humans in Africa. Therefore, this study aimed to investigate the occurrence of SARS-CoV-2 in various animals in Nigeria. Overall, 791 animals from Ebonyi, Ogun, Ondo, and Oyo States, Nigeria were screened for SARS-CoV-2 using RT-qPCR (n = 364) and IgG ELISA (n = 654). SARS-CoV-2 positivity rates were 45.9% (RT-qPCR) and 1.4% (ELISA). SARS-CoV-2 RNA was detected in almost all animal taxa and sampling locations except Oyo State. SARS-CoV-2 IgGs were detected only in goats from Ebonyi and pigs from Ogun States. Overall, SARS-CoV-2 infectivity rates were higher in 2021 than in 2022. Our study highlights the ability of the virus to infect various animals. It presents the first report of natural SARS-CoV-2 infection in poultry, pigs, domestic ruminants, and lizards. The close human-animal interactions in these settings suggest ongoing reverse zoonosis, highlighting the role of behavioral factors of transmission and the potential for SARS-CoV-2 to spread among animals. These underscore the importance of continuous monitoring to detect and intervene in any eventual upsurge.

Risk factors and characteristics influencing humoral response to COVID-19 vaccination in patients after allogeneic stem cell transplantation.

Vaccination against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is approved and recommended for immunocompromised patients such as patients after allogeneic stem cell transplantation (allo-SCT). Since infections represent a relevant cause of transplant related mortality we analyzed the advent of immunization to SARS-CoV-2 vaccination in a bicentric population of allogeneic transplanted patients. We retrospectively analyzed data of allo-SCT recipients in two German transplantation centers for safety and serologic response after two and three SARS-CoV-2 vaccinations. Patients received mRNA vaccines or vector-based vaccines. All patients were monitored for antibodies against SARS-CoV2-spike protein (anti-S-IgG) with an IgG ELISA assay or an EIA Assay after two and three doses of vaccination. A total of 243 allo-SCT patients underwent SARS-CoV-2 vaccination. The median age was 59 years (range 22-81). While 85% of patients received two doses of mRNA vaccines, 10% had vector-based vaccines and 5% received a mixed vaccination. The two vaccine doses were well tolerated with only 3% patients developing a reactivation of graft versus host disease (GvHD). Overall, 72% of patients showed a humoral response after two vaccinations. In the multivariate analysis age at time of allo-SCT (p=0.0065), ongoing immunosuppressive therapy (p= 0.029) and lack of immune reconstitution (CD4-T-cell counts <200/μl, p< 0.001) were associated with no response. Sex, intensity of conditioning and the use of ATG showed no influence on seroconversion. Finally, 44 out of 69 patients that did not respond after the second dose received a booster and 57% (25/44) showed a seroconversion. We showed in our bicentric allo-SCT patient cohort, that a humoral response could be achieve after the regular approved schedule, especially for those patients who underwent immune reconstitution and were free from immunosuppressive drugs. In over 50% of the initial non-responders after 2-dose vaccination, a seroconversion can be achieved by boostering with a third dose.

Indirect IgG ELISA and serotype-specific neutralizing antibody titers are associated with protection against dengue in children in Cebu, Philippines

Abstract Standard measures of dengue virus (DENV) antibodies have not been established as protective against dengue. We assess whether an indirect dengue IgG ELISA (PanBio; Brisbane, QLD, Australia) and serotype-specific neutralizing antibody titers measured by a two-dilution focus reduction neutralization test (FRNT) are associated with protection against dengue. Healthy children (n = 1,214) aged 9–14 years in Cebu, Philippines were enrolled in a prospective population-based cohort study in May – June 2017 and were tested for dengue when they reported a febrile illness through March 2020. Serum samples were collected at enrollment, and all were tested by ELISA. FRNTs were performed using the WHO DENV1–4 reference strains on a random subset to quantify serotype-specific neutralizing antibodies (nAbs). Inverse probability weighting was used to adjust for subset size. The odds of dengue as predicted by antibody measures were assessed by logistic regressions and adjusted for age, gender, and residential site. Dengue naïve children were used as the reference group in all models. The probability of dengue was 9.2% (95% CI: 4.5 – 17.9) for the naïve group, 9.5% (4.8 – 17.8) for those with ELISA &amp;lt; 2, but 4.5% (2.8 – 7.2) for those with ELISA &amp;gt;= 2 (p=0.04). The probability was even lower at 1.4% (0.6 – 3.1) for those with the highest DENV1–4 geometric mean titers (GMT, p = 0.0001). Pre-vaccine nAbs to DENV2 and DENV3 were protective against a homotypic dengue case (DENV2: OR 0.28, 95% CI 0.12 to 0.65; DENV3: OR 0.27, 95% CI 0.13 to 0.57), but not heterotypic dengue. We show a commercial ELISA and serotype-specific nAbs are associated with the probability of dengue, providing useful assays for use in population and vaccine trials. This work was supported by the Philippine Department of Health, the Intramural Research Program of the National Institute of Allergy and Infectious Diseases (NIAID), and NIH Extramural Grant: P01AI106695.

A SARS-CoV-2 vaccine designed for manufacturability results in unexpected potency and non-waning humoral response.

Abstract Despite the availability of a number of COVID-19 vaccines, there still exists a large unmet need for vaccines which provide durable immunity and protection against emerging SARS-CoV-2 variants, and for vaccines with lower manufacturing costs and reduced logistical requirements for distribution. We have developed a novel protein component vaccine candidate, MT-001, based on a fragment of the SARS-CoV-2 spike protein surrounding the receptor binding domain (RBD). Mice vaccinated with a 2-dose prime-boost regimen of MT-001 adjuvanted with alum and CpG exhibited peak anti-spike IgG ELISA titers comparable to those reported for mRNA vaccines from Pfizer/BioNTech (BNT162b2) and Moderna (mRNA-1273), and, in contrast to the mRNA vaccines, these titers were found to be durable with midpoint GMTs in the range of 105 – 106 up to 12 months post-vaccination. Syrian golden hamsters vaccinated with a similar 2-dose regimen of MT-001 exhibited undetectable levels of SARS-CoV-2 in lung tissue four days after intranasal challenge with SARS-CoV-2/US-WA1. In mice, the results showed an increased breadth of the response, with significant neutralization titers against the Omicron BA.1 variant at this timepoint. These attributes make MT-001 a compelling candidate for a next-generation COVID-19 vaccine. MT-001 could be particularly valuable as an annual booster for individuals with diverse histories of vaccination, SARS-CoV-2 infection, and/or predispositions resulting in an immunocompromised state. MT-001 was designed for manufacturability and ease of distribution, and we demonstrate that these attributes are not inconsistent with a highly immunogenic vaccine that confers durable and broad immunity to SARS-CoV-2 and its emerging variants. Supported by grants from Rutgers University CCRP2 and the New Jersey Health Foundation. In-kind support from CEPI is also gratefully acknowledged.

Investigating persistent factor VIII-specific IgM in the humoral immune response to factor VIII

Abstract Hemophilia A is an X-linked bleeding disorder resulting in bleeding events due to insufficient levels of factor VIII (FVIII). The most significant complication in the management of hemophilia A is the formation of polyclonal neutralizing IgG (i.e., inhibitors) which impede FVIII procoagulant activity. In a hemophilia A (FVIII KO) murine model injected with multiple doses of FVIII, FVIII-specific IgM were found to persist despite an established IgG response. In attempt to characterize the role of IgM in FVIII immunity, 18 IgMs were purified from immortal FVIII-specific hybridomas and FVIII binding was confirmed via ELISA. IgMs demonstrated weak binding to FVIII in a static ELISA model with mean optical densities (OD) at 405 nm of 0.33 ± 0.43 compared to anti-FVIII IgG with a mean OD of 1.85 ± 0.02. A novel fluid-phase ELISA, developed in our lab, utilizing N-hydroxysuccinimide (NHS)-activated magnetic beads indirectly conjugated to FVIII increased IgM-FVIII binding with mean OD of 1.15 ± 0.60. IgM binding also demonstrated porcine FVIII cross-reactivity. To evaluate the effect of IgM on antibody titers in vivo, FVIII KO mice received 5 weekly injections of either FVIII or 4 separate immune complexes (IC) of IgM-FVIII. Mice injected with IgM-FVIII IC showed slightly higher median IgG ELISA titers than FVIII alone. These findings suggest a potential role for persistent anti-FVIII IgM in propagating FVIII inhibitor development. Further studies determining the effect of IgM-FVIII IC on complement activation, as well as anti-FVIII IgM epitope specificity and clonality utilizing computational methods of RNA-sequencing, may provide additional mechanistic insight into the role of persistent IgM in the humoral immune response to FVIII. Hemostasis and Thrombosis Research Society- Student Research Award (EY), NIH K99HL150595 (GB), and Hemophilia of Georgia Clinical Scientist Development Grant (GB).

Professional Athletes Maintain High TNF-Alpha or IFN-Gamma Related Inflammatory Status after Recovering from COVID-19 Infection without Developing a Neutralizing Antibody Response

Introduction: Professional athletes are endangered by COVID-19 and belong to the high-risk population due to their lifestyle. To obtain information on the behavior of COVID-19 in professional athletes, serological, cytokine, and virus neutralization capacities were analyzed. Materials and methods: Hungarian national teams participated in international sports events during the early phases of the COVID-19 epidemic in 2020. Altogether, 29 professional athletes volunteered to donate plasma. Their serological status was evaluated by IgA, IgM, and IgG ELISAs and the highest virus neutralization titer in an in vitro live tissue assay. Plasma cytokine patterns were analyzed with a Bioplex multiplex ELISA system. Results: Surprisingly, only one athlete (3%) had anti-SARS-CoV-2 IgG, while IgA was more common (31%). Neither plasma showed direct virus neutralization in a titer over 1:10; hence, they were not suitable for reconvalescent treatment. The ‘cytokine storm’ markers IL-6 and IL-8 were at baseline levels. In contrast, either the TNF-alpha-related cytokines or the IFN-gamma-associated cytokines were elevated. There was a strong negative correlation between the TNF-alpha- or IFN-gamma-related cytokines. Conclusions: Professional athletes are susceptible to the SARS-CoV-2 infection without developing long-term immunity through neutralizing immunoglobulins. Elevated secretory and cellular immunity markers indicate that these systems are probably responsible for virus elimination in this subpopulation.

Development and evaluation of an indirect ELISA using a multiepitope antigen for the diagnosis of intestinal schistosomiasis.

The laboratory diagnosis of intestinal schistosomiasis, carried out by detecting parasite eggs in feces, has low sensitivity when applied to individuals with low parasitic load. Serological tests can be more sensitive for the diagnosis of the disease. Therefore, the objective of this work was to develop and evaluate an ELISA-based immunoenzymatic assay, using a Schistosoma mansoni multiepitope antigen (ELISA IgG anti-SmME). For this, the amino acid sequences of S. mansoni cathepsin B and asparaginyl endopeptidase were submitted to the prediction of B cell epitopes and, together with peptide sequences obtained from earlier works, were used in the construction of a minigene. The multiepitope protein was expressed in Escherichia coli and the performance of the ELISA IgG anti-SmME for schistosomiasis was evaluated using serum samples from 107 individuals either egg positive or negative. In addition, 11 samples from individuals with other helminth infections were included. The ELISA IgG anti-SmME showed a sensitivity of 81.1% and a specificity of 46.1%. Further analysis revealed a 77.2% sensitivity in diagnosis of individuals with egg counts of ≤12 epg (eggs per gram feces) and 87.5% for individuals with 13–99 epg. It is worth mentioning that, to our knowledge, this was the first study using a multiepitope recombinant antigen in an ELISA for diagnosis of intestinal schistosomiasis, which demonstrated promising results in the diagnosis of individuals with low parasitic loads.

Human immune response against filarial HSP70 and its role in the diagnosis of lymphatic filariasis

A sensitive and specific diagnostic kit is crucial for the detection of human lymphatic filariasis at the early stage of infection as the existing diagnostic tools are inefficient and expensive. In the present study, we have cloned and expressed Brugia malayi HSP70 (BmHSP70) protein and characterized it as a potential antigen for diagnosis of the asymptomatic microfilariae stage of Wuchereria. bancrofti infection using ELISA, western blot, and bioinformatics tools. The antigenic efficacy of BmHSP70 was also compared with ScHSP70. The BmHSP70 and ScHSP70 peptide showed highly antigenic in nature and they showed immunogenic cross-reactivity endemic normal (EN) < chronic (CH) < microfilaraemic (MF) in IgG, IgG1, and IgG4 ELISA. IgG4-specific immunoblotting of BmHSP70 with MF sera further explicated its stage-specific antigenic cross-reactivity. These antigens (ScHSP70 and BmHSP70) showed a positive immunogenic correlation with the number of MF in blood samples. Thus, proposing BmHSP70 as a potential immunodiagnostic antigen against lymphatic filariasis. A triplet of GGMP tetrapeptide specific to the filarial HSP70 was also identified which was absent in human HSP70. In terms of sensitivity and specificity of antigens, these results suggest that recombinant BmHSP70 is a good antigen and could be used to diagnose early-stage of microfilariae infection.

High and Persistent Anti-GM1 Antibody Titers Are Associated With Poor Clinical Recovery in Guillain-Barré Syndrome.

Guillain-Barré syndrome (GBS) is an acute immune-mediated polyradiculoneuropathy that may follow a preceding infection inducing a cross-reactive antibody response to glycosphingolipids in peripheral nerves. The immune response in GBS is considered to be short lasting, explaining its monophasic clinical course. However, the disease course varies between patients, and residual deficits frequently occur. The duration of the antibody response has not been defined extensively in GBS, and the persistence of these antibodies may impair clinical recovery. The aim of this study was to determine the titer course of serum antibody titers to the ganglioside GM1 in relation to clinical course and outcome in patients with GBS. Acute-phase sera from patients with GBS included in previous therapeutic trials were screened for anti-GM1 IgG and IgM antibodies in ELISA. Anti-GM1 antibody titers were determined in sera collected at entry and during a 6-month follow-up. Clinical course and outcomes were compared between groups based on the titer course. Anti-GM1 antibodies were detected in 78 (20.7%) of 377 included patients. The anti-GM1 IgG and IgM antibody titer course was highly variable between patients. A subset of anti-GM1-positive patients had persistent anti-GM1 antibodies at 3 months (n = 27/43 [62.8%]) and 6 months (n = 19/41 [46.3%]). Patients with a high anti-GM1 IgG and IgM titer at entry recovered more slowly and less complete than anti-GM1-negative patients (IgG: p = 0.015, IgM: p = 0.03). High vs low IgG titers were independently associated with poor outcome after correcting for known prognostic factors (p = 0.046). Among patients with a high anti-GM1 IgG titer at entry, a slow titer decline was associated with poor outcome at 4 weeks (p = 0.003) and 6 months (p = 0.032). Persistent high IgG titers at 3 and 6 months were associated with poor outcome at 6 months (3 months: p = 0.022, 6 months: p = 0.004). High anti-GM1 IgG and IgM antibody titers at entry and persistent high anti-GM1 IgG antibody titers are associated with poor outcome in patients with GBS. Antibody persistency indicates ongoing antibody production long after the acute disease state in GBS. Further research is required to determine whether antibody persistency interferes with nerve recovery and is a target for treatments.

Trends in ELISA-Based Flavivirus IgG Serosurveys: A Systematic Review

Flaviviruses include virus species that are major public health threats worldwide. To determine the immunity landscape of these viruses, seroprevalence studies are often performed using IgG ELISA, which is a simple and rapid alternative to the virus neutralization test. In this review, we aim to describe the trends in flavivirus IgG ELISA-based serosurveys. A systematic literature review using six databases was performed to collate cohort and cross-sectional studies performed on the general population. A total of 204 studies were included in this review. The results show that most studies were performed on dengue virus (DENV), whereas Japanese Encephalitis Virus (JEV) was the least studied. For geographic distribution, serosurveys followed known disease prevalence. Temporally, the number of serosurveys increased after outbreaks and epidemics except for JEV, for which studies were performed to demonstrate the effectiveness of vaccination campaigns. Commercial kits were more commonly used than in-house assays for DENV, West Nile Virus (WNV), and Zika virus (ZIKV). Overall, most studies employed an indirect ELISA format, and the choice of antigens varied per virus. This review shows that flavivirus epidemiology is related to the regional and temporal distribution of serosurveys. It also highlights that endemicity, cross-reactivities, and kit availabilities affect assay choice in serosurveys.

Human papillomavirus-specific antibody status among unvaccinated subjects in the region of Vojvodina, Serbia.

The aim of the study was to evaluate the immune status of young people from the Vojvodina province, Serbia, through the detection of IgG antibodies specific for the L1 protein of HPV types 6, 11, 16, and 18 contained in quadrivalent vaccine. The study enrolled 514 healthy persons of both genders, aged between 18 and 30 years. All potential participants were informed about the project's aims by trained interviewers before venous blood collection. Also, participants completed a specially designed anonymous questionnaire to identify socio-demographic characteristics and individual behaviours associated with HPV seroprevalence. VPL HPV L1-specific IgG antibodies were measured using a semi-quantitative HPV IgG ELISA kit (Dia.Pro, Italy). A total of 472 (91.8%) young subjects had no detectable antibodies against high- and low-risk HPV types covered by the quadrivalent vaccine. A slightly higher number of seropositive individuals were detected in the age group of 26-30 years compared to younger than 25. Multivariate analysis showed that the number of lifetime sexual partners was the most powerful predictor of HPV seropositivity (OR = 3.483, 95% CI: 1.294-9.379). Obtained data point out low levels of naturally induced HPV-specific serum antibodies among the target population in the Vojvodina province. The present work highlights the significance and potential benefits of HPV vaccination. Routine HPV vaccination should be the public health priority in our country and should be included in the national immunization programme as soon as possible.

Twelve-Month Follow-up of the Immune Response After COVID-19 Vaccination in Patients with Genitourinary Cancers: A Prospective Cohort Analysis.

Vaccinations against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have had a transformative impact on morbidity and mortality. However, the long-term impact of vaccination on patients with genitourinary cancers is currently unknown. This study aimed to assess seroconversion rates in patients with genitourinary cancers receiving COVID-19 vaccination. Patients with prostate cancer, renal cell carcinoma, or urothelial cancer who had not been vaccinated for COVID-19 were included. Blood samples were obtained at baseline and after 2, 6, and 12 months of one dose of an FDA-approved COVID-19 vaccine. Antibody titer analysis was performed using the SCoV-2 Detect IgG ELISA assay, and the results were reported as immune status ratio (ISR). A paired t-test was used for comparison of ISR values between timepoints. In addition, T-cell receptor (TCR) sequencing was performed to assess for differences in TCR repertoire 2 months after vaccination. Out of 133 patients enrolled, 98 baseline blood samples were collected. At 2-, 6-, and 12-month time points 98, 70, and 50 samples were collected, respectively. Median age was 67 (IQR, 62-75), with the majority of patients diagnosed with prostate (55.1%) or renal cell carcinoma (41.8%). Compared to baseline (0.24 [95% CI, 0.19-0.31]) a significant increase in the geometric mean ISR values was observed at the 2-month timepoint (5.59 [4.76-6.55]) (P < .001). However, at the 6-month timepoint, a significant decrease in the ISR values was observed (4.66 [95% CI, 4.04-5.38]; P < .0001). Notably, at the 12-month timepoint, the addition of a booster dose resulted in an absolute increase in the ISR values compared to those who did not receive a booster dose (P = .04). Only a minority of patients with genitourinary cancers did not ultimately achieve satisfactory seroconversion after receiving commercial COVID-19 vaccination. Cancer type or treatment rendered did not appear to affect the immune response mounted after vaccination.

Tick-borne encephalitis virus IgG antibody surveillance: vaccination- and infection-induced seroprevalences, south-western Germany, 2021.

BackgroundThe exact epidemiology of tick-borne encephalitis virus (TBEV) infections is unknown because many TBEV infections have an influenza-like or asymptomatic course. Surveillance data are based on patients with any (predominantly neurological) symptoms that prompted diagnostic testing. Infection- and vaccine-induced antibodies against TBEV can be distinguished using an NS1IgG ELISA.AimIn a seroprevalence study we aimed to investigate TBEV antibody prevalence, incidences, manifestation indices and potential protection rates in a highly endemic district in south-western Germany.MethodsWe analysed 2,220 samples from healthy blood donors collected between May and September 2021. The reported number of TBEV infections was provided on a sub-district level by the local public health authorities. Blood samples were first screened using a TBEVIgG ELISA. In a second step, all positive samples were further analysed with a recently established NS1IgG ELISA. The presence of specific antibodies against TBEV (excluding cross-reacting antibodies against other flaviviruses) was confirmed by testing screening-positive samples with a microneutralisation assay.ResultsOf 2,220 included samples, 1,257 (57%) tested positive by TBEVIgG ELISA and 125 tested positive for infection-induced TBEV NS1 antibodies, resulting in a TBEV NS1IgG seroprevalence at 5.6% in our population. The yearly incidence based on the NS1 ELISA findings resulted in 283 cases per 100,000 inhabitants.ConclusionUsing the TBEV NS1IgG assay, we confirmed a manifestation index of ca 2% and a high incidence of predominantly silent TBEV infections (> 250/100,000/year), which exceeds the incidence of notified cases (4.7/100,000/year) considerably.

Improving dengue diagnosis and case confirmation in children by combining rapid diagnostic tests, clinical, and laboratory variables

BackgroundDengue is the most widely distributed arboviral disease in tropical and subtropical countries. Most suspected cases are diagnosed according to the clinical criteria, and early diagnosis is difficult. Moreover, in underdeveloped countries, several factors continue to challenge the diagnosis and surveillance of dengue cases. This study aimed to design a diagnostic algorithm using rapid diagnostic tests (RDTs), ELISA tests, and clinical and hematological variables to confirm dengue cases in febrile patients in Colombia.MethodsAltogether, 505 samples were collected. Serum samples were evaluated by RDTs (IgM and IgG antibodies and NS1 antigen), capture IgM and IgG ELISAs, and endpoint hemi-nested RT-PCR assay (qualitative). We statistically analyzed the performance of individual tests to determine the most useful ones to confirm dengue cases accurately.ResultsIndividual results for IgM, IgG, and NS1 RDTs yielded lower sensitivity and specificity values than the reference standard. High sensitivity and specificity were obtained after combining IgM and NS1 ELISA results (96.3% and 96.4%) and NS1 RDT plus IgM ELISA results (90.3% and 96.2%), respectively. Adjusted odds ratios (aORs) were calculated for clinical variables and laboratory tests to differentiate dengue from other febrile illnesses (OFI). This approach showed that myalgia, abdominal tenderness, and platelet count were identified with higher sensitivity to confirm dengue cases. IgM RDT and NS1 RDT differentiated dengue cases from OFI. A positive IgM RDT or a positive NS1 RDT combined with specific signs or symptoms confirmed 81.6% of dengue cases. A combination of clinical findings and a positive NS1 RDT or positive ELISA IgM confirmed 90.6% of the cases.ConclusionOur findings showed that clinical diagnoses in pediatric population alone cannot confirm true dengue cases and needs to be complemented by laboratory diagnostic tests. We also demonstrate the usefulness of combining clinical criteria with RDTs, suggesting that their implementation with the IgM ELISA test improves dengue case confirmation.

PREVALENCE OF SALMONELLA AND INTESTINAL PARASITES AMONG FOOD HANDLERS PREDISPOSE CONSUMERS TO SIGNIFICANT HEALTH RISKS

Background and objectives: Food borne diseases are a global public health problem and food handlers play a major role for the transmission of food borne diseases. This study was aimed at exploring the prevalence of intestinal parasites, Salmonella typhi carrier rate and risk factors of infection with typhoid and/or intestinal parasites among food handlers at Ibb city, Yemen. Subjects and methods: A cross sectional survey was conducted among three hundred and fifteen food handlers, in age ranges from 14 to 65 years. All individuals were working in restaurants, cafeterias or school buffets in Ibb city. For collecting data; a pre-tested structured questionnaire was used. Stool samples were examined for intestinal parasites microscopy and for S. typhi by stool culture media and blood for detection antibodies per the standard laboratory methods were used. Results: A total of 315 food handlers in Ibb city over a 12-month period were enrolled in this study, ages ranged from 14 to 65 years, with a mean±SD age of 31.2±11.9 years. The highest prevalence of antibodies against S. typhi antigen suspension O was 18.4%, while antibodies against S. typhi H antigen suspension were 7.6%. Also, the positive rate for total S. typhi antibodies ELISA IgG was 9.5% and the positive rate for S. typhi stool cultures was 7.3%. The overall prevalence of intestinal protozoa was 20%, the most intestinal parasitic prevalent was Entamoeba histolytica (15.6%), followed by Ascaris lumbricoides (12.1%), Hymenolepis nana (4.4%), and Schistosoma mansoni (3.2%). Conclusion: Inexperienced and poor personal hygienic food handlers play a role in the transmission of food-borne infections. Local health authorities should implement food handlers training on food safety, institute periodic focused medical check-up for food handlers and improve human waste disposal. Peer Review History: Received: 4 January 2023; Revised: 13 February; Accepted: 8 March 2023, Available online: 15 March 2023 Academic Editor: Dr. A.A. Mgbahurike, University of Port Harcourt, Nigeria, amaka_mgbahurike@yahoo.com Received file: Reviewer's Comments: Average Peer review marks at initial stage: 5.5/10 Average Peer review marks at publication stage: 7.0/10 Reviewers: Rola Jadallah, Arab American University, Palestine, rola@aauj.edu Dr. Tamer Elhabibi, Suez Canal University, Egypt, tamer_hassan@pharm.suez.edu.eg Dr. Wadhah Hassan Ali Edrees, Hajja University, Yemen, edress2020@gmail.com Dr. Rawaa Souhil Al-Kayali, Aleppo University, Syria, rawah67@hotmail.com Similar Articles: EVALUATION OF ANTIBACTERIAL RESISTANCE OF BIOFILM FORMS OF AVIAN SALMONELLA GALLINARUM TO FLUOROQUINOLONES

Characterisation of the Antibody Response in Sinopharm (BBIBP-CorV) Recipients and COVID-19 Convalescent Sera from the Republic of Moldova.

The early availability of effective vaccines against SARS-CoV-2, the aetiologic cause of COVID-19, has been at the cornerstone of the global recovery from the pandemic. This study aimed to assess the antispike RBD IgG antibody titres and neutralisation potential of COVID-19 convalescent plasma and the sera of Moldovan adults vaccinated with the Sinopharm BBIBP-CorV vaccine. An IgG ELISA with recombinant SARS-CoV-2 spike RBD and two pseudovirus-based neutralisation assays have been developed to evaluate neutralising antibodies against SARS-CoV-2 in biosafety level 2 containment facilities. A significant moderate correlation was observed between IgG titres and the overall neutralising levels for each neutralisation assay (ρ = 0.64, p < 0.001; ρ = 0.52, p < 0.001). A separate analysis of convalescent and vaccinated individuals showed a higher correlation of neutralising and IgG titres in convalescent individuals (ρ = 0.68, p < 0.001, ρ = 0.45, p < 0.001) compared with vaccinated individuals (ρ = 0.58, p < 0.001; ρ = 0.53, p < 0.001). It can be concluded that individuals who recovered from infection developed higher levels of antispike RBD IgG antibodies. In comparison, the Sinopharm-vaccinated individuals produced higher levels of neutralising antibodies than convalescent plasma.

Measles Seroprevalence and Related Factors in Women Aged 15-49 Years Old, in Mersin, Turkey.

If the mother is immune to measles, the infant is protected against measles infection after birth with maternal immunity. Therefore, the mother's immunity to measles is the most important factor in protecting the baby from measles in the first year. This study aimed to investigate measles seroprevalence and related factors in women between Oct 2019 and Jun 2021. The cross-sectional study was conducted on women aged 15-49 yr in Mersin city. Overall, 400 people were included in the study. NovaLisa Measles IgG ELISA (NovaTec Immunodiagnostica GmbH®) kit was used to measure measles IgG antibodies in serological analyses. The research was conducted between Oct 2019 and Jun 2021. In the analysis of the data; descriptive statistics, chi-square analysis, and binary logistic regression analysis were used. The statistical significance level was accepted as P≤0.05. Measles seropositivity was detected in 103 (25.7%) of the women. This rate was found 5.5% in the 15-19 yr age group, 20.0% in the 20-24 yr age group, 14.5% in the 25-29 yr age group, 23.0% in the 30-34 yr age group, 42.3% in the 35-39 yr age group, 42.3% in the 40-44 yr age group and 37.5% in the 45-49 yr age group. In the logistic regression analysis, the rate of seropositivity was compared to those in the 15-19 yr age group; it was found to be 4.33 times (P=0.03) at the age of 20-24 yr, 12.71 times (P<0.001) at the age of 40-44 yr, and 10.40 times (P<0.001) at the age of 45-49. Three out of every four babies born in our region are not adequately protected against measles.

Evaluation of RUT, and ELISA Tests for Detection of Helicobacter pylori in Dyspeptic Patients Visiting a Tertiary Care Hospital, South India

Helicobacter pylori is main causative agent of acute gastritis and peptic ulcer disease. In certain population, this infection leads to gastric cancers viz., adenocarcinoma, and mucosal-associated lymphoid tissue (MALT) lymphoma. The objective of this study was to comparatively evaluate invasive (RUT) and non-invasive (IgM and IgG ELISA) methods for detection of H. pylori infection among patients visiting a tertiary care hospital. A total of 285 dyspeptic patients undergoing endoscopic examination were included in this study. From each patient one biopsy specimen and serum samples were collected. Biopsy specimen was subjected to RUT and IgM &amp; IgG ELISA tests were performed using serum samples. H. pylori was detected in 127 (44.6%) and 126 (44.2%) cases by RUT and IgM ELISA, respectively. H. pylori were detected in 85 (29.8%) samples by IgG ELISA. Based on the combination of RUT and IgM ELISA test, total 128 (44.9%) patients were positive for H. pylori infection. Most of the positive cases belonged to 21-40 years age group (60 of 128) followed by 41-60 years age group (31 0f 128). All the three diagnostic methods viz., RUT, IgM ELISA and IgG ELISA used in this study showed a greater prevalence of H. pylori infection in female gender compared to male gender. In this study, sensitivity of both RUT and IgM ELISA was similar across different age groups and gender. The advantage of IgM ELISA over RUT is that it does not require endoscopy. Therefore, IgM ELISA could be considered as safe and an alternative method for detection of this pathogen.