Sociodemographic and clinical characteristics associated with maternal and congenital syphilis - A prospective study in Peru.

OBJECTIVES: The objective of this study was to explore the factors and outcomes associated with gestational syphilis in Peru. METHODS: Women from the miscarriage, vaginal delivery, and C-section wards from a large maternity hospital in Lima with or without syphilis diagnosis were enrolled and their pregnancy outcomes compared. Maternal syphilis status using maternal blood and child serostatus using cord blood were determined by rapid plasma reagin (RPR) and rapid syphilis tests. The newborns' clinical records were used to determine congenital syphilis. RESULTS: A total of 340 women were enrolled, 197 were positive and 143 were negative for RPR/rapid syphilis tests. Antibody titers in sera from cord and maternal blood were comparable with RPR titers and were highly correlated (rho = 0.82, P <0.001). Young age (P = 0.009) and lower birth weight (P = 0.029) were associated with gestational syphilis. Of the women with gestational syphilis, 76% had received proper treatment. Mothers of all newborns with congenital syphilis also received appropriate treatment. Treatment of their sexual partners was not documented. CONCLUSIONS: Syphilis during pregnancy remains a major cause of the fetal loss and devastating effects of congenital syphilis in newborns.

Detection of Anaplasma spp. and Ehrlichia spp. in dogs from a veterinary teaching hospital in Italy: a retrospective study 2012-2020.

Anaplasma phagocytophilum, Anaplasma platys and Ehrlichia canis, responsible of diseases in dogs, are tick-borne pathogens with a proven or potential zoonotic role that have shown increasing prevalence worldwide. The aims of this retrospective study were to assess the frequency of Anaplasma spp. and Ehrlichia spp. exposure in dogs tested in a veterinary teaching hospital in Italy over a 9-year period, to compare the performance of the diagnostic tests used, to evaluate correlations with clinical data, and to genetically analyse the identified bacteria. During the study period, 1322 dogs tested by at least one of the rapid immunoenzymatic test, indirect immunofluorescent antibody test or end-point PCR assay for Anaplasmataceae detection were included. Dogs were tested if they had clinical signs or clinicopathological alteration or risk factors related to infection, and if they were potential blood-donor animals. Ninety-four of 1322 (7.1%) dogs tested positive for at least one pathogen: 53 (4.3%) for A. phagocytophilum, one (0.1%) for A. platys and 63 (4.6%) for E. canis. The number of dogs tested increased and the positivity rate progressively declined over the years. Comparison of tests showed a near-perfect agreement between serological tests and a poor agreement between PCR and indirect assays. A breed predisposition has been highlighted for A. phagocytophilum infection in hunting breed dogs and for E. canis infection in mixed breed dogs. Phylogeny confirmed potential zoonotic implications for A. phagocytophilum and showed no correlation of the identified bacteria with the geographical origin. Our study provides new insights into possible risk factors in dogs and evidenced discordant results between different tests, suggesting that a combination of serological and molecular assays is preferable for a correct diagnosis.

Clinical and laboratory diagnosis of Mayaro virus (MAYV): Current status and opportunities for further development.

The recent outbreaks related to Mayaro virus (MAYV) infection in the Americas have brought this neglected virus as a potential threat to global public health. Given the range of symptoms that can be associated with MAYV infection, it can be challenging to diagnose individuals based on clinical signs, especially in countries with simultaneous circulation of other mosquito-borne viruses, such as dengue virus (DENV) and chikungunya virus (CHIKV). With this challenge in mind, laboratory-based diagnosis assumes a critical role in the introduction of measures to help prevent virus dissemination and to adequately treat patients. In this review, we provide an overview of the clinical features reported in infected patients and currently available laboratory tools that are used for MAYV diagnosis, discussing their advances, advantages, and limitations to apply in the field. Moreover, we explore novel point-of-care (PoC) diagnostic platforms that can provide de-centralised diagnostics for use in areas with limited laboratory infrastructure.

Evaluation of serum and urine biomarkers for severe COVID-19.

Introduction: The new coronavirus disease, COVID-19, poses complex challenges exacerbated by several factors, with respiratory tissue lesions being notably significant among them. Consequently, there is a pressing need to identify informative biological markers that can indicate the severity of the disease. Several studies have highlighted the involvement of proteins such as APOA1, XPNPEP2, ORP150, CUBN, HCII, and CREB3L3 in these respiratory tissue lesions. However, there is a lack of information regarding antibodies to these proteins in the human body, which could potentially serve as valuable diagnostic markers for COVID-19. Simultaneously, it is relevant to select biological fluids that can be obtained without invasive procedures. Urine is one such fluid, but its effect on clinical laboratory analysis is not yet fully understood due to lack of study on its composition. Methods: Methods used in this study are as follows: total serum protein analysis; ELISA on moderate and severe COVID-19 patients' serum and urine; bioinformatic methods: ROC analysis, PCA, SVM. Results and discussion: The levels of antiAPOA1, antiXPNPEP2, antiORP150, antiCUBN, antiHCII, and antiCREB3L3 exhibit gradual fluctuations ranging from moderate to severe in both the serum and urine of COVID-19 patients. However, the diagnostic value of individual anti-protein antibodies is low, in both blood serum and urine. On the contrary, joint detection of these antibodies in patients' serum significantly increases the diagnostic value as demonstrated by the results of principal component analysis (PCA) and support vector machine (SVM). The non-linear regression model achieved an accuracy of 0.833. Furthermore, PCA aided in identifying serum protein markers that have the greatest impact on patient group discrimination. The study revealed that serum serves as a superior analyte for describing protein quantification due to its consistent composition and lack of organic salts and drug residues, which can otherwise affect protein stability.

Examination of SARS-CoV-2 serological test results from multiple commercial and laboratory platforms with an in-house serum panel.

Severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2) is a novel human coronavirus that was identified in 2019. SARS-CoV-2 infection results in an acute, severe respiratory disease called coronavirus disease 2019 (COVID-19). The emergence and rapid spread of SARS-CoV-2 has led to a global public health crisis, which continues to affect populations across the globe. Real time reverse transcription polymerase chain reaction (rRT-PCR) is the reference standard test for COVID-19 diagnosis. Serological tests are valuable tools for serosurveillance programs and establishing correlates of protection from disease. This study evaluated the performance of one in-house enzyme linked immunosorbent assay (ELISA) utilizing the pre-fusion stabilized ectodomain of SARS-CoV-2 spike (S), two commercially available chemiluminescence assays Ortho VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total Reagent Pack and Abbott SARS-CoV-2 IgG assay and one commercially available Surrogate Virus Neutralization Test (sVNT), GenScript USA Inc., cPass SARS-CoV-2 Neutralization Antibody Detection Kit for the detection of SARS-CoV-2 specific antibodies. Using a panel of rRT-PCR confirmed COVID-19 patients' sera and a negative control group as a reference standard, all three immunoassays demonstrated high comparable positivity rates and low discordant rates. All three immunoassays were highly sensitive with estimated sensitivities ranging from 95.4-96.6 %. ROC curve analysis indicated that all three immunoassays had high diagnostic accuracies with area under the curve (AUC) values ranging from 0.9698 to 0.9807. High positive correlation was demonstrated among the conventional microneutralization test (MNT) titers and the sVNT inhibition percent values. Our study indicates that independent evaluations are necessary to optimize the overall utility and the interpretation of the results of serological tests. Overall, we demonstrate that all serological tests evaluated in this study are suitable for the detection of SARS-CoV-2 antibodies.

Estimates of sensitivity and specificity of serological tests for SARS-CoV-2 specific antibodies using a Bayesian latent class model approach.

OBJECTIVES: Assessing the accuracy of serological tests for SARS-CoV-2 was challenging due to the lack of a gold standard. This study aimed to estimate the accuracy of SARS-CoV-2-specific serological tests using Bayesian latent class models (BLCM) and compare methods with and without a gold standard. STUDY DESIGN AND SETTING: In this study, we analyzed 356 samples-254 positives, ie, from individuals with a previous SARS-CoV-2 infection diagnosis, and 102 negatives, ie, prepandemic samples-using six different rapid serological tests and one laboratory assay. A BLCM was employed to concurrently estimate the sensitivity and specificity of all serological tests for the immunoglobulin (Ig) M and IgG antibodies specific for SARS-CoV-2. Noninformative priors were used. A sensitivity analysis was conducted considering three methods: 1) reverse transcription-polymerase chain reaction test (RT-PCR) as the gold standard, 2) BLCM with RT-PCR as an imperfect gold standard, and 3) frequentist latent class model (LCM). All analyses used software R version 4.3.0, and BLCM were fitted using package runjags using the software JAGS (Just Another Gibbs Sampler). RESULTS: The BLCM-derived sensitivity for IgM varied from 10.7% [95% credibility interval (CrI):1.9-24.6] to 96.9% (95% CrI: 91.0-100.0), with specificities ranging from 48.3% (95% CrI: 39.0-57.6) to 98.9% (95% CrI: 96.2-100.0). Sensitivity for IgG varied between 76.9% (95% CrI: 68.2-84.7) and 99.1% (95% CrI: 96.1-100.0), and specificity ranged from 49.9% (95% CrI: 19.4-95.8) to 99.3% (95% CrI: 97.2-100.0). LCM results were comparable to BLCM. Considering the RT-PCR as a gold standard underestimated the tests' sensitivity, particularly for IgM. CONCLUSION: BLCM-derived results deviated from those using a gold standard, which underestimated the tests' characteristics, particularly sensitivity. Although Bayesian and frequentist LCM approaches yielded comparable results, BLCM had the benefit of enabling credibility interval computation even when sample power is limited.

A novel Bayesian Latent Class Model (BLCM) evaluates multiple continuous and binary tests: A case study for Brucella abortus in dairy cattle.

Bovine brucellosis, primarily caused by Brucella abortus, severely affects both animal health and human well-being. Accurate diagnosis is crucial for designing informed control and prevention measures. Lacking a gold standard test makes it challenging to determine optimal cut-off values and evaluate the diagnostic performance of tests. In this study, we developed a novel Bayesian Latent Class Model that integrates both binary and continuous testing outcomes, incorporating additional fixed (parity) and random (farm) effects, to calibrate optimal cut-off values by maximizing Youden Index. We tested 651 serum samples collected from six dairy farms in two regions of Henan Province, China with four serological tests: Rose Bengal Test, Serum Agglutination Test, Fluorescence Polarization Assay, and Competitive Enzyme-Linked Immunosorbent Assay. Our analysis revealed that the optimal cut-off values for FPA and C-ELISA were 94.2 mP and 0.403 PI, respectively. Sensitivity estimates for the four tests ranged from 69.7% to 89.9%, while specificity estimates varied between 97.1% and 99.6%. The true prevalences in the two study regions in Henan province were 4.7% and 30.3%. Parity-specific odds ratios for positive serological status ranged from 1.2 to 2.2 for different parity groups compared to primiparous cows. This approach provides a robust framework for validating diagnostic tests for both continuous and discrete tests in the absence of a gold standard test. Our findings can enhance our ability to design targeted disease detection strategies and implement effective control measures for brucellosis in Chinese dairy farms.

Use of recombinant malate dehydrogenase (MDH) and superoxide dismutase (SOD) [CuZn] as antigens in indirect ELISA for diagnosis of bovine brucellosis.

The objective of this study was to validate an indirect enzyme-linked immunoassay (iELISA) using the recombinant proteins, malate dehydrogenase (MDH) and superoxide dismutase (SOD) [CuZn], as antigens and to evaluate its ability to discriminate antibodies produced by vaccination from those induced by infection in the diagnosis of bovine brucellosis. Sera from six groups were evaluated: G1 - culture-positive animals (52 serum samples) (naturally infected); G2 - non-vaccinated animals (28 serum samples) positive in RBT (Rose Bengal test) and 2ME (2-mercaptoethanol test) selected from brucellosis-positive herds; G3 - animals from a brucellosis-free area (32 serum samples); G4 - S19 vaccinated heifers (114 serum samples); G5 - RB51 vaccinated heifers (60 serum samples); G6 - animals inoculated with inactivated Yersinia enterocolitica O:9 (42 serum samples). Diagnostic sensitivity (DSe) and diagnostic specificity (DSp) were estimated using the frequentist approach and the confidence interval (CI) (95%) calculated by the Clopper-Pearson (exact) method. The DSe for iELISA_MDH in the G1 group was 71.7% (CI 95%: 57.6-83.2%) and for the G2 100.0% (CI 95%: 87.7-100.0%), whereas the DSp was 84.4% in the G3 (CI 95%: 67.2-94.7%). For the iELISA_SOD the DSe was estimated 67.3% for the G1 (CI 95%: 52.9-79.7%) and 71.4% for G2 (CI 95%: 51.3-86.8%), while the DSp for G3 was 87.5% (CI 95%: 71.0-96.5%). iELISA_MDH and iELISA_SOD showed potential to be used in the diagnosis of infected animals, increasing the range of serological tests available for the diagnosis of bovine brucellosis, with the advantage of being S-LPS-free. However, none of the tests could differentiate between infection and vaccination.

Avaliação da acurácia do teste rápido para diagnóstico de Helicobacter pylori em pacientes não submetidos à terapia de erradicação prévia sujeitados á endoscopia digestiva alta / Assessment of the accuracy of the rapid test for the diagnosis of helicobacter pylori in patients that didn't undergo previous eradication therapy and who went through endoscopy

ABSTRACT Background: Helicobacter pylori infection is widely spread globally and is known to cause potentially serious diseases. Several diagnostic methods exist to identify and treat carriers of this bacterium. Serological tests for the diagnosis of infection are based on the detection of antibodies immunoglobulin G against H. pylori, a non-invasive, inexpensive, and easy-to-perform option. Objective: This research aims to ascertain the accuracy of an immunochromatographic serological test to verify the feasibility of using this method in patients who have not undergone previous eradication therapy. Methods: Rapid tests and questionnaires were applied to 53 patients that underwent upper digestive endoscopy with research for H. pylori between the period of September and October 2021. The results were compared with histopathology. Results: In the rapid tests, seven positive and 46 negative results were obtained. When compared with the gold stan­dard, the following values were described: sensitivity 54.5%, specificity 97.6%, positive predictive value 85.7%, and negative predictive value 89.1%. Conclusion: In the present study, the immunochromatographic serological tests had an accuracy close to the values found in other similar studies. Therefore, it may be concluded that the rapid serological test remains a reasonable choice for screening large populations due to its low cost and ease of application, especially in those individuals who have not undergone previous treatment.

RESUMO Contexto: A infecção pelo Helicobacter pylori apresenta-se amplamente difundida globalmente e é comprovadamente causadora de patologias potencialmente graves. Diversos métodos diagnósticos existem com o propósito de identificar e tratar os portadores dessa bactéria. Testes sorológicos para diagnóstico da infecção se baseiam na detecção de anticorpos imunoglobulina G anti-H.pylori, sendo uma opção não-invasiva, barata e de fácil realização. Objetivo: O objetivo dessa pesquisa é determinar a acurácia de um teste sorológico imunocromatográfico para verificar a viabilidade do uso desse método em pacientes que não realizaram terapia de erradicação prévia. Métodos: Foram aplicados testes rápidos e questionários em 53 participantes que realizaram endoscopia digestiva alta com pesquisa de H. pylori entre o período de setembro e outubro de 2021. Os resultados foram comparados com a histopatologia. Resultados: Foram obtidos nos testes rápidos 7 resultados positivos e 46 negativos. Ao comparar com o padrão-ouro, os seguintes valores foram descritos: Sensibilidade 54,5%, especificidade 97,6%, valor preditivo positivo 85,7% e valor preditivo negativo 89,1%. No presente estudo, os testes sorológicos imunocromatográficos tiveram acurácia próxima aos valores encontrados em outros trabalhos semelhantes. Conclusão: Sendo assim, conclui-se que o teste rápido sorológico permanece como escolha razoável para screening de grandes populações devido ao seu baixo custo e facilidade de aplicação, especialmente naqueles indivíduos que não realizaram tratamento prévio.

Assessment of the diagnostic performance of serological tests in areas where Leishmania infantum and Leishmania tarentolae occur in sympatry.

BACKGROUND: Visceral leishmaniosis caused by infection with the zoonotic protozoan Leishmania infantum is a life-threatening disease affecting dogs and humans. The sympatric occurrence of L. infantum and Leishmania tarentolae in an area of southern Italy endemic for canine leishmaniosis, where dogs are also exposed to the latter species, suggests the persistence of herpetophilic L. tarentolae in a non-permissive host, therefore raising questions about the performance of serological diagnostic tests routinely employed. METHODS: The diagnostic performance of serological tests such as the immunofluorescence antibody test (IFAT), two commercial immunoenzymatic assays (i.e. NovaTec VetLine Leishmania ELISA® and rK39 ICT®) and an in-house enzyme-linked immunosorbent assay (ELISA) was evaluated in healthy dogs seropositive to L. infantum, whereas the only IFAT available was used to detect antibodies to L. tarentolae. RESULTS: With the IFAT, out of a total of 104 dogs tested, 15 were seronegative for L. infantum of which three were L. tarentolae seropositive' and 89 were L. infantum seropositive. Of the latter 89 dogs, representing the highest proportion of seropositive animals (85.6%) detected by IFAT' 66 were also seropositive for L. tarentolae. Cohen's kappa (κ) agreement coefficient between the IFAT results and those of all the other tests was very low, and the IFAT results were significantly different from those of all the other serological tests as calculated by Cochran's Q-test. Analysis using the Bayesian latent class (Bayes-LCA) showed that the in-house ELISA and IFAT contributed the most towards identifying infected and non-infected dogs, respectively. The IFAT test showed low positive predictive value (59.5%), but high negative predictive value (100%). CONCLUSIONS: These results demonstrate that the IFAT for L. infantum, although highly sensitive, may not be considered a useful diagnostic test due to its low specificity. Therefore, an accurate serological tool with high specificity is mandatory for avoiding cross-reaction in epidemiological contexts where the two species of Leishmania occur in sympatry.

Performance evaluation of in-house developed Covid-19 IgG/IgM antibody rapid diagnostic kit.

In the interest of preventing the Coronavirus Disease 2019 (COVID-19) pandemic from spreading, it is crucial to promptly identify and confine afflicted patients. Serological antibody testing is a significant diagnostic technique that is increasingly employed in clinics, however its clinical use is still being investigated. The present study was carried out to scrutinize how well Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) antibody testing using in-house developed rapid antibody assay worked against the chemiluminescence (CLIA) assay. Either IgG positive (IgG + IgM-) or IgM positive (IgM + IgG-); both IgG and IgM positive (IgM + IgG+); and negatives (IgM- IgG-) have been evaluated. A total of 300 samples with diverse age and sexual identity data were included. The combined sensitivities for IgG + IgM+, IgM + IgG-, IgG + IgM- and IgG-IgM- were evaluated. More accurate diagnostic results may be obtained using molecular diagnostic tools. The Antibody Rapid Diagnostic kit's (in-house developed) performance was satisfactory for determining the presence of Covid-19 infection with IgG and IgM positivity. The IgG and IgM positivity helped evaluate the immune response in the individual for the COVID-19 infection. These results lend support to the additional utilisation of serological antibody tests in the COVID-19 diagnosis.

Enteric Fever: Diagnostic Challenges and the Importance of Early Intervention.

Enteric fever is a systemic infection caused by highly virulent Salmonella enterica serovars: Typhi and Paratyphi. Diagnosis of enteric fever is challenging due to a wide variety of clinical features which overlap with other febrile illnesses. The current diagnostic methods are limited because of the suboptimal sensitivity of conventional tests like blood culture in detecting organisms and the invasive nature of bone marrow culture. It emphasizes the need to develop improved and more reliable diagnostic modalities. The rising rates of multidrug-resistant Salmonella strains call for an accurate understanding of the current management of the disease. Proper public health measures and large-scale immunization programs will help reduce the burden of the disease. A comprehensive surveillance system can help detect the chronic carrier state and is crucial in understanding antibiotic susceptibility patterns. We conducted an all-language literature search on Medline, Cochrane, Embase, and Google Scholar till May 2022. The following search words and medical subject headings (MeSH) were used: "enteric fever," "Salmonella Typhi," "multidrug-resistant Salmonella," chronic carrier state," "Salmonella detection, "and "typhoid vaccine." We reviewed the literature on clinical features, pathophysiology, new diagnostic tests, and interventions to prevent the disease. This article explores enteric fever and its various clinical features and addresses the emerging threat of multidrug resistance. It focuses on novel methods for diagnosis and prevention strategies, including vaccines and the use of surveillance systems employed across different parts of the world.

The total testing process harmonization: the case study of SARS-CoV-2 serological tests.

The total testing process harmonization is central to laboratory medicine, leading to the laboratory test's effectiveness. In this opinion paper the five phases of the TTP are analyzed, describing, and summarizing the critical issues that emerged in each phase of the TTP with the SARS-CoV-2 serological tests that have affected their effectiveness. Testing and screening the population was essential for defining seropositivity and, thus, driving public health policies in the management of the COVID-19 pandemic. However, the many differences in terminology, the unit of measurement, reference ranges and parameters for interpreting results make analytical results difficult to compare, leading to the general confusion that affects or completely precludes the comparability of data. Starting from these considerations related to SARS-CoV-2 serological tests, through interdisciplinary work, the authors have highlighted the most critical points and formulated proposals to make total testing process harmonization effective, positively impacting the diagnostic effectiveness of laboratory tests.

High seropositivity against NDO-LID in a group of household contacts of leprosy patients. Are we close to leprosy elimination in Colombia?

INTRODUCTION: Leprosy is a chronic infectious disease caused by two mycobacteria (Mycobacterium leprae and Mycobacterium lepromatosis). The household contacts (HHC) of leprosy index cases are at higher risk of being infected with these mycobacteria. Therefore, serological testing in HHC would be an effective strategy to eliminate leprosy in Colombia. OBJECTIVE: To determine the seroprevalence and factors associated with the infection by M. leprae in HHC. METHODS: An observational study was conducted in 428 HHC located in the Colombian Caribbean, Andean, Pacific, and Amazonian regions. We evaluated the seropositivity and titrations of IgM, IgG, and protein A against NDO-LID. RESULTS: The evaluated HHC showed high seropositivity, precisely 36.9% anti-NDO-LID IgM, 28.3% anti-NDO-LID IgG, and 47.7% protein A. Furthermore, Protein A showed a greater capacity to detect infected individuals than other anti-NDO-LID conjugates (p < 0.0001). This study did not show differences in the seropositivity according to sex or age of the HHC (p > 0.05). Higher seropositivity for IgM was evidenced mainly in HHC located in the Colombian Pacific region (p 0.001). This research did not show differences in the seropositivity for these serological tests between HHC of PB or MB leprosy patients (p > 0.05). CONCLUSION: Leprosy transmission is still active between Colombian HHC. Consequently, controlling leprosy transmission in this population is fundamental to eradicating this disease.

SARS-CoV-2: The Self-Nonself Issue and Diagnostic Tests.

Objective At present, false negatives/positives have been reported in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostics. Searching for the molecular basis of such tests' unreliability, this study aimed at defining how specific are the sequences used in serological and polymerase chain reaction (PCR) tests to detect SARS-CoV-2. Materials and Methods Analyses were performed on the leading SARS-CoV-2 biomarker spike glycoprotein (gp). Sharing of peptide sequences between the spike antigen and the human host was analyzed using the Peptide Search program from Uniprot database. Sharing of oligonucleotide sequences was investigated using the nucleotide Basic Local Alignment Search Tool (BLASTn) from National Center for Biotechnology Information (NCBI). Results Two main points stand out: (1) a massive pentapeptide sharing exists between the spike gp and the human proteome, and only a limited number of pentapeptides (namely 107) identify SARS-CoV-2 spike gp as nonself when compared with the human proteome, and (2) the small phenetic difference practically disappears at the genetic level. Indeed, almost all of the 107 pentadecameric nucleotide sequences coding for the pentapeptides unique to SARS-CoV-2 spike gp are present in human nucleic acids too. Conclusion The data are of immunological significance for defining the issue of the viral versus human specificity and likely explain the fact that false positives can occur in serological and PCR tests for SARS-CoV-2 detection.

A longitudinal analysis of humoral, T cellular response and influencing factors in a cohort of healthcare workers: Implications for personalized SARS-CoV-2 vaccination strategies.

Introduction: SARS-CoV-2 mRNA vaccinations elicit both virus-specific humoral and T-cell responses, but a complex interplay of different influencing factors, such as natural immunity, gender, and age, guarantees host protection. The present study aims to assess the immune dynamics of humoral, T-cell response, and influencing factors to stratify individual immunization status up to 10 months after Comirnaty-vaccine administration. Methods: To this aim, we longitudinally evaluated the magnitude and kinetics of both humoral and T-cell responses by serological tests and enzyme-linked immunospot assay at 5 time points. Furthermore, we compared the course over time of the two branches of adaptive immunity to establish an eventual correlation between adaptive responses. Lastly, we evaluated putative influencing factors collected by an anonymized survey administered to all participants through multiparametric analysis. Among 984 healthcare workers evaluated for humoral immunity, 107 individuals were further analyzed to describe SARS-CoV-2-specific T-cell responses. Participants were divided into 4 age groups: <40 and ≥40 years for men, <48 and ≥48 years for women. Furthermore, results were segregated according to SARS-CoV-2-specific serostatus at baseline. Results: The disaggregated evaluation of humoral responses highlighted antibody levels decreased in older subjects. The humoral responses were higher in females than in males (p=0.002) and previously virus-exposed subjects compared to naïve subjects (p<0.001). The vaccination induced a robust SARS-CoV-2 specific T-cell response at early time points in seronegative subjects compared to baseline levels (p<0.0001). However, a contraction was observed 6 months after vaccination in this group (p<0.01). On the other hand, the pre-existing specific T-cell response detected in natural seropositive individuals was longer-lasting than the response of the seronegative subjects, decreasing only 10 months after vaccination. Our data suggest that T-cell reactiveness is poorly impacted by sex and age. Of note, SARS-CoV-2-specific T-cell response was not correlated to the humoral response at any time point. Discussion: These findings suggest prospects for rescheduling vaccination strategies by considering individual immunization status, personal characteristics, and the appropriate laboratory tests to portray immunity against SARS-CoV-2 accurately. Deepening our knowledge about T and B cell dynamics might optimize the decision-making process in vaccination campaigns, tailoring it to each specific immune response.

A comparative study of eight serological methods shows that spike protein-based ELISAs are the most accurate tests for serodiagnosing SARS-CoV-2 infections in cats and dogs.

Introduction: Coronavirus disease 2019 (COVID-19) is an infectious zoonotic disease caused by SARS-CoV-2. Monitoring the infection in pets is recommended for human disease surveillance, prevention, and control since the virus can spread from people to animals during close contact. Several diagnostic tests have been adapted from humans to animals, but limited data on the validation process are available. Methods: Herein, the first comparative study of six "in house" and two commercial serological tests developed to monitor SARS-CoV-2 infection in pets was performed with a well-coded panel of sera (61 cat sera and 74 dog sera) with a conservative criterion (viral seroneutralisation and/or RT-qPCR results) as a reference. Four "in house" tests based on either the RBD fragment of the spike protein (RBD-S) or the N-terminal fragment of the nucleoprotein (N) were developed for the first time. The analytical specificity (ASp) of those tests that showed the best diagnostic performance was assessed. The validation included the analysis of a panel of sera obtained pre-pandemic from cats and dogs infected with other coronaviruses to determine the analytical Sp (17 cat sera and 41 dog sera). Results and discussion: ELISAS based on the S protein are recommended in serosurveillance studies for cats (RBD-S SALUVET ELISA, ELISA COVID UNIZAR and INgezim® COVID 19 S VET) and dogs (INgezim® COVID 19 S VET and RBD-S SALUVET ELISA). These tests showed higher diagnostic sensitivity (Se) and DSp in cats (>90%) than in dogs. When sera obtained prior to the pandemic and from animals infected with other coronaviruses were analyzed by RBD-S and N SALUVET ELISAs and INgezim® COVID 19 S VET, a few cross reactors or no cross reactions were detected when dog and cat sera were analyzed by tests based on the S protein, respectively. In contrast, the number of cross reactions increased when the test was based on the N protein. Thus, the use of tests based on the N protein was discarded for serodiagnosis purposes. The results obtained revealed the most accurate serological tests for each species. Further studies should attempt to improve the diagnostic performance of serological tests developed for dogs.

COVID-19 in a Pre-Omicron Era: A Cross-Sectional Immuno-Epidemical and Genomic Evaluation.

The seventh human coronavirus was discovered and reported primarily in Wuhan, China. After intense seasons with repercussions in all areas of humanity, the pandemic demonstrates a new perspective. In Brazil, the pandemic concept had impacts in vast areas, including healthcare hospitals. This present study aims to describe and synthesize data from a determined period from the year 2021 that correlate the symptoms of passive and/or active patients for COVID-19 and their respective results of IgG/IgM serological tests in hospitals in the city of Cruzeiro, São Paulo, Brazil. The form had been applied to 333 people and obtained conclusive results and several symptoms were presented; in addition, asymptomatic cases were also analyzed and directed in the genomic study of variants of concern, as well as vaccination data in the study region.

Assessment of the Possible Correlation between the Presence of Helicobacter Pylori Infection and Hairy Tongue Lesion in a Group of Patients in Syria: A Cross-Sectional and Pilot Study.

BACKGROUND: This study aimed to evaluate the correlation between the presence of hairy tongue and H. pylori infection in patients referring to their blood test based on the serum levels of anti-H pylori IgG antibodies. METHODS: This cross-sectional study was conducted in the Department of Oral Medicine, University of Damascus Dental School, between February 2021 and January 2022. The sample size of 40 patients (23 males, 17 females), whose ages ranged from 20-79 years with a mean age of 41.5 ± 12 years, was calculated using the G*power 3.1.3, with a statistical power of 80% and a significance level of 0.05. The hairy tongue index was assessed by a visual method based on observing the dorsum tongue appearance. Then, a blood test was performed to detect the presence of H. pylori by Immulite 2000 XPi. Statistical analysis was performed using SPSS software 22.0, Chi-square. RESULTS: The prevalence of hairy tongue was higher among males (75%) as compared to females (25%) and was found to be statistically significant (p = 0.026). The hairy tongue lesions were found to be least in the 20-39 age group and most prevalent in the 40-59 age group, without statistically significant correlation. H. pylori infection was detected positive in 70% and negative in 30% of hairy tongue patients, compared to the control group, where the rates were 15% and 85%, respectively, with a statistically significant correlation between infection with H. pylori and hairy tongue (p = 0.001). CONCLUSION: Our results strongly suggest that the hairy tongue might be considered an indicator of H. pylori infection.

Peptide microarray analysis of in-silico predicted B-cell epitopes in SARS-CoV-2 sero-positive healthcare workers in Bulawayo, Zimbabwe.

Immunogenic peptides that mimic linear B-cell epitopes coupled with immunoassay validation may improve serological tests for emerging diseases. This study reports a general approach for profiling linear B-cell epitopes derived from SARS-CoV-2 using an in-silico method and peptide microarray immunoassay, using healthcare workers' SARS-CoV-2 sero-positive sera. SARS-CoV-2 was tested using rapid chromatographic immunoassays and real-time reverse-transcriptase polymerase chain reaction. Immunogenic peptides mimicking linear B-cell epitopes were predicted in-silico using ABCpred. Peptides with the lowest sequence identity with human protein and proteins from other human pathogens were selected using the NCBI Protein BLAST. IgG and IgM antibodies against the SARS-CoV-2 spike protein, membrane glycoprotein and nucleocapsid derived peptides were measured in sera using peptide microarray immunoassay. Fifty-three healthcare workers included in the study were RT-PCR negative for SARS-CoV-2. Using rapid chromatographic immunoassays, 10 were SARS-CoV-2 IgM sero-positive and 7 were SARS-CoV-2 IgG sero-positive. From a total of 10 SARS-CoV-2 peptides contained on the microarray, 3 (QTH34388.1-1-14, QTN64908.1-135-148, and QLL35955.1-22-35) showed reactivity against IgG. Three peptides (QSM17284.1-76-89, QTN64908.1-135-148 and QPK73947.1-8-21) also showed reactivity against IgM. Based on the results we predicted one peptide (QSM17284.1-76-89) that had an acceptable diagnostic performance. Peptide QSM17284.1-76-89 was able to detect IgM antibodies against SARS-CoV-2 with area under the curve (AUC) 0.781 when compared to commercial antibody tests. In conclusion in silico peptide prediction and peptide microarray technology may provide a platform for the development of serological tests for emerging infectious diseases such as COVID-19. However, we recommend using at least three in-silico peptide prediction tools to improve the sensitivity and specificity of B-cell epitope prediction, to predict peptides with excellent diagnostic performances.