High seroprevalence of anti-SARS-CoV-2 antibodies in the capital of Chad

Background. Since the start of the COVID-19 pandemic, Chad has had 7,417 confirmed cases and 193 deaths, one of the lowest in Africa. Objective. This study assessed SARS-CoV-2 immunity in N'Djamena. Methods. In August-October 2021, eleven N'Djamena hospitals collected outpatient data and samples. IgG antibodies against SARSCoV- 2 nucleocapsid protein were identified using ELISA. "Bambino Gesu" Laboratory, Rome, Italy, performed external quality control with chemiluminescence assay. Results. 25-34-year-old (35.2%) made up the largest age group at 31.9 12.6 years. 56.4% were women, 1.3 women/men. The 7th district had 22.5% and the 1st 22.3%. Housewives and students dominated. Overall seroprevalence was 69.5% (95% CI: 67.7-71.3), females 68.2% (65.8-70.5) and males 71.2% (68.6-73.8). >44-year-old had 73.9% seroprevalence. Under-15s were 57.4% positive. Housewives (70.9%), civil servants (71.5%), and health workers (9.7%) had the highest antibody positivity. N'Djamena's 9th district had 73.1% optimism and the 3rd district had 52.5%. Seroprevalences were highest at Good Samaritan Hospital (75.4%) and National General Referral Hospital (74.7%). Conclusion. Our findings indicate a high circulation of SARS-CoV- 2 in N'Djamena, despite low mortality and morbidity after the first two COVID-19 pandemic waves. This high seroprevalence must be considered in Chad's vaccine policy.

Clinical and epidemiologic features of SARS-CoV-2 in dogs and cats compiled through national surveillance in the United States

OBJECTIVE: To characterize clinical and epidemiologic features of SARS-CoV-2 in companion animals detected through both passive and active surveillance in the US. ANIMALS: 204 companion animals (109 cats, 95 dogs) across 33 states with confirmed SARS-CoV-2 infections between March 2020 and December 2021. PROCEDURES: Public health officials, animal health officials, and academic researchers investigating zoonotic SARS-CoV-2 transmission events reported clinical, laboratory, and epidemiologic information through a standardized One Health surveillance process developed by the CDC and partners. RESULTS: Among dogs and cats identified through passive surveillance, 94% (n = 87) had reported exposure to a person with COVlD-19 before infection. Clinical signs of illness were present in 74% of pets identified through passive surveillance and 27% of pets identified through active surveillance. Duration of illness in pets averaged 15 days in cats and 12 days in dogs. The average time between human and pet onset of illness was 10 days. Viral nucleic acid was first detected at 3 days after exposure in both cats and dogs. Antibodies were detected starting 5 days after exposure, and titers were highest at 9 days in cats and 14 days in dogs. CLINICAL RELEVANCE: Results of the present study supported that cats and dogs primarily become infected with SARS-CoV-2 following expo- sure to a person with COVID-19, most often their owners. Case investigation and surveillance that include both people and animals are necessary to understand transmission dynamics and viral evolution of zoonotic diseases like SARS-CoV-2.

Serological Profile of SARS-CoV-2 in Unvaccinated Blood Donors: A Nationwide Study During the Fifth Wave of the Pandemic in Iran

Background: Serological studies can demonstrate pathogen circulation in regional populations and reflect public health mea-sures' effectiveness during different pandemic phases. By late November 2021, coinciding with the third pandemic wave, the sero-prevalence of SARS-CoV-2 spike IgG antibodies among the Iranian population was 32.63%. Objective(s): This study aimed to assess the Iranian population's seroprevalence during the fifth pandemic wave by analyzing donated blood samples. Method(s): This population-based cross-sectional study was conducted on Iranian blood donors referred to all 31 main provincial capitals between August 2021 and September 2021. The participants selected through quota sampling were asked to complete a questionnaire on socio-demographics and coronavirus disease 2019 (COVID-19)-related information. Also, SARS-CoV-2 spike IgG antibodies were measured in serum samples using SARS-CoV-2 enzyme-linked immunosorbent assay (ELISA) kits. The seroprevalence was weighted based on the gender and age groups of the population and then adjusted for test performance. Result(s): Totally 3,339 blood donors participated in this study. The overall population-weighted seroprevalence adjusted for test performance was 52.67% (95% confidence interval (CI): 50.14-55.21). Seroprevalence was higher among participants with a high school diploma (55.45%, 95% CI 50.61-60.29), a positive history of close contact with COVID-19 patients (65.23%, 95% CI 60.83-69.63), and previous positive COVID-19 PCR tests (86.51%, 95% CI 82.32-90.7). Conclusion(s): More than half of the study population was exposed to SARS-CoV-2, indicating a 1.7-fold increase in the seroprevalence between late November 2020 and mid-September 2021. Our finding illuminated the pattern of Iran's fifth wave of the pandemic.Copyright © 2023, Author(s).

Generalized Linear Regression Model to Determine the Threshold Effects of Climate Variables on Dengue Fever: A Case Study on Bangladesh

One of the leading causes of the increase in the intensity of dengue fever transmission is thought to be climate change. Examining panel data from January 2000 to December 2021, this study discovered the nonlinear relationship between climate variables and dengue fever cases in Bangladesh. To determine this relationship, in this study, the monthly total rainfall in different years has been divided into two thresholds: (90 to 360 mm) and (<90 or >360 mm), and the daily average temperature in different months of the different years has been divided into four thresholds: (16degreeC to <=20degreeC), (>20degreeC to <=25degreeC), (>25degreeC to <=28degreeC), and (>28degreeC to <=30degreeC). Then, quasi-Poisson and zero-inflated Poisson regression models were applied to assess the relationship. This study found a positive correlation between temperature and dengue incidence and furthermore discovered that, among those four average temperature thresholds, the total number of dengue cases is maximum if the average temperature falls into the threshold (>28degreeC to <=30degreeC) and minimum if the average temperature falls into the threshold (16degreeC to <=20degreeC). This study also discovered that between the two thresholds of monthly total rainfall, the risk of a dengue fever outbreak is approximately two times higher when the monthly total rainfall falls into the thresholds (90 mm to 360 mm) compared to the other threshold. This study concluded that dengue fever incidence rates would be significantly more affected by climate change in regions with warmer temperatures. The number of dengue cases rises rapidly when the temperature rises in the context of moderate to low rainfall. This study highlights the significance of establishing potential temperature and rainfall thresholds for using risk prediction and public health programs to prevent and control dengue fever.Copyright © 2023 Shamima Hossain.

Machine Learning and Laboratory Values in the Diagnosis, Prognosis and Vaccination Strategy of COVID-19

In March 2020, the World Health Organization (WHO) declared a pandemic status for COVID-19 disease caused by SARS-CoV-2 infection. Early diagnosis undoubtedly plays a fundamental role in the management of emergencies for the treatment of infected patients, whose prognosis may benefit from early treatment and containment of contagions in asymptomatic or pauci-symptomatic subjects. To date, the gold-standard technique for diagnosing SARS-CoV-2 infection is the identification of viral genomic material (RNA) by molecular diagnosis. To improve the pandemic management, the need for enhanced diagnostic capacity for SARS-CoV-2 infections soon emerged, with rapid, accurate, and easily accessible methods. Machine learning (ML) models could help define the diagnosis and, in some cases, even the prognosis of COVID-19 patients. This chapter describes ML models based on laboratory tests combined with other biometric parameters;the applications aimed at optimizing diagnosis and prognosis were mainly described. Finally, the vaccination campaign against SARS-CoV-2. The fields most considered were the heterogeneity in patient selection, laboratory parameters used, the machine learning models and their validation and implementation. Furthermore, we briefly describe artificial intelligence's potentialities in planning different strategies for the vaccination campaigns against SARS-COV-2 through laboratory tests. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

Seroprevalence of anti-SARS-CoV-2 antibodies in high-risk occupational and low-risk groups in southwestern Iran

Background: Monitoring the spread of SARS-CoV-2 has been considered by the World Health Organization (WHO). We examined the prevalence of anti-SARS-CoV-2 immunoglobulin antibodies in southwestern Iran in spring 2020. The circulation of SARS-CoV-2 is high in the general population, especially among health care workers (HCWs) who are in close contact with patients. Objectives: The aim of this study was to determine the prevalence of anti-SARS-CoV-2 antigen in high-risk occupational and low-risk groups to investigate risk factors for serum positivity in Shiraz, southwestern Iran. Methods: A cross-sectional survey was performed on 366 participants (204 from high-risk and 162 from low-risk subjects). IgG and IgM antibodies were detected using Pishtaz Teb COVID-19 ELISA Kits to evaluate SARS-CoV-2-antigen in serum samples. After enzyme-linked immunosorbent assay (ELISA), serum prevalence, as well as IgG/IgM positive factors, was determined using logistic regression. Results: From July to September 2020 (a few months after reporting the first case of COVID-19 cases in Iran), out of 366 survived people, 72 (40.9%) were IgG positive, and 50 (27.5%) were IgM positive. The frequency of positive serology for IgG and IgM antibodies in individuals aged < 30 years was higher in the low-risk group than in the high-risk group. Multivariate logistic regression showed that headache (OR 0.312 [95% CI: 0.136 - 0.717]) and cough (OR 0.427 [95% CI: 0.182 - 1.004]) factors were associated with IgG or IgM positive serology. Conclusions: Between July and September 2020, the prevalence of anti-SARS-CoV-2 antigen was high in Shiraz. The prevalence of SARS-CoV-2 IgG/IgM antibodies in the high-risk group and their family as low risk was shown to increase viral infection due to close contact with COVID 19 patients than in the general population. Several factors were found to be related to the prevalence of anti-SARS-CoV-2 antigen that needs to be considered by policymakers to determine what to do about the SARS-CoV-2 pandemic.

Seroprevalence and cumulative incidence of COVID-19 in Ravansar cohort study participants 2020: a cross-sectional study

Background and Objectives: Serological studies are based on the detection of antibodies. However, the produced antibodies decrease over time;therefore, such methods cannot provide a valid estimate of prevalence and incidence. The present study aimed to determine the serum prevalence and cumulative incidence in the Ravansar cohort population (Youth and RaNCD Cohort) in October 2020. Methods: A random sample of 716 people aged > 18 years old were selected from the participants in the Ravansar cohort study in October 2020. Euroimmun anti-SARS COV-2 IgG ELISA kits (Lubeck, Germany) were used to measure antibody levels. Seroprevalence was estimated with considering of cut-off = 1, and cumulative incidence (modified and modified based on test specificity) was determined using modeling. Results: In the present study, the serum prevalence of COVID-19 viral infection in the Ravansar cohort population from 22 October 2020 to 18 November 2020 was estimated to be %35.16 (95%CI: %31.64, %38.79). Modified Cumulative incidence and modified based on test characteristics from 20 February to 18 November 2020 were estimated to be %68.85 and %67.71, respectively. Conclusion: Although very high cumulative incidence may be a sign of approaching herd immunity, adherence to health protocols is still recommended due to the potential role of asymptomatic cases in transmitting the disease to other members of the community;and the presence of new variants of the virus and reduced antibody levels should be considered.

Diagnosis and main types of coronavirus in humans: a narrative review / Uma análise dos principais diagnósticos de Sars-cov-2 disponíveis no Brasil: uma revisão de literatura / Diagnóstico y principales tipos de coronavirus en humanos: una revisión narrativa

Introdução: Com a emergência do SARS-CoV-2 foi disponibilizado uma grande quantidade de ferramentas de diagnóstico. Neste contexto, a falta de vacina, de tratamento e o grande número de casos graves e morte, possibilitou a aprovação emergencial de diversos testes, que ainda necessitam de estudos populacionais para seu registro definitivo. Objetivo: Realizar uma revisão de literatura para avaliar as metodologias de diagnóstico disponíveis no Brasil, de acordo com a realidade local de saúde, explorando o momento epidemiológico a complexidade do teste e a finalidade da sua aplicação. Metodologia: Trata-se de um estudo bibliográfico, descritivo do tipo revisão de literatura. Foram utilizadas as seguintes bases de dados científicos para buscas: PUBMED, MEDLINE, LILACS E COCHRANE LIBRARY, através de descritores selecionados na plataforma DECS. Resultados: O cenário de diversos ensaios, baseados em diferentes metodologias, como os testes baseados em RNA viral, em detecção de antígenos virais ou de anticorpos, associados ao conhecimento da história natural do vírus, possibilita uma análise crítica do melhor diagnóstico de acordo com a clínica do paciente, os epidemiológicos, o objetivo do diagnóstico e a acurácia do ensaio. Atualmente, há mudança no padrão imunológico da população e a descrição de tipos e subtipos de SARS-CoV-2 com mudanças gênicas, que podem levar a mudanças na acurácia diagnóstica ou a re-emergência em surtos de doença grave. Conclusão: Ainda é incerto o caminho evolutivo da história natural da Covid-19 e os ensaios diagnósticos estão em diferentes estágios de desenvolvimento, validação e produção e cada tipo de teste tem suas próprias vantagens e desvantagens distintas inerentes a plataforma tecnológica de origem e uma combinação de tipos de testes usados em momentos diferentes pode ser útil para a condução clínica dos pacientes e no controle da pandemia por SARS-CoV-2.

Introduction: With the emergence of SARS-CoV-2, a large number of diagnostic tools were made available. In this context, the lack of vaccine, treatment and the large number of severe cases and death, allowed the emergency approval of several tests, which still require population studies for their definitive registration. Objective: To carry out a literature review to evaluate the diagnostic methodologies available in Brazil, according to the local health reality, exploring the epidemiological moment, the complexity of the test and the purpose of its application. Methodology: This is a bibliographic, descriptive study of the literature review type. The following scientific databases were used for searches: PUBMED, MEDLINE, LILACS AND COCHRANE LIBRARY, through selected descriptors on the DECS platform. Results: The scenario of several tests, based on different methodologies, such as tests based on viral RNA, on detection of viral antigens or antibodies, associated with knowledge of the natural history of the virus, allows a critical analysis of the best diagnosis according to the patient's clinical, epidemiological, diagnostic objective and assay accuracy. Currently, there is a change in the immune pattern of the population and the description of types and subtypes of SARS-CoV-2 with genetic changes, which can lead to changes in diagnostic accuracy or the re-emergence in outbreaks of severe disease. Conclusion: The evolutionary path of the natural history of Covid-19 is still uncertain and diagnostic assays are at different stages of development, validation and production and each type of test has its own distinct advantages and disadvantages inherent in the technology platform of origin and a combination of types of tests used at different times can be useful for the clinical management of patients and in the control of the SARS-CoV-2 pandemic.

Introducción: Con la aparición del SARS-CoV-2, se dispuso de un gran número de herramientas diagnósticas. En este contexto, la falta de vacuna, tratamiento y el gran número de casos graves y muerte, permitieron la aprobación de urgencia de varias pruebas, que aún requieren estudios poblacionales para su registro definitivo. Objetivo: Realizar una revisión bibliográfica para evaluar las metodologías diagnósticas disponibles en Brasil, de acuerdo con la realidad sanitaria local, explorando el momento epidemiológico, la complejidad de la prueba y la finalidad de su aplicación. Metodología: Se trata de un estudio bibliográfico, descriptivo, del tipo revisión de literatura. Para las búsquedas se utilizaron las siguientes bases de datos científicas PUBMED, MEDLINE, LILACS Y COCHRANE LIBRARY, a través de descriptores seleccionados en la plataforma DECS. Resultados: El escenario de varias pruebas, basadas en diferentes metodologías, como pruebas basadas en el ARN viral, en la detección de antígenos virales o anticuerpos, asociado al conocimiento de la historia natural del virus, permite un análisis crítico del mejor diagnóstico de acuerdo con la clínica del paciente, epidemiológica, objetivo diagnóstico y precisión de la prueba. Actualmente, hay un cambio en el patrón inmunológico de la población y la descripción de tipos y subtipos de SARS-CoV-2 con cambios genéticos, que pueden conducir a cambios en la precisión diagnóstica o la reaparición en brotes de enfermedad grave. Conclusiones: El camino evolutivo de la historia natural del Covid-19 es aún incierto y los ensayos de diagnóstico se encuentran en diferentes etapas de desarrollo, validación y producción y cada tipo de prueba tiene sus propias ventajas y desventajas distintas inherentes a la plataforma tecnológica de origen y una combinación de tipos de pruebas utilizadas en diferentes momentos puede ser útil para el manejo clínico de los pacientes y en el control de la pandemia de SARS- CoV-2.

A systematical association analysis of 25 common virus infection and genetic susceptibility of COVID-19 infection.

OBJECTIVES: Previous studies identified a number of diseases were associated with 2019 coronavirus disease (COVID-19). However, the associations between these diseases related viral infections and COVID-19 remains unknown now. METHODS: In this study, we utilized single nucleotide polymorphisms (SNPs) related to COVID-19 from genome-wide association study (GWAS) and individual-level genotype data from the UK biobank to calculate polygenic risk scores (PRS) of 487,409 subjects for eight COVID-19 clinical phenotypes. Then, multiple logistic regression models were established to assess the correlation between serological measurements (positive/negative) of 25 viruses and the PRS of eight COVID-19 clinical phenotypes. And we performed stratified analyses by age and gender. RESULTS: In whole population, we identified 12 viruses associated with the PRS of COVID-19 clinical phenotypes, such as VZV seropositivity for Varicella Zoster Virus (Unscreened/Exposed_Negative: ß = 0.1361, P = 0.0142; Hospitalized/Unscreened: ß = 0.1167, P = 0.0385) and MCV seropositivity for Merkel Cell Polyomavirus (Unscreened/Exposed_Negative: ß = -0.0614, P = 0.0478). After age stratification, we identified seven viruses associated with the PRS of eight COVID-19 clinical phenotypes. After gender stratification, we identified five viruses associated with the PRS of eight COVID-19 clinical phenotypes in the women group. CONCLUSION: Our study findings suggest that the genetic susceptibility to different COVID-19 clinical phenotypes is associated with the infection status of various common viruses.

A novel S2-derived peptide-based ELISA for broad detection of antibody against infectious bronchitis virus.

Avian infectious bronchitis (IB) is a highly contagious disease caused by infectious bronchitis virus (IBV). Vaccination is an effective approach for controlling IBV. Therefore, reliable immune monitoring for IB is critical for poultry. In this study, a novel peptide derived from S2 protein was used to develop an enzyme-linked immunosorbent assay (ELISA) for the detection of broadly cross-reactive antibodies against IBV. The peptide-based ELISA (pELISA) showed good specificity and sensitivity in detecting IBV antibodies against different serotypes. A semilogarithmic regression method for determining IBV antibody titers was also established. Antibody titers detected by pELISA and calculated with this equation were statistically similar to those evaluated by indirect fluorescence assay (IFA). Moreover, the comparison analysis showed a 96.07% compatibility between the pELISA and IDEXX ELISA. All these data demonstrate that the pELISA generated here can be as a rapid and reliable serological surveillance tool for monitoring IBV infection or vaccination.

Dynamics of SARS-CoV-2 seroassay sensitivity: a systematic review and modelling study.

BackgroundSerological surveys have been the gold standard to estimate numbers of SARS-CoV-2 infections, the dynamics of the epidemic, and disease severity. Serological assays have decaying sensitivity with time that can bias their results, but there is a lack of guidelines to account for this phenomenon for SARS-CoV-2.AimOur goal was to assess the sensitivity decay of seroassays for detecting SARS-CoV-2 infections, the dependence of this decay on assay characteristics, and to provide a simple method to correct for this phenomenon.MethodsWe performed a systematic review and meta-analysis of SARS-CoV-2 serology studies. We included studies testing previously diagnosed, unvaccinated individuals, and excluded studies of cohorts highly unrepresentative of the general population (e.g. hospitalised patients).ResultsOf the 488 screened studies, 76 studies reporting on 50 different seroassays were included in the analysis. Sensitivity decay depended strongly on the antigen and the analytic technique used by the assay, with average sensitivities ranging between 26% and 98% at 6 months after infection, depending on assay characteristics. We found that a third of the included assays departed considerably from manufacturer specifications after 6 months.ConclusionsSeroassay sensitivity decay depends on assay characteristics, and for some types of assays, it can make manufacturer specifications highly unreliable. We provide a tool to correct for this phenomenon and to assess the risk of decay for a given assay. Our analysis can guide the design and interpretation of serosurveys for SARS-CoV-2 and other pathogens and quantify systematic biases in the existing serology literature.

SARS-CoV-2 seroprevalence among blood donors in Uganda: 2019-2022.

BACKGROUND: The true burden of COVID-19 in low- and middle-income countries remains poorly characterized, especially in Africa. Even prior to the availability of SARS-CoV-2 vaccines, countries in Africa had lower numbers of reported COVID-19 related hospitalizations and deaths than other regions globally. METHODS: Ugandan blood donors were evaluated between October 2019 and April 2022 for IgG antibodies to SARS-CoV-2 nucleocapsid (N), spike (S), and five variants of the S protein using multiplexed electrochemiluminescence immunoassays (MesoScale Diagnostics, Rockville, MD). Seropositivity for N and S was assigned using manufacturer-provided cutoffs and trends in seroprevalence were estimated by quarter. Statistically significant associations between N and S antibody seropositivity and donor characteristics in November-December 2021 were assessed by chi-square tests. RESULTS: A total of 5393 blood unit samples from donors were evaluated. N and S seropositivity increased throughout the pandemic to 82.6% in January-April 2022. Among seropositive individuals, N and S antibody levels increased ≥9-fold over the study period. In November-December 2021, seropositivity to N and S antibody was higher among repeat donors (61.3%) compared with new donors (55.1%; p = .043) and among donors from Kampala (capital city of Uganda) compared with rural regions (p = .007). Seropositivity to S antibody was significantly lower among HIV-seropositive individuals (58.8% vs. 84.9%; p = .009). CONCLUSIONS: Despite previously reported low numbers of COVID-19 cases and related deaths in Uganda, high SARS-CoV-2 seroprevalence and increasing antibody levels among blood donors indicated that the country experienced high levels of infection over the course of the pandemic.

Covid-19 in Patients Presenting with Malaria-Like Symptoms at the Korle Bu Polyclinic, Accra

Intro: Malaria is one of Ghana's most frequent illnesses and the most common cause of febrile sickness. Most infectious diseases including COVID-19 and arboviral infections mimic malaria due to the overlapping of non-specific symptoms they both share.This study investigated COVID-19 in patients presenting with malaria-like symptoms at the Korle Bu Polyclinic, Accra. Method(s): This study enrolled 300 patients presenting with malaria-like symptoms aged <= 18. After consent was obtained from study patients, two to three millilitres of whole blood, nasopharyngeal and oropharyngeal swab samples was collected for screening of Plasmodium falciparum using malaria rapid diagnostic test, microscopy and nested PCR and SARS-CoV-2 using SARSCoV-2 antigen test and Real-time PCR respectively. The whole blood sample was also used for COVID-19 antibody test and full blood count using hematological analyser. Finding(s): The detection of SARS-CoV-2 by COVID-19 Rapid Antigen Test and Real-time PCR were 60/300 (20%) and 26/300 (8.7%) respectively. Delta variant was reported in most SARS-CoV-2 positives with CT values below 30. The prevalence of malaria by microscopy, RDT and nested PCR were 7/300 (2.3%), 7/300 (2.3%) and 8/300 (2.7%) respectively. The most common symptom experienced by the study patients at the polyclinic was headache (95%;57/60). Comorbidities reported were hypertension, diabetes, Asthma, hypertension and diabetes. Most of the study patients had been previously exposure to SARS CoV-2 (113/300) and 66.7% (34/51) of AstraZeneca vaccinated patients had no antibody. Conclusion(s): Due to the synergy of symptoms, screening for COVID-19 in patients presenting with malaria-like symptoms is vital for immediate diagnosis and treatment.Copyright © 2023

Incidence and sero-surveillance of feline viruses in Korean cats residing in Gyeonggi-do

Incidences of major feline viral diseases provide basic information for preventing viral disease in cats. Despite the growing interest in feline viral diseases, sero-surveillances have been lacking. In this study, we analyzed the diagnoses of feline viral diseases and conducted a sero surveillance of feline panleukopenia virus (FPV), feline calicivirus (FCV), feline herpesvirus-1 (FHV-1), and feline infectious peritonitis virus (FIPV) in Korean cats. Of the 204 confirmed cases since 2015, the numbers of diagnoses for FPV, FIPV, FCV, feline influenza virus, and FHV-1 were 156, 32, 12, 3, and 1 case, respectively. In total, 200 sera, collected between 2019 and 2021, were screened for the presence of antibodies against FPV, 2 FCVs, FHV-1, and FIPV using a hemagglutination inhibition test and a virus-neutralizing assay (VNA). The overall seropositive rates in cats tested for FPV, the 2 FCVs, FHV-1, and FIPV were 92.5%. 42.0%, 37.0%, 52.0%, and 14.0%, respectively. A low correlation (r = 0.466) was detected between the VNA titers of 2 FCV strains. The highest incidence and seropositive rate of FPV reveal that FPV is circulating in Korean cats. The low r-value between 2 FCVs suggests that a new feline vaccine containing the 2 kinds of FCVs is required.

Seroprevalence of antibodies against SARS-CoV-2 in the Valencian Community (Spain) as of October 2022.

OBJECTIVE: To estimate the seroprevalence of SARS-CoV-2 antibodies in the Valencian Community (Spain) in October 2022, when BA.5 was the predominant variant. METHOD: Cross-sectional, region-wide, population-based serosurvey study in 88 randomly selected primary care centers of the Valencian Community. RESULTS: Seroprevalence of anti-nucleocapsid (indicative of past infection) and total receptor binding domain (indicative of past infection or vaccination) antibodies was 71.0% (confidence interval [CI]: 67.8-74.2) and 98.4% (CI: 97.5-99.3), respectively. 66.7% (CI: 63.4-70.0) of the population shows hybrid immunity, but only 43.2% in those 80 and over. CONCLUSIONS: The high proportion of hybrid immunity detected is relevant for public health strategies. A second vaccination booster was advisable in the elderly population.

Current State of Molecular and Serological Methods for Detection of Porcine Epidemic Diarrhea Virus.

Porcine epidemic diarrhea virus (PEDV), a member of the Coronaviridae family, is the etiological agent of an acute and devastating enteric disease that causes moderate-to-high mortality in suckling piglets. The accurate and early detection of PEDV infection is essential for the prevention and control of the spread of the disease. Many molecular assays have been developed for the detection of PEDV, including reverse-transcription polymerase chain reaction (RT-PCR), real-time RT-PCR (qRT-PCR) and loop-mediated isothermal amplification assays. Additionally, several serological methods have been developed and are widely used for the detection of antibodies against PEDV. Some of them, such as the immunochromatography assay, can generate results very quickly and in field conditions. Molecular assays detect viral RNA in clinical samples rapidly, and with high sensitivity and specificity. Serological assays can determine prior immune exposure to PEDV, can be used to monitor the efficacy of vaccination strategies and may help to predict the duration of immunity in piglets. However, they are less sensitive than nucleic acid-based detection methods. Sanger and next-generation sequencing (NGS) allow the analysis of PEDV cDNA or RNA sequences, and thus, provide highly specific results. Furthermore, NGS based on nonspecific DNA cleavage in clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems promise major advances in the diagnosis of PEDV infection. The objective of this paper was to summarize the current serological and molecular PEDV assays, highlight their diagnostic performance and emphasize the advantages and drawbacks of the application of individual tests.

Advancements in COVID- 19 Testing: An in-depth overview.

COVID-19 rapidly evolved as a pandemic, killing and hospitalising millions of people, creating unprecedented hurdles for communities and health care systems worldwide. The rapidly evolving pandemic prompted the head of the World Health Organisation to deliver a critical message: "test, test, test." The response from the diagnostic industry and researchers worldwide was overwhelming, resulting in more than a thousand commercial tests available in the market worldwide. Several sampling approaches and diagnostic techniques have been employed from the early stages of the pandemic, such as SARS-CoV-2 detection by targeting the viral RNA or protein, indirectly via antibody testing, biochemical estimation, and various imaging techniques, and many are still in the various stages of development and yet to be marketed. Accurate testing techniques and appropriate sampling are the need of the hour to manage, diagnose and treat the pandemic, especially in the current crisis, where SARS-CoV-2 undergoes constant mutation, evolving into various strains, which are pretty challenging. The article discusses various testing techniques as well as screening methods for detection, treatment, and management of COVID-19 transmission, such as NAAT, PCR, isothermal detection including RT-LAMP, RPA, NASBA, RCA, SDA, NEAR, and TMA, CRISPR strategy, nanotechnology approach, metagenomic profiling, point of care tests, virus neutralization test, ELISA, biomarker estimation, utilization of imaging techniques such as CT, ultrasonography, brain MRI in COVID-19 complications, and other novel strategies including microarray methods, microfluidic methods and artificial intelligence with an emphasis on advancements in the testing strategies for the diagnosis, management, and prevention of COVID-19.

Preparation and identification of broad-spectrum monoclonal antibodies against N protein of avian infectious bronchitis virus

[Objective] To prepare broad-spectrum monoclonal antibody against N protein of avian infectious bronchitis virus (IBV), so as to lay a foundation for identifying conservative domain epitope of N protein and establish a universal IBV detection method. [Method] N protein of GX-YL5, a representative strain of IBV dominant serotype in Guangxi, was expressed in prokaryote. BALB/c mice were immunized with the purified protein. After the serum titer of the immunized mice reached 104 or more, the splenocytes were fused with SP2/0 myeloma cells. After screening by indirect ELISA, monoclonal antibody was prepared by ascites-induced method. Western blotting, IFA and indirect ELISA were used to identify the titer, subtype, reaction specificity and cross-reaction spectrum. And the prepared monoclonal antibody was used for immunohistochemical detection. And the prepared monoclonal antibody was used to detect the IBV in the trachea and kidney tissues of SPF chickens artificially infected with 4 representative IBV variants (GX-N130048, GX-N160421, GX-QZ171023 and GX-QZ170728). [Result] The prepared monoclonal antibody N2D5 had a titer greater than 217 and its subtype was IgG2b. The Western blotting and IFA results showed that the monoclonal antibody N2D5 only reacted with IBV, and were negative with Newcastle disease virus (NDV), infectious laryngotracheitis virus (ILTV), avian metapneumovirus (aMPV), infectious bursal disease virus (IBDV), avian leukosis virus (ALV) and Marek's disease virus (MDV). Monoclonal antibody N2D5 reacted with many genotypes in China and all 7 serotypes of IBV currently prevalent in Guangxi, including commonly used standard strains, vaccine strains and field strains. Immunohistochemistry showed that the virus signals could be detected in the trachea and kidney tissues of SPF chickens at different time after artificial infection of 3 representative IBV strains from chicken and 1 isolated strain from duck, which further proved its broad spectrum. [Conclusion] The monoclonal antibody N2D5 of IBV prepared based on hybridoma technology belongs to the IgG2b subtype. It has the characteristics of high specificity, wide response spectrum and strong binding ability with IBV. It can be used as a specific diagnostic antibody for clinical diagnosis of IBV and the study of virus distribution.

SARS-CoV-2 SEROPREVALENCE TREND AMONG PREGNANT WOMEN IN ZAMBIA, 2021-2022

Background: Confirmed COVID-19 case counts underestimate SARS-CoV-2 infections, particularly in countries with limited testing capacity. Pregnant women attending antenatal care (ANC) clinics have served as healthy population surrogates to monitor diseases like HIV and malaria. We measured SARS-CoV-2 seroprevalence among women attending ANC clinics to assess infection trends over time in Zambia. Method(s): We conducted repeated cross-sectional surveys among pregnant women aged 15-49 years attending their first ANC visits in 3 districts of Zambia during September 2021-September 2022. Up to 200 women per district were enrolled each month, completing a standardized questionnaire. Dried blood spot samples were collected for serologic testing for prior infection using the Tetracore FlexImmArrayTM SARS-CoV-2 Human IgG Antibody Test and HIV testing according to national guidelines. We calculated odds ratios (ORs) for SARS-CoV-2 seroprevalence by demographic characteristics, adjusting for the district. Result(s): A total of 5,351 women were enrolled at 29 study sites between September 2021 and September 2022. Participants' median age was 25 years (interquartile range: 21-30), 530 (9.9%) tested positive for HIV, and 101 (1.9%) reported a prior positive COVID-19 test. Overall, SARS-CoV-2 seroprevalence was 67%, and rose from 49% in September 2021 to 85% in September 2022 (Figure 1). The greatest increase in seroprevalence occurred during the 4th wave caused by the Omicron variant (48% in December 2021 to 63% in January 2022). Seroprevalence was significantly higher among women living in urban districts (Chipata and Lusaka) compared to rural Chongwe District (Chipata OR: 1.2, 95% confidence interval [CI]: 1.1-1.4;Lusaka OR: 1.7, 95% CI: 1.5-2.0). The age group was not significantly associated with seroprevalence after adjusting for the district (aOR: 1.1, 95% CI: 1.0-1.2). Seroprevalence was significantly lower among women living with HIV than women living without HIV (aOR: 0.8, 95% CI: 0.6-0.9). Conclusion(s): Overall, two-thirds of women in the three surveyed districts in Zambia had evidence of SARS-CoV-2 exposure, rising to 85% after the Omicron variant spread throughout the country. ANC clinics have a potential role in ongoing SARS-CoV-2 serosurveillance and can continue to provide insights into SARS-CoV-2 infection dynamics. Furthermore, they provide a platform for focused SARS-CoV-2 prevention messaging and COVID-19 management in pregnant women at higher risk of severe disease. (Figure Presented).