Seroprevalence Of Antibodies Research Articles

Immunoglobulin-M (IgM) antibody against cytomegalovirus among females of reproductive age in Buguma, Rivers State, Nigeria

Infection with the human cytomegalovirus (HCMV), particularly in pregnant women, can result in congenital abnormalities and is frequently linked to significant side effects such as microcephaly, mental retardation, deafness, and spastic paralysis. In the Buguma city of Rivers State, a cross-sectional study was conducted to ascertain the seroprevalence of HCMV infection and related risk factors among females of reproductive age. A structured questionnaire was given to 93 females in Buguma of reproductive age and matched for socio-demographic traits between December 2021 and January 2023. By venous puncture, five millilitres (5 ml) of blood were obtained, centrifuged, and plasma was collected. Using an enzyme-linked immunosorbent test, plasma was analyzed for the presence of HCMV immunoglobulin M (IgM) antibodies (ELISA). SPSS Version 17 was used to analyze the data. There were 93 participants in all. The findings indicated that the highest proportions of participants were found in the age range of 31 to 40 years, the married (59.1%), those with tertiary education (64.5%), and business/traders (38.0%). Nineteen females (20.4%) tested positive for HCMV IgM antibodies. Compared to other age groups, the HCMV IgM age-specific seroprevalence was highest in people under 20 (25.0%) and closely followed by those in the 21–30 age range (23.3%). As people get older, HCMV infection rates decline. The frequency of HCMV IgM was higher in married people (21.8%) than in single people (18.4%). Compared to women with secondary education (12.1%), those with university education (25.0%) had a higher prevalence. Compared to other occupational groups, teachers had a higher frequency (33.3%). None of the patient demographic traits revealed a statistically significant correlation with HCMV serostatus. In the Nigerian town of Buguma, Rivers State, the investigation verified the existence of HCMV infections among females of reproductive age. The significant seroprevalence of anti-HCMV IgM antibodies in these females suggested recent virus exposure. This observation suggests that the virus is widespread in the research region. It is advised that routine CMV infection screening be adopted for all females of reproductive age across the state and the nation.

Seroprevalence of Anti-Echinococcus granulosus Antibodies and Risk Factors for Infection in Blood Donors from Western Romania.

Cystic echinococcosis is a worldwide-distributed zoonotic parasitic disease. This cross-sectional study aimed to assess the seroprevalence and risk factors potentially associated with Echinococcus granulosus in healthy blood donors from Timis County, an endemic region in Western Romania. Serum samples were collected from 1347 Romanian blood donors. Serologic tests to determine the presence of anti-Echinococcus antibodies were performed using an anti-Echinococcus-ELISA immunoassay. Anti-Echinococcus antibodies were detected in 38 blood donors, indicating an overall seroprevalence of 2.8%. The seropositivity rate was 3.7% in females and 3.1% in blood donors residing in urban areas. The highest seropositivity was found in the age group of 31-40 years (3.6%). There were no significant differences between Echinococcus seropositivity and gender, area of residence, age, contact with dogs, or raising sheep. This serologic survey evaluated for the first time the presence of Echinococcus antibodies in healthy blood donors from Western Romania and the potential risk factors associated with echinococcosis. Our results suggest that this zoonotic infection might evolve asymptomatically in apparently healthy individuals. Further studies should be conducted in the general population to estimate the true extent of human echinococcosis and its risk factors.

Assessment of indicators of specific humoral immune against COVID-19 in children during the distribution of a new coronavirus infection in the Irkutsk region (2020–2021)

Background. There are many aspects of the development of immunity to the SARSCoV-2 virus, that remain poorly understood, like the influence of age-related characteristics on the intensity of immunity and the course of the disease. Studies of the state of immunity are widely used, mainly in the adults. But questions of the patho- and immunogenesis in children remain unsolved. Determining the nature of seroconversion of antibodies to SARS-CoV-2 in this age group is important information for serological monitoring for targeted immunoprophylaxis of the population and forecasting the epidemic situation in the region.The aim. Evaluation of the dynamics of seroprevalence of specific antibodies to SARS-CoV-2 in children of the Irkutsk region during the pandemic of a new coronavirus infection.Materials and methods. Study was conducted among the child population of the Irkutsk region in the period June 2020 – December 2021 as part of the Rospotrebnadzor project to assess population immunity to SARS-CoV-2 in the population of the Russian Federation. The content of antibodies to SARS-CoV-2 was determined by ELISA using native commercial test systems.Results. Population immunity among the child population of the Irkutsk region was characterized by an upward trend from 7.8 % at stage 1 to 98.4 % at stage 6 of the study. IgG to SARS-CoV-2 remained in 72.8 % and formed in 25.6 % of previously seronegative children. Antibodies were detected in 66.1 % of cases and persisted for up to 10–15 months after COVID-19 infection. The proportion of asymptomatic forms of infection among seropositive volunteers was 69.5 %, which determines the high intensity of the latent epidemic process.Conclusion. The level of seroprevalence was 98.4%. The current results of serological monitoring serve as a scientific basis for adjusting the list and scope of management decisions on the organization of preventive anti-epidemic measures, including vaccination.

Design and Implementation of a Nationwide Population-Based Longitudinal Survey of SARS-CoV-2 Infection in Spain: The ENE-COVID Study.

Data System. The Spanish National Seroepidemiological Survey of SARS-CoV-2 (or ENE-COVID; SARS-CoV-2 [severe acute respiratory syndrome coronavirus 2] is the causative agent of COVID-19) was funded by the Spanish Ministry of Health, the Instituto de Salud Carlos III, and the Spanish National Health System. Data Collection/Processing. A stratified 2-stage probability sampling was used to select a representative cohort of the noninstitutionalized population of Spain. ENE-COVID collected longitudinal data from epidemiological questionnaires and 2 SARS-CoV-2 IgG antibody tests. From April 27 to June 22, 2020, 68 287 participants (77.0% of contacted persons) received a point-of-care test and 61 095 (68.9%) also underwent a laboratory immunoassay. A second follow-up phase was conducted between November 16 and 30, 2020. Data Analysis/Dissemination. Analyses use weights to adjust for oversampling and nonresponse and account for design effects of stratification and clustering. ENE-COVID data for research purposes will be available upon request from the official study Web page. Public Health Implications. ENE-COVID, a nationwide population-based study, allowed monitoring seroprevalence of antibodies against SARS-CoV-2 at the national and regional levels, providing accurate figures by gender, age (from babies to nonagenarians), and selected risk factors; characterizing symptomatic and asymptomatic infections; and estimating the infection fatality risk during the first pandemic wave. (Am J Public Health. 2023;113(5):525-532. https://doi.org/10.2105/AJPH.2022.307167).

Increased seroprevalence of anti-Toxoplasma gondii antibodies in dogs in southern Brazil after an outbreak of human toxoplasmosis

Toxoplasmosis is a worldwide disease caused by Toxoplasma gondii, which can infect diverse hosts, including dogs. Although T. gondii infection in dogs is usually subclinical, they are susceptible to infection and develop a specific immune response to the parasite. In 2018, the largest outbreak of human toxoplasmosis in the world occurred in Santa Maria, in southern Brazil; however, the impact of this outbreak on other hosts was not investigated at the time. Considering that dogs often share the same environmental sources of infection as humans, mainly water sources, and that in Brazil, the detection rates of anti-T. gondii immunoglobulin G (IgG) in dogs is very high, this study investigated the frequency of anti-T. gondii IgG in dogs in Santa Maria before and after the outbreak. A total of 2.245 serum samples were analyzed, 1159 collected before the outbreak and 1086 collected after the outbreak. Serum samples were tested for anti-T. gondii antibodies using an indirect immunofluorescence antibody test (IFAT). The infection detection of T. gondii was 16% (185/1159) before the outbreak and 43% (466/1086) after the outbreak. These results showed the infection of dogs with T. gondii and the high frequency of anti-T. gondii antibodies in dogs after the outbreak in humans in 2018, reinforcing water as a possible source of infection and the importance of including toxoplasmosis in the differential diagnosis of dogs.

Correlation of Herd Immunity to Measles Vaccination Rate and Disease Incidence

Background: Measles is one of the most contagious diseases faced by humans. Despite considerable progress, measles remains one of the leading global causes of death among children. Methods and Results: The seroprevalence of antibodies against measles in Kosovo was determined with a serological survey of measles. In total, 768 participants aged between 3 days and 45 years of both sexes were included. Enzyme-linked immunosorbent assay results revealed total seropositivity of 74.5% (95% CI: 0.70–0.88) among participants. Those in the unvaccinated 0–1.9-year age group had the lowest seropositivity (33.2%). The 2–6-year age group, which received one dose of the vaccine, had higher seropositivity (78.6%) than the youngest group. The 8–17-year age group, which received two doses of the measles vaccine, had significantly higher seropositivity (91.3%) than the 2–6-year age group. The highest level of seropositivity (93.4%) was observed in the 18–45-year age group. An analysis of sex-specific IgG antigen levels indicated that female participants had significantly higher seropositivity than male participants (P<0.01). Conclusion: The seroprevalence of measles antibodies in Kosovo has not yet reached the required 95% threshold, and the threat of a possible measles epidemic exists. An immunization strategy that targets vulnerable groups and the entire population is required.

Serological Survey of Infectious Bronchitis Virus in Chickens in Sokoto State Nigeria

In the present study, blood samples were collected from 400 chickens and sera harvested for serology using an IgG based indirect enzyme linked immunosorbent assay (ELISA). This research aimed at determining the prevalence of antibodies to infectious bronchitis virus in chickens in sokoto state Nigeria. The samples were collected from selected areas in each of the four Agricultural zones of Sokoto State. The overall sero-prevalence obtained was 346 (86.50%). The sero-prevalence of infectious bronchitis viral antibodies in indigenous and exotic chickens was 88.72% and 84.39% respectively, chi square showed no significant relationship between the two groups, the chi value was 1.603 and P value was 0.205 (>0.05%). In young and adult chickens sampled, the sero-prevalence was 89.50% and 82.87% respectively, chi square showed significant relationship between the two age groups with chi value 3.179 and P value 0.038 (<0.05), binary logistic regression for the two age groups showed no significant association with P= 0.09 (>0.05). The result in male and female chickens tested was 86.88% and 86.17% positives respectively showing slightly higher positives in males than in females with no significant statistical relationship using chi square, chi value was 0,043 and P value 0.836 (>0.05%). This study has provided an update on sero-prevalence of IBV in Sokoto State. It was concluded that there was high sero-prevalence of IBV in the chickens sampled in the State. General survey of the virus in the entire region where Sokoto belongs (Northwestern Nigeria) or the country as a whole is recommended, so as to have a clearer picture of IB and Veterinarians probably consider vaccination as a mean of prevention of the disease, and vaccine be produced using local strains

Risk analysis of bovine viral diarrhea in Kazakhstan

Bovine viral diarrhea (BVD) is an acute infectious disease caused by BVD virus (BVDV). BVD is characterized by fever, lesions of the mucosal lining of the digestive tract, diarrhea, conjunctivitis and rhinitis. This disease is considered as one of the most dangerous infectious diseases in animal husbandry worldwide because of its high prevalence, persistence in the environment, and severe clinical consequences. The purpose of this study is to assess the epizootological situation on BVD of cattle, which has developed by the beginning of 2021 in various regions of the Republic of Kazakhstan.  For this purpose, we retrospectively analyzed samples of cattle serum collected in 2018-2020 by ELISA for the presence of antibodies to BVDV in them. It was found that BVD in cattle was prevalent even before 2021 in a significant area of Kazakhstan, while the total seroprevalence for BVDV was 67.3% (243/361; 95% CI: 0.37-0.63). Among the animals from which serum was taken, 51.2% of the animals were vaccinated with BVDV vaccines and 48.8% of the animals were unvaccinated. The average seroprevalence of antibodies to BVDV in unvaccinated animals was 36.4% (64/176; 95% CI: 1.2-2.5) positive samples were detected in unvaccinated animals in Zerenda, Astrakhan, Tselinograd and Shortanda districts of Akmola region, also in Akzhar and Kyzylzhar districts of North Kazakhstan region and Aksu district of Almaty region. The results obtained contribute to the disclosure of the epizootological situation of BVD in the territory of Kazakhstan, which will allow the full use of effective control measures, such as total vaccination of livestock in the risky regions of the infection and the introduction of strict restrictive measures to prevent further spread of the infection to other regions of the country. Keywords: Bovine viral diarrhea, cattle, enzyme immunoassay, Pestivirus, Togaviridae.

Seroprevalence of SARS-CoV2 Antibodies among Patients and Healthy Individuals of Lahore

Objective: To determine the seroprevalence of SARS-CoV2 antibodies in patients and healthy individuals presenting to a tertiary care hospital in Lahore.
 Study Design: Cross-sectional study
 Place and Duration of Study: Pathology Department of Surayya Azeem Hospital, Lahore Pakistan, from May to Jul 2020.
 Methodology: The study included clinically suspected patients of COVID-19 referred by clinicians and healthy individuals presenting to the hospital for the SARS-CoV-2 antibody test, irrespective of age and gender.
 Results: The SARS-CoV-2 antibody positivity was 704(59.4%) in our study. Out of 1184 individuals tested, 690 patients had a positive clinical history of COVID-19 infection, and 517(74.9%) were positive for COVID-19 antibodies. Out of 494 asymptomatic healthy individuals, positivity for COVID-19 antibodies was 187(37.8%). It was observed that positivity was significantly higher 169(44.0%) in contacts of COVID-19 infection patients compared to asymptomatic healthy individuals 18(16.3%).
 Conclusion: Our study shows that the seroprevalence of SARS-CoV-2 antibodies in the general public in Pakistan has greatly increased.

Association between the Seroprevalence of Antibodies against Seasonal Alphacoronaviruses and SARS-CoV-2 Humoral Immune Response, COVID-19 Severity, and Influenza Vaccination.

The present study assesses the seroprevalence of antibodies against seasonal human alphacoronaviruses 229E and NL63 among adult patients infected with SARS-CoV-2, and its association with the humoral response to SARS-CoV-2 infection and its severity, and influenza vaccination. A serosurvey was conducted to quantify the presence of IgG antibodies against the nucleocapsid of 229E (anti-229E-N) and NL63 (anti-NL63-N), and anti-SARS-CoV-2 IgG antibodies (against nucleocapsid, receptor-binding domain, S2 domain, envelope, and papain-like protease) for 1313 Polish patients. The seroprevalence of anti-229E-N and anti-NL63 in the studied cohort was 3.3% and 2.4%. Seropositive individuals had a higher prevalence of anti-SARS-CoV-2 IgG antibodies, higher titers of the selected anti-SARS-CoV2 antibodies, and higher odds of an asymptomatic SARS-CoV-2 infection (OR = 2.5 for 229E and OR = 2.7 for NL63). Lastly, the individuals vaccinated against influenza in the 2019/2020 epidemic season had lower odds of seropositivity to 229E (OR = 0.38). The 229E and NL63 seroprevalence was below the expected pre-pandemic levels (up to 10%), likely due to social distancing, increased hygiene, and face masking. The study also suggests that exposure to seasonal alphacoronaviruses may improve humoral responses to SARS-CoV-2 while decreasing the clinical significance of its infection. It also adds to accumulating evidence of the favorable indirect effects of influenza vaccination. However, the findings of the present study are of a correlative nature and thereby do not necessarily imply causation.

Seroprevalence of Anti-SARS-CoV-2 Antibodies Following the Omicron BA.1 Wave.

We conducted a seroprevalence study using convenient residual sera samples from the Slovenian population collected after the end of the Omicron BA.1 pandemic wave. Serum samples were tested for spike glycoprotein (anti-S) and nucleocapsid protein (anti-N) antibodies. Participants' data regarding confirmed infection and vaccination was obtained from national registries. Anti-S antibodies were detected in 2439 (84.1%) of 2899 sera from persons aged 0-90 years, with the lowest prevalence in the 0-17 age group. The proportion of anti-N positives was the lowest in the ≥70 age group. The proportion of anti-N positives was significantly higher among participants with confirmed past infection and among those who had never been vaccinated. In participants who had not been notified as infected and who had never been vaccinated, the seroprevalence of anti-S and anti-N antibodies was 53% and 35.5%, respectively. From the time of serum collection to mid-November 2022, 445 participants (15.3%) tested positive for SARS-CoV-2, with higher odds in seronegative participants, participants in the 40-59 age group, and those without notified previous infection. Vaccination status and gender had no significant effects on infection risk. This study underlines the importance of serosurveys in understanding the development of the pandemic.

Low risk of human T-lymphotropic virus infection in U.S. blood donors; Is it time to consider a one-time selective testing approach?

U.S. blood donors are tested at each donation for human T-lymphotropic virus (HTLV) antibodies. Depending on donor incidence and other mitigation/removal technologies, a strategy of one-time selective donor testing should be considered. Antibody seroprevalence was calculated for HTLV-confirmed-positive American Red Cross allogeneic blood donors from 2008 to 2021. Incidence was estimated for seven 2-year time periods using confirmed-positive repeat donors having seroconverted in 730 days. Leukoreduction failure rates were obtained from internal data from July 1, 2008-June 30, 2021. Residual risks were calculated using a 51-day window period. Between 2008 and 2021, >75 million donations (>18 million donors) yielded 1550 HTLV seropositives. HTLV seroprevalence was 2.05 antibody-positives per 100,000 donations (0.77 HTLV-1, 1.03 HTLV-2, 0.24 HTLV-1/2), and 10.32 per 100,000 among >13.9 million first-time donors. Seroprevalence differed significantly by virus type, sex, age, race/ethnicity, donor status, and U.S. census region. Over 14 years and 24.8 million person-years of observation, 57 incident donors were identified (25 HTLV-1, 23 HTLV-2, and 9 HTLV-1/2). Incidence decreased from 0.30 (13 cases) in 2008-2009 to 0.25 (7 cases) in 2020-2021. Female donors accounted for most incident cases (47 vs. 10 males). In the last 2-year reporting period, the residual risk was 1 per 2.8 million donations and 1 per 3.3 billion donations when coupled with successful leukoreduction (0.085% failure rate). HTLV donation seroprevalence for the years 2008-2021 varied by virus type and donor characteristics. Low HTLV residual risk and use of leukoreduction processes support the conclusion that a selective one-time donor testing strategy should be considered.

Seroprevalence of Antibodies to SARS-CoV-2 in Rural Households in Eastern Uganda, 2020-2022

Estimating the true burden of SARS-CoV-2 infection has been difficult in sub-Saharan Africa owing to asymptomatic infections and inadequate testing capacity. Antibody responses from serologic surveys can provide an estimate of SARS-CoV-2 exposure at the population level. To estimate SARS-CoV-2 seroprevalence, attack rates, and reinfection in eastern Uganda using serologic surveillance from 2020 to early 2022. This cohort study was conducted in the Tororo and Busia districts of eastern Uganda. Plasma samples from participants in the Program for Resistance, Immunology, Surveillance, and Modeling of Malaria in Uganda Border Cohort were obtained at 4 sampling intervals: October to November 2020, March to April 2021, August to September 2021, and February to March 2022. Each participant contributed up to 4 time points for SARS-CoV-2 serology, with almost half of all participants contributing at all 4 time points, and almost 90% contributing at 3 or 4 time points. Information on SARS-CoV-2 vaccination status was collected from participants, with the earliest reported vaccinations in the cohort occurring in May 2021. The main outcomes of this study were antibody responses to the SARS-CoV-2 spike protein as measured with a bead-based serologic assay. Individual-level outcomes were aggregated to population-level SARS-CoV-2 seroprevalence, attack rates, and boosting rates. Estimates were weighted by the local age distribution according to census data. A total of 1483 samples from 441 participants living in 76 households were tested. Of the 441 participants, 245 (55.6%) were female, and their mean (SD) age was 16.04 (16.04) years. By the end of the Delta wave and before widespread vaccination, adjusted SARS-CoV-2 seroprevalence was 67.7% (95% credible interval [CrI], 62.5%-72.6%) in the study population. During the subsequent Omicron wave, 84.8% (95% CrI, 67.9%-93.7%) of unvaccinated, previously seronegative individuals were infected for the first time, and 50.8% (95% CrI, 40.6%-59.7%) of unvaccinated, already seropositive individuals were likely reinfected, leading to an overall seropositivity of 96.0% (95% CrI, 93.4%-97.9%) in this population. These results suggest a lower probability of reinfection in individuals with higher preexisting antibody levels. There was evidence of household clustering of SARS-CoV-2 seroconversion. No significant associations were found between SARS-CoV-2 seroconversion and gender, household size, or recent Plasmodium falciparum malaria exposure. In this cohort study in a rural population in eastern Uganda, there was evidence of very high SARS-CoV-2 infection rates throughout the pandemic inconsistent with national level case data and high reinfection rates during the Omicron wave.

Comparing Control Intervention Scenarios for Raccoon Rabies in Southern Ontario between 2015 and 2025.

The largest outbreak of raccoon rabies in Canada was first reported in Hamilton, Ontario, in 2015 following a probable translocation event from the United States. We used a spatially-explicit agent-based model to evaluate the effectiveness of provincial control programs in an urban-centric outbreak if control interventions were used until 2025, 2020, or never used. Calibration tests suggested that a seroprevalence of protective rabies antibodies 2.1 times higher than that inferred from seroprevalence in program assessments was required in simulations to replicate observed raccoon rabies cases. Our simulation results showed that if control interventions with an adjusted seroprevalence were used until 2025 or 2020, the probability of rabies elimination due to control intervention use was 49.2% and 42.1%, respectively. However, if controls were never used, the probability that initial rabies cases failed to establish a sustained outbreak was only 18.2%. In simulations where rabies was not successfully eliminated, using control interventions until 2025 resulted in 67% fewer new infections compared to only applying controls until 2020 and in 90% fewer new infections compared to no control intervention use. However, the model likely underestimated rabies elimination rates since we did not adjust for adaptive control strategies in response to changes in rabies distributions and case numbers, as well as extending control interventions past 2025. Our agent-based model offers a cost-effective strategy to evaluate approaches to rabies control applications.

Gender differences in prevalence of hepatitis C virus infection in Egypt: a systematic review and meta-analysis

Egypt is the country with the highest known hepatitis C virus (HCV) prevalence worldwide. The origin of gender differences in HCV prevalence is not usually well understood. This systematic review and meta-analysis aimed to review and evaluate the gender differences in HCV infection rates amongst Egyptians. Such data would be important to support prevention and control programs aiming to minimize HCV-related morbidity and mortality. PubMed, Scopus, and Web of Science (WOS) were searched for relevant articles published from 1st January 2011 to 13th December 2021, using the search terms (HCV OR “hepatitis C” OR hepacivirus) AND (prevalence OR seroprevalence OR epidemiology OR incidence OR magnitude). At first, retrieved articles were screened, and then relevant data were extracted and analyzed. Descriptive statistics were used for data analysis. Out of 616 studies from databases, only 30 were included after the full-text screening, with 193,621 included participants: 97,597 male and 96,024 female. The overall seroprevalence of HCV antibodies in all included studies was 0.02 (CI − 0.23 to 0.28), with no significant difference between males and females. However, HCV RNA positivity was significantly more prevalent in males than females in adults and the general population (after excluding high-risk groups). In children, no statistically significant differences between males and females were found in the seroprevalence of HCV antibodies nor in the prevalence of PCR positivity. HCV RNA positivity is significantly higher in males than females in adults, while there are no gender differences in children.

SARS-CoV-2 seroprevalence among children in Latvia: A cross-sectional study.

Coronavirus disease 2019 (COVID-19) is a major global health concern. In contrast to adults, the course of the disease has been observed to be mild or even asymptomatic in children. It is therefore both clinically and epidemiologically important to measure the seroprevalence in children and adolescents to discern the overall morbidity of the disease and to compare these findings with similar data collected globally. We conducted a cross-sectional study between March and July of 2022 at the Children Clinical University Hospital in Riga, Latvia, to evaluate the seroprevalence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Participants aged 0 to 18 years were enrolled during hospitalization for reasons other than COVID-19. The levels of SARS-CoV-2 spike protein and nucleocapsid antibodies were measured in blood samples. The possibility of transplacental antibody transport was evaluated by directly interviewing the mothers of participants aged 18 months and younger. Various demographic and epidemiological risk factors and their association with seroprevalence were analyzed. Positive SARS-CoV-2 nucleocapsid antibodies were designated the main criterion for seropositivity. Of 200 enrolled children, 173 were found to be seropositive, resulting in an overall seroprevalence of 86.5%. The highest seroprevalence was detected in children and adolescents aged 12 to 18 years. With the progression of the COVID-19 pandemic, the seroprevalence in children has increased significantly. We found that almost 1-third of seropositive children in our study population were unaware of being previously infected with SARS-CoV-2 due to an asymptomatic course of the disease. Our study findings pertaining to high seropositivity among children and adolescents might be beneficial for public authorities to adapt epidemiological strategies and prevention measures. The high seroprevalence rate reported here and in many other populations around the world suggests that COVID-19 will likely become one of the many seasonal viral infections.

Seroprevalence of anti-Lassa Virus IgG antibodies in three districts of Sierra Leone: A cross-sectional, population-based study.

Lassa virus (LASV), the cause of the acute viral hemorrhagic illness Lassa fever (LF), is endemic in West Africa. Infections in humans occur mainly after exposure to infected excrement or urine of the rodent-host, Mastomys natalensis. The prevalence of exposure to LASV in Sierra Leone is crudely estimated and largely unknown. This cross-sectional study aimed to establish a baseline point seroprevalence of IgG antibodies to LASV in three administrative districts of Sierra Leone and identify potential risk factors for seropositivity and LASV exposure. Between 2015 and 2018, over 10,642 participants from Kenema, Tonkolili, and Port Loko Districts were enrolled in this cross-sectional study. Previous LASV and LF epidemiological studies support classification of these districts as "endemic," "emerging," and "non-endemic", respectively. Dried blood spot samples were tested for LASV antibodies by ELISA to determine the seropositivity of participants, indicating previous exposure to LASV. Surveys were administered to each participant to assess demographic and environmental factors associated with a higher risk of exposure to LASV. Overall seroprevalence for antibodies to LASV was 16.0%. In Kenema, Port Loko, and Tonkolili Districts, seroprevalences were 20.1%, 14.1%, and 10.6%, respectively. In a multivariate analysis, individuals were more likely to be LASV seropositive if they were living in Kenema District, regardless of sex, age, or occupation. Environmental factors contributed to an increased risk of LASV exposure, including poor housing construction and proximity to bushland, forested areas, and refuse. In this study we determine a baseline LASV seroprevalence in three districts which will inform future epidemiological, ecological, and clinical studies on LF and the LASV in Sierra Leone. The heterogeneity of the distribution of LASV and LF over both space, and time, can make the design of efficacy trials and intervention programs difficult. Having more studies on the prevalence of LASV and identifying potential hyper-endemic areas will greatly increase the awareness of LF and improve targeted control programs related to LASV.

A seroepidemiological survey of adenovirus type 7 circulation among healthy adults in China and in Sierra Leone, West Africa.

Adenovirus type 7 (HAdV7) is one of the most pathogenic human adenoviruses (HAdVs) and can cause severe illness and even death, particularly in people with weakened immune systems. Many countries worldwide have experienced epidemics of this highly contagious pathogen, including China and Sierra Leone; however, studies describing the seroprevalence of anti-HAdV7 neutralizing antibodies (nAbs) are still lacking. Herein, we established an efficient neutralization assay based on a recombinant luciferase-expressing HAdV7 virus (HAd7-Luc) to monitor historical HAdV7 infections and predict outbreak distributions. Among the 2,350 serum samples collected from eight sites in China and Sierra Leone in this cross-sectional serological survey, the overall proportion of anti-HAdV7-seropositive individuals was nearly 60%, with higher seroprevalence rates in Sierra Leone than in China. Regionally, HAdV7 nAb titers were higher in China than in Sierra Leone and showed a geographic variation across different regions. Regardless of the location, the seropositive rate of HAdV7 nAb was lower than that of HAdV5 nAb, as was the nAb titer. The prevalence rates of antibodies against HAdV7 and HAdV5 were both related to age but not to sex. In addition, serologic cross-reactions were rarely observed among people infected with HAdV7 and HAdV5. These results indicate a humoral immune response acquired through endemic HAdV7 infection and enrich the understanding of not only the epidemiological prevention and control of HAdV7 but also the clinical application of HAdV7-based vaccines or gene therapy tools.

Seroprevalence of Herpes Simplex Virus type-1antibodies (IgM,IgG) in smokers in Kirkuk city-Iraq

Herpes Simplex Virus type-1 (HSV-1) is classified in the α-herpes virus group of the Herpesviridae and HSV-1 infections are very common in the human population. The objective of this study is to determine the prevalence of anti-herpes simplex virus type-1 IgM and anti-herpes simplex virus type-1 IgG among smokers and nonsmokers. In the current study, A total of one hundred two serum samples from males were collected (70 smokers and 32 nonsmokers), there ages were ranged between 20- 50 year; this study which was done during the period between September 2014 to the January 2015. All obtained sera samples from all persons were tested using ELISA method for determine of Herpes simplex virus type-1 antibodies. Results in this study showed that the herpes simplex virus type-1 IgM seropositivity among smoker persons was 24 (34.3%). In addition, the result revealed that the percentage rate of the herpes simplex virus type-1 IgG among smokers was 61(87.1%). There was a significant effect of smoking on the seroprevalence of Herpes simplex virus type-1 antibodies (IgM , IgG).

Seroprevalence of SARS-CoV-2 Antibodies and Associated Factors Among Health Care Workers at the Departmental and Teaching Hospital of Borgou (Republic of Benin) in 2022

COVID-19 is a contagious viral infection, responsible for a pandemic that started in China in December 2019. Health Care Workers (HCWs) have been particularly exposed to this virus. The aim of this study was to estimate the seroprevalence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) antibodies and predictors among health care workers at the Departmental and Teaching Hospital of Borgou (DTH-B). This was a descriptive and analytical cross-sectional study conducted from June 27 to July 27, 2022. Participants were recruited using a simple random draw from the list of HCWs in each hospital department. All participants gave free and informed oral consent to participate in the survey. A pre-established questionnaire was used to collect epidemiological and clinical data. Each participant received a rapid screening test for SARS-CoV-2 antibodies (Immunoglobulin [Ig] G and M). STATA/MP 14.1 software was used for data analysis. A total of 139 HCWs participated in the survey. The sex ratio was 0.51 and the mean age was 40.48±9.12 years. The SARS-CoV-2 antibodies seroprevalence was 92.02%. Eighty-six participants (63.70%) had received a complete COVID-19 vaccination and 135 (97.12%) had received at least one dose of one of the available COVID-19 vaccines in Benin. A history of confirmed COVID-19 was recorded in 31 participants (22.30%). Hospital exposure of confirmed COVID-19 cases was noted in 104 (74.82%) participants. Family exposure was noted in 18 (12.95%) participants. Factors significantly associated with SARS-CoV-2 antibodies positivity in multivariate analysis were female gender (p = 0.001) and complete vaccination against COVID-19 (p = 0.002). The SARS-CoV-2 antibodies seroprevalence among HCWs was as high as the vaccination coverage in the departmental and teaching hospital at Borgou. It would reflect the joint effect of significant exposure to the virus and the effectiveness of the COVID-19 vaccines.