Seroepidemiology of bluetongue disease in small ruminants of northeast of Iran

Objective:To estimate the prevalence and distribution of bluetongue vims antibody in sheep and goats in 25 townships of Khorasan Razavi.Bluetongue is an infectious,non-contagious,arthropod born viral disease of ruminants and has been reported from most of the tropical and subtropical regions of the world.Methods:A total number of 1034 serum samples from sheep and goats were collected and transmitted to Serological Laboratory of Veterinary Council of Khorasan Razavi.Serums were screened for the presence of group-specific bluetongue virus antibody using competitive Enzyme Linked Immuno Sorbent Assay(c-ELISA).Kesults:The seropositivitv of sheep and goats for bluetongue was found to be 89.2%.The highest prevalence rate was seen in Taybad.Khalil-abad and Torbat-jam(100%)and the least prevalence rate was seen in Jovein(55%).Conclusions:The results showed that the majority of animals in the north-east of Iran are infected with bluetongue vims.High correlation between abortion history and seroposivity emphasize the economical importance of bluetongue virus in the sheep herds of the region.

Seroepidemiology of Helicobacter pylori infection among asymptomatic Chinese children

INTRODUCTIONIncreasing data has demonstrated that Helicobacterpylori(H.pylori),a spiral gram negativebacterium,colonized in human stomach,can causetype B gastritis,is strongly associated withgastric and duodenal ulceration,and has beenimplicated in the causation of gastric carcinomaand mucosa-associated lymphoid tissue(MALT)lymphomas.It has been reported that there

Seroepidemiology of echovirus 30 in Korean children

Background:Although aseptic meningitis associated with echovirus type 30 has emerged as a global public health concern,no data have been reported on children's immune status against echovirus type 30.The current study aimed to investigate the seropositivity among Korean children for antibodies against echovirus 30.Methods:Two hundred and fifty residual serum samples were collected at St.Paul's Hospital.Individuals were categorized by age into four groups:group 1 (3 months-2 years),group 2 (3-6 years),group 3 (7-10 years) and group 4 (11-15 years).Neutralizing antibodies against echovirus 30 were measured.Results:Seroprotective neutralizing antibodies against echovirus 30 were detected in 129 (49%) individuals.Seropositivity rates were 23%,48%,55% and 73% in groups 1-4,respectively.For antibody titers,1:256-1:512 was the highest neutralizing antibody titer range in group 2,while 1:1024-1:2048 in group 3 and 4.Among the seropositive individuals in group 3 and 4,6% and 12% had neutralizing antibody titers of 1:2048,respectively.Conclusions:The seropositivity rate increased significantly with age..The distribution of neutralizing antibody titers varied by age group,and higher ranges of neutralizing antibody titers were observed in higher age groups.These findings suggest high susceptibility to echovirus 30 infection in children younger than 2 years old.Echovirus 30 infection in childhood may have contributed to increased neutralizing antibody titers with age.

Seroepidemiological Study of Dengue Virus Infection Suspected Cases in Burkina Faso

Dengue fever is a mosquito-borne disease caused by four related but antigenically distinct dengue viruses. In the last half-century, the prevalence of dengue fever has increased dramatically (up to 30%) worldwide, especially in Sub-Saharan Africa. In Burkina Faso, the last dengue epidemic occurred in 2016, and the epidemiological situation is still poorly documented at the national level. Therefore, the present study aimed to conduct a sentinel seroepidemiology of suspected dengue virus infections from 2017 to 2020 at Charles de Gaulle University Pediatric Hospital Center of Ouagadougou. This investigation was designed to be a descriptive and analytical study. Patients with suspected cases of dengue fever were recruited from January 2017 to December 2020 during general medicine consultation and referred to Charles de Gaulle University Pediatric Hospital Center of Ouagadougou for the serological diagnosis of dengue. Venous blood was collected in dry or EDTA tubes and tested for DENV NS1 antigen, anti-dengue IgM, and anti-dengue IgG using SD Bioline Dengue Duo Rapid Detection Kit (Standard Diagnostic Inc., Korea). A total of 3400 blood samples from clinically suspected dengue cases were analyzed, of which 1784 (52.5%) were males, and 1616 (47.5%) were females. Among the 3400 patients included in the study, 661 (19.4%) were tested at least positive for NS1 antigen, anti-dengue IgM or anti-IgG. Among them, individuals positive for IgG suggesting past dengue virus infection were found in more than a third of 262 (7.7%) of the cases. Approximately, 80.0% (2705/3400) dengue suspected cases and 85.5% (341/399) early or primary dengue infections were recorded in the last four months of the study (September to December 2020), with a peak in mid-October and mid-November. There was no statistically significant difference in seroprevalence between males and females (p = 0.7), but an increasing seropositivity trend with age, from 11.6% for the patient under 5 years group to 39.7% for 30 years and over age group were noted. This study puts in evidence a considerable level of transmission of dengue viruses in Burkina Faso and provides baseline seroprevalence data. The recurrent outbreaks of dengue infection in multiple geographical areas need comprehensive surveillance and a diagnostic system to identify the actual burden and pinpoint the risk factors. A larger study is, therefore, needed to determine the actual prevalence of dengue in Burkina Faso and map the serotypes.

Hepatitis B virus coinfection in human immunodeficiency virus-infected patients: A review

Hepatitis B virus(HBV)infection is a leading cause of chronic hepatitis,liver cirrhosis,and hepatocellular carcinoma worldwide.Due to the shared modes of transmission,coinfection with HBV and human immunodeficiency virus(HIV)is not uncommon.It is estimatedthat 10%of HIV-infected patients worldwide are coinfected with HBV.In areas where an HBV vaccination program is implemented,the HBV seroprevalence has declined significantly.In HIV/HBV-coinfected patients,HBV coinfection accelerates immunologic and clinical progression of HIV infection and increases the risk of hepatotoxicity when combination antiretroviral therapy(cART)is initiated,while HIV infection increases the risk of hepatitis events,cirrhosis,and end-stage liver disease related to chronic HBV infection.With the advances in antiviral therapy,concurrent,successful longterm suppression of HIV and HBV replication can be achieved in the cART era.To reduce the disease burden of HBV infection among HIV-infected patients,adoption of safe sex practices,avoidance of sharing needles and diluent,HBV vaccination and use of cART containing tenofovir disoproxil fumarate plus emtricitabine or lamivudine are the most effective approaches.However,due to HIV-related immunosuppression,using increased doses of HBV vaccine and novel approaches to HBV vaccination are needed to improve the immunogenicity of HBV vaccine among HIV-infected patients.

Toxoplasma gondii and human immunodeficiency virus co-infection in western Iran: A cross sectional study

Objective: To determine Toxoplasma gondii(T. gondii) as a cause of morbidity and mortality in human immunodeficiency virus(HIV) infected patients by ELISA method and to investigate toxoplasmosis-associated risk factors. Methods: This cross sectional study was conducted with 385 patients with HIV/AIDS referred to the behavior disease consultation center in Kermanshah, Iran between May 2012 and June 2013. Anti-Toxoplasma IgG and IgM antibodies were measured by using the ELISA method. Also, the relationship between the infection and age, gender, education, occupation, antiretroviral status, CD4+ cell counts and some other factors of the patients were assessed. P<0.05 was considered statistically significant. Results:Among the HIV-positive patients, 40.8%(157/358) and 2.6%(10/358) patients were positive for anti-T. gondii IgG and IgM antibodies, respectively. The mean CD4+ count in the patients with HIV was 327 cells/μL. A significant correlation was observed between the toxoplasmosis infections with the age group(P<0.05). Nevertheless, no statistically significant difference was found between gender, living area, educational level, occupational, marital status, antiretroviral status, prophylaxis, CD4+ cell count and toxoplasmosis. Conclusions: This study revealed that the patients with HIV infection were at the high risk of developing toxoplasmosis disease especially those patients who do not receive antiretroviral therapy and prophylaxis. The development and use of the effectiveness-based guidelines for controlling and the prevention reactivation of the latent T. gondii infection is required.

Seroprevalence of human enterovirus A71 in Guangzhou,China,2019-2021

Enterovirus A71 (EV-A71) is a significant hand-foot-mouth disease (HFMD) etiology. The inactivated EV-A71 vaccines were approved in China in 2016. However, the seroprevalence of EV-A71 after the vaccine application and its potential association with the EV-A71 epidemic in the population are rarely studied. In this study, we analyzed the incidence of EV-A71 infection and seroepidemiology in Guangzhou City, China. From 2019 to 2021, 167,920 clinically confirmed HFMD cases were reported in Guangzhou. In 6,868 enterovirus-positive samples, Coxsackievirus A6 and Coxsackievirus A16 were dominant genotypes, and only 3 EV-A71-positive samples were detected, highlighting the deficient epidemic activity of EV-A71. Microneutralization assay was performed on 1,000 representative serum samples. Notably, the seroprevalence and geometric mean titer (GMT) decreased significantly in 2020, and that in the < 3-year age group were increased and even higher than that in 3–5-year age group in 2019 and 2021, which was contrary to our previous surveillance result and other studies in Guangzhou. Furthermore, a moderate decline of GMT level was observed following the vaccination, but the seropositive serums were still detected for 49 months after second immunization, suggesting the long-term persistence of the immunity. Our seroepidemiology study revealed relatively higher neutralizing antibody activity in the susceptible population after the EV-A71 vaccine was adopted in 2016 in Guangzhou. It may be one of the reasons for the lower epidemic activity of EV-A71 in Guangzhou from 2019 to 2021.

Seroepidemiologic study on convalescent sera from dengue fever patients in Jinghong,Yunnan

After dengue virus(DENV)infection,antibody-dependent enhancement(ADE)is easy to occur when the neutralizing antibody(NAb)gradually decreases to a sub-neutralizing concentration.In this cohort surveillance,we utilized sera samples collected from dengue fever patients at different convalescent phases in Jinghong City,to investigate the dynamic change rule of DENV-specific antibodies,and to analyze the risk of ADE caused by secondary infection with heterologous serotypes DENVs.For baseline serosurvey,191 four-year and 99 six-year sera samples during convalescence were collected in 2017 and 2019,respectively.The positive rate of DENVspecific immunoglobulin G was 98.4%in 2017,which significantly decreased to 82.8%in 2019.The geometric mean titer(GMT)of NAb decreased from 1:155.35 to 1:46.66.Among 290 overall samples,73 paired consecutive samples were used for follow-up serosurvey.In four-year sera,the GMTs of NAb against DENV-3 and cross-reactive antibodies against DENV-1,DENV-2 and DENV-4 were 1:167.70,1:13.80,1:18.54 and 1:45.26,respectively,which decreased to 1:53.18,1:10.30,1:14.60 and 1:8.17 in six-year sera.In age-stratified analysis,due to the increasing number of ADE positive samples from 2017 to 2019 in 31–40 and 51–60 years groups,the risk of ADE in DENV-4 infection was positively associated with the extension of convalescent phase,and the odd ratio was higher than other groups.With the recovery period lengthened,the risk of secondary infection with DENV-1 and DENV-2 was reduced.Our results offer essential experimental data for risk prediction of severe dengue in hyper-endemic dengue areas,and provide crucial scientific insight for the development of effective dengue vaccines.

Cross-sectional Seroprevalence and Genotype of Hepatitis E Virus in Humans and Swine in a High-density Pig-farming Area in Central China

Hepatitis E virus(HEV)infection is a common public health problem in developing countries.However,the current prevalence of HEV and the relationship of HEV genotype between swine and human within high-density pig-farming areas in central China are still inadequately understood.Here,cross-sectional serological and genotypic surveys of HEV among the 1232 general population,273 workers occupationally exposed to swine,and 276 pigs in a high-density pig-breeding area,were undertaken by ELISA and nested RT-PCR methods.Anti-HEV IgG was detected in 26.22%of general population and 48.35%of occupational workers.The prevalence of swine serum HEV-Ag was 6.52%.The prevalence of anti-HEV IgG was significantly higher among the workers occupationally exposed to swine than among the general population.An increased HEV seropositivity risk among the general population was associated with either being a peasant or male and was very strongly associated with the increase of age.Among the occupationally exposed group,the prevalence of anti-HEV IgG antibodies increased with age and working years.Among the 30 HEV-IgM-positive people,the infection rates of clerks in the public,peasants,pork retailers,and pig farmers were higher than those of others.A phylogenetic analysis revealed that all the isolates belonged to subgenotype 4d,and four people and four pigs shared 97.04%-100%sequence homology.This study revealed a high HEV seroprevalence among the general population and workers occupationally exposed to swine in the Anlu City,and supports the notion that swine are a source of human HEV infection.

Variation in SARS-CoV-2 seroprevalence in children in the region of Asturias,Northern Spain

Background Updated seroprevalence estimates are important to describe the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)landscape and to guide public health decisions.The aims are to describe longitudinal changes in seroprevalence in children in a region in Northern Spain and to analyze factors associated with SARS-CoV-2 seropositivity.Methods Prospective multicenter longitudinal study with subjects recruited from July to September 2020.Children(up to 14 years old)were included and followed up until September 2021.Venous blood samples were collected every six months during three testing rounds and were analyzed for SARS-CoV-2 antibodies.The data regarding epidemiological features,contact tracing,symptoms,and virological tests were collected.The evolution of SARS-CoV-2 seroprevalence during the study and the differences between children with positive and negative SARS-CoV-2 antibody tests were analyzed.Results Two hundred children were recruited(50.5%girls,median age 9.7 years).The overall seroprevalence increased from round 1[1.5%,95%confidence interval(CI)0.3%–4.3%]to round 2(9.1%,95%CI 4.6%–12.7%)and round 3(16.6%,95%CI 9.5%–19.6%)(P<0.001).Main changes occurred in children aged zero to four years(P=0.001)who lived in urban areas(P<0.001).None of the children who were previously positive became seronegative.Following multivariable analysis,three variables independently associated with SARS-CoV-2 seropositivity were identified:close contact with coronavirus disease 2019(COVID-19)confirmed or suspected cases[odds ratio(OR)=3.9,95%CI 1.2–12.5],previous positive virological test(OR=17.1,95%CI 3.7–78.3)and fatigue(OR=18.1,95%CI 1.7–193.4).Conclusions SARS-CoV-2 seroprevalence in children has remarkably increased during the time of our study.Fatigue was the only COVID-19-compatible symptom that was more frequent in seropositive than in seronegative children.

Low SARS-CoV-2 seroprevalence but high perception of risk among healthcare workers at children’s hospital before second pandemic wave in Germany

Background Healthcare workers are considered a particularly high-risk group during the coronavirus disease 2019(COVID-19)pandemic.Healthcare workers in paediatries are a unique subgroup:they come into frequent contact with children,who often experience few or no symptoms when infected with severe acute respiratory syndrome coronavirus 2(SARS CoV-2)and,therefore,may transmit the disease to unprotected staff.In Germany,no studies exist evaluating the risk of COVID-19 to healthcare workers in paediatric institutions.Methods We tested the staff at a large children's hospital in Germany for immunoglobulin(Ig)G antibodies against the nucle-ocapsid protein of SARS CoV-2 in a period between the first and second epidemic wave in Germany.We used a questionnaire to assess each individual's exposure risk and his/her own perception of having already been infected with SARS-CoV-2.Results We recruited 619 participants from all sectors,clinical and non-clinical,constituting 70%of the entire staff.The seroprevalence of SARS CoV-2 antibodies was 0.325%(95%confidence interval 0.039-I.168).Self-perceived risk of a previ-ous SARS-CoV-2 infection decreased with age(odds ratio,0.81;95%confidence interval,0.70-0.93).Having experienced symptoms more than doubled the odds of a high self-perceived risk(odds ratio,2.18;95%confidence interval,1.59--3.00).There was no significant difference in self perceived risk between men and women.Conclusions Seroprevalence was low among healtheare workers at a large children's hospital in Germany before the second epidemic wave,and it was far from a level that confers herd immunity.Self-perceived risk of infection is often overestimated.