A comparative study of antibody response, virus neutralization efficiency & metabolites in SARS-CoV-2-infected adults & children

Background & objectives: COVID-19 has been a global pandemic since early 2020. It has diverse clinical manifestations, but consistent immunological and metabolic correlates of disease severity and protection are not clear. This study was undertaken to compare seropositivity rate, antibody levels against nucleocapsid and spike proteins, virus neutralization and metabolites between adult and child COVID-19 patients. Methods: Plasma samples from naïve control (n=14) and reverse transcription (RT)-PCR positive COVID-19 participants (n=132) were tested for reactivity with nucleocapsid and spike proteins by ELISA, neutralization of SARS-CoV-2 infectivity in Vero cells and metabolites by 1H nuclear magnetic resonance (NMR) spectroscopy. Results: An ELISA platform was developed using nucleocapsid and spike proteins for COVID-19 serosurvey. The participants showed greater seropositivity for nucleocapsid (72%) than spike (55.3%), and males showed higher seropositivity than females for both the proteins. Antibody levels to both the proteins were higher in intensive care unit (ICU) than ward patients. Children showed lower seropositivity and antibody levels than adults. In contrast to ICU adults (81.3%), ICU children (33.3%) showed lower seropositivity for spike. Notably, the neutralization efficiency correlated with levels of anti-nucleocapsid antibodies. The levels of plasma metabolites were perturbed differentially in COVID-19 patients as compared with the naive controls. Interpretation & conclusions: Our results reflect the complexity of human immune response and metabolome to SARS-CoV-2 infection. While innate and cellular immune responses are likely to be a major determinant of disease severity and protection, antibodies to multiple viral proteins likely affect COVID-19 pathogenesis. In children, not adults, lower seropositivity rate for spike was associated with disease severity

Serological survey for SARS-CoV-2 antibodies among tribal communities of Odisha post-second wave

Background & objectives: Serial national level serosurveys in India have provided valuable information regarding the spread of COVID-19 pandemic in the general population, but the impact of the ongoing pandemic on the tribal population in India is not well understood. In this study, we evaluated the seroprevalence of COVID-19 antibodies in the tribal population of Odisha post-second wave (September 2021). Methods: A population-based, age-stratified, cross-sectional study design was adopted for the survey, carried out in seven tribal districts of Odisha from 30th August to 16th September 2021. A multistage random sampling method was used where serum samples were tested for antibodies against the SARS-CoV-2 nucleocapsid (N) protein in each district, and a weighted seroprevalence with 95 per cent confidence interval (CI) was estimated for each district. Results: A total of 2855 study participants were included from the seven tribal districts of Odisha in the final analysis. The overall weighted seroprevalence was 72.8 per cent (95% CI: 70.1-75.3). Serological prevalence was the highest among 18-44 yr (74.4%, 95% CI: 71.3-77.3) and from Sambalpur district [75.90% (66.90-83.10)]. Among participants, 41.93 per cent had received at least one dose of any COVID-19 vaccine. Kandhamal district had the highest number of fully immunized participants (24.78%), and in Sundergarh district, most of the study participants (58.1%) were unimmunized.Interpretation & conclusions: This study found high seroprevalence against SARS-CoV-2 in the tribal population of Odisha. The vaccination coverage is at par with the general population, and efforts to address some knowledge gaps may be needed to improve the coverage in the future

Time-dependent decay of detectable antibodies against SARS-CoV-2: A comparison of ELISA with two batches of a lateral-flow test

ABSTRACT Background: Large-scale epidemiological studies of seroprevalence of antibodies against SARS-CoV-2 often rely on point-of-care tests that provide immediate results to participants. Yet, little is known on how long rapid tests remain positive after the COVID-19 episode, or how much variability exists across different brands and even among batches of the same test. Methods: In November 2020, we assessed the sensitivity of three tests applied to 133 individuals with a previous positive PCR result between April and October. All subjects provided finger prick blood samples for two batches (A and B) of the Wondfo lateral-flow IgG/IgM test, and dried blood spot samples for the S-UFRJ ELISA test. Results: Overall sensitivity levels were 92.5% (95% CI 86.6-96.3), 63.2% (95% CI 54.4-71.4) and 33.8% (95% CI 25.9-42.5) for the S-UFRJ test, Wondfo A and Wondfo B tests, respectively. There was no evidence of a decline in the positivity of S-UFRJ with time since the diagnosis, but the two Wondfo batches showed sharp reductions to as low as 41.9% and 19.4%, respectively, for subjects with a positive PCR in June or earlier. Positive results for batch B of the rapid test were 35% to 54% lower than for batch A at any given month of diagnosis. Interpretation: Whereas the ELISA test showed high sensitivity and stability of results over the five months of the study, both batches of the rapid test showed substantial declines, with one of the batches consistently showing lower sensitivity levels than the other. ELISA tests based on dried-blood spots are an inexpensive alternative to rapid lateral-flow tests in large-scale epidemiological studies.

Assessment on the Effects of Hepatitis B Prevention and Control Measures in Western China: A Comparison of Three Population-based Serosurveys / 生物医学与环境科学（英文）

Objective@#Despite the remarkable progress in efforts to control disease spread, the nationwide elimination of hepatitis B in China is still hindered by the persistently high rate of hepatitis B virus (HBV) infection in Western China. This study aimed to evaluate the strategy of hepatitis B prevention and control in Western China and identify potential areas and strategies for improvement.@*Methods@#Susceptible population vaccination, health education, professional training of doctors, and other prevention and control measures have been implemented in Wuwei city since 2010. Data were obtained from three representative cross-sectional serosurveys conducted in 2010, 2013, and 2015. The serum samples were subjected to enzyme-linked immunosorbent assays to detect the following seromarkers: HBV surface antigen (HBsAg), antibody against hepatitis B surface antigen (anti-HBs), and antibody against hepatitis B core antigen (anti-HBc). Estimates of variance were determined using Taylor series linearization methods.@*Results@#The three serosurveys revealed decreases in the prevalence of HBsAg (7.19% in 2010 @*Conclusion@#Although vaccine-based prevention and control measures reduced the rate of HBV infection in Wuwei City over time, the hepatitis B infection rate in children younger than 10 years was still higher than the national average level. Therefore, the prevention and control of mother-to-child transmission and the management of the infected should be the focus of future prevention and control work.

Serological survey on hepatitis E virus infection of public health practitioners in Xinjiang region / 吉林大学学报(医学版)

Objective:To investigate the infection status and influencing factors of hepatitis E virus infection among different occupational populations in Xinjiang region,and to provide a available evidence for control of hepatitis E.Methods:A randomly sampling survey was carried out in the population of public health practitioners, the serum IgG antibodies against hepatitis E virus in 1 720 samples were tested by indirect enzyme-linked immunosorbent assay,and the experimental data was analyzed with SPSS 19.0 software;the differences of infection rates between genders,ages and occupations were analyzed.Results:Among 1 720 subjects,440 persons were anti-HEV IgG positive,and the total positive rate was 25.58%;the positive rate of males (27.99%)was higher than that of females (23.35%),and the IgG positive rate was increased along with the age;there were significant differences of the anti-HEV-IgG antibody positive rates between the populations with different ages (χ2 =118.262, P = 0.000 ). There was a statistically significant difference of infection rate of hepatitis E between different occupational populations (χ2 = 98.262,P = 0.000),the slaughterman had the highest positive rate (81.53%), followed by the livestock and meat salesperson (79.37%),food service population (30%),supermarket population (11.21%)and others (9.03%).Conclusion:The hepatitis E infection rate is high among the public health practitioners in Xinjiang region,and occupation,age and gender are the major influencing factors of hepatitis E infection rate.

Immunological evidence of Zika virus transmission in Thailand

OBJECTIVE@#To identify immunological evidence of Zika virus transmission in Thailand.@*METHODS@#To undertake a preliminary serosurvey of possible exposure to Zika virus, 21 serum samples from cohort of acute undifferentiated fever patients were examined for immunoreactivity to Zika, Dengue, Japanese encephalitis and Chikungunya envelope antigens by Western blot analysis.@*RESULTS@#Twenty of the 21 serum samples showed immunoreactivity to at least one of the antigens, with seven samples showing immunoreactivity to all antigens. Of particular note, two serum samples showed immunoreactivity only to Zika envelope antigen, with no immunoreactivity to other envelope antigens.@*CONCLUSIONS@#This study presents the first evidence of Zika virus transmission in Thailand, although as yet the relationship between transmission and possible cases of Zika fever in Thailand requires further investigation.

Immunological evidence of Zika virus transmission in Thailand

Objective: To identify immunological evidence of Zika virus transmission in Thailand. Methods: To undertake a preliminary serosurvey of possible exposure to Zika virus, 21 serum samples from cohort of acute undifferentiated fever patients were examined for immunoreactivity to Zika, Dengue, Japanese encephalitis and Chikungunya envelope antigens by Western blot analysis. Results: Twenty of the 21 serum samples showed immunoreactivity to at least one of the antigens, with seven samples showing immunoreactivity to all antigens. Of particular note, two serum samples showed immunoreactivity only to Zika envelope antigen, with no immunoreactivity to other envelope antigens. Conclusions: This study presents the first evidence of Zika virus transmission in Thailand, although as yet the relationship between transmission and possible cases of Zika fever in Thailand requires further investigation.

Occurrence of antibodies anti -Toxoplasma gondii, Neospora caninum and Leptospira interrogans in a captive deer herd in Southern Brazil / Ocorrência de anticorpos anti -Toxoplasma gondii, Neospora caninum e Leptospira interrogans em um rebanho de cervídeos de cativeiro do sul do Brasil

Abstract A large number of Brazilian zoos keep many endangered species of deer, however, very few disease surveillance studies have been conducted among captive cervids. Blood samples from 32 Brazilian deer (Blastocerus dichotomus, Mazama nana and Mazama americana) kept in captivity at Bela Vista Biological Sanctuary (Foz do Iguaçu, Brazil) were investigated for 10 ruminant pathogens, with the aims of monitoring deer health status and evaluating any potential zoonotic risk. Deer serum samples were tested for Brucella abortus, Leptospira (23 serovars), Toxoplasma gondii, Neospora caninum, bovine viral diarrhea virus, infectious bovine rhinotracheitis virus, foot-and-mouth disease virus, western equine encephalitis virus, eastern equine encephalitis virus and Venezuelan equine encephalitis virus. Antibodies against T. gondii (15.6%), N. caninum (6.2%) and L. interrogans serogroup Serjoe (3.1%) were detected. The serological results for all other infectious agents were negative. The deer were considered to be clinically healthy and asymptomatic regarding any disease. Compared with studies on free-ranging deer, the prevalences of the same agents tested among the captive deer kept at the Sanctuary were lower, thus indicating good sanitary conditions and high-quality management practices at the zoo.

Resumo Um grande número de zoológicos brasileiros abriga espécies de cervídeos ameaçados de extinção, entretanto, estudos de vigilância de doenças em cervídeos de cativeiro são escassos. Amostras de sangue de 32 cervídeos brasileiros (Blastocerus dichotomus, Mazama nana e Mazama americana), mantidos em cativeiro no Refúgio Biológico Bela Vista (Foz do Iguaçu, Brasil), foram investigados para 10 patógenos de ruminantes, visando monitorar o estado de saúde dos cervídeos e avaliar a presença de agentes zoonóticos. As amostras de soro foram testadas para Brucella abortus, Leptospira (23 sorovares), Toxoplasma gondii, Neospora caninum, diarreia viral bovina, rinotraqueíte infecciosa bovina, febre aftosa, encefalomielite equina do oeste, encefalomielite equina do leste e encefalomielite equina venezuelana. Foram detectados anticorpos para T. gondii (15,6%), N. caninum (6,2%) e para L. interrogans sorogrupo Serjoe (3,1%). As sorologias apresentaram resultado negativo para as demais doenças. Os cervídeos foram considerados clinicamente sadios e assintomáticos para doenças. Comparados aos estudos de populações de vida livre, as soroprevalências para os mesmos agentes testados foram menores para os cervídeos mantidos no Refúgio, indicando as boas condições sanitárias e a qualidade das práticas de manejo no zoológico.

A Saint Louis encephalitis and Rocio virus serosurvey in Brazilian horses

Introduction Arboviruses are an important public health problem in Brazil, in especially flaviviruses, including the Saint Louis encephalitis virus (SLEV) and the Rocio virus (ROCV), are especially problematic. These viruses are transmitted to humans or other vertebrates through arthropod bites and may cause diseases with clinical manifestations that range from asymptomatic infection, viral hemorrhagic fever to encephalitis. Methods A serological survey of horses from various regions of Brazil using an enzyme-linked immunosorbent assay (ELISA) with recombinant SLEV domain III peptides and ROCV E protein as antigens. Results Overall, 415 (55.1%) of the 753 horses that were screened were seropositive for flavivirus and, among them, monotypic reactions were observed to SLEV in 93 (12.3%) and to ROCV in 46 (6.1%). These results suggested that these viruses, or other closely related viruses, are infecting horses in Brazil. However, none of the studied horses presented central nervous system infection symptoms. Conclusions Our results suggest that SLEV and ROCV previously circulated among horses in northeast, west-central and southeast Brazil. .

Age Related Serosurvey of Immunity to Tetanus in Korean Populations / 감염

BACKGROUND: The incidence of tetanus in adults and neonatal tetanus have been markedly reduced by world-wide use of DTP vaccines. But, tetanus is still one kind of major health problems in many developing countries, and several serosurvey stduies in developed countries revealed that substantial proportions of adult population may lack immunity against tetanus and immunity level against tetanus is continuously decreasing by age. In Korea, tetanus outbreaks have been disappeared since the 1980s by high acceptant DTaP vaccination rates. Annually, few tetanus patient has been reported since 1990s. But, there have been no seroepidemiological studies to tetanus, no trials to assess tetanus immunizations. And we do not use Td vaccine in adults for maintaning tetanus immunity. In this aspect, we conducted age related survey of immunity to tetanus and indirectly assessed the immunogenecity of tetanus vaccines, used in Korea. METHODS: For the evaluation of age related serosurvey of tetanus immunity in Korean population, study subjects were classified into 16 groups (A~J group; below 10 years with one year interval, K~O group; 11~60 yrs with 10 years interval, P group; over 60 yrs). The numbers of each group were 100, and sex distributions of each group were almostly equal. And for the indirect assessment of tetanus immunization in Korean children, children under 15 years old age were classified into 6 groups (I~VI) according to the status of DTaP vaccination. The numbers of this each group were 50, and sex ratio was almostly equal. Specific IgG antibody to tetanus toxin were detected by ELISA. And the ANOVA repeated t-test was used to compare antibody levels in study groups. RESULTS: In age related groups, the antibody levels to tetanus toxin were well maintained until 20 years old age group (L group), but thereafter the titers abruptly decreased below 0.1 IU/mL and over 75% populations among the groups over 30 years old age needed maintenance of protective immunity to tetanus. The antibody level of male was statistically higher than that of female in P group. In the groups related DTaP vaccination status, the antibody titer was very low in prevaccination group (I), but the titers after primary vaccinations were sharply increased and highly maintained until 15 years. CONCLUSOIN: The results of our study revealed that the immunity to tetanus was dramatically decreased in age groups over 30 years old. This result indicates that Td vaccination program in adults should be considered for maintenance of immunity to tetanus. And our study indicate that DTaP vaccination programs and vaccines, used in Korea, are effective for acquisition and maintenance of tetanus immunity in Korean children.