scholarly journals Validation of a SARS-CoV-2 spike protein ELISA for use in contact investigations and sero-surveillance

2020 ◽  
Author(s):  
Brandi Freeman ◽  
Sandra Lester ◽  
Lisa Mills ◽  
Mohammad Ata Ur Rasheed ◽  
Stefany Moye ◽  
...  
Keyword(s):  
Disease Burden ◽  
Large Scale ◽  
Case Fatality ◽  
Asymptomatic Infection ◽  
Cross Reactivity ◽  
Spike Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Specific Enzyme ◽  
Cross Sectional ◽  
Contact Investigations

AbstractSince emergence of SARS-CoV-2 in late 2019, there has been a critical need to understand prevalence, transmission patterns, to calculate the burden of disease and case fatality rates. Molecular diagnostics, the gold standard for identifying viremic cases, are not ideal for determining true case counts and rates of asymptomatic infection. Serological detection of SARS-CoV-2 specific antibodies can contribute to filling these knowledge gaps. In this study, we describe optimization and validation of a SARS-CoV-2-specific-enzyme linked immunosorbent assay (ELISA) using the prefusion-stabilized form of the spike protein [1]. We performed receiver operator characteristic (ROC) analyses to define the specificities and sensitivities of the optimized assay and examined cross reactivity with immune sera from persons confirmed to have had infections with other coronaviruses. These assays will be used to perform contact investigations and to conduct large-scale, cross sectional surveillance to define disease burden in the population.

scholarly journals Dogs as Sentinels for Flavivirus Exposure in Urban, Peri-Urban and Rural Hanoi, Vietnam

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 507
Author(s):  
Long Pham-Thanh ◽  
Thang Nguyen-Tien ◽  
Ulf Magnusson ◽  
Vuong Bui-Nghia ◽  
Anh Bui-Ngoc ◽  
...  
Keyword(s):  
Mosquito Control ◽  
Risk Mitigation ◽  
Significant Risk ◽  
Cross Sectional Study ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Cross Sectional ◽  
Major Health ◽  
Household Level

Diseases caused by flaviviruses, including dengue fever and Japanese encephalitis, are major health problems in Vietnam. This cross-sectional study explored the feasibility of domestic dogs as sentinels to better understand risks of mosquito-borne diseases in Hanoi city. A total of 475 dogs serum samples from 221 households in six districts of Hanoi were analyzed by a competitive enzyme-linked immunosorbent assay (cELISA) for antibodies to the pr-E protein of West Nile virus and other flaviviruses due to cross-reactivity. The overall flavivirus seroprevalence in the dog population was 70.7% (95% CI = 66.4–74.8%). At the animal level, significant associations between seropositive dogs and district location, age, breed and keeping practice were determined. At the household level, the major risk factors were rural and peri-urban locations, presence of pigs, coil burning and households without mosquito-borne disease experience (p < 0.05). Mosquito control by using larvicides or electric traps could lower seropositivity, but other measures did not contribute to significant risk mitigation of flavivirus exposure in dogs. These results will support better control of mosquito-borne diseases in Hanoi, and they indicate that dogs can be used as sentinels for flavivirus exposure.

SARS-CoV-2 Herd Immunity of the Kyrgyz Population in 2021

2021 ◽  
Author(s):  
Anna Y. Popova ◽  
Omor T. Kasymov ◽  
Vyacheslav Y. Smolenski ◽  
Вячеслав Смирнов ◽  
Svetlana A. Egorova ◽  
...  
Keyword(s):  
Randomized Study ◽  
Herd Immunity ◽  
Statistical Processing ◽  
Cloud Service ◽  
Asymptomatic Infection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Pasteur Institute ◽  
Cross Sectional ◽  
Saint Petersburg ◽  
Kyrgyz Population

Abstract Background. In the fight against coronavirus infection, an important direction is control of herd immunity to the pathogen. SARS-CoV-2 herd immunity is formed naturally as a result of manifest or asymptomatic infection, or artificially as a result of vaccination Aim: To assess the SARS-CoV-2 herd immunity status of the Kyrgyz population. Materials and methods. A cross-sectional, randomized study of SARS-CoV-2 herd immunity was carried out according to a program developed by Rospotrebnadzor, with the participation of the Saint Petersburg Pasteur Institute, taking into account WHO recommendations. In all study stages cloud service (internet) technologies were used. The ethics committees of the Preventive Medicine Association (Kyrgyzstan) and the Saint Petersburg Pasteur Institute (Russia) approved the study. A total of 9,471 volunteers were selected, representing 0.15% (95% CI 0.14-0.15) of the total population. They were randomized according to age and region. Antibodies (Abs) to the nucleocapsid antigen (Nag) were determined by enzyme-linked immunosorbent assay (ELISA) of volunteer blood plasma. For vaccinated individuals, Abs to the SARS-CoV-2 receptor-binding domain antigen (RBDag) were determined. Statistical processing of the results was carried out using Excel 2010 and other programs. Differences were designated as statistically significant at p<0.05. Results. The seroprevalence of the general population was 48.7% (95% CI 47.7-49.7), with a maximum in the group of '60-69 year old' (59.2% (56.6-61.7)) and a minimum in the group '1-17 y.o.' (32.7% (95 CI 29.4-36.1)). The largest proportion seropositive was found in the Chui region (51.3% (95% CI 47.9-54.8)). The lowest was in Osh city (38.1% (95 CI 32.6-43.9)). The maximum seropositivity was detected among healthcare workers (57.1% (95% CI 55.4-58.8); the minimum was noted among artists (38.6% (95% CI 26.0-52.4)). Asymptomatic SARS-CoV-2 positivity was 79.1% (96% CI 77.9-80.3). Vaccination with Sputnik V, EpiVacCorona, or Sinopharm formed comparable levels of immunity. Conclusions. The herd immunity to SARS-CoV-2 Nag is 48.75% (95% CI 47.7-49.7), and the overall immunity (Nag + RBDag) is 57%.

scholarly journals SARS-CoV-2 S1 and N-based serological assays reveal rapid seroconversion and induction of specific antibody response in COVID-19 patients

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Abdullah Algaissi ◽  
Mohamed A. Alfaleh ◽  
Sharif Hala ◽  
Turki S. Abujamel ◽  
Sawsan S. Alamri ◽  
...  
Keyword(s):  
Antibody Response ◽  
Specific Antibody ◽  
Large Scale ◽  
Disease Onset ◽  
High Specificity ◽  
Epidemiological Studies ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Specificity And Sensitivity ◽  
Human Coronaviruses

Abstract As the Coronavirus Disease 2019 (COVID-19), which is caused by the novel SARS-CoV-2, continues to spread rapidly around the world, there is a need for well validated serological assays that allow the detection of viral specific antibody responses in COVID-19 patients or recovered individuals. In this study, we established and used multiple indirect Enzyme Linked Immunosorbent Assay (ELISA)-based serological assays to study the antibody response in COVID-19 patients. In order to validate the assays we determined the cut off values, sensitivity and specificity of the assays using sera collected from pre-pandemic healthy controls, COVID-19 patients at different time points after disease-onset, and seropositive sera to other human coronaviruses (CoVs). The developed SARS-CoV-2 S1 subunit of the spike glycoprotein and nucleocapsid (N)-based ELISAs not only showed high specificity and sensitivity but also did not show any cross-reactivity with other CoVs. We also show that all RT-PCR confirmed COVID-19 patients tested in our study developed both virus specific IgM and IgG antibodies as early as week one after disease onset. Our data also suggest that the inclusion of both S1 and N in serological testing would capture as many potential SARS-CoV-2 positive cases as possible than using any of them alone. This is specifically important for tracing contacts and cases and conducting large-scale epidemiological studies to understand the true extent of virus spread in populations.

scholarly journals SARS-CoV-2 S1 and N-Based Serological Assays Reveal Rapid Seroconversion and Induction of Specific Antibody Response in COVID-19 Patients

2020 ◽  
Author(s):  
Abdullah Algaissi ◽  
Mohamed A. Alfaleh ◽  
Sherif Hala ◽  
Turki S. Abujamel ◽  
Sawsan S. Alamri ◽  
...  
Keyword(s):  
Antibody Response ◽  
Specific Antibody ◽  
Large Scale ◽  
Disease Onset ◽  
High Specificity ◽  
Epidemiological Studies ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Specificity And Sensitivity ◽  
Human Coronaviruses

As the coronavirus disease 2019 (COVID-19), which is caused by the novel SARS-CoV-2, continues to spread rapidly around the world, there is a need for well validated serological assays that allow the detection of viral specific antibody responses in COVID-19 patients or recovered individuals. In this study, we established and used multiple indirect Enzyme Linked Immunosorbent Assay (ELISA)-based serological assays to study the antibody response in COVID-19 patients. In order to validate the assays we determined the cut off values, sensitivity and specificity of the assays using sera collected from pre-pandemic healthy controls, COVID-19 patients at different time points after disease-onset, and seropositive sera to other human coronaviruses. The developed SARS-CoV-2 S1 subunit of the spike glycoprotein and nucleocapsid (N)-based ELISAs not only showed high specificity and sensitivity but also did not show any cross-reactivity with other CoVs. We also show that all RT-PCR confirmed COVID-19 patients tested in our study developed both virus specific IgM and IgG antibodies as early as week one after disease onset. Our data also suggest that the inclusion of both S1 and N in serological testing would capture as many potential SARS-CoV-2 positive cases as possible than using any of them alone. This is specifically important for tracing contacts and cases and conducting large-scale epidemiological studies to understand the true extent of virus spread in populations.

scholarly journals Epidemiological Characteristic of Malaria Coinfected with Dengue Fever in Hodeidah, Yemen

2020 ◽  
pp. 1-10
Author(s):  
Asma’a Al-Areeqi ◽  
Saeed Alghalibi ◽  
Qais Yusuf ◽  
Isra'a Al-Masrafi ◽  
Mohammed Amood Al-Kamarany
Keyword(s):  
Dengue Fever ◽  
Clinical Symptoms ◽  
Case Fatality ◽  
Cross Sectional Study ◽  
High Density ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cross Sectional ◽  
Vector Borne Diseases ◽  
Potential Risk Factors ◽  
Group B

Introduction: Malaria and dengue fever are the most prevalent vector-borne diseases in tropical areas and represent major public health problems. They are transmitted by mosquito namely Anopheles and Aedes aegypti, respectively. Hodeidah is a high density with these vectors. Also, co-infection of these diseases has (malaria and dengue) become undetected due to lack of suspicious clinical suspicion and overlapping symptoms. Aim of the Study: The study aimed to detect the prevalence of co-infection with malaria and dengue fever, determine the clinical presentation within febrile patients in Hodeidah city and determine some potential risk factors associated with co-infection. Methods: A cross-sectional study was conducted (from January to December 2017) in febrile patients. All patients were designed into three groups: Group A (co-infected with malaria and dengue); Group B (malaria as mono-infection) and Group C (dengue as mono-infection). The diagnosis of malaria was by microscopic and rapid diagnostic test (RDT) and the dengue virus was detected using enzyme-linked immunosorbent assay (ELISA). The diagnosis was performed in Center of Tropical Medicine and Infectious Diseases (CTMID), Authority of AL-Thawra Public Hospital-Hodeidah, in collaboration with the Tihama Foundation for Medical-Pharmaceutical Studies and Research (TFMPSR), Hodeidah, Yemen. Results: Out of 270 febrile patients, 82 cases (30.4%) patients were malaria – dengue coinfection, 100 cases (37.0%) of malaria, 21 cases (7.7%) of dengue and 67 cases (24.8%) were non-malaria and non-dengue. The most common symptoms were fever, headache, arthralgia, myalgia and retro-orbital pain, where the clinical symptoms of co-infected patients were more like dengue than malaria. One death was reported in malaria – dengue coinfection, with a case fatality rate (CFR%)  of 1.2% (1/82). Conclusion: Our results show a high prevalence of malaria – dengue coinfecion in Hodeidah, Yemen as the first time. These due to a high density of vectors in this region and endemic areas for malaria and dengue. Furthermore, surveillance strategies, preventive measures and healthcare worker's education are critical for curtailing this problem and lifesaving.

scholarly journals Serological assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), March 2020

2020 ◽  
Vol 25 (16) ◽  
Author(s):  
Ranawaka APM Perera ◽  
Chris KP Mok ◽  
Owen TY Tsang ◽  
Huibin Lv ◽  
Ronald LW Ko ◽  
...  
Keyword(s):  
Public Health ◽  
Severe Acute Respiratory Syndrome ◽  
Large Scale ◽  
Herd Immunity ◽  
Cross Reactivity ◽  
Spike Protein ◽  
Infectious Dose ◽  
Virus Challenge ◽  
Illness Onset ◽  
Public Health Decision

Background The ongoing coronavirus disease (COVID-19) pandemic has major impacts on health systems, the economy and society. Assessing infection attack rates in the population is critical for estimating disease severity and herd immunity which is needed to calibrate public health interventions. We have previously shown that it is possible to achieve this in real time to impact public health decision making. Aim Our objective was to develop and evaluate serological assays applicable in large-scale sero-epidemiological studies. Methods We developed an ELISA to detect IgG and IgM antibodies to the receptor-binding domain (RBD) of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We evaluated its sensitivity and specificity in combination with confirmatory microneutralisation (MN) and 90% plaque reduction neutralisation tests (PRNT90) in 51 sera from 24 patients with virologically confirmed COVID-19 and in age-stratified sera from 200 healthy controls. Results IgG and IgM RBD ELISA, MN and PRNT90 were reliably positive after 29 days from illness onset with no detectable cross-reactivity in age-stratified controls. We found that PRNT90 tests were more sensitive in detecting antibody than MN tests carried out with the conventional 100 tissue culture infectious dose challenge. Heparinised plasma appeared to reduce the infectivity of the virus challenge dose and may confound interpretation of neutralisation test. Conclusion Using IgG ELISA based on the RBD of the spike protein to screen sera for SARS-CoV-2 antibody, followed by confirmation using PRNT90, is a valid approach for large-scale sero-epidemiology studies.

scholarly journals Evolution of the COVID-19 pandemic over six weeks in four French-speaking countries in West Africa

2020 ◽  
Author(s):  
Tamba Mina Millimouno ◽  
Mohamed Ali Ag Ahmed ◽  
Birama Apho Ly ◽  
Sana Boukary ◽  
Christophe Laba Faye ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Large Scale ◽  
International Health ◽  
Case Fatality ◽  
Cross Sectional Study ◽  
Disease Spread ◽  
Epidemiological Surveillance ◽  
Cross Sectional ◽  
Health Crisis ◽  
Project Data

Abstract Background The COVID-19 pandemic is an unprecedented international health crisis with different approaches to the response at country levels. The objective of this study was to analyze the evolution of this pandemic in Guinea, Mali, Senegal, and Burkina Faso over the first six weeks. We hypothesize that there exist significant differences in the incidence of COVID-19 between countries. Methods A cross-sectional study was conducted as part of a collaborative project. Data collection focused on the epidemiological surveillance indicators available in the countries’ COVID-19 daily situation reports. Data were entered into a standardized Microsoft Excel spreadsheet which was exported to the STATA 15 software for analysis. Results COVID-19 had a different dynamic in the four countries over the first six weeks. Its incidence in Burkina Faso and Senegal was dropping, while it was increasing slowly in Mali; only in Guinea, it increased rapidly. The analysis of variance revealed that the differences observed in the weekly COVID-19 incidence in the four countries were statistically significant (p ˂ 0.01). Different screening approaches have been used by the four countries. Guinea (n = 4,539) performed more tests compared to Senegal (n = 2,961), Burkina Faso (n = 2,455) and Mali (n = 2,397). The positivity rates were significantly higher in Mali (25.5%) and Burkina Faso (23.7%) than in Guinea (19.0%) and Senegal (9.5%) (p ˂ 0.0001). Hospitalization rates by country ranged from 32.0–79.6%, with Guinea’s hospitalization rate (79.6%) being significantly higher as compared to that of the three other countries (p ˂ 0.0001). The cure rates were significantly higher in Burkina Faso (61.4%) and Senegal (61.1%) than in Mali (37.3%) and Guinea (19.7%) (p ˂ 0.0001). The case fatality rate was significantly higher in Burkina Faso (6.5%) than in Mali (5.2%) (p ˂ 0.001), Guinea (0.7%), and Senegal (0.7%) (p ˂ 0.0001). Conclusion This study highlighted insights from COVID-19 surveillance data, as a basis for improving response strategies in the four countries. Large-scale screening seems relevant to not only facilitate controlling the disease spread but also reducing case fatality rates by early case detection, prior to the occurrence of complications.

scholarly journals Multiple Indirect ELISAs for Serological Detection of SARS-CoV-2 Antibodies

2020 ◽  
Author(s):  
Abdullah Algaissi ◽  
Mohamed A. Alfaleh ◽  
Sherif Hala ◽  
Turki S. Abujamel ◽  
Sawsan S. Alamari ◽  
...  
Keyword(s):  
Antibody Response ◽  
Large Scale ◽  
Disease Onset ◽  
High Specificity ◽  
Epidemiological Studies ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serological Tests ◽  
Specificity And Sensitivity ◽  
Novel Coronavirus

As the coronavirus disease 2019 (COVID-19), which is caused by the novel coronavirus SARS-CoV-2, continues to spread rapidly around the world, there is an urgent need for validated serological assays to evaluate viral specific antibody responses in COVID-19 patients or recovered individuals. In this study, we established and used indirect Enzyme Linked Immunosorbent Assay (ELISA)-based serological tests to study the antibody response in COVID-19 patients. In order to validate the assays, we determined the cut-off values, sensitivity and specificity of the developed assays using sera collected from COVID-19 patients in Saudi Arabia at different time points after disease onset, as well as sera that are seropositive to other human CoVs; namely MERS-CoV, hCoV-OC43, hCoV-NL63, hCoV-229E, and hCoV-HKU1. The SARS-CoV-2 S1 subunit of the spike glycoprotein and nucleocapsid (N) ELISAs that we developed here not only showed high specificity and sensitivity, but also did not show any cross-reactivity with other CoVs. We also showed that all RT-PCR confirmed COVID-19 patients included in our study developed both virus specific IgM and IgG as early as one week after the onset of disease. The availability of these validated assays will enable us to determine the nature and duration of the antibody response mounted in response to SARS-CoV-2 infection. It will also allow conducting large-scale epidemiological studies to determine evidence of previous exposure to the virus and assess the true extent of virus spread within communities.

Epidemiology of Q – Fever in Flocks of Sheep in Yobe State, Nigeria

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
S. G. Adamu
Keyword(s):  
Large Scale ◽  
Q Fever ◽  
Sampling Technique ◽  
Simple Random Sampling ◽  
Enzyme Linked Immunosorbent Assay ◽  
Epidemiological Investigation ◽  
Negative Bacterium ◽  
Cross Sectional ◽  
Livestock Farmers ◽  
Male Sheep

Q-fever is a zoonotic disease caused by Coxiella burnetii, an intracellular Gram-negative bacterium. A cross sectional epidemiological study was conducted to determine the seroprevalence of Q-fever in flocks of sheep in Yobe State, Nigeria. Simple random sampling technique was used in selecting the animals. A total of 420 blood samples from sheep of various ages were tested from April, 2018 to July, 2018 for Q-fever using indirect enzyme linked immunosorbent assay (ELISA). Out of the 420 sera tested 49 (11.7%) were seeropositive for Q fever. Of the 315 females sheep tested, 39 (12.4%) were seropositive and out of 105 male sheep tested, 10 (9.5%) were seropositive. There was no significant association (p>0.05) between the sex of sheep tested for Q fever. The seroprevalence was higher in animals greater than 2 years 41 (12.1%) than in animals less than 2 years 8 (9.8%). There were no significant associations between age and infection with Q-fever even though that animal greater than 2 years showed higher prevalence than those less than 2 years. The highest seroprevalence 22 (12.3%) was recorded in Yankasa sheep, and the least seroprevalence 8(9.9%) was recorded in Uda. The seroprevalence of 19 (13.6%), 16 (11.4%) and 14 (10.0%) were recorded in Damaturu, Potiskum and Gashua zones respectively. There was no significant association (p>0.05) between the breed and location of the animals tested for Q fever infection. This study concludes that Q-fever is endemic in sheep in Yobe State. Enlightenment campaign is recommended to educate the livestock farmers, herders and the general public on the dangers of Q-fever infection. There is need for large scale epidemiological investigation of the disease in other livestock farms in the state.

Sensitive Measurement of Thrombopoietin by a Monoclonal Antibody Based Sandwich Enzyme-linked Immunosorbent Assay

1997 ◽  
Vol 78 (04) ◽  
pp. 1262-1267 ◽  
Author(s):  
Claudia C Folman ◽  
Albert E G K von dem Borne ◽  
Irma H J A M Rensink ◽  
Winald Gerritsen ◽  
C Ellen van der Schoot ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Immunosorbent Assay ◽  
Platelet Transfusion ◽  
Large Scale ◽  
Limit Of Detection ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Reliable Tool

SummaryIn this report a sensitive enzyme-linked immunosorbent assay (ELISA) for the measurement of plasma thrombopoietin (Tpo) is described that is solely based on monoclonal antibodies (MoAbs).The assay has an intra and inter-assay variance of 5-7% and 7-13%, respectively. Native and recombinant human Tpo (rhTpo) were recognized equally well, no cross reactivity with other cytokines was found and rhTpo added to plasma and serum was completely recovered. With the ELISA, Tpo concentrations in EDTA-anticoagulated plasma of all controls (n = 193) could be determined, since the limit of detection (2 ± 0.8 A.U./ml, mean ± sd) was lower than the concentration found in controls (11 ± 8 A.U./ml, mean ± sd; 2.5th-97.5th percentile: 4-32 A.U./ml). Tpo levels in serum were on average 3.4 times higher than in plasma.We showed in vivo that Tpo is bound by platelets, as in thrombocytopenic patients (n = 5) a platelet transfusion immediately led to a drop in plasma Tpo level, whereas in patients receiving chemotherapy the induced thrombocytopenia was followed by a rise in plasma Tpo levels.In summary, these results indicate that this ELISA is a reliable tool for Tpo measurements and is applicable for large scale studies.

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