Rapid Enzyme-linked Immunosorbent Assay Research Articles

Straightforward high-temperature antibody immobilization for rapid and simple microfluidic paper-based ELISA for detection of β’-component (Onc k 5) protein, a major IgE-binding protein in salmon roe

Detection of allergenic proteins in food is required for maintaining the health of persons with food allergies. Enzyme-linked immunosorbent assay (ELISA) is a common technique for the detection of proteins. However, conventional ELISA is expensive, time-consuming, and needs technical expertise. Here, a microfluidic paper-based analytical device (µPAD) combined with a sandwich ELISA technique is developed for rapid, simple, and sensitive colorimetric detection of β’-component protein, a major allergen in salmon roe. The developed µPAD-ELISA employs a capture antibody and enzyme-labeled detection antibody. In addition to the µPAD, a technique for immobilization of the capture antibody has been developed, which completes the immobilization within 5 min by drying the antibody solution on a paper substrate in an oven at 50 °C without any chemical modification. The immobilized antibody exhibited higher binding capability to an antigen and stability against washing processes than those immobilized at room temperature. Since this technique allows simple and rapid preparation of the ELISA in the µPAD, the present µPAD-ELISA completed the analysis within only 15 min, including the immobilization step, compared to a conventional ELISA, which takes about 19 h. This µPAD-ELISA offered a good limit of detection of 1.59 ng mL−1 and reduced the amounts of reagents by a factor of about 17–67, which decreases the analysis cost. This µPAD-ELISA approach employing the present antibody immobilization is expected to be an effective strategy for the detection of allergenic proteins in food.

Comparative evaluation of rapid plasma reagin and ELISA with Treponema pallidum hemagglutination assay for the detection of syphilis in blood donors: a single center experience

IntroductionThe prime responsibility of blood transfusion services in India is to provide safe blood. The donated blood is tested for human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), malaria and syphilis. In India, the screening of donated blood for syphilis is performed by rapid plasma reagin (RPR) or venereal disease research laboratory (VDRL), whereas the World Health Organization (WHO) recommends screening of syphilis in blood donors by enzyme-linked immunosorbent assay (ELISA). Therefore, the aim of this study was to evaluate the performance of RPR and ELISA with the Treponema pallidum hemagglutination assay (TPHA – the gold standard) for the detection of syphilis in blood donors. MethodsIn this cross-sectional study, 1524 consecutive whole blood donors were screened from April to October 2022. All blood samples collected during the study period were tested by RPR, ELISA and the TPHA and the results obtained were compared. ResultsThe seroprevalence of syphilis in blood donors in this study was 0.06% by RPR and 0.72% by ELISA and TPHA. On considering ELISA and the TPHA as the gold standard, ELISA had comparable sensitivity (100%), a higher specificity (100% vs. 99.34%), a higher positive predictive value (PPV - 100% vs. 9.1%) and no biological false positive/false negative results (0 vs. 10 false negatives) when compared to RPR. ConclusionELISA performed better as a screening assay than RPR in the detection of syphilis in blood donors, which is in agreement with the WHO recommendations for syphilis testing in blood donors with low prevalence.

Development of fluorescence-linked immunosorbent assay for rapid detection of Staphylococcus aureus.

Staphylococcus aureus is a major pathogen that causes infections and life-threatening diseases. Although antibiotics, such as methicillin, have been used, methicillin-resistant S. aureus (MRSA) causes high morbidity and mortality rates, and conventional detection methods are difficult to be used because of time-consuming process. To control the spread of S. aureus, a development of a rapid and simple detection method is required. In this study, we generated a fluorescent anti-S. aureus antibody, and established a novel fluorescence-linked immunosorbent assay (FLISA)-based S. aureus detection method. The method showed high sensitivity and low limit of detection toward MRSA detection. The assay time for FLISA was 5h, which was faster than that of conventional enzyme-linked immunosorbent assay (ELISA) or rapid ELISA. Moreover, the FLISA-based detection method was applied to diagnose clinically isolated MRSA samples that required only 5.3h of preincubation. The FLISA method developed in this study can be widely applied as a useful tool for convenient S. aureus detection. KEY POINTS: • A fluorescence-linked immunosorbent assay-based S. aureus detection method • Simultaneous quantification of a maximum of 96 samples within 5h • Application of the novel system to diagnosis clinical isolates.

Development of Kinetic Microplate Immunoenzyme Determination of Dibutyl Phthalate

Phthalic acid esters are integral components of modern plastic products and packaging materials, which causes significant contamination of food products and the environment, leading to the need for simple productive monitoring methods. The article presents a rapid enzyme-linked immunosorbent assay (ELISA) for the determination of dibutyl phthalate (DBP) in fruit juices, based on the competitive interaction between free and bound antigen for the binding sites of specific antibodies. The analytical characteristics of the method were studied in various kinetic regimes of the competition stage. Optimal conditions have been established to ensure the minimum detection limit and high measurement accuracy. The duration of the competitive stage of ELISA was chosen 30 min; the range of determined concentrations of DBP was from 0.37 to 68.34 ng/mL with a detection limit of 0.08 ng/mL. The efficiency of the proposed ELISA for testing fruit juices was shown for the chosen DBP extraction mode.

Salivary and serum IgA and IgG responses to SARS-CoV-2-spike protein following SARS-CoV-2 infection and after immunization with COVID-19 vaccines.

Background: Secretory immunoglobulin A (sIgA) plays an important role in antiviral protective immunity. Although salivary testing has been used for many viral infections, including severe acute respiratory syndrome (SARS) and Middle East Respiratory Syndrome (MERS), its use has not yet been well established with the SARS coronavirus 2 (SARS-CoV-2). Quantification of salivary IgA and IgG antibodies can elucidate mucosal and systemic immune responses after natural infection or vaccination. Here, we report the development and validation of a rapid enzyme-linked immunosorbent assay (ELISA) for anti-SARS-CoV-2 salivary IgA and serum IgG antibodies, and present quantitative results for immunized subjects both prior to or following COVID-19 infections. Objective: Total and serum SARS-CoV-2 spike-specific IgG responses were compared with salivary spike-specific IgA and IgG responses in samples obtained from patients recently infected with SARS-CoV-2 and from subjects recently immunized with COVID-19 vaccines. Methods: A total of 52 paired saliva and serum samples were collected from 26 study participants: 7 subjects after COVID-19 infection and 19 subjects who were uninfected. The ELISA results from these samples were compared with five prepandemic control serum samples. Total IgG and SARS-CoV-2 spike-specific IgG in the serum samples from the subjects who were infected and vaccinated were also measured in a commercial laboratory with an enzyme immunoassay. Results: A wide variation in antibody responses was seen in salivary and serum samples measured by both methods. Three groups of serum total and IgG spike-specific SARS-CoV-2 antibody responses were observed: (1) low, (2) intermediate, and (3) high antibody responders. A correlational analysis of salivary IgA (sIgA) responses with serum IgG concentrations showed a statistical correlation in the low and intermediate antibody responder groups but not in the high group (which we believe was a result of saturation). Conclusion: These preliminary findings suggest measuring salivary and serum IgG and IgA merit further investigation as markers of current or recent SARS-CoV-2 infections.

Rapid enzyme-linked immunosorbent assay and colloidal gold immunoassay for assessing okadaic acid and its derivatives in shellfish

ABSTRACT Okadaic acid (OA) and the analogs of dinophysistoxin (DTX) are important members of diarrhetic shellfish poisoning (DSP) toxins. In this study, five OA-specific mAbs (monoclonal antibodies) were developed from five stable cells of hybridoma. The anti-OA mAb-2D7 showed high sensitivity to OA, the IC50 of the antibody was 0.24 ng/mL, and its cross-reactivity was 91.6% with DTX-1 and 110.5% with DTX-2., In dcELISA, the IC50 was set at 0.182 ng/mL, and the detection limit was set at 0.023 ng/mL by using the anti-OA mAb-2D7. The level of OA recovered from spiked mussel samples was 2–50 ng/g, ranging from 97.6 ± 7.2% to 106.4 ± 9.8%. In contrast, the immunostrip assay with a limit of 5 ng/mL, conducted for detecting OA, was completed in 10 min. The mAb-based dcELISA and immunostrip assay developed were precise and sensitive enough to quickly assess OA, DTX-1, and DTX-2 in shellfish specimens.

Evaluating the Diagnostic Accuracy of Rapid Immuno-chromatographic Tests for Early Detection of Rotavirus in Fecal Samples from Children Less than Five Years with Acute Watery Diarrhea

Acute diarrheal illness is a serious public health issue in developing and developed economies, with high morbidity and mortality rates. Children below five years are the most vulnerable, with one in every six dying from diarrhea. Diarrhea may be caused by various viruses, protozoa, and bacteria. Rotavirus, in particular, is often associated with diarrhea in children. Early detection of rotavirus infection reduces the need for medication and the spread of the virus and helps determine the optimal treatment strategies. In this study, we compared the efficacy of the rapid immunochromatography technique (ICT) with that of enzyme-linked immunosorbent assay (ELISA) to detect rotavirus antigens in stool samples. Overall, 361 stool samples were obtained from hospitalized children under five-years-old, with acute watery diarrhea symptoms and were tested by both rapid ICT and ELISA. Among these samples, 104 (28.81%) tested positive by ICT and 109 (30.19%) by ELISA. Furthermore, the specificity and sensitivity of ICT were assessed using ELISA, the gold standard test. ICT had a 95.41% sensitivity and a 100% specificity. Thus, during emergency testing, ICT may be utilized as an alternative test for quick diagnosis with high specificity and sensitivity in patients with rotavirus diarrhea.

Evaluation of COVID-19 Biokit IgG/IgM Clinical Effectiveness in COVID-19 Vaccinated Individuals

Background: This study compared the neutralizing antibody kit using the Enzyme-Linked Immunosorbent Assay (ELISA) method with the rapid antibody diagnostic kit using the Lateral Flow Immunoassay (LFIA) method to evaluate the clinical effectiveness of the COVID-19 Biokit IgG/IgM regarding evaluation of antibody formation after COVID-19 vaccination.Methods: The neutralizing antibody test was performed with antibody detection kit of diagnostic medical devices for the qualitative method using the standard ELISA method. The rapid antibody diagnostic kit was measured with the COVID-19 Biokit IgG/IgM using the LFIA method. Based on the results of the neutralizing antibody measurement test of the standard test method, the test results of the rapid antibody diagnostic kit are compared and analyzed to confirm its the sensitivity and specificity.Results: When the consistency was determined as positive and negative for the two test results, 118 cases were matched and two cases were inconsistent, showing a 98.3% consistency rate. That is, sensitivity 98%, specificity 100% and correctly classified proportion 98%.Conclusions: Although the positive results of antibody formation of this kit would mean that individual has immunity to COVID-19, the result cannot be used to confirm or evaluate for re-infection. But the strong agreement between rapid antibody diagnostic kit results and ELISA results suggests that the kit used in this study is available as a screening test for antibody and neutralizing antibody responses, which could help evaluate the need for additional vaccinations, collect data quickly and cheaply and monitor individual immune responses.

Seropositivity of main vector-borne pathogens in dogs across Europe

BackgroundCanine vector-borne disease (CVBD) has been an area of increasing interest in Europe over the last few decades, and there have been changes in the prevalence and distribution of many of these diseases. Monitoring CVBD infections in Europe is often done by individual countries, but aggregated data for the European countries are helpful to understand the distribution of CVBDs.MethodsWe used an extensive retrospective database of results from point-of-care rapid enzyme-linked immunosorbent assay (ELISA) tests on dogs across Europe to identify distribution and seropositivity in animals tested for selected CVBDs (Anaplasma spp., Ehrlichia spp., Borrelia burgdorferi, Leishmania spp., and Dirofilaria immitis) from 2016 through 2020. Geographic distribution of positive tests and relative percent positive values were mapped by the Nomenclature of Territorial Units for Statistics classification for regions with sufficient test results for reporting.ResultsA total of 404,617 samples corresponding to 1,134,648 canine results were available from dogs tested in 35 countries over the 5-year study period. Over this period the number of test results per year increased whereas test positivity decreased. Leishmania spp. had the largest increase in total test results from 25,000 results in 2016 to over 60,000 results in 2020. Test positivity for Leishmania spp. fell from 13.9% in 2016 to 9.4% in 2020. Test positivity fell for Anaplasma spp. (7.3 to 5.3%), Ehrlichia spp. (4.3 to 3.4%), and Borrelia burgdorferi (3.3 to 2.4%). Dirofilaria immitis test positivity trended down with a high of 2.7% in 2016 and low of 1.8% in 2018. Leishmania spp. test positivity was highest in endemic areas and in several non-endemic countries with low numbers of test results. Co-positivity rates were significantly higher than expected for all pathogen test positive pairs except for Ehrlichia spp. with Borrelia burgdorferi and D. immitis with Borrelia burgdorferi.ConclusionsThis study represents the largest data set on CVBD seropositivity in Europe to date. The increase in the number of test results and decreasing test positivity over the study period may reflect changes in testing behavior and increased screening of healthy animals. The Europe-wide mapping of CVBD provides expected test positivity that can help inform veterinarians’ decisions on screening and improve prevention and identification of these important, sometimes zoonotic, diseases.Graphical

Use of preventive measures and serological screening tools for Leishmania infantum infection in dogs from Europe

BackgroundThere are several screening tools for detecting Leishmania infantum infection in dogs and various preventive measures to protect against it. Some studies have investigated them, but not many have described their current use. The aim of this study was to investigate which preventive measures and serological screening tools for L. infantum infection were employed from 2012 to 2018 in dogs from different endemic European countries.MethodsA set of electronic datasheets was completed for each dog from several veterinary centres. Classification of preventive measures included: (1) repellents, (2) vaccines and (3) immunomodulators. Classification of serological tests included the: (1) direct agglutination test (DAT), (2) enzyme-linked immunosorbent assay (ELISA), (3) indirect immunofluorescence (IFI), (4) rapid tests and (5) other assays. Dogs were also classified depending on their risk of exposure and living area.ResultsInformation from 3762 dogs was gathered. Preventive measures were applied in 91.5% of dogs and the most frequently used were repellents (86.2%) followed by vaccines (39.8%) and Leisguard® (15.3%). The different types of repellents (collar and spot-on) were used similarly. A combination of a vaccine and repellents was preferred in the high-risk group while the low-risk preferred a combination of Leisguard® and a repellent (Chi-square test: X2 = 88.41, df = 10, P < 0.001). Furthermore, all preventive measures were similarly used through the years except for repellents, which were predicted to have a small increase of use each year. Regarding serological screening tools, the most used were rapid and ELISA tests. Rapid tests, ELISA tests and DAT were used similarly through the years, but a significant change was found in the use of IFI and other assays whose use decreased a little each year.ConclusionsRepellents were the preferred measure, while vaccines and Leisguard® were second-line options. Some dogs were not treated by any measures, which highlights the need for dog owner education. Moreover, there seems to be a preference for rapid tests in the clinical setting to detect specific L. infantum antibodies while ELISA or IFI are less often employed. This underlines an increasing problem, as qualitative rapid tests have a variable diagnostic performance limiting the adequate diagnosis of seropositive dogs in endemic areas.Graphical abstract

Individual and Community Level Factors Related to HIV Diagnosis, Treatment, and Stigma in Kumasi, Ghana: A Field Report

The human immunodeficiency virus (HIV) is a public health issue globally and in Ghana. While efforts are underway to reduce HIV prevalence in Ghana, there are still some HIV-related issues (duration lived with HIV, mode of HIV diagnosis, HIV status disclosure, HIV treatment, HIV knowledge, and HIV prevention and stigma) that need to be addressed. The purpose of the field study was to examine individual and community level factors related to HIV diagnosis, treatment, and stigma in Kumasi, Ghana. Specifically, we conducted a field-based comparison of HIV-related issues in Kumasi and the US to determine areas of similarities and differences. Since our focus was the Kumasi district in general, and the Suntreso Government Hospital in particular, we used convenient sampling. Thus, study results are not generalizable to the entire population of Ghana. Given the short duration of the entire field study (three weeks) and the fact that most information on the HIV-related issues focused in Ghana are available in the US, secondary data from various sources were used for the US comparison. Results from the study showed that 29.2% of participants in Kumasi had lived with HIV for seven or more years, while data from the US showed that people generally live with HIV for 20 years or more after testing positive for the disease. Most of the study participants in Kumasi (68.5%) stated that they were diagnosed with HIV through a laboratory blood sample test, while rapid antibody and ELISA (enzyme-linked immunosorbent assay) tests were found to be the most commonly used methods in HIV diagnosis in the US. The majority of participants living with HIV in Kumasi (71.7%) and the US (67%) were concerned about their friends and family knowing of their HIV status. Unlike the US where patient assisted programs administered by pharmaceutical companies offer free to lowly priced HIV medication to low-income people living with HIV (PLWH), 92.7% of PLWH in Kumasi had free access to HIV medication. HIV-related stigma was an issue in both Kumasi and the US. Copyright © 2022 Mosley et al. Published by Global Health and Education Projects, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution License CC BY 4.0.

Prevalence and Risk Factors of Feline Immunodeficiency Virus and Feline Leukemia Virus Infection in Healthy Cats in Thailand.

Infections with feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) occur worldwide and are among the most important infectious diseases in cats. The aim of the present study was to determine the prevalence of FIV and FeLV infection in healthy outdoor cats in North, Northeast and Central Thailand. So far, a study on retrovirus prevalence of healthy cats in Thailand in a larger geographic area has not been published yet. In addition, risk factors for FIV and FeLV infections were evaluated. Two hundred sixty healthy cats were prospectively recruited. They originated from 13 locations in North, Northeast, and Central Thailand and were presented for either preventive health care and/or neutering. In each cat, a physical examination was performed to confirm health status. FIV and FeLV status was determined using a commercial rapid enzyme-linked immunosorbent assay (ELISA) (SNAP Combo Plus FeLV/FIV, IDEXX). Risk factors were analyzed by binary logistic regression analysis. Samples of 15/260 (5.8%) cats were positive for FIV antibodies, and 11/260 (4.2%) samples were positive for FeLV antigen. One of the 260 (0.4%) cats was positive for both, FIV and FeLV infection. In binary logistic regression analysis, no parameter was associated with a higher risk for FeLV infection. However, cats had a significantly (p = 0.025) higher risk for FIV infection when they were 2 years or older. FIV and FeLV infections occur in healthy cats in North, Northeast and Central Thailand, but prevalence was lower than expected. No risk factors for FeLV infection were detected, but risk for FIV infection increases with age.

A Comparison of Rapid Screening Test and ELISA for the Diagnosis of Hepatitis B Surface Antigen in Patients Attending a Tertiary Care Hospital, Tamil Nadu, India

Introduction: Hepatitis B virus infection is a major public health problem and leading cause of death worldwide. World Health Organisation (WHO) estimates that in 2015 about 257 million population were living with chronic Hepatitis B virus infection with a global prevalence of 3.5%. Among the several viral antigens of Hepatitis B, Hepatitis B Surface Antigen (HBsAg) is an important viral antigen which is recognised as a superior marker for Hepatitis B virus detection. For proper diagnosis of infection as well as disease management and prevention, identification of appropriate test kit is necessary. Aim: To compare the results of rapid screening tests and ELISA for the diagnosis of HBsAg. Materials and Methods: A cross-sectional study was conducted from July 2019-August 2019 in a tertiary care hospital. A total of 200 blood samples received for HBsAg testing were centrifuged. Serum of all the 200 blood samples were tested for HBsAg using both rapid Immuno Chromatographic Card (ICT) method (HEPAVIEW - one step test for HBsAg, Viola Diagnostic System, A Division of Tulip Diagnostics Pvt., Ltd.) and Enzyme Linked Immuno Sorbent Assays (ELISA) (Merilisa HBsAg- Meril Diagnostics Pvt., Ltd.) method. Data for rapid card method and ELISA were noted and entered into MS excel spread sheet and analysed. Results: Among the total 200 blood samples tested by HbsAg rapid card, five samples were positive and the remaining 195 were negative. For rapid card test, the sensitivity was 83.4%, specificity 100%, Positive Predictive Value (PPV) 100% and Negative Predictive Value (NPV) 99.4% and for ELISA the sensitivity, specificity, PPV and NPV were all 100%. Conclusion: The overall performance of the rapid ICT for HBsAg was less sensitive to ELISA. So, only ELISA can be encouraged in all setups irrespective of their developmental and economical status not only to prevent the complications of Hepatitis B infection but also for early diagnosis and better treatment of patients.

Comparison of NS1 Antigen Detection by RDT and ELISA and its Concordance with RT-PCR for the Early Diagnosis of Dengue in Ananthapuramu District, Andhra Pradesh, India

Introduction: Early detection of dengue fever is important for effective clinical care and vector control. For the detection of dengue viral antigen and antibodies, several serological techniques based on the concept of immunochromatography and Enzyme-Linked Immunosorbent Assays (ELISA) are routinely utilised. The performance of these tests depends on the sensitivity and specificity. Aim: To compare Non Structural protein-1 (NS1) antigen detection by Rapid Diagnostic Tests (RDTs) and ELISA and its association with Real-Time Polymerase Chain Reaction (RT-PCR). Materials and Methods: This diagnostic cross-sectional study was done on 100 clinically suspected cases of Dengue between July-November 2021 at a tertiary care hospital in Ananthapuramu, Andhra Pradesh, India. All the sera samples were collected and subjected to NS1 antigen detection test by rapid test, NS1 ELISA, and RT-PCR, and also serotypes DENV-1, 2, 3, 4 were detected from serum sample by RT-PCR test. The results of rapid and ELISA tests were compared with RT-PCR. Data was analysed by Statistical Package for the Social Sciences (SPSS) version 16.0. Results: Out of total 100 samples, 29 samples were tested positive by NS1 rapid test, 30 samples were tested positive by NS1 ELISA, and 32 samples were tested positive by RT-PCR. The sensitivity, specificity of dengue NS1 antigen rapid test were 87.50% and 98.52%, respectively when compared to RT-PCR whereas that of NS1 ELISA were 93.75% and 100% when compared to RT-PCR. Out of 32 samples tested positive by RT-PCR, two samples were positive for DENV-1, 26 samples were positive for DENV-2, and four samples were positive were DENV-3. Conclusion: The NS1 ELISA test requires extra procedures and time. RDTs need a one-step operation that takes roughly 15-30 minutes. Despite the fact that RT-PCR and ELISA have better performance than RDTs, RDTs are more effective for early diagnosis and therapy of dengue fever in countries with limited infrastructure and in remote places.

Detection of SARS-CoV-2 by antigen ELISA test is highly swayed by viral load and sample storage condition

ABSTRACT Background Rapid increase in COVID-19 suspected cases has rendered disease diagnosis challenging, mainly depending upon RT-qPCR. Reliable, rapid, and cost-effective diagnostic assays that complement RT-qPCR should be introduced after thoroughly evaluating their performance upon various disease phases, viral load, and sample storage conditions. Objective We investigated the correlation of cycle threshold (Ct) value, which implies the viral load and infection phase, and the storage condition of the clinical specimen with the diagnosis of SARS-CoV-2 through our newly developed in-house rapid enzyme-linked immunosorbent assay (ELISA) system. Method Naso-oropharyngeal samples of 339 COVID-19 suspected cases were collected and evaluated through RT-qPCR that were stored up to 30 days in different conditions (i.e. −80°C, −20°C and initially at 4°C followed by −80°C). The clinical specimens were evaluated with our in-house ELISA system after finalizing the assay method through checkerboard assay and minimizing the signal/noise ratio. Result The ELISA system showed the highest sensitivity (92.9%) for samples with Ct ≤30 and preserving at −80°C temperature. The sensitivity reduced proportionally with increasing Ct value and preserving temperature. However, the specificity ranged between 98.3% and 100%. Conclusion The results indicate the necessity of early infection phase diagnosis and lower temperature preservation of samples to perform rapid antigen ELISA tests.

Lipid bilayer coatings for rapid enzyme-linked immunosorbent assay

The enzyme-linked immunosorbent assay (ELISA) is a widely used method for protein detection and relies on the specific capture of target proteins while minimizing the nonspecific binding of other interfering proteins and biomolecules. To prevent nonspecific binding events, blocking agents such as bovine serum albumin (BSA) protein, mixtures of proteins in media such as milk or serum, and/or surfactants are typically added to ELISA plates after probe attachment and before analyte capture. Herein, we developed a streamlined ELISA strategy in which readily prepared lipid nanoparticles are utilized as the blocking agent and are added together with the probe molecule to the ELISA plate, resulting in fewer processing steps, quicker protocol time, and superior detection performance compared to conventional BSA blocking. These measurement capabilities were established for coronavirus disease-2019 (COVID-19) antibody detection in saline and human serum conditions and are broadly applicable for developing rapid ELISA diagnostics.

Filariasis

Introduction: Expatriate workers usually contribute to the origination of some infectious diseases in the countries they reside. The aim of this study was to identify and analyze available information on filariasis imported into Najran, Saudi Arabia, by expatriate workers. Methodology: Serum (n = 497) were acquired from expatriate workers of both genders from different nationalities and various ages and also from randomly chosen parts and at different time periods of Najran. The serum samples were stored in a deep freezer at a temperature of − 65°C until utilized for the serological diagnosis of filariasis by using filariasis immunoglobulin G/immunoglobulin M (IgG/IgM) combo rapid test and human filariasis antibody (IgG4) enzyme-linked immunosorbent assay (ELISA). Results: Based on IgG/IgM rapid test, the prevalence of filariasis IgG was 3.8% (19 out of 497), whereas IgG4 ELISA showed that the prevalence of filariasis was 10.9% (10 out of 92). The highest prevalence of filariasis occurred in Indian workers, in adulthood (30–49 years), and in male workers. There was no significant agreement in results between IgG/IgM rapid test and ELISA. The percentage specificity of IgG/IgM rapid test, relative to filariasis IgG4 ELISA was 80.5%. Conclusions: The possibility of health hazard due to imported filariasis and preeminently the initiation of a novel carrier focal point of the disease are likely to relied upon the abundance of carriers of microfilaria and the density of vector mosquitoes who feed on the carriers. Furthermore, the results of this study underscore the need for screening and therapeutic strategies that guarantee the control and prevention of parasitic infectious diseases.

Prevalence of Rotavirus among Iraqi children with diarrhea in Diyala province

Background: Rotavirus is the most common cause of acute gastroenteritis in children below five years.&#x0D; Objectives: The aim of this study to evaluate the prevalence of rotavirus among children with diarrhea, the efficacy of Immuno Chromatography Assay (ICA) and Enzyme-linked Immunosorbent assay (ELISA) and evaluate the relationship between the demographic agent and clinical presentation associated with rotavirus.&#x0D; Material and Methods: A cross-sectional study was conducted at AL-Batool Teaching Hospital in Baqubah, from the first of April 2019 to 31 of March 2020, on (300) children with diarrhea below five years of age. The patients included (n=161, 53.6%) males and (n=139, 46.3%) females. The patient’s age, gender, living area, season, mode of feeding, source of water supply and sterilization, were collected through a questionnaire prepared for this study. The Rapid Test and ELISA are used for the detection of rotavirus in fecal specimens.&#x0D; Results: The rotavirus antigen was detected in (47.33%) stool specimens by the ELISA test and (59%) by ICA from (300) children with diarrhea and high infection in the age group between 13-24 months at the rate (49.40%). The highest infection rate in spring was (56.00%) and lower in summer (33.33%). The infection males more than females (42.24% vs. 39.57%). High significant infection among children living in rural areas (55.68%) compared to those living in urban areas (35.48%). According to the clinical features, the results showed the rate of rotavirus infection in children with fever was (54.90%), vomiting (42.03%), those suffering from severe dehydration (48.85) some dehydration 78 (46.15%), however, rotavirus infection was significant with fever only.

Seroprevalence of Hepatitis B Virus Infection and Risk Factors among Adolescents and Youth in Secondary School in 2018, Commune of Cov&amp;#232;, Benin

Background: Hepatitis B is a vaccine-preventable liver infection caused by the hepatitis B virus. The study aimed to determine the prevalence and associated factors of hepatitis B infection in adolescents and youth attending secondary school in Cove, urban area in Benin. Methods: From 4th to 10th February 2018, a cross-sectional survey was conducted among adolescents and youth aged 15 to 24 years old. Subjects were randomly selected. Hepatitis B surface antigenaemia (HBsAg) was assayed in blood using rapid enzyme-linked immunosorbent assay kits. Univariate and multivariate analyses were performed. Results: Two hundred adolescents and youth were recruited. The seroprevalence of hepatitis B virus infection was 18.50%. According to the multivariate logistic regression model, being infected by hepatitis B was 4.32 times higher in the age group of 15 - 19 years old than in 20 - 24 years age group (PR = 4.32 95% CI [1.51 - 12.34], p = 0.0063). Similarly, students who had not been aware of hepatitis B were more infected than those who were sensitized (PR = 14.60 [95% CI 4.98 - 4.27], p = 0.0001). With regard to lifestyle, individuals with tattoos or piercings were 8.60 times more likely to have been infected by HBV than those without tattoos or piercings, (PR = 8.60; 95% CI [3.41 - 21.70], p < 0.0001). Conclusion: The seroprevalence of hepatitis B among adolescents and youth attending secondary school was high. Regular screening of HVB infection status should be included in school health services in Benin. Awareness campaigns and health education on HVB transmission and prevention should be promoted and strengthened.

Verification of a rapid von Willebrand factor propeptide assay

Background: Von Willebrand disease (VWD) is the most common inherited bleeding disorder caused by a deficiency or defect in von Willebrand factor (VWF). Quantitative defects include, type 1 VWD and type 3 VWD. Type 1 VWD is either due to decreased synthesis and secretion, or increased clearance of VWF. It is essential to diagnose individuals with increased VWF clearance, as treatment of these patients with 1-deamino-8-D-arginine vasopressin is not effective. Currently, there is one commercial assay that measures von Willebrand factor propeptide (VWFpp) levels. This assay is time consuming to perform. With this research we developed and verified a rapid assay to determine VWFpp levels in patient plasma. Methods: The commercial VWF mouse anti-human VWF propeptide matched antibody pair (clones CLB-Pro 35 and CLB-Pro 14.3) was used in enzyme-linked immunosorbent assays of the commercial and the rapid method. While the CLB-Pro commercial assay uses two-hour incubations, our rapid assay uses 30 minute incubations. We compared our assay to the CLB-Pro commercial assay using twenty type 1 VWD patient plasma. Two samples, the World Health Organization (WHO) 6th International Standard (IS) for factor VIII (FVIII)/VWF and a type 1 VWD patient with increased clearance were also tested four times in duplicate for five consecutive days to determine the inter- and intra-assay precision. Results: Our rapid assay showed equal sensitivity to the CLB-Pro commercial assay by detecting 1.5625% VWFpp. The intra- and interassay CVs of our assay were acceptable according to the Food and Drug Administration guideline of 2018. Conclusion: This rapid enzyme-linked immunosorbent assay (ELISA) is as sensitive and precise as the CLB-Pro commercial assay. Therefore, it can be used to rapidly diagnose patients with increased VWF clearance.