Healthcare Worker Seroconversion in SARS Outbreak

Serum samples were obtained from healthcare workers 5 weeks after exposure to an outbreak of severe acute respiratory syndrome (SARS). A sensitive dot blot enzyme-linked immunosorbent assay, complemented by a specific neutralization test, shows that only persons in whom probable SARS was diagnosed had specific antibodies and suggests that subclinical SARS is not an important feature of the disease

Use of Saliva for Early Dengue Diagnosis

The importance of laboratory diagnosis of dengue cannot be undermined. In recent years, many dengue diagnostic tools have become available for various stages of the disease, but the one limitation is that they require blood as a specimen for testing. In many incidences, phlebotomy in needle-phobic febrile individuals, especially children, can be challenging, and the tendency to forgo a dengue blood test is high. To circumvent this, we decided to work toward a saliva-based assay (antigen-capture anti-DENV IgA ELISA, ACA-ELISA) that has the necessary sensitivity and specificity to detect dengue early. Overall sensitivity of the ACA-ELISA, when tested on saliva collected from dengue-confirmed patients (EDEN study) at three time points, was 70% in the first 3 days after fever onset and 93% between 4 to 8 days after fever onset. In patients with secondary dengue infections, salivary IgA was detected on the first day of fever onset in all the dengue confirmed patients. This demonstrates the utility of saliva in the ACA-ELISA for early dengue diagnostics. This technique is easy to perform, cost effective, and is especially useful in dengue endemic countries

Development of ASSURE® Dengue IgA Rapid Test for the Detection of Anti-dengue IgA from Dengue Infected Patients

Background: Rapid and early dengue diagnosis is essential for patient management and early disease intervention. MP Diagnostics ASSURE® Dengue IgA Rapid Test (Dengue IgA RT) was developed for the rapid detection of anti-dengue IgA in patients′ biological samples. The performance of Dengue IgA RT was examined using multiple categories of well-characterized samples. Materials and Methods: Dengue IgA RT was designed and developed. Following characterization of samples by reference ELISAs, the performance of the kit was evaluated. Results: The overall sensitivity and specificity of Dengue IgA RT were 86.70% (n=233) and 86.05% (n=681) respectively; in which Dengue IgA RT detected 77.42% primary and 92.86% secondary cases; compared to 70.97% and 72.14% by IgM-Cap ELISA and 89.25% and 20% by Non-Structural Protein 1 (NS1) Ag ELISA respectively. Using 125 paired samples, Dengue IgA RT showed 84.80% sensitivity at acute phase and 99.20% sensitivity at convalescent phase; with 92% specificity at both phases. Dengue IgA RT also demonstrated a consistent performance (sensitivity: 85.53%, specificity: 80%) with 76 whole blood samples. In detecting all four serotypes of DENV (n=162), the performance of Dengue IgA RT was comparable with in-house IgM-Cap ELISA. Kinetics of anti-dengue IgA production was elucidated with 42.86% detection level as early as one-two days after fever onset, which increased to 83.33% between five and seven days after fever onset. Conclusion: Dengue IgA RT demonstrated a good performance and is applicable as one of the dengue early diagnostic tools at all levels of health care system

Potential Therapeutic Approach of Melatonin against Omicron and Some Other Variants of SARS-CoV-2

The Omicron variant (B.529) of COVID-19 caused disease outbreaks worldwide because of its contagious and diverse mutations. To reduce these outbreaks, therapeutic drugs and adjuvant vaccines have been applied for the treatment of the disease. However, these drugs have not shown high efficacy in reducing COVID-19 severity, and even antiviral drugs have not shown to be effective. Researchers thus continue to search for an effective adjuvant therapy with a combination of drugs or vaccines to treat COVID-19 disease. We were motivated to consider melatonin as a defensive agent against SARS-CoV-2 because of its various unique properties. Over 200 scientific publications have shown the significant effects of melatonin in treating diseases, with strong antioxidant, anti-inflammatory, and immunomodulatory effects. Melatonin has a high safety profile, but it needs further clinical trials and experiments for use as a therapeutic agent against the Omicron variant of COVID-19. It might immediately be able to prevent the development of severe symptoms caused by the coronavirus and can reduce the severity of the infection by improving immunity

COVID-19 diagnostics: Current and Prospective Tools

COVID-19 presents a major challenge to the current healthcare system worldwide while exposing multifaceted problems underlying the infrastructure as well as the preparedness of disaster management in relation to emerging infectious disease. Timely detection and confinement of infected cases present the first step in combating COVID-19. In this review, we explore different COVID-19 diagnostic methods that are available or under investigation. Cell culture followed by an indirect fluorescent antibody presents the most accurate method for SARS-CoV-2 detection through regulatory and commercial infeasibility prohibits its general implementation. Diagnosis by radiologic imaging along with reverse transcriptase PCR is widespread and is considered as standard while isothermal amplification methods are currently on the verge. CRISPR-Cas and microfluidics adds new dimension to SARS-CoV-2 detection. Moreover, immunoassays such as ELISA, LFIA, neutralization assay, and chemiluminescent assay, can also be used for detection and surveillance. Additionally, NGS and metagenomic analysis are smoothing the obscurities further in this challenge

Development and performance evaluation of a rapid in-house ELISA for retrospective serosurveillance of SARS-CoV-2.

BackgroundIn the ongoing pandemic situation of COVID-19, serological tests can complement the molecular diagnostic methods, and can be one of the important tools of sero-surveillance and vaccine evaluation.AimTo develop and evaluate a rapid SARS-CoV-2 specific ELISA for detection of anti-SARS-CoV2 IgG from patients' biological samples.MethodsIn order to develop this ELISA, three panels of samples (n = 184) have been used: panel 1 (n = 19) and panel 2 (n = 60) were collected from RT-PCR positive patients within 14 and after 14 days of onset of clinical symptoms, respectively; whereas panel 3 consisted of negative samples (n = 105) collected either from healthy donors or pre-pandemic dengue patients. As a capturing agent full-length SARS-CoV2 specific recombinant nucleocapsid was immobilized. Commercial SARS-CoV2 IgG kit based on chemiluminescent assay was used for the selection of samples and optimization of the assay. The threshold cut-off point, inter-assay and intra-assay variations were determined.ResultsThe incubation/reaction time was set at a total of 30 minutes with the sensitivity of 84% (95% confidence interval, CI, 60.4%, 96.6%) and 98% (95% CI, 91.1%, 100.0%), for panel 1 and 2, respectively; with overall 94.9% sensitivity (95% CI 87.5%, 98.6%). Moreover, the clinical specificity was 97.1% (95% CI, 91.9%, 99.4%) with no cross reaction with dengue samples. The overall positive and negative predictive values are 96.2% (95% CI 89.2%, 99.2%) and 96.2% (95% CI, 90.6% 99.0%), respectively. In-house ELISA demonstrated 100% positive and negative percent agreement with Elecsys Anti-SARS-CoV-2, with Cohen's kappa value of 1.00 (very strong agreement), while comparing 13 positive and 17 negative confirmed cases.ConclusionThe assay is rapid and can be applied as one of the early and retrospective sero-monitoring tools in all over the affected areas