Evaluation of a SARS-CoV-2 Surrogate Virus Neutralization Test for Detection of Antibody in Human, Canine, Cat, and Hamster Sera.

Surrogate neutralization assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that can be done without biosafety level 3 containment and in multiple species are desirable. We evaluate a recently developed surrogate virus neutralization test (sVNT) in comparison to 90% plaque reduction neutralization tests (PRNT90) in human, canine, cat, and hamster sera. With PRNT90 as the reference, sVNT had sensitivity of 98.9% and specificity of 98.8%. Using a panel of immune sera corresponding to other coronaviruses, we confirm the lack of cross-reactivity to other coronaviruses in SARS-CoV-2 sVNT and PRNT90, except for cross-reactivity to SARS-CoV-1 in sVNT.

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

BackgroundThe 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.AimOur objective was to develop and evaluate serological assays applicable in large-scale sero-epidemiological studies.MethodsWe 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.ResultsIgG 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.ConclusionUsing 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.

Lack of serological evidence of Middle East respiratory syndrome coronavirus infection in virus exposed camel abattoir workers in Nigeria, 2016.

BackgroundMiddle East respiratory syndrome coronavirus (MERS-CoV) is a zoonotic threat of global public health concern and dromedary camels are the source of zoonotic infection. Although MERS-CoV is enzootic in dromedaries in Africa as well as the Middle East, zoonotic disease has not been reported in Africa. Methods: In an abattoir in Kano, Nigeria, we tested nasal swabs from camels and investigated 261 humans with repeated occupational exposure to camels, many of whom also reported drinking fresh camel milk (n = 138) or urine (n = 94) or using camel urine for medicinal purposes (n = 96). Results: Weekly MERS-CoV RNA detection in January-February 2016 ranged from 0-8.4% of camels sampled. None of the abattoir workers with exposure to camels had evidence of neutralising antibody to MERS-CoV. Conclusion: There is a need for more studies to investigate whether or not zoonotic transmission of MERS-CoV does take place in Africa.

Therapeutic effect of Duhuo Jisheng Decoction add-on Tui-na manipulation on osteoarthritis of knee: a randomized controlled trial.

BACKGROUND: Knee osteoarthritis (KOA) is a common degenerative joint condition that causes disability and pain in the elderly population. The prevalence of KOA among persons aged 63 or above is approximately 30%. Previous studies have reported the positive effects of Tui-na treatment and the Chinese herbal formula Du-Huo-Ji-Sheng Decoction (DHJSD) for KOA treatment. The current study aims to evaluate the add-on therapeutic effect of oral administration of DHJSD on KOA in addition to Tui-na. METHODS: We conducted a prospective, randomized, controlled clinical trial. Seventy study subjects with KOA were randomly assigned to the treatment and control groups in a 1:1 ratio. Both two groups received eight sessions of Tui-na manipulation for 4 weeks. The DHJSD was only administered to the study subjects in the treatment group. The primary outcome measure was rated using the WOMAC at the end of treatment (4 weeks). Secondary outcomes were assessed using EQ-5D-5L, a health-related quality of life with 5-level EQ-5D version at end of treatment (week 4) and follow-up (week 8). RESULTS: No statistically significant difference was found between two groups on WOMAC scores at the end of treatment. The mean WOMAC Pain subscale score was significantly lower in the treatment group than control group at week 8 follow up (mean difference, MD - 1.8, 95% CI - 3.5 to - 0.02, P = 0.048). The mean WOMAC Stiffness subscale score was significantly lower in the treatment group than in the control group at week 2 (MD 0.74, 95% CI 0.05 to 1.42, P = 0.035) and week 8 follow up (MD 0.95, 95% CI 0.26 to 1.65, P = 0.008). The mean EQ-5D index value was significantly improved in the treatment group than in the control group at week 2 (MD 0.17, 95% CI 0.02 to 0.31, P = 0.022). The analysis of WOMAC scores and EQ-5D-5L in both groups showed statistically significant improvement with time. No significant adverse effect was found during the trial. CONCLUSION: DHJSD may have an add-on effect in addition to Tui-na manipulation relieving pain and improving stiffness as well as quality of life (QOL) in patients with KOA. The combined treatment was generally safe and well tolerated. Trial registration The study was registered at the ClinicalTrials.gov (website: https://clinicaltrials.gov/ct2/show/NCT04492670 , registry number: NCT04492670), registered on 30 July 2020.

Bi-directional Refractive Compensation for With-the-Rule and Against-the-Rule Astigmatism in Young Adults.

Purpose: The purpose of this study was to investigate the short-term effect of imposing astigmatism on the refractive states of young adults. Methods: Nineteen visually healthy low-astigmatic young adults (age = 20.94 ± 0.37 years; spherical-equivalent errors [M] = -1.47 ± 0.23 diopters [D]; cylindrical errors = -0.32 ± 0.05 D) were recruited. They were asked to wear a trial frame with treated and control lenses while watching a video for an hour. In three separate visits, the treated eye was exposed to one of three defocused conditions in random sequence: (1) with-the-rule (WTR) astigmatism = +3.00 DC × 180 degrees; (2) against-the-rule (ATR) astigmatism = +3.00 DC × 90 degrees; and (3) spherical defocus (SPH) = +3.00 DS. The control eye was fully corrected optically. Before and after watching the video, non-cycloplegic autorefraction was performed over the trial lenses. Refractive errors were decomposed into M, J0, and J45 astigmatism. Interocular differences in refractions (treated eye - control eye) were analyzed. Results: After participants watched the video with monocular astigmatic defocus for an hour, the magnitude of the J0 astigmatism was significantly reduced by 0.25 ± 0.10 D in both WTR (from +1.53 ± 0.07 D to +1.28 ± 0.09 D) and 0.39 ± 0.15 D in ATR conditions (from -1.33 ± 0.06 D to -0.94 ± 0.18 D), suggesting an active compensation. In contrast, changes in J0 astigmatism were not significant in the SPH condition. No compensatory changes in J45 astigmatism or M were found under any conditions. Conclusions: Watching a video for an hour with astigmatic defocus induced bidirectional, compensatory changes in astigmatic components, suggesting that refractive components of young adults are moldable to compensate for orientation-specific astigmatic blur over a short period.

Evolution of self-organised division of labour driven by stigmergy in leaf-cutter ants.

Social insects owe their widespread success to their ability to efficiently coordinate behaviour to carry out complex tasks. Several leaf-cutter ant species employ an advanced type of division of labour known as task partitioning, where the task of retrieving leaves is distributed between workers that cut and drop and those that collect the fallen leaves. It is not entirely clear how such highly coordinated behaviour can evolve, as it would seem to require the simultaneous mutations of multiple traits during the same generation. Here, we use an agent-based simulation model to show how task partitioning in leaf-cutter ants can gradually evolve by exploiting stigmergy (indirect coordination through the environment) through gravity (leaves falling from the treetop on the ground forming a cache). Our simple model allows independent variation in two core behavioural dimensions: the tendency to drop leaves and the tendency to pick up dropped leaves. Task partitioning readily evolves even under these minimal assumptions through adaptation to an arboreal environment where traveling up and down the tree is costly. Additionally, we analyse ant movement dynamics to demonstrate how the ants achieve efficient task allocation through task switching and negative feedback control.