Pyrethrum extract from dry flowers of Tanacetum cinerariifolium (formally Chrysanthemum cinerariifolium) has been used globally as a popular insect repellent against arthropod pests for thousands of years. However, the mechanistic basis of pyrethrum repellency remains unknown. check details In this study, we found that pyrethrum spatially repels and activates olfactory responses in Drosophila melanogaster, a genetically tractable model insect, and the closely-related D. suzukii which is a serious invasive fruit crop pest. The discovery of spatial pyrethrum repellency and olfactory response to pyrethrum in D. melanogaster facilitated our identification of four odorant receptors, Or7a, Or42b, Or59b and Or98a that are responsive to pyrethrum. Further analysis showed that the first three Ors are activated by pyrethrins, the major insecticidal components in pyrethrum, whereas Or98a is activated by (E)-β-farnesene (EBF), a sesquiterpene and a minor component in pyrethrum. Importantly, knockout of Or7a, Or59b or Or98a individually abolished fly avoidance to pyrethrum, while knockout of Or42b had no effect, demonstrating that simultaneous activation of Or7a, Or59b and Or98a is required for pyrethrum repellency in D. melanogaster. Our study provides insights into the molecular basis of repellency of one of the most ancient and globally used insect repellents. Identification of pyrethrum-responsive Ors opens the door to develop new synthetic insect repellent mixtures that are highly effective and broad-spectrum.The World Health Organization (WHO) recommends continuing azithromycin mass drug administration (MDA) for trachoma until endemic regions drop below 5% prevalence of active trachoma in children aged 1-9 years. Azithromycin targets the ocular strains of Chlamydia trachomatis that cause trachoma. Regions with low prevalence of active trachoma may have little if any ocular chlamydia, and, thus, may not benefit from azithromycin treatment. Understanding what happens to active trachoma and ocular chlamydia prevalence after stopping azithromycin MDA may improve future treatment decisions. We systematically reviewed published evidence for community prevalence of both active trachoma and ocular chlamydia after cessation of azithromycin distribution. We searched electronic databases for all peer-reviewed studies published before May 2020 that included at least 2 post-MDA surveillance surveys of ocular chlamydia and/or the active trachoma marker, trachomatous inflammation-follicular (TF) prevalence. We assessed trends in the prevalence of both indicators over time after stopping azithromycin MDA. Of 140 identified studies, 21 met inclusion criteria and were used for qualitative synthesis. Post-MDA, we found a gradual increase in ocular chlamydia infection prevalence over time, while TF prevalence generally gradually declined. Ocular chlamydia infection may be a better measurement tool compared to TF for detecting trachoma recrudescence in communities after stopping azithromycin MDA. These findings may guide future trachoma treatment and surveillance efforts.The complement system is activated in tuberculous pleural effusion (TPE), with increased levels of the anaphylatoxins stimulating pleural mesothelial cells (PMCs) to secrete chemokines, which recruit nonclassical monocytes to the pleural cavity. The differentiation and recruitment of naive CD4+ T cells are induced by pleural cytokines and PMC-produced chemokines in TPE. However, it is unclear whether anaphylatoxins orchestrate CD4+ T cell response via interactions between PMCs and monocytes in TPE. In this study, CD16+ and CD16- monocytes isolated from TPE patients were cocultured with PMCs pretreated with anaphylatoxins. After removing the PMCs, the conditioned monocytes were cocultured with CD4+ T cells. The levels of the cytokines were measured in PMCs and monocyte subsets treated separately with anaphylatoxins. The costimulatory molecules were assessed in conditioned monocyte subsets. Furthermore, CD4+ T cell response was evaluated in different coculture systems. The results indicated that anaphylatoxins induced PMCs and CD16+ monocytes to secrete abundant cytokines capable of only inducing Th17 expansion, but Th1 was feeble. In addition, costimulatory molecules were more highly expressed in CD16+ than in CD16- monocytes isolated from TPE. The interactions between monocytes and PMCs enhanced the ability of PMCs and monocytes to produce cytokines and that of monocytes to express HLA-DR, CD40, CD80 and CD86, which synergistically induced Th17 expansion. In the above process, anaphylatoxins enhanced the interactions between monocytes and PMCs by increasing the level of the cytokines IL-1β, IL-6, IL-23 and upregulating the phenotype of CD40 and CD80 in CD16+ monocytes. Collectively, these data indicate that anaphylatoxins play a central role in orchestrating Th17 response mainly via interactions between CD16+ monocytes and PMCs in TPE.

Individuals infected with SARS-CoV-2 develop neutralising antibodies. We investigated the proportion of individuals with SARS-CoV-2 neutralising antibodies after infection and how this proportion varies with selected covariates.

This systematic review and meta-analysis examined the proportion of individuals with SARS-CoV-2 neutralising antibodies after infection and how these proportions vary with selected covariates. Three models using the maximum likelihood method assessed these proportions by study group, covariates and individually extracted data (protocol CRD42020208913). A total of 983 reports were identified and 27 were included. The pooled (95%CI) proportion of individuals with neutralising antibodies was 85.3% (83.5-86.9) using the titre cut off >120 and 83.9% (82.2-85.6), 70.2% (68.1-72.5) and 54.2% (52.0-56.5) with titres >140, >180 and >1160, respectively. These proportions were higher among patients with severe COVID-19 (e.g., titres >180, 84.8% [80.0-89.2], >1160, 74.4% [67.5-79.7]) than those with mild presentation (56.7% [49.9-62.9] and 44.1% [37.3-50.6], respectively) and lowest among asymptomatic infections (28.6% [17.9-39.2] and 10.0% [3.7-20.1], respectively). IgG and neutralising antibody levels correlated poorly.

85% of individuals with proven SARS-CoV-2 infection had detectable neutralising antibodies. This proportion varied with disease severity, study setting, time since infection and the method used to measure antibodies.

85% of individuals with proven SARS-CoV-2 infection had detectable neutralising antibodies. This proportion varied with disease severity, study setting, time since infection and the method used to measure antibodies.