Background: The use of respiratory devices can mitigate the spread of diseases such as COVID-19 in community settings. We aimed to determine the effectiveness of closed face shields with surgical face masks to prevent SARS-CoV-2 transmission in working adults during the COVID-19 pandemic in Bogotá, Colombia. Methods: An open-label non-inferiority randomized controlled trial that randomly assigned participants to one of two groups: the intervention group was instructed to wear closed face shields with surgical face masks, and the active control group was instructed to wear only surgical face masks. The primary outcome was a positive reverse transcription polymerase chain reaction test, IgG/IgM antibody test for SARS-CoV-2 detection, or both during and at the end of the follow-up period of 21 days. The non-inferiority limit was established at − 5%. Results: A total of 316 participants were randomized, 160 participants were assigned to the intervention group and 156 to the active control group. In total, 141 (88.1%) participants in the intervention group and 142 (91.0%) in the active control group completed the follow-up. Primary outcome: a positive SARS-CoV-2 test result was identified in one (0.71%) participant in the intervention group and three (2.1%) in the active control group. In the intention-to-treat analysis, the absolute risk difference was − 1.40% (95% CI [− 4.14%, 1.33%]), and in the per-protocol analysis, the risk difference was − 1.40% (95% CI [− 4.20, 1.40]), indicating non-inferiority of the closed face shield plus face mask (did not cross the non-inferiority limit). Conclusions: The use of closed face shields and surgical face masks was non-inferior to the surgical face mask alone in the prevention of SARS-CoV-2 infection in highly exposed groups. Settings with highly active viral transmission and conditions such as poor ventilation, crowding, and high mobility due to occupation may benefit from the combined use of masks and closed face shields to mitigate SARS-CoV-2 transmission. Trial registration: ClinicalTrials.gov NCT04647305. Registered on November 30, 2020

Most community-specific serological surveys for SARS-CoV-2 antibodies have been performed in healthcare workers and institutions. In this study, IgG antibodies specific to the virus were evaluated in individuals working at a university campus in Bogotá, Colombia. The aim of this work was to determine previous exposure to SARS-CoV-2 in those attending the campus during city lockdown. A total of 237 individuals, including 93 women and 144 men were evaluated using chemiluminescent detection of IgG anti N-viral protein between November and December 2020. There were 32 positives individuals corresponding to a seroprevalence of 13.5% (10 women and 22 men) and mostly asymptomatic (68.75%) and three cluster of seropositive individuals were identified. Only 13 of the seropositive individuals had previous positive detection of SARS-CoV-2 RNA by RT-qPCR performed in average 91 days before serological test. Seropositive individuals did not come from boroughs having higher percentages of SARS-CoV-2 cases in the city. This survey was carried out after the first peak of SARS-CoV-2 transmission in the city, and before the preparedness to reopening the campus for students in 2021, demonstrating a low seroprevalence in high percentage of asymptomatic. These results will help to evaluate some of the strategies stablished to control virus spread in the campus or other similar communities.

Trypanosoma cruzi, the etiological agent of Chagas disease, is a parasite known for its diverse genotypic variants, or Discrete Typing Units (DTUs), which have been associated with varying degrees of tissue involvement. However, aspects such as parasite attachment remain unclear. It has been suggested that the TcI genotype is associated with cardiac infection, the most common involved site in chronic human infection, while TcII is associated with digestive tract involvement. Traditional models for T. cruzi infection provide limited in vivo observation, making it challenging to observe the dynamics of parasite-host interactions. This study evaluates the cardiac attachment of trypomastigotes from TcI and TcII DTUs in zebrafish larvae. Labeled trypomastigotes were injected in the duct of Cuvier of zebrafish larvae and tracked by stereomicroscopy and light-sheet fluorescence microscopy (LSFM). Remarkably, it was possible to observe TcI parasites adhered to the atrium, atrioventricular valve, and circulatory system, while TcII trypomastigotes demonstrated adhesion to the atrium, atrioventricular valve, and yolk sac extension. When TcI and TcII were simultaneously injected, they both attached to the heart; however, more of the TcII trypomastigotes were observed attached to this organ. Although TcII DTU has previously been associated with digestive tissue infection, both parasite variants showed cardiac tissue attachment in this in vivo model.

Fusarium oxysporum is a widespread phytopathogenic fungus that affects a variety of crops worldwide. This study evaluated the independent effects of three species of Trichoderma ( T. harzianum , T. viride , and T. longibrachiatum ) and the springtail Folsomia candida on the suppression of F. oxysporum under laboratory conditions. We conducted separate in vitro assays to assess fungal antagonism and feeding preferences of the springtail. The results demonstrated that all Trichoderma species significantly inhibited F. oxysporum growth, whilst F. candida showed a marked preference for consuming F. oxysporum mycelium over that of the tested Trichoderma species. These findings suggest that both organisms may contribute to the reduction of F. oxysporum independently. This preliminary work lays the foundation for future studies investigating potential interactions and combined biocontrol applications under more complex and ecological settings.

The pandemic has generated a radical transformation in the lives of millions of workers. Working at home, job loss, and extended hours are among the stressors this past year has brought. Professionals in the medical and biological sciences, in particular, have faced challenges that put their psychological health at risk: “The pressure is maximum to generate vaccines, locate antibodies and carry out large-scale tests that benefit public health" (Chan et al. 2020). In this experience, we share the results of an implementation of implementing a coping skills intervention for lab scientists in Colombia working with SARS-CoV-2 samples and patients.