Biosafety in Dental Health Care During Covid-19 Pandemic: A Longitudinal Study (preprint)

Background: The COVID-19 pandemic highly impacted dental healthcare assistance owing to concerns about the risk of transmission by contaminant fluids, droplet formation during dental practice, drastically reducing the number of dental procedures worldwide. This longitudinal study was conducted to monitor SARS-CoV-2 contamination in dental clinics during activities return of students at university.Methods: We evaluated the presence of SARS-CoV-2 RNA by RT-PCR in a dental school clinic environment, on professors, undergraduate dental students, dental assistants, and patients from January 11th to March 12th, 2021 (9 weeks). Serological testing was performed on dental healthcare personnel (DHCP) during the first and last weeks. Additionally, samples with low Ct values were sequenced to identify circulating SARS-CoV-2 variants and possible transmission clusters.Findings: A low number of dental staff (5·8%), patients (0·9%), and environmental sites (0·8%) tested positive for SARS-CoV-2. Most positive cases were asymptomatic to mildly symptomatic, and two asymptomatic DHCP tested positive in longitudinal follow-up RT-PCR test. Previous exposition to COVID-19 were found in 16·2% of the DHCP that showed IgM or IgG antibodies against SARS-CoV-2, and 1/3 of them had undetected antibodies in the last week. Variant Zeta (P.2) were detected. No cross-infection was observed among the participants.Interpretation: Our study suggests that dental practice can be executed safely when control measures and biosafety protocols are applied adequately. DHCP and patient testing, telemonitoring, proper use of personal protection equipment, and surface sanitisation are essential to avoid SARS-CoV-2 cross-infection in dental practice.Funding Information: UFMG/RTR/PRPq, FAPEMIG, CNPq, CAPES/MEC, FINEP, and Rede Corona-ômica BR MCTI/FINEP affiliated to RedeVírus/MCTI.Declaration of Interests: All authors declare to have no conflict of interests.Ethics Approval Statement: The present study was approved by the Ethics Committee of Universidade Federal de Minas Gerais (UFMG) (Protocol nº31041720.3.0000.5149) (https://plataformabrasil.saude.gov.br/login.jsf). All participants enrolled in this study were volunteers, and their samples and clinical data were collected only via signed consent forms.

Female puma (Puma concolor) highway crossings in the Yucatan Peninsula

La infraestructura humana, particularmente las carreteras, ha demostrado ser un peligro para la capacidad de mantenimiento de las poblaciones de grandes felinos en el mundo. La península de Yucatán no es una excepción a esta situación;aunado al establecimiento del Tren Maya, un ferrocarril continental, que reformará la red de carreteras de la Península. Describimos 12 cruces exitosos de una carretera de cuatro carriles por un puma hembra equipado con un radio-transmisor de GPs. El tiempo entre ubicaciones secuenciales tuvo una mediana de 24 h (con un rango de 8 a 56 h). El número promedio de días entre cruces fue de 4.33 (SD = 2.50). Este comportamiento pudo ser influido por una reducción en la movilidad humana por la pandemia producida por COVID-19. Identificamos un tramo de 3 km de largo donde ocurrieron los cruces de carretera. Describimos las características de esta porción de carretera y recomendamos construir estructuras de paso de vida silvestre de acuerdo a ellas.Alternate abstract:Human infrastructure, particularly highway infrastructure, has proven to be a hazard for the resilience of large felid populations throughout the world. The Yucatan Peninsula is no exception and is presently confronted with the establishment of the "Tren Maya," a continental railway that will reshape the road network of the peninsula. We describe 12 successful crossings of a 4-lane highway on the peninsula by a female puma (Puma concolor) fitted with a GPS radio-transmitter. The median time between sequential locations was 24 h (range 8-56 h), and the average number of days between crossings was 4.33 (SD = 2.50). Felid behavior and movements in relation to roads may be influenced by reduced human mobility due to the COVID-19 pandemic lockdown. We identified a 3-km stretch of highway where the crossings occurred. We describe the characteristics of the area and recommend building wildlife passage structures appropriate for the site.

Intravenous Administration of Umbilical Cord Mesenchymal Stromal Cells in Advanced-stage Critical COVID-19: a Case Report (preprint)

Background: Coronavirus disease 2019 (COVID-19) associated- severe acute respiratory distress syndrome (ARDS) patients may require prolonged mechanical ventilation, thus resulting in lung fibrosis and high fatality rates. Several therapies have been developed in patients with pneumonia requiring oxygen therapy as well as during the early course of invasive mechanical ventilation. Mesenchymal stromal cells (MSCs) may have a role in controlling the hyperinflammatory response seen in such cases and prevent aggravation or increase/accelerate recovery. While MSC-based therapies have been studied mostly in patients that did not require invasive ventilation or during the first hours of tracheal intubation, to date the potential of MSC therapy to treat advanced-stage of severe/critical COVID-19 cases has not been extensively studied. Methods: This is a case report of a 30-year-old male patient who presented progressive clinical deterioration of COVID-19 in ICU after 21-day admission and 14 days with invasive mechanical ventilation. The first symptom onset was 35 days before MSC therapy. The patient was treated with allogenic human umbilical cord-derived MSCs [5 x 107 (2 doses 2 days interval)].Results: No serious adverse events attributed to MSC administration were observed during and after the procedure. Oxygenation (PaO2/FiO2 ratio) and the need for vasoactive drugs improved. Chest CT scan imaging, which showed signs of bilateral and peripheral ground-glass, consolidation as well as fibrosis, improved significantly during the time course of the disease. Patient was discharged 13 days after cell therapy. Cytokine analysis demonstrated modulation of different mediators accompanied by modulation of different cell populations in peripheral blood, including a reduction in inflammatory monocytes, increased frequency of patrolling monocytes, CD4+ lymphocytes and type 2 classical dendritic cells (cDC2). Conclusion: This study described for the first time the effects of MSC therapy in a patient at late stage COVID-19 associated severe lung injury and fibrosis. Therefore, further clinical trials should be design assessing the efficacy of MSC therapy in ARDS patients undergoing prolonged mechanical ventilation due to COVID-19.