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The causative agent of tuberculosis in pinnipeds is Mycobacterium pinnipedii, a member of the Mycobacterium tuberculosis complex (MTC). The natural hosts are pinnipeds; however, other non-marine mammals, including humans, can also be infected. The transmissibility of a pathogen is related to its virulence. The transmissibility of a M. pinnipedii strain (i.e., 1856) was investigated in a murine model and compared with that of two Mycobacterium bovis strains (i.e., 534 and 04-303) with different reported virulence. Non-inoculated mice (sentinels) were co-housed with intratracheally inoculated mice. Detailed inspection of mice to search for visible tuberculosis lesions in the lungs and spleen was performed, and bacillus viability at 30, 60, and 90 days post-inoculation (dpi) was assayed. A transmissibility of 100% was recorded at 30 dpi in sentinel mice co-housed with the inoculated mice from the M. pinnipedii and M. bovis 04-303 groups, as evidenced by the recovery of viable M. pinnipedii and M. bovis from the lungs of sentinel mice. Mice inoculated with M. pinnipedii (1856) and M. bovis (534) survived until euthanized, whereas five of the M. bovis 04-303-inoculated mice died at 17 dpi. This study constitutes the first report of the transmissibility of a M. pinnipedii strain in mice and confirms the utility of this experimental model to study virulence features such as the transmission of poorly characterized MTC species.

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Herein, we conducted simulations of trimeric Spike from several SARS-CoV-2 variants of concern (Delta and Omicron sub-variants BA.2, BA.5, and BQ.1) and investigated the mechanisms by which specific mutations confer resistance to neutralizing antibodies. We observed that the mutations primarily affect the cooperation between protein domains within and between protomers. The substitutions K417N and L452R expand hydrogen bonding interactions, reducing their interaction with neutralizing antibodies. By interacting with nearby residues, the K444T and N460K mutations in the SpikeBQ.1 variant potentially reduces solvent exposure, thereby promoting resistance to antibodies. We also examined the impact of D614G, P681R, and P681H substitutions on Spike protein structure that may be related to infectivity. The D614G substitution influences communication between a glycine residue and neighboring domains, affecting the transition between up- and -down RBD states. The P681R mutation, found in the Delta variant, enhances correlations between protein subunits, while the P681H mutation in Omicron sub-variants weakens long-range interactions that may be associated with reduced fusogenicity. Using a multiple linear regression model, we established a connection between inter-protomer communication and loss of sensitivity to neutralizing antibodies. Our findings underscore the importance of structural communication between protein domains and provide insights into potential mechanisms of immune evasion by SARS-CoV-2. Overall, this study deepens our understanding of how specific mutations impact SARS-CoV-2 infectivity and shed light on how the virus evades the immune system.

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Severe acute respiratory syndrome-related coronavirus (SARS-CoV-2) transmission occurs even among fully vaccinated individuals; thus, prompt identification of infected patients is central to control viral circulation. Antigen rapid diagnostic tests (Ag-RDTs) are highly specific, but sensitivity is variable. Discordant RT-qPCR vs. Ag-RDT results are reported, raising the question of whether negative Ag-RDT in positive RT-qPCR samples could imply the absence of infectious viruses. To study the relationship between negative Ag-RDT results with virological, molecular, and serological parameters, we selected a cross-sectional and a follow-up dataset and analyzed virus culture, subgenomic RNA quantification, and sequencing to determine infectious viruses and mutations. We demonstrated that RT-qPCR positive while SARS-CoV-2 Ag-RDT negative discordant results correlate with the absence of infectious virus in nasopharyngeal samples. A decrease in sgRNA detection together with an expected increase in detectable anti-S and anti-N IgGs was also verified in these samples. The data clearly demonstrate that a negative Ag-RDT sample is less likely to harbor infectious SARS-CoV-2 and, consequently, has a lower transmissible potential.

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Resumen El objetivo fue describir los resultados de la implementación de una estrategia de vigilancia con el uso de test rápidos de detección de antígeno de SARS-CoV-2. Se realizó un estudio de cohorte retrospectiva entre diciembre de 2020 y marzo de 2021, que incluyó casos sospechosos de COVID-19 evaluados en un hospital público mediante test rápidos y, en los negativos, por test moleculares. Se realizó seguimiento telefónico de los casos positivos y sus contactos estrechos. Se estimaron indicadores de implementación y de transmisibilidad viral (probabilidad de generar transmisión, cantidad de contagios secundarios generados, tasa de ataque secundaria e índice de sobredispersión). Se analizó su asociación con el resultado del test diag nóstico por modelos multivariados. De 1706 pacientes analizados con test rápidos de detección de antígeno, 526 resultaron positivos y 1180 negativos (65 fueron positivos por test moleculares). Se contactaron 579 casos confirmados e identificaron 1669 contactos estrechos (85% con seguimiento completo); 398 contactos fueron positivos durante su cuarentena (tasa de ataque secundaria de 27.9%). De los 579 casos, 205 (35%) reportaron contagios sintomáticos, con un promedio de 0.91 casos secundarios por infector. Se observó sobredispersión de la transmisión. Los positivos confirmados por test rápido tuvieron mayores chances de generar casos secun darios, más casos secundarios por infector y mayor tasa de ataque que los confirmados por test molecular. En conclusión, la estrategia con test rápido de detección de antígeno tuvo una aceptabilidad y cobertura elevada y aceleró el diagnóstico e identificación de los individuos con mayor contagiosidad.

Abstract The objective was to describe the results of a surveillance strategy based on the use of SARS-CoV-2 rapid antigen de tection tests. A retrospective cohort study was held between December 2020 and March 2021, which included suspected cases of COVID-19 evaluated by rapid antigen tests at a public hospital, with confirmatory molecular tests in negative cases. Positive cases and their close contacts were followed up by telephone. The scope, ac ceptability, follow-up coverage and positivity rate of the strategy were estimated, as well as indicators of viral transmissibility (probability of generating transmission, number of secondary infections generated, secondary attack rate, and overdispersion index). Its association with diagnostic tests results was analyzed by multivariate models. Of 1706 patients tested by rapid antigen tests, 526 were positive and 1180 were negative (65 tested positive by molecular tests); 579 confirmed cases could be contacted and 1669 close contacts were identified (85% of these contacts had full follow-up); 398 contacts tested positive during their quarantine (secondary attack rate of 27.9%). Of the 579 contacted cases, 205 (35%) reported symptomatic transmission, with an average of 0.91 secondary cases per infector. Transmission overdispersion was observed. Positive cases confirmed by rapid antigen tests had a higher chance of generating secondary cases, a higher number of secondary cases per infector and a higher secondary attack rate than those confirmed by molecular tests. In conclusion, the rapid antigen tests strategy showed high acceptability and coverage, and accelerated the diagnosis and identification of individuals with the highest contagiousness.

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The objective was to describe the results of a surveillance strategy based on the use of SARS-CoV-2 rapid antigen detection tests. A retrospective cohort study was held between December 2020 and March 2021, which included suspected cases of COVID-19 evaluated by rapid antigen tests at a public hospital, with confirmatory molecular tests in negative cases. Positive cases and their close contacts were followed up by telephone. The scope, acceptability, follow-up coverage and positivity rate of the strategy were estimated, as well as indicators of viral transmissibility (probability of generating transmission, number of secondary infections generated, secondary attack rate, and overdispersion index). Its association with diagnostic tests results was analyzed by multivariate models. Of 1706 patients tested by rapid antigen tests, 526 were positive and 1180 were negative (65 tested positive by molecular tests); 579 confirmed cases could be contacted and 1669 close contacts were identified (85% of these contacts had full follow-up); 398 contacts tested positive during their quarantine (secondary attack rate of 27.9%). Of the 579 contacted cases, 205 (35%) reported symptomatic transmission, with an average of 0.91 secondary cases per infector. Transmission overdispersion was observed. Positive cases confirmed by rapid antigen tests had a higher chance of generating secondary cases, a higher number of secondary cases per infector and a higher secondary attack rate than those confirmed by molecular tests. In conclusion, the rapid antigen tests strategy showed high acceptability and coverage, and accelerated the diagnosis and identification of individuals with the highest contagiousness.

El objetivo fue describir los resultados de la implementación de una estrategia de vigilancia con el uso de test rápidos de detección de antígeno de SARS-CoV-2. Se realizó un estudio de cohorte retrospectiva entre diciembre de 2020 y marzo de 2021, que incluyó casos sospechosos de COVID-19 evaluados en un hospital público mediante test rápidos y, en los negativos, por test moleculares. Se realizó seguimiento telefónico de los casos positivos y sus contactos estrechos. Se estimaron indicadores de implementación y de transmisibilidad viral (probabilidad de generar transmisión, cantidad de contagios secundarios generados, tasa de ataque secundaria e índice de sobredispersión). Se analizó su asociación con el resultado del test diagnóstico por modelos multivariados. De 1706 pacientes analizados con test rápidos de detección de antígeno, 526 resultaron positivos y 1180 negativos (65 fueron positivos por test moleculares). Se contactaron 579 casos confirmados e identificaron 1669 contactos estrechos (85% con seguimiento completo); 398 contactos fueron positivos durante su cuarentena (tasa de ataque secundaria de 27.9%). De los 579 casos, 205 (35%) reportaron contagios sintomáticos, con un promedio de 0.91 casos secundarios por infector. Se observó sobredispersión de la transmisión. Los positivos confirmados por test rápido tuvieron mayores chances de generar casos secundarios, más casos secundarios por infector y mayor tasa de ataque que los confirmados por test molecular. En conclusión, la estrategia con test rápido de detección de antígeno tuvo una aceptabilidad y cobertura elevada y aceleró el diagnóstico e identificación de los individuos con mayor contagiosidad.

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Cattle vaccination is an attractive approach in compliance with control and eradication programs against Bovine Tuberculosis (bTB). Today, there is no anti bTB vaccine licensed. Two vaccine candidates, MbΔmce2 and MbΔmce2-phoP previously designed were evaluated in BALB/c mice, including the parental M. bovis NCTC10772 and a M. bovis hypervirulent Mb04-303 strains as controls. Sentinel mice (non-inoculated) cohoused with subcutaneous inoculated mice. Persistence, visible tuberculosis lesions (VTL) in lungs and spleens and bacillary load were investigated subcutaneously delivered at 60 and 90 days after inoculation (dpi) as well as their potential transmission to naïve mice. While a 100% survival was observed at 90 dpi without VTL in all groups, transmission was not evidenced in the sentinels mice. Vaccine candidates and control strains were isolated from the spleen of all inoculated mice, while Mb04-303 was isolated from the lungs of one inoculated mouse. Vaccine candidate's attenuation considering survival, lung bacillary load and VTL was confirmed, administrated by the subcutaneous route. Future experiments are necessary to demonstrate whether the persistence of both mutants in the spleen, with low CFU, remains over time to increase the potential increasing risk of dissemination to organs and subsequent transmission to other animals by airborne or other routes.

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Novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOC) are constantly threatening global public health. With no end date, the pandemic persists with the emergence of novel variants that threaten the effectiveness of diagnostic tests and vaccines. Mutations in the Spike surface protein of the virus are regularly observed in the new variants, potentializing the emergence of novel viruses with different tropism from the current ones, which may change the severity and symptoms of the disease. Growing evidence has shown that mutations are being selected in favor of variants that are more capable of evading the action of neutralizing antibodies. In this context, the most important factor guiding the evolution of SARS-CoV-2 is its interaction with the host's immune system. Thus, as current vaccines cannot block the transmission of the virus, measures complementary to vaccination, such as the use of masks, hand hygiene, and keeping environments ventilated remain essential to delay the emergence of new variants. Importantly, in addition to the involvement of the immune system in the evolution of the virus, we highlight several chemical parameters that influence the molecular interactions between viruses and host cells during invasion and are also critical tools making novel variants more transmissible. In this review, we dissect the impacts of the Spike mutations on biological parameters such as (1) the increase in Spike binding affinity to hACE2; (2) bound time for the receptor to be cleaved by the proteases; (3) how mutations associate with the increase in RBD up-conformation state in the Spike ectodomain; (4) expansion of uncleaved Spike protein in the virion particles; (5) increment in Spike concentration per virion particles; and (6) evasion of the immune system. These factors play key roles in the fast spreading of SARS-CoV-2 variants of concern, including the Omicron.

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The city of Manaus (the capital of Brazil's state of Amazonas) has become a key location for understanding the dynamics of the global pandemic of COVID-19. Different groups of scientists have foreseen different scenarios, such as the second wave or that Manaus could escape such a wave by having reached herd immunity. Here we test five hypotheses that explain the second wave of COVID-19 in Manaus: 1) The greater transmissibility of the Amazonian (gamma or P.1) variant is responsible for the second wave; 2) SARS-CoV-2 infection levels during the first wave were overestimated by those foreseeing herd immunity, and the population remained below this threshold when the second wave began at the beginning of December 2020; 3) Antibodies acquired from infection by one lineage do not confer immunity against other lineages; 4) Loss of immunity has generated a feedback phenomenon among infected people, which could generate future waves, and 5) A combination of the foregoing hypotheses. We also evaluated the possibility of a third wave in Manaus despite advances in vaccination, the new wave being due to the introduction of the delta variant in the region and the loss of immunity from natural contact with the virus. We developed a multi-strain SEIRS (Susceptible-Exposed-Infected-Removed-Susceptible) model and fed it with data for Manaus on mobility, COVID-19 hospitalizations, numbers of cases and deaths. Our model contemplated the current vaccination rates for all vaccines applied in Manaus and the individual protection rates already known for each vaccine. Our results indicate that the SARS-CoV-2 gamma (P.1) strain that originated in the Amazon region is not the cause of the second wave of COVID-19 in Manaus, but rather this strain originated during the second wave and became predominant in January 2021. Our multi-strain SEIRS model indicates that neither the doubled transmission rate of the gamma variant nor the loss of immunity alone is sufficient to explain the sudden rise of hospitalizations in late December 2020. Our results also indicate that the most plausible explanation for the current second wave is a SARS-CoV-2 infection level at around 50% of the population in early December 2020, together with loss of population immunity and early relaxation of restrictive measures. The most-plausible model indicates that contact with one strain does not provide protection against other strains and that the gamma variant has a transmissibility rate twice that of the original SARS-CoV-2 strain. Our model also shows that, despite the advance of vaccination, and even if future vaccination advances at a steady pace, the introduction of the delta variant or other new variants could cause a new wave of COVID-19.

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Meteorological parameters modulate transmission of the SARS-Cov-2 virus, the causative agent related to coronavirus disease-2019 (COVID-19) development. However, findings across the globe have been inconsistent attributed to several confounding factors. The aim of the present study was to investigate the relationship between reported meteorological parameters from July 1 to October 31, 2020, and the number of confirmed COVID-19 cases in 4 Brazilian cities: São Paulo, the largest city with the highest number of cases in Brazil, and the cities with greater number of cases in the state of Parana during the study period (Curitiba, Londrina and Maringa). The assessment of meteorological factors with confirmed COVID-19 cases included atmospheric pressure, temperature, relative humidity, wind speed, solar irradiation, sunlight, dew point temperature, and total precipitation. The 7- and 15-day moving averages of confirmed COVID-19 cases were obtained for each city. Pearson's correlation coefficients showed significant correlations between COVID-19 cases and all meteorological parameters, except for total precipitation, with the strongest correlation with maximum wind speed (0.717, <0.001) in São Paulo. Regression tree analysis demonstrated that the largest number of confirmed COVID-19 cases was associated with wind speed (between ≥0.3381 and <1.173 m/s), atmospheric pressure (<930.5mb), and solar radiation (<17.98e+3). Lower number of cases was observed for wind speed <0.3381 m/s and temperature <23.86°C. Our results encourage the use of meteorological information as a critical component in future risk assessment models.

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The city of Manaus (the capital of Brazil’s state of Amazonas) has become a key location for understanding the dynamics of the global pandemic of COVID-19. Different groups of scientists have foreseen different scenarios, such as the second wave or that Manaus could escape such a wave by having reached herd immunity. Here we test five hypotheses that explain the second wave of COVID-19 in Manaus: 1) The greater transmissibility of the Amazonian (gamma or P.1) variant is responsible for the second wave; 2) SARS-CoV-2 infection levels during the first wave were overestimated by those foreseeing herd immunity, and the population remained below this threshold when the second wave began at the beginning of December 2020; 3) Antibodies acquired from infection by one lineage do not confer immunity against other lineages; 4) Loss of immunity has generated a feedback phenomenon among infected people, which could generate future waves, and 5) A combination of the foregoing hypotheses. We also evaluated the possibility of a third wave in Manaus despite advances in vaccination, the new wave being due to the introduction of the delta variant in the region and the loss of immunity from natural contact with the virus. We developed a multi-strain SEIRS (Susceptible-Exposed-Infected-Removed-Susceptible) model and fed it with data for Manaus on mobility, COVID-19 hospitalizations, numbers of cases and deaths. Our model contemplated the current vaccination rates for all vaccines applied in Manaus and the individual protection rates already known for each vaccine. Our results indicate that the SARS-CoV-2 gamma (P.1) strain that originated in the Amazon region is not the cause of the second wave of COVID-19 in Manaus, but rather this strain originated during the second wave and became predominant in January 2021. Our multi-strain SEIRS model indicates that neither the doubled transmission rate of the gamma variant nor the loss of immunity alone is sufficient to explain the sudden rise of hospitalizations in late December 2020. Our results also indicate that the most plausible explanation for the current second wave is a SARS-CoV-2 infection level at around 50% of the population in early December 2020, together with loss of population immunity and early relaxation of restrictive measures. The most-plausible model indicates that contact with one strain does not provide protection against other strains and that the gamma variant has a transmissibility rate twice that of the original SARS-CoV-2 strain. Our model also shows that, despite the advance of vaccination, and even if future vaccination advances at a steady pace, the introduction of the delta variant or other new variants could cause a new wave of COVID-19.

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Ha surgido una nueva variante de preocupación de SARS-CoV-2, cuyos efectos en la evolución de la pandemia parecen inciertos. Sin embargo, ha comenzado a surgir evidencia con respecto al comportamiento viral en cuanto a su transmisibilidad, unión a receptor de la célula hospedadora y escape del sistema inmune. Presentamos una revisión actualizada de los datos existentes en la literatura respecto a los aspectos microbiológicos y epidemiológicos que pueden ayudarnos a comprender las futuras investigaciones en esta variante.(AU)

A new variant of concern for SARS-CoV-2 has emerged, the effects of which on the evolution of the pandemic appear uncertain. However, evidence has begun to emerge regarding viral behavior in terms of its transmissibility, receptor binding on the host cell, and escape from the immune system. We present an updated review of the existing data in the literature regarding the microbiological and epidemiological aspects that can help us understand future research on this variant.(AU)

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The worldwide spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused an unprecedented public health crisis in the 21st century. As the pandemic evolves, the emergence of SARS-CoV-2 has been characterized by the emergence of new variants of concern (VOCs), which resulted in a catastrophic impact on SARS-CoV-2 infection. In light of this, research groups around the world are unraveling key aspects of the associated illness, coronavirus disease 2019 (COVID-19). A cumulative body of data has indicated that the SARS-CoV-2 viral load may be a determinant of the COVID-19 severity. Here we summarize the main characteristics of the emerging variants of SARS-CoV-2, discussing their impact on viral transmissibility, viral load, disease severity, vaccine breakthrough, and lethality among COVID-19 patients. We also provide a rundown of the rapidly expanding scientific evidence from clinical studies and animal models that indicate how viral load could be linked to COVID-19 prognosis and vaccine efficacy among vaccinated individuals, highlighting the differences compared to unvaccinated individuals.

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ABSTRACT Introduction: The SARS-CoV-2 pandemic has been a major challenge for the international scientific community. Since its inception, studies aiming to describe pathophysiological aspects and clinical manifestations of the disease have been conducted, raising hypotheses and confirming possible associations. One aspect of this scientific medical production is the role of the ocular surface as a means of transmission and clinical presentation of viral syndrome. Objectives: To analyze the role of the ocular surface in transmission, pathophysiology, and clinical manifestations of SARS-CoV-2, by means of a systematic review. Methods: The search was carried out in three databases: Cochrane, PubMed Central Journals and MEDLINE, using the following descriptors: "COVID-19, ophthalmology". The filters last five years and studies on humans resulted in 32 studies; in that 12 were excluded for not meeting the purpose of the study. Results: There are still few published studies on the relation between SARS-CoV-2 and the ocular route. Most studies showed an association between the presence of nonspecific ocular manifestations and infection by the new coronavirus, with limitations in the number of patients analyzed and the methodology adopted. Hypotheses about the pathophysiological role are largely anchored in the association of SARS-CoV and the ocular surface evaluated in the past. Comments: The results found are still not sufficient to confirm the role of the ocular surface in the pathophysiology of the disease. Most of these preliminary studies are of considerable importance in raising hypotheses based on the medical analysis of the patients studied. However, larger studies with standardized methodology for diagnostic protocol and laboratory analysis of the individuals assessed are required.

RESUMO Introdução: A pandemia da SARS-CoV-2 tem sido um grande desafio para a comunidade científica internacional. Desde seu surgimento, estudos com a intenção de descrever os aspectos fisiopatológicos e as manifestações clínicas da doença vêm sendo conduzidos, levantando hipóteses e confirmando possíveis associações. Um dos temas dessa produção médica científica é o papel da superfície ocular como meio de transmissão e apresentação clínica da síndrome viral. Objetivo: Analisar o papel da superfície ocular na transmissão, na fisiopatologia e nas manifestações clínicas de SARS-CoV-2, através de uma revisão sistemática. Realizou-se a busca em três bancos de dados Cochrane Database, PubMed® e MEDLINE®, utilizando os descritores "COVID-19 e ophthalmology". Foram definidos como filtros o artigo ter sido publicado nos últimos 5 anos e estudo realizado em humanos, tendo sido encontrados 32 artigos. Destes, foram excluídos 12 por não corresponderem ao objetivo do estudo. Resultados: Ainda são poucos os estudos publicados sobre a relação entre o coronavírus 2 da síndrome respiratória aguda grave (SARS-CoV-2) e a via ocular. A maioria dos estudos mostrou associação entre a presença de manifestações oculares inespecíficas e a infecção pelo novo coronavírus, com limitações no número de pacientes analisados e na metodologia adotada. Hipóteses sobre o papel fisiopatológico se ancoram, em grande parte, na associação estudada entre o SARS-CoV-2 e a superfície ocular no passado. Comentários: Os resultados encontrados ainda não são suficientes para confirmar o papel da superfície ocular na fisiopatologia da doença. Grande parte desses estudos preliminares têm importância considerável ao levantar hipóteses baseadas na análise clínica dos pacientes estudados. No entanto, são necessários estudos maiores e com metodologia padronizada para protocolo diagnóstico e análise laboratorial dos indivíduos avaliados.

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BACKGROUND: Respiratory syncytial virus (RSV) is responsible for most respiratory tract infections and hospitalizations in infants and represents a significant economic burden for public health. The development of a safe, effective, and affordable vaccine is a priority for the WHO. METHODS: We conducted a double-blinded, escalating-dose phase 1 clinical trial in healthy males aged 18-50 years to evaluate safety, tolerability, and immunogenicity of a recombinant Mycobacterium bovis BCG vaccine expressing the nucleoprotein of RSV (rBCG-N-hRSV). Once inclusion criteria were met, volunteers were enrolled in three cohorts in an open and successive design. Each cohort included six volunteers vaccinated with 5 × 103, 5 × 104, or 1 × 105 CFU, as well as two volunteers vaccinated with the full dose of the standard BCG vaccine. This clinical trial (clinicaltrials.gov NCT03213405) was conducted in Santiago, Chile. FINDINGS: The rBCG-N-RSV vaccine was safe, well-tolerated, and no serious adverse events related to the vaccine were recorded. Serum IgG-antibodies directed against Mycobacterium and the N-protein of RSV increased after vaccination, which were capable of neutralizing RSV in vitro. Additionally, all volunteers displayed increased cellular response consisting of IFN-γ and IL-2 production against PPD and the N-protein, starting at day 14 and 30 post-vaccination respectively. INTERPRETATION: The rBCG-N-hRSV vaccine had a good safety profile and induced specific cellular and humoral responses. FUNDING: This work was supported by Millennium Institute on Immunology and Immunotherapy from Chile (P09/016), FONDECYT 1190830, and FONDEF D11E1098.

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The purpose is to estimate the oxygen diffusion coefficient and the relaxation time of the cornea with respect to the oxygen tension at the cornea-tears interface. Both findings are discussed. From the experimental data provided by Bonanno et al., the oxygen tension measurements in vivo for human cornea-tears-contact lens (CL), the relaxation time of the cornea, and their oxygen diffusion coefficient were obtained by numerical calculation using the Monod-kinetic model. Our results, considering the relaxation time of the cornea, observe a different behavior. At the time less than 8 s, the oxygen diffusivity process is upper-diffusive, and for the relaxation time greater than 8 s, the oxygen diffusivity process is lower-diffusive. Both cases depend on the partial pressure of oxygen at the entrance of the cornea. The oxygen tension distribution in the cornea-tears interface is separated into two different zones: one for conventional hydrogels, which is located between 6 and 75 mmHg, with a relaxation time included between 8 and 19 s, and the other zone for silicone hydrogel CLs, which is located at high oxygen tension, between 95 and 140 mmHg, with a relaxation time in the interval of 1.5-8 s. It is found that in each zone, the diffusion coefficient varies linearly with the oxygen concentration, presenting a discontinuity in the transition of 8 s. This could be interpreted as an aerobic-to-anaerobic transition. We attribute this behavior to the coupling formalism between oxygen diffusion and biochemical reactions to produce adenosine triphosphate. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:14-21, 2020.

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OBJETIVO: Determinar el impacto causado por el tipo de herramienta y tipo de guante sobre la transmisibilidad de la vibración mano-brazo. MÉTODOS: Se realizó un diseño experimental a trabajadores del sector de hidrocarburos, con el objetivo de identificar la transmisibilidad global de los guantes en diferentes actividades. Las mediciones se realizaron a través de dos acelerómetros: uno instalado en la máquina y otro en la palma de la mano. La transmisibilidad fue calculada en el rango de frecuencias 0-2 kHz, para cinco tipos de herramientas y 3 tipos de guantes. Finalmente, se compararon los tiempos de exposición a los que puede estar expuesto el trabajador con el uso de los guantes. RESULTADOS: Se identificó la efectividad de los guantes para proteger a los operarios, permitiéndoles trabajar un mayor número de horas por día. El análisis estadístico evidencia que la variable tipo de herramienta tiene un efecto significativo sobre la transmisibilidad, mientras que el tipo de guante no presenta efecto estadístico alguno. El estudio presenta los porcentajes de aumento de tiempos de exposición y el estudio de las transmisibilidades. CONCLUSIONES: Los tres tipos de guantes evaluados mostraron tener un desempeño eficaz como atenuadores de la vibración. El aumento del tiempo de exposición permitido al usar guantes es muy significativo para todas las herramientas.

OBJECTIVE: Determine the impact caused by the type of tool and type of glove on the transmissibility of the hand-arm vibration. METHODS: An experimental design was carried out for workers in the hydrocarbon sector, in order to identify the global transmissibility of gloves in different activities. The measurements were made through two accelerometers: one installed in the machine and the other in the palm of the hand. The transmissibility was calculated in the fre quency range 0-2 kHz, for five types of tools and 3 types of gloves. Finally, the exposure times to which the worker may be exposed with the use of gloves were compared. RESULTS: The effectiveness of the gloves was identified to protect the workers, allowing them to work a greater number of hours per day. The statistical analysis shows that the variable type of tool has a significant effect on transmissibility, while the type of glove does not have any statistical effect. The study presents the percentages of increase in exposure times and the study of transmissibilities. CONCLUSIONS: The three types of gloves evaluated showed an effec tive performance as vibration attenuators. The increase of the expo sure time allowed when wearing gloves is very significant for all tools.

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Vibration in cycling has been proved to have undesirable effects over health, comfort and performance of the rider. In this study, 15 participants performed eight 6-min sub-maximal pedalling exercises at a constant power output (150W) and pedalling cadence (80 RPM) being exposed to vibration at different frequencies (20, 30, 40, 50, 60, 70 Hz) or without vibration. Oxygen uptake (VO2), heart rate (HR), surface EMG activity of seven lower limb muscles (GMax, RF, BF, VM, GAS, SOL and TA) and 3-dimentional accelerations at ankle, knee and hip were measured during the exercises. To analyse the dynamic response, the influence of the pedalling movement was taken into account. The results show that there was not significant influence of vibrations on HR and VO2 during this pedalling exercise. However, muscular activity presents a significant increase with the presence of vibration that is influenced by the frequency, but this increase was very low (< 1%). Also, the dynamic response shows an influence of the frequency as well as an influence of the different parts of the pedalling cycle. Those results help to explain the effects of vibration on the human body and the influence of the rider/bike interaction in those effects.

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INTRODUCTION: Epidemiological studies of the 1957 influenza pandemic are scarce, particularly from lower-income settings. METHODS: We analyzed the spatial-temporal mortality patterns of the 1957 influenza pandemic in Chile, including detailed age-specific mortality data from a large city, and investigated risk factors for severe mortality impact across regions. RESULTS: Chile exhibited two waves of excess mortality in winter 1957 and 1959 with a cumulative excess mortality rate of 12 per 10 000, and a ~10-fold mortality difference across provinces. High excess mortality rates were associated with high baseline mortality (R2 =41.8%; P=.02), but not with latitude (P>.7). Excess mortality rates increased sharply with age. Transmissibility declined from R=1.4-2.1 to R=1.2-1.4 between the two pandemic waves. CONCLUSIONS: The estimated A/H2N2 mortality burden in Chile is the highest on record for this pandemic-about three to five times as severe as that experienced in wealthier nations. The global impact of this pandemic may be substantially underestimated from previous studies based on high-income countries.

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MG-F protects chickens from MG Mycoplasmosis and monitoring is done by serology (SAR and ELISA) and PCR. Histopathology is used to evaluate bird response to MG. This study evaluated MG-F profile vaccination in SPF chicken. This trial used 100 chickens, being 40 unvaccinated (G1), 40 eye-drop vaccinated at 8 weeks of age with MG-F ( Ceva Animal Health , São Paulo , SP , Brazil ) (G2) and 20 immunized by contact (G3) . Samples were obtained on the 8th, 12th, 15th, 18th, 20th and 24th week for SAR, ELISA and PCR. Fragments of trachea and air sac, for microscopy, were got after necropsies on the 15th and 24th week. Up to 12 weeks there was no significant difference among groups by SAR. SAR reactions appeared from the 15th week with these averages: G1 (1.7, 1.76 , 0.1, 0.15) , G2 (7.81, 7.65, 8.25, 6.29) and G3 (8.1, 8.5, 9.5, 6.16), while by ELISA it occurred after the 18th week with optical densities averages: G1 (0.19, 0.14, 0.16) , G2 (0.47, 0.45, 0.41) and G3 (0.55, 0.51, 0.51) . Positivity in G3 by PCR occurred seven weeks after exposure. At the 15th week the air sac score means were 0.20, 0.55, and 0.32 and 24th week were 0.15, 0.80 and 0.66 (p>0.05). For trachea, G2 (0.48) yielded higher score average than G1 (0.10) and G3 (0.00) on the 15th week. Changes in G3 were seen only at 24th week, being this average (1.00) significantly different (p<0,05) from G1 (0.08) and G2 (0.46). SAR and PCR detected MG-F in G3 earlier than ELISA...

Mycoplasma gallisepticum cepa F (MG-F) é altamente utilizada em vacinação de poedeiras. MG-F confere bons níveis de proteção às galinhas, deslocando MG de campo ou diminuindo o número deles no trato respiratório. Soroaglutinação Rápida (SAR), ELISA e PCR são testes no monitoramento da micoplasmose, enquanto a histopatologia, mesmo não sendo rotineira, é usada para avaliar a resposta das aves à infecção por MG. O objetivo deste estudo foi avaliar a transmissibilidade, soroconversão e alterações teciduais de MG-F em galinhas. Um total de 100 galinhas SPF foi utilizado, sendo 40 delas não vacinadas (G1), 40 vacinadas na 8ª semana de idade com MG-F (Ceva Saúde Animal, São Paulo/SP, Brasil) (G2) e 20 imunizadas por contato com aves do G2 (G3). Soros e suabes traqueais foram obtidos na 8ª, 12ª, 15ª, 18ª, 20ª, 24ª semana para monitoramento por SAR, ELISA e PCR. Fragmentos de traqueia e saco aéreo, para microscopia, foram feitas após necropsias na 15ª e 24ª semana. Até a 12ª semana não houve diferença significativa entre os grupos pela SAR. Houve reação a SAR a partir da 15ª semana com as seguintes médias: G1 (1,7; 1,76; 0,1; 0,15), G2 (7,81; 7,65; 8,25; 6,29) e G3 (8,1; 8,5; 9,5; 6,16), enquanto por ELISA a soroconversão ocorreu a partir da 18ª semana com médias de densidades óticas de G1 (0,19; 0,14; 0,16), G2 (0,47; 0,45; 0,41) e G3 (0,55; 0,51; 0,51). Todas as aves do G3 apresentaram positividade pela PCR sete semanas após exposição. Não houve diferença significativa entre as medias dos escores de saco aéreo entre os grupos, na 15ª semana (0,20; 0,55; 0,32) e 24ª semana (0,15; 0,80 e 0,66). Em relação à traqueia, G2 apresentou média maior na 15ª semana (0,48) que G3 (0,00) e G1 (0,10). Alterações em G3 foram observadas somente na 24ª semana onde as médias foram de 0,08(G1); 0,46 (G2) e 1,00 (G3), havendo significância (p<0,05) entre G1 e G3. SAR e PCR foram capazes de detectar a transmissão de MG-F de forma precoce em relação ao ELISA...

Assuntos

RESUMO

MG-F protects chickens from MG Mycoplasmosis and monitoring is done by serology (SAR and ELISA) and PCR. Histopathology is used to evaluate bird response to MG. This study evaluated MG-F profile vaccination in SPF chicken. This trial used 100 chickens, being 40 unvaccinated (G1), 40 eye-drop vaccinated at 8 weeks of age with MG-F ( Ceva Animal Health , São Paulo , SP , Brazil ) (G2) and 20 immunized by contact (G3) . Samples were obtained on the 8th, 12th, 15th, 18th, 20th and 24th week for SAR, ELISA and PCR. Fragments of trachea and air sac, for microscopy, were got after necropsies on the 15th and 24th week. Up to 12 weeks there was no significant difference among groups by SAR. SAR reactions appeared from the 15th week with these averages: G1 (1.7, 1.76 , 0.1, 0.15) , G2 (7.81, 7.65, 8.25, 6.29) and G3 (8.1, 8.5, 9.5, 6.16), while by ELISA it occurred after the 18th week with optical densities averages: G1 (0.19, 0.14, 0.16) , G2 (0.47, 0.45, 0.41) and G3 (0.55, 0.51, 0.51) . Positivity in G3 by PCR occurred seven weeks after exposure. At the 15th week the air sac score means were 0.20, 0.55, and 0.32 and 24th week were 0.15, 0.80 and 0.66 (p>0.05). For trachea, G2 (0.48) yielded higher score average than G1 (0.10) and G3 (0.00) on the 15th week. Changes in G3 were seen only at 24th week, being this average (1.00) significantly different (p<0,05) from G1 (0.08) and G2 (0.46). SAR and PCR detected MG-F in G3 earlier than ELISA. Higher tracheal changes for G2 and G3 as compared to G1 could be ascribed to MG-F vaccine infection.(AU)

Mycoplasma gallisepticum cepa F (MG-F) é altamente utilizada em vacinação de poedeiras. MG-F confere bons níveis de proteção às galinhas, deslocando MG de campo ou diminuindo o número deles no trato respiratório. Soroaglutinação Rápida (SAR), ELISA e PCR são testes no monitoramento da micoplasmose, enquanto a histopatologia, mesmo não sendo rotineira, é usada para avaliar a resposta das aves à infecção por MG. O objetivo deste estudo foi avaliar a transmissibilidade, soroconversão e alterações teciduais de MG-F em galinhas. Um total de 100 galinhas SPF foi utilizado, sendo 40 delas não vacinadas (G1), 40 vacinadas na 8ª semana de idade com MG-F (Ceva Saúde Animal, São Paulo/SP, Brasil) (G2) e 20 imunizadas por contato com aves do G2 (G3). Soros e suabes traqueais foram obtidos na 8ª, 12ª, 15ª, 18ª, 20ª, 24ª semana para monitoramento por SAR, ELISA e PCR. Fragmentos de traqueia e saco aéreo, para microscopia, foram feitas após necropsias na 15ª e 24ª semana. Até a 12ª semana não houve diferença significativa entre os grupos pela SAR. Houve reação a SAR a partir da 15ª semana com as seguintes médias: G1 (1,7; 1,76; 0,1; 0,15), G2 (7,81; 7,65; 8,25; 6,29) e G3 (8,1; 8,5; 9,5; 6,16), enquanto por ELISA a soroconversão ocorreu a partir da 18ª semana com médias de densidades óticas de G1 (0,19; 0,14; 0,16), G2 (0,47; 0,45; 0,41) e G3 (0,55; 0,51; 0,51). Todas as aves do G3 apresentaram positividade pela PCR sete semanas após exposição. Não houve diferença significativa entre as medias dos escores de saco aéreo entre os grupos, na 15ª semana (0,20; 0,55; 0,32) e 24ª semana (0,15; 0,80 e 0,66). Em relação à traqueia, G2 apresentou média maior na 15ª semana (0,48) que G3 (0,00) e G1 (0,10). Alterações em G3 foram observadas somente na 24ª semana onde as médias foram de 0,08(G1); 0,46 (G2) e 1,00 (G3), havendo significância (p<0,05) entre G1 e G3. SAR e PCR foram capazes de detectar a transmissão de MG-F de forma precoce em relação ao ELISA. [...](AU)

Assuntos