Early Genomic, Epidemiological, and Clinical Description of the SARS-CoV-2 Omicron Variant in Mexico City.

Omicron is the most mutated SARS-CoV-2 variant-a factor that can affect transmissibility, disease severity, and immune evasiveness. Its genomic surveillance is important in cities with millions of inhabitants and an economic center, such as Mexico City. Results. From 16 November to 31 December 2021, we observed an increase of 88% in Omicron prevalence in Mexico City. We explored the R346K substitution, prevalent in 42% of Omicron variants, known to be associated with immune escape by monoclonal antibodies. In a phylogenetic analysis, we found several independent exchanges between Mexico and the world, and there was an event followed by local transmission that gave rise to most of the Omicron diversity in Mexico City. A haplotype analysis revealed that there was no association between haplotype and vaccination status. Among the 66% of patients who have been vaccinated, no reported comorbidities were associated with Omicron; the presence of odynophagia and the absence of dysgeusia were significant predictor symptoms for Omicron, and the RT-qPCR Ct values were lower for Omicron. Conclusions. Genomic surveillance is key to detecting the emergence and spread of SARS-CoV-2 variants in a timely manner, even weeks before the onset of an infection wave, and can inform public health decisions and detect the spread of any mutation that may affect therapeutic efficacy.

The Evolutionary Landscape of SARS-CoV-2 Variant B.1.1.519 and Its Clinical Impact in Mexico City.

The SARS-CoV-2 pandemic is one of the most concerning health problems around the globe. We reported the emergence of SARS-CoV-2 variant B.1.1.519 in Mexico City. We reported the effective reproduction number (Rt) of B.1.1.519 and presented evidence of its geographical origin based on phylogenetic analysis. We also studied its evolution via haplotype analysis and identified the most recurrent haplotypes. Finally, we studied the clinical impact of B.1.1.519. The B.1.1.519 variant was predominant between November 2020 and May 2021, reaching 90% of all cases sequenced in February 2021. It is characterized by three amino acid changes in the spike protein: T478K, P681H, and T732A. Its Rt varies between 0.5 and 2.9. Its geographical origin remain to be investigated. Patients infected with variant B.1.1.519 showed a highly significant adjusted odds ratio (aOR) increase of 1.85 over non-B.1.1.519 patients for developing a severe/critical outcome (p = 0.000296, 1.33-2.6 95% CI) and a 2.35-fold increase for hospitalization (p = 0.005, 1.32-4.34 95% CI). The continuous monitoring of this and other variants will be required to control the ongoing pandemic as it evolves.

Saliva is a reliable and accessible source for the detection of SARS-CoV-2.

OBJECTIVES: The aim of this study was to investigate the feasibility of saliva sampling as a non-invasive and safer tool to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to compare its reproducibility and sensitivity with nasopharyngeal swab samples (NPS). The use of sample pools was also investigated. METHODS: A total of 2107 paired samples were collected from asymptomatic healthcare and office workers in Mexico City. Sixty of these samples were also analyzed in two other independent laboratories for concordance analysis. Sample processing and analysis of virus genetic material were performed according to standard protocols described elsewhere. A pooling analysis was performed by analyzing the saliva pool and the individual pool components. RESULTS: The concordance between NPS and saliva results was 95.2% (kappa 0.727, p = 0.0001) and 97.9% without considering inconclusive results (kappa 0.852, p = 0.0001). Saliva had a lower number of inconclusive results than NPS (0.9% vs 1.9%). Furthermore, saliva showed a significantly higher concentration of both total RNA and viral copies than NPS. Comparison of our results with those of the other two laboratories showed 100% and 97% concordance. Saliva samples are stable without the use of any preservative, and a positive SARS-CoV-2 sample can be detected 5, 10, and 15 days after collection when the sample is stored at 4 °C. CONCLUSIONS: The study results indicate that saliva is as effective as NPS for the identification of SARS-CoV-2-infected asymptomatic patients. Sample pooling facilitates the analysis of a larger number of samples, with the benefit of cost reduction.

Evolucionismo en América y Europa. Antropología, biología, política y educación

La reflexión y debate sobre el origen y evolución de las especies, y sus implicaciones filosóficas, teológicas y científicas, han ejercido una fascinación entre los seres humanos, especialmente a partir de la publicación de Charles Darwin, El origen de las especies, en 1859. Los debates suscitados por el mecanismo de la selección natural primero, y en torno al origen de la especie humana casi de inmediato, trascendieron los ámbitos de la historia natural y la biología. La revolución darwiniana suscitó apasionados y en ocasiones ideologizados debates en la sociología, la antropología, la medicina, el colonialismo, la educación, la política, la ética, el arte. La teoría de la evolución se convirtió en un elemento de las discusiones sobre las «razas» humanas y sus relaciones de poder, los proyectos eugenésicos, los determinismos geográficos, entre otros. Y con el tiempo, las complejas formas mediante las cuales las ideas evolucionistas han circulado en el mundo se tornaron en objeto de análisis histórico. Debatir sobre el darwinismo y la teoría de la evolución como cultura es el objetivo de este libro, que reúne los trabajos presentados durante el VI Coloquio Internacional sobre Darwinismo en Europa y América, llevado a cabo en Puerto Ayora (Galápagos, Ecuador) en mayo de 2015. En los artículos se analizan las imbricaciones del darwinismo con la ética, la conservación de la naturaleza, la antropología, la eugenesia, la política, la educación y la investigación biológica, entre otros campos, desde perspectivas históricas y contemporáneas, en diversos lugares desde Estados Unidos hasta Argentina, y en la Europa occidental. (AU)

Memoria y porvenir en el aparato psíquico freudiano / Memory and future in the freudian psyquic apparatus

En este texto hago un cruce entre algunas de las características de las huellas mnémicas que se inscriben en la pizarra mágica que describe Freud en su texto Nota sobre la pizarra mágica y el pensamiento de la huella y la escritura en Derrida. Sostengo que el pensamiento de la huella en Freud se puede colocar dentro de la crítica a la metafísica de la presencia de la deconstrucción. La capa de cera de la pizarra mágica es el estrato donde se inscriben huellas que tienen la característica de no ser inalterables. Esta alterabilidad trae como consecuencia que el aparato psíquico se coloque en el medio de un juego entre presencia y ausencia y memoria y espera. La consecuencia no es sólo que el aparato psíquico funcione en esta lógica de una huella siempre abierta al porvenir, sino que es también el ser humano como existencia que queda inscrito en esta lógica del asedio de los fantasmas de su pasado y de su futuro, para bien o para mal, para una mejor o peor vida.