Presence of SARS-CoV-2-specific T cells before vaccination in the Mexican population.

The immune response to SARS-CoV-2 has been extensively studied following the pandemic outbreak in 2020; however, the presence of specific T cells against SARS-CoV-2 before vaccination has not been evaluated in Mexico. In this study, we estimated the frequency of T CD4+ and T CD8+ cells that exhibit a specific response to S (spike) and N (nucleocapsid) proteins in a Mexican population. We collected 78 peripheral blood samples from unvaccinated subjects and the presence of antibodies against spike (RBD) and N protein was determined. PBMCs (peripheral blood mononuclear cells) were isolated and stimulated with a pool of S or N protein peptides (Wuhan-Hu-1 strain). IL-1ß, IL-4, IL-6, IL-10, IL-2, IL-8, TNF-α, IFN-γ, and GM-CSF levels were quantified in the supernatant of the activated cells, and the cells were stained to assess the activation and memory phenotypes. Differential activation frequency dependent upon serological status was observed in CD4+ cells, but not in CD8+ cells. The predominantly activated population was the central memory T CD4+ cells. Only 10% of the population exhibited the same phenotype with respect to the response to nucleocapsid peptides. The cytokine profile differed between the S and N responses. S peptides induced a more proinflammatory response compared with the N peptides. In conclusion, in a Mexican cohort before vaccination, there was a significant response to the S and N SARS-CoV-2 proteins resulting from previous infections with seasonal coronaviruses or previous undetected exposure to SARS-CoV-2.

Single nucleotide polymorphisms of ANKK1, DDR4, and GRIN2B genes predict behavior in a prospective cohort of Mexican children and adolescents.

Numerous studies have established associations between single nucleotide polymorphisms (SNPs) and various behavioral and neurodevelopmental conditions. This study explores the links between SNPs in candidate genes involved in central nervous system (CNS) physiology and their implications for the behavioral and emotional aspects in children and teenagers. A total of 590 participants, aged 7-15 years, from the Early Life Exposures In Mexico To Environmental Toxicants (ELEMENT) cohort study in Mexico City, underwent genotyping for at least one of 15 CNS gene-related SNPs at different timepoints. We employed multiple linear regression models to assess the potential impact of genetic variations on behavioral and cognitive traits, as measured by the Behavioral Assessment System for Children (BASC) and Conners parent rating scales. Significant associations were observed, including the rs1800497 TC genotype (ANKK1) with the Cognitive Problems/Inattention variable (p value = 0.003), the rs1800955 CT genotype (DDR4) with the Emotional Lability Global index variable (p value = 0.01), and the rs10492138 GA and rs7970177 TC genotypes (GRIN2B) with the Depression variable (p values 0.007 and 0.012, respectively). These finds suggest potential genetic profiles associated with "risk" and "protective" behaviors for these SNPs. Our results provide valuable insights into the role of genetic variations in neurobehavior and highlight the need for further research in the early identification and intervention in individuals at risk for these conditions.

Encuesta Nacional de Salud y Nutrición 2023: metodología y avances de la Ensanut Continua 2020-2024.

OBJETIVO: Presentar la metodología de la Encuesta Nacional de Salud y Nutrición 2023 (Ensanut 2023) y describir los procedimientos de inferencia para conjuntar la información colectada por la Ensanut Continua 2020-2024. Material y métodos. La Ensanut 2023 es la cuarta encuesta de la serie Ensanut Continua. Se describe el alcance de la Ensanut 2023 junto con sus procedimientos de muestreo, estimación, medición y organización logística. Además, se discute el procedimiento básico de estimación para analizar la integración de las encuestas Ensanut Continua 2020-2024. RESULTADOS: La Ensanut 2023 obtendrá a nivel nacional al menos 11 720 entrevistas completas de hogar y 13 378 cuestionarios completos de adulto. La unión de las Ensanut Continua 2020-2023 permitirá, en general, estimar a nivel estatal prevalencias p≥5% en adultos, con confiabilidad tolerable según las recomendaciones del Instituto Nacional de Estadística y Geografía. CONCLUSIONES: El análisis de la unión de la Ensanut Continua 2020-2023 permitirá iniciar la generación de estimaciones nacionales y estatales sobre el estado de salud y nutrición de la población mexicana.

Prevalencia de anticuerpos y vacunación contra SARS-CoV-2 en 2022 en México.

OBJETIVO: Describir la prevalencia de anticuerpos contra SARS-CoV-2, vacunación, barreras y rechazo a la vacunación Covid-19 en población mexicana. Material y métodos. Se utilizó información de los integrantes del hogar de uno y más años, incluidos en la Encuesta Nacional de Salud y Nutrición Continua 2022 (Ensanut Continua 2022) realizada de agosto-noviembre. Se estimó la prevalencia de anticuerpos antiproteínas N y S de SARS-CoV-2 en muestras de sangre capilar, dosis reportadas de vacunación a Covid-19 y las razones de barreras y rechazo a la vacunación. RESULTADOS: La prevalencia de anticuerpos anti-N fue de 94.4% y de anti-S 98.1%. La prevalencia de anticuerpos anti-S fue mayor en personas vacunadas con una, dos o tres o más dosis que en no vacunadas. Dentro de la población elegible a vacunación, 20.2% no estaba vacunada, 16.2% tenía una dosis, 30% dos dosis y 33.6% tres dosis o más. El 11.2% de la población elegible rechazó la vacunación, 5.5% reportó una barrera y 3.2% reportó que la vacuna no había llegado a su localidad. Conclusión. La prevalencia de anticuerpos por infección natural y por vacunación Covid-19 es alta en México. Las variaciones de rechazo y barreras a la vacunación entre grupos de edad y regiones deben tomarse en cuenta para intensificar esfuerzos específicos para la vacunación.

SARS-CoV-2 seroprevalence and vaccine coverage from August to November 2021: A nationally representative survey in Mexico.

We aimed to estimate self-reported vaccine coverage and SARS-CoV-2 anti-N and anti-S seroprevalence in Mexico overall and for five vaccine types. We used a nationally representative survey with 7236 dried blood spot samples for adults 18 years and older collected from August to November 2021. Anti-N and anti-S seroprevalence were estimated adjusting for the sensitivity and specificity of the immunoassay test. A multivariate Poisson regression model was used to estimate seroprevalence by vaccine type and by age group adjusting for confounders and test performance. Vaccination coverage was 74%, being higher in women compared to men, high socioeconomic status (SES) compared to low and middle SES, graduates compared to people with high school, and formal workers compared to other employment statuses. Anti-N seroprevalence was 59.2%, compared to 84.1% anti-S seroprevalence. Anti-S seroprevalence was higher for vaccinated than unvaccinated participants. All vaccines were associated with more than 70% anti-S seroprevalence, with the lowest being observed for CoronaVac and Ad5-nCoV. Fully vaccinated participants over 60 years presented a lower seroprevalence (77.6%) compared to younger adults (91.1%), with larger differences for ChAdOx1 and CoronaVac vaccines. Between August and November 2021, three out of four Mexican adults had been vaccinated. Vaccination was associated with a higher positivity to anti-S antibodies. While antibodies do not reflect immunity, our results suggest that booster doses should be offered to people over 60 years of age and to adults who received Ad5-nCoV or CoronaVac as primary vaccination schemes.

Elevated levels of enteric IgA in an unimmunised mouse model of Hyper IgM syndrome derived from gut-associated secondary lymph organs even in the absence of germinal centres.

Introduction: Patients with Human Hyper IgM syndromes (HIGM) developed pulmonary and gastrointestinal infections since infancy and most patients have mutations in the CD40 ligand (CD40L) gene. Most HIGM patients compared to healthy subjects have higher/similar IgM and lower IgG, and IgA serum concentrations but gut antibody concentrations are unknown. CD40L on activated T-cells interacts with CD40 on B-cells, essential for the formation of germinal centres (GCs) inside secondary lymphoid organs (SLOs), where high-affinity antibodies, long-lived antibody-secreting plasma cells, and memory B-cells, are produced. C57BL6-CD40 ligand deficient mice (C57BL6-cd40l -/-), are a model of HIGM, because serum immunoglobulin concentrations parallel levels observed in HIGM patients and have higher faecal IgA concentrations. In mice, TGFß and other cytokines induce IgA production. Aims: To compare and evaluate B-cell populations and IgA-producing plasma cells in peritoneal lavage, non-gut-associated SLOs, spleen/inguinal lymph nodes (ILN), and gut-associated SLOs, mesenteric lymph nodes (MLN)/Peyer´s patches (PP) of unimmunised C57BL6-cd40l -/- and C57BL6-wild-type (WT) mice. Material and methods: Peritoneal lavages, spleens, ILN, MLN, and PP from 8-10 weeks old C57BL6-cd40l -/- and WT mice, were obtained. Organ cryosections were analysed by immunofluorescence and B-cell populations and IgA-positive plasma cell suspensions by flow cytometry. Results: In unimmunised WT mice, GCs were only observed in the gut-associated SLOs, but GCs were absent in all C57BL6-cd40l -/- SLOs. PP and MLN of C57BL6-cd40l -/- mice exhibited a significantly higher number of IgA-producing cells than WT mice. In the spleen and ILN of C57BL6-cd40l- /- mice IgA-producing cells significantly decreased, while IgM-positive plasma cells increased. C57BL6-cd40l -/- B-1 cells were more abundant in all analysed SLOs, whereas in WT mice most B-1 cells were contained within the peritoneal cavity. C57BL6-cd40l -/- B-cells in MLN expressed a higher TGFß receptor-1 than WT mice. Mouse strains small intestine microvilli (MV), have a similar frequency of IgA-positive cells. Discussion: Together our results confirm the role of PP and MLN as gut inductive sites, whose characteristic features are to initiate an IgA preferential immune response production in these anatomical sites even in the absence of GCs. IgA antibodies play a pivotal role in neutralising, eliminating, and regulating potential pathogens and microorganisms in the gut.

Structural and immunological basis of cross-reactivity between dengue and Zika infections: Implications in serosurveillance in endemic regions.

Dengue and Zika are arthropod-borne viral diseases present in more than 100 countries around the world. In the past decade, Zika emerged causing widespread outbreaks in new regions, where dengue has been endemic-epidemic for a long period. The wide and extensive dissemination of the mosquito vectors, Aedes aegypti, and Ae. albopictus, favor the co-existence of both infections in the same regions. Together with an important proportion of asymptomatic infections, similar clinical manifestations, and a short time window for acute infection confirmatory tests, it is difficult to differentially estimate both dengue and Zika incidence and prevalence. DENV and ZIKV flavivirus share high structural similarity, inducing a cross-reactive immune response that leads to false positives in serological tests particularly in secondary infections. This results in overestimation of recent Zika outbreaks seroprevalence in dengue endemic regions. In this review, we address the biological basis underlying DENV and ZIKV structural homology; the structural and cellular basis of immunological cross reactivity; and the resulting difficulties in measuring dengue and Zika seroprevalence. Finally, we offer a perspective about the need for more research to improve serological tests performance.

Characterization of immunoglobulin loci in the gigantic genome of Ambystoma mexicanum.

Background: The axolotl, Ambystoma mexicanum is a unique biological model for complete tissue regeneration. Is a neotenic endangered species and is highly susceptible to environmental stress, including infectious disease. In contrast to other amphibians, the axolotl is particularly vulnerable to certain viral infections. Like other salamanders, the axolotl genome is one of the largest (32 Gb) and the impact of genome size on Ig loci architecture is unknown. To better understand the immune response in axolotl, we aimed to characterize the immunoglobulin loci of A. mexicanum and compare it with other model vertebrates. Methods: The most recently published genome sequence of A. mexicanum (V6) was used for alignment-based annotation and manual curation using previously described axolotl Ig sequences or reference sequences from other vertebrates. Gene models were further curated using A. mexicanum spleen RNA-seq data. Human, Xenopus tropicalis, Danio rerio (zebrafish), and eight tetrapod reference genomes were used for comparison. Results: Canonical A. mexicanum heavy chain (IGH), lambda (IGL), sigma (IGS), and the putative surrogate light chain (SLC) loci were identified. No kappa locus was found. More than half of the IGHV genes and the IGHF gene are pseudogenes and there is no clan I IGHV genes. Although the IGH locus size is proportional to genome size, we found local size restriction in the IGHM gene and the V gene intergenic distances. In addition, there were V genes with abnormally large V-intron sizes, which correlated with loss of gene functionality. Conclusion: The A. mexicanum immunoglobulin loci share the same general genome architecture as most studied tetrapods. Consistent with its large genome, Ig loci are larger; however, local size restrictions indicate evolutionary constraints likely to be imposed by high transcriptional demand of certain Ig genes, as well as the V(D)J recombination over very long genomic distance ranges. The A. mexicanum has undergone an extensive process of Ig gene loss which partially explains a reduced potential repertoire diversity that may contribute to its impaired antibody response.

AIRR-C IG Reference Sets: curated sets of immunoglobulin heavy and light chain germline genes.

Introduction: Analysis of an individual's immunoglobulin (IG) gene repertoire requires the use of high-quality germline gene reference sets. When sets only contain alleles supported by strong evidence, AIRR sequencing (AIRR-seq) data analysis is more accurate and studies of the evolution of IG genes, their allelic variants and the expressed immune repertoire is therefore facilitated. Methods: The Adaptive Immune Receptor Repertoire Community (AIRR-C) IG Reference Sets have been developed by including only human IG heavy and light chain alleles that have been confirmed by evidence from multiple high-quality sources. To further improve AIRR-seq analysis, some alleles have been extended to deal with short 3' or 5' truncations that can lead them to be overlooked by alignment utilities. To avoid other challenges for analysis programs, exact paralogs (e.g. IGHV1-69*01 and IGHV1-69D*01) are only represented once in each set, though alternative sequence names are noted in accompanying metadata. Results and discussion: The Reference Sets include less than half the previously recognised IG alleles (e.g. just 198 IGHV sequences), and also include a number of novel alleles: 8 IGHV alleles, 2 IGKV alleles and 5 IGLV alleles. Despite their smaller sizes, erroneous calls were eliminated, and excellent coverage was achieved when a set of repertoires comprising over 4 million V(D)J rearrangements from 99 individuals were analyzed using the Sets. The version-tracked AIRR-C IG Reference Sets are freely available at the OGRDB website (https://ogrdb.airr-community.org/germline_sets/Human) and will be regularly updated to include newly observed and previously reported sequences that can be confirmed by new high-quality data.

Comparable diagnostic accuracy of SARS-CoV-2 Spike RBD and N-specific IgG tests to determine pre-vaccination nation-wide baseline seroprevalence in Mexico.

A major challenge for developing countries during the COVID-19 pandemic is affordable and adequate monitoring of disease progression and population exposure as the primary source relevant epidemiological indicators. Serology testing enables assessing population exposure and to guide vaccination strategies but requires rigorous accuracy validation before population-wide implementation. We adapted a two-step ELISA protocol as a single-step protocol for detection of IgG against the Receptor Binding Domain (RBD) of SARS-CoV-2 spike protein and compared its diagnostic accuracy with a commercial immunoassay anti-nucleoprotein IgG. Both methods yielded adequate and comparable diagnostic accuracy after 3 weeks post-symptom onset and were implemented in a nation-wide population based serological survey during August-November 2020. Anti-RBD National seroprevalence was 23.6%, 1.3% lower, but not significantly, than for anti-N. Double positive seroprevalence was 19.7%. Anti-N single-positive seroprevalence was 3.72% and anti-RBD single-positive seroprevalence was 1.98%. Discrepancies in the positivity to either single marker may be due to different kinetics of each antibody marker as well as the heterogeneity of the sampling time in regards to local epidemic waves. Baseline single positivity prevalence will be useful to assess the serological impact of vaccination and natural infection in further serosurveillance efforts.

Three highly variable genome regions of the four dengue virus serotypes can accurately recapitulate the CDS phylogeny.

The circulation of the four-dengue virus (DENV) serotypes has significantly increased in recent years, accompanied by an increase in viral genetic diversity. In order to conduct disease surveillance and understand DENV evolution and its effects on virus transmission and disease, efficient and accurate methods for phylogenetic classification are required. Phylogenetic analysis of different viral genes sequences is the most used method, the envelope gene (E) being the most frequently selected target. We explored the genetic variability of the four DENV serotypes throughout their complete coding sequence (CDS) of sequences available in GenBank and used genomic regions of different variability rate to recapitulate the phylogeny obtained with the DENV CDS. Our results indicate that the use of high or low variable regions accurately recapitulate the phylogeny obtained with CDS of sequences from different DENV genotypes. However, when analyzing the phylogeny of a single genotype, highly variable regions performed better in recapitulating the distance branch length, topology, and support of the CDS phylogeny. The use of three concatenated highly variable regions was not statistically different in distance branch length and support to that obtained in CDS phylogeny.•This study demonstrated the ability of highly variable regions of the DENV genome to recapitulate the phylogeny obtained with the full coding sequence (CDS).•The use of genomic regions of high or low variability did not affect the performance in recapitulating the phylogeny obtained with CDS from different genotypes. However, when phylogeny was analyzed for sequences from a single genotype, highly variable regions performed better in recapitulating the distance branch length, topology, and support of the CDS phylogeny.•The use of concatenated highly variable genome regions represent a useful option for recapitulating genome-wide phylogenies in analyses of sequences belonging to the same DENV genotype.

Metodología de la Encuesta Nacional de Salud y Nutrición 2022 y Planeación y diseño de la Ensanut Continua 2020-2024.

OBJETIVO: Presentar el diseño de la Encuesta Nacional de Salud y Nutrición (Ensanut) 2022 y cuantificar el avance de la Ensanut Continua 2020-2024. Material y métodos. La Ensanut 2022 es la tercera encuesta de la serie de en-cuestas denominada Ensanut Continua 2020-2024. En este documento se describe el alcance de la Ensanut 2022 y sus procedimientos de muestreo, medición y organización logís-tica. Además, se presenta el avance esperado de la Ensanut Continua 2020-2024 al concluir la Ensanut 2022. Resulta-dos. La Ensanut 2022 obtendrá, a nivel nacional, al menos 10 160 entrevistas completas de hogar y 9 441 resultados de seropositividad a SARS-CoV-2. CONCLUSIONES: La Ensanut 2022 estimará la prevalencia de seropositividad a SARS-CoV-2 a nivel nacional y regional y avanzará en la acumulación de información para alcanzar los objetivos de la Ensanut Con-tinua 2020-2024.

Prevalence of anti-SARS-CoV-2 antibodies and associated factors in healthcare workers of a Mexican Covid-19 hospital

OBJECTIVE: To determine the prevalence of SARS-CoV-2 antibodies among healthcare workers (HCW) and to identify factors associated with infection. Materials and meth-ods. A cross-sectional study was conducted in a Covid-19 hospital in Morelos, Mexico. Antibodies against SARS-CoV-2 spike and nucleocapsid proteins were detected by ELISA. A bivariate and multivariable Poisson regression model were performed to identify factors associated with infection. RESULTS: Among all participants, 31% had anti-SARS-CoV-2 antibodies, while only 13.1% had reported a history of positive RT-PCR. Individuals who reported cohabiting with someone with Covid-19, and those who had a previous RT-PCR test, were more likely to be seropositive. Laboratory personnel had the lowest seroprevalence (12.0%), while social workers had the highest (35.7%). CONCLUSIONS: The results of this study show the seroprevalence of SARS-CoV-2 antibodies among HCW in a hospital in Mexico, and underline the importance of serological tests for a better estimate of prevalence in health systems where only symptomatic cases are recorded.

Genetic diversity and spatiotemporal dynamics of DENV-1 and DENV-2 infections during the 2012-2013 outbreak in Mexico.

Dengue fever is caused by four related dengue virus serotypes, DENV-1 to DENV-4, where each serotype comprises distinct genotypes and lineages. The last major outbreak in Mexico occurred during 2012 and 2013, when 112,698 confirmed cases were reported (DENV-1 and DENV-2 were predominant). Following partial E, NS2A and NS5 gene sequencing, based on the virus genome variability, we analyzed 396 DENV-1 and 248 DENV-2 gene sequences from serum samples from dengue acute clinical cases from 13 Mexican states, Mutations were identified, and their genetic variability estimated, along with their evolutionary relationship with DENV sequences sampled globally. DENV-1 genotype V and DENV-2 Asian-American genotype V were the only genotypes circulating during the outbreak. Mutations in NS2A and NS5 proteins were widely disseminated and suggested local emergence of new lineages. Phylogeographic analysis suggested viral spread occurred from coastal regions, and tourist destinations, such as Yucatan and Quintana Roo, which played important roles in disseminating these lineages.

Nationally representative SARS-CoV-2 antibody prevalence estimates after the first epidemic wave in Mexico.

Seroprevalence surveys provide estimates of the extent of SARS-CoV-2 infections in the population, regardless of disease severity and test availability. In Mexico in 2020, COVID-19 cases reached a maximum in July and December. We aimed to estimate the national and regional seroprevalence of SARS-CoV-2 antibodies across demographic and socioeconomic groups in Mexico after the first wave, from August to November 2020. We used nationally representative survey data including 9,640 blood samples. Seroprevalence was estimated by socioeconomic and demographic characteristics, adjusting by the sensitivity and specificity of the immunoassay test. The national seroprevalence of SARS-CoV-2 antibodies was 24.9% (95%CI 22.2, 26.7), being lower for adults 60 years and older. We found higher seroprevalence among urban and metropolitan areas, low socioeconomic status, low education and workers. Among seropositive people, 67.3% were asymptomatic. Social distancing, lockdown measures and vaccination programs need to consider that vulnerable groups are more exposed to the virus and unable to comply with lockdown measures.

Metodología de la Encuesta Nacional de Salud y Nutrición 2021 / National Health and Nutrition Survey 2021 methodology

Resumen: Objetivo: Describir el diseño de la Encuesta Nacional de Salud y Nutrición 2021 (Ensanut 2021). Material y métodos: La Ensanut 2021 es una encuesta probabilística de hogares que forma parte de la serie de Ensanut Continua 2020-2024. En esta ocasión se describen el alcance, el muestreo, la medición y la organización logística. Resultados: Se planea obtener al menos 12 060 entrevistas de hogar completas a nivel nacional y 9 837 muestras para determinar seropositividad a SARS-CoV-2 a nivel nacional. Conclusiones: La Ensanut 2021 permitirá realizar inferencias regionales sobre la prevalencia de seropositividad a SARS-CoV-2 y también acumular información para realizar inferencias estatales en el año 2024.

Abstract: Objective: To describe the design of the Mexican 2021 National Health and Nutrition Survey (Ensanut 2021). Materials and methods: The Ensanut 2021 is a probabilistic household survey that is part of the continuous Ensanut 2020-2024; survey outreach, sampling, measurement and logistic organization are described. Results: It is planned to obtain at least 12 060 complete household interviews and 9 837 samples to determine SARS-CoV-2 seropositivity at the national level. Conclusions: Ensanut 2021 will allow to estimate the seroprevalence of SARS-CoV-2 antibodies at regional and national level; also, it will accumulate information to make state inferences for the year 2024.

Metodología de la Encuesta Nacional de Salud y Nutrición 2020 sobre Covid-19 / National Health and Nutrition Survey 2020 Covid-19 methodology

Resumen Objetivo: Describir el diseño y los resultados de campo de la Encuesta Nacional de Salud y Nutrición (Ensanut) 2020 sobre Covid-19. Material y métodos: La Ensanut Covid-19 es una encuesta probabilística de hogares. En este artículo se describen los siguientes elementos del diseño: alcance, muestreo, medición, inferencia y logística. Resultados: Se obtuvieron 10 216 entrevistas de hogar completas y 9 464 resultados sobre seropositividad a SARS-CoV-2. La tasa de respuesta de hogar fue 80% y la de prueba de seropositividad de 44%. Conclusiones: El diseño probabilístico de la Ensanut Covid-19 permite hacer inferencias estadísticas válidas sobre parámetros de interés para la salud pública a nivel nacional y regional; en particular, permitirá hacer inferencias de utilidad práctica sobre la prevalencia de seropositividad a SARS-CoV-2 en México. Además, la Ensanut Covid-19 podrá ser comparada con Ensanut previas para identificar potenciales cambios en los estados de salud y nutrición de la población mexicana.

Abstract Objective: To describe the design and field results of the National Health and Nutrition Survey (Ensanut, for its Spanish acronym) Covid-19. Materials and methods: Ensanut Covid-19 is a probabilistic household survey. The following elements of the design are described in this article: scope, sampling, measurement, inference, and logistic organization. Results: Ensanut, Covid-19 got 10 216 completed household interviews and 9 464 individual results on SARS-CoV-2 seropositivity. The household response rate was 80%. The response rate to the seropositivity test was 44%. Conclusions: The probabilistic design of Ensanut Covid-19 allows to make valid statistical inferences on parameters of interest to public health at the national and regional levels. In particular, Ensanut, Covid-19 will enable to make inferences of practical utility on the prevalence of seropositivity to SARS-CoV-2 in Mexico. In addition, Ensanut Covid-19 2020 can be compared to previous Ensanut, in order to identify potential changes in the health and nutrition status of the Mexican population.

Metodología de la Encuesta Nacional de Salud y Nutrición 2020 sobre Covid-19.

Objetivo. Describir el diseño y los resultados de campo de la Encuesta Nacional de Salud y Nutrición (Ensanut) 2020 so-bre Covid-19. Material y métodos. La Ensanut Covid-19 es una encuesta probabilística de hogares. En este artículo se describen los siguientes elementos del diseño: alcance, muestreo, medición, inferencia y logística. Resultados. Se obtuvieron 10 216 entrevistas de hogar completas y 9 464 resultados sobre seropositividad a SARS-CoV-2. La tasa de respuesta de hogar fue 80% y la de prueba de seropositividad de 44%. Conclusiones. El diseño probabilístico de la Ensa-nut Covid-19 permite hacer inferencias estadísticas válidas sobre parámetros de interés para la salud pública a nivel nacional y regional; en particular, permitirá hacer inferencias de utilidad práctica sobre la prevalencia de seropositividad a SARS-CoV-2 en México. Además, la Ensanut Covid-19 podrá ser comparada con Ensanut previas para identificar potenciales cambios en los estados de salud y nutrición de la población mexicana.

Metodología de la Encuesta Nacional de Salud y Nutrición 2021.

Objetivo. Describir el diseño de la Encuesta Nacional de Salud y Nutrición 2021 (Ensanut 2021). Material y métodos. La Ensanut 2021 es una encuesta probabilística de hogares que forma parte de la serie de Ensanut Continua 2020-2024. En esta ocasión se describen el alcance, el muestreo, la medición y la organización logística. Resultados. Se planea obtener al menos 12 060 entrevistas de hogar completas a nivel nacional y 9 837 muestras para determinar seropositividad a SARS-CoV-2 a nivel nacional. Conclusiones. La Ensanut 2021 permitirá realizar inferencias regionales sobre la prevalencia de seropositividad a SARS-CoV-2 y también acumular información para realizar inferencias estatales en el año 2024.

Prediction of neuropeptide precursors and differential expression of adipokinetic hormone/corazonin-related peptide, hugin and corazonin in the brain of malaria vector Nyssorhynchus albimanus during a Plasmodium berghei infection.

Insect neuropeptides, play a central role in the control of many physiological processes. Based on an analysis of Nyssorhynchus albimanus brain transcriptome a neuropeptide precursor database of the mosquito was described. Also, we observed that adipokinetic hormone/corazonin-related peptide (ACP), hugin and corazonin encoding genes were differentially expressed during Plasmodium infection. Transcriptomic data from Ny. albimanus brain identified 29 pre-propeptides deduced from the sequences that allowed the prediction of at least 60 neuropeptides. The predicted peptides include isoforms of allatostatin C, orcokinin, corazonin, adipokinetic hormone (AKH), SIFamide, capa, hugin, pigment-dispersing factor, adipokinetic hormone/corazonin-related peptide (ACP), tachykinin-related peptide, trissin, neuropeptide F, diuretic hormone 31, bursicon, crustacean cardioactive peptide (CCAP), allatotropin, allatostatin A, ecdysis triggering hormone (ETH), diuretic hormone 44 (Dh44), insulin-like peptides (ILPs) and eclosion hormone (EH). The analysis of the genome of An. albimanus and the generated transcriptome, provided evidence for the identification of myosuppressin neuropeptide precursor. A quantitative analysis documented increased expression of precursors encoding ACP peptide, hugin and corazonin in the mosquito brain after Plasmodium berghei infection. This work represents an initial effort to characterize the neuropeptide precursors repertoire of Ny. albimanus and provides information for understanding neuroregulation of the mosquito response during Plasmodium infection.