Direccion General de Epidemiologia

Infection of backyard and poultry with low pathogenicity avian influenza LPAI A(H5N2) viruses has occurred in Mexico since 1994, and the first human infection caused by this influenza virus was detected in 2024. Since its emergence in the Americas, frequent reassortments between high pathogenicity avian influenza HPAI A(H5N1) and LPAI viruses has occurred. In September 2025, the Instituto Nacional de Enfermedades Respiratorias of Mexico City identified an unsubtypeable influenza A virus infection in a young adult patient later determined to be a reassortant HPAI (H5N2) virus with a clade 2.3.4.4b HA. We analyzed clinical and epidemiologic data from this patient. Respiratory samples were tested for influenza RT-qPCR assays. Genomic sequence and phylogenetics analyses were performed to provisionally assign a new genotype to the novel HPAI A(H5N2) reassortant virus. The patient presented with fever and tachypnea, later developed hemoptysis and thoracic pain, with oxygen saturation decreasing to 70%. CT scan showed bilateral ground-glass opacities consistent with diffuse alveolar hemorrhage and zones consistent with consolidation. Clinical improvement was observed and the patient was discharged. Through viral complete genome analysis, we identified an HPAI A(H5N2) virus with genes from both clade 2.3.4.4b A(H5N1) viruses similar to those detected in North America during 2022-2023 and genes from the LPAI A(H5N2) viruses detected in Mexico during 2024. This is the first ever laboratory-confirmed human infection caused by an HPAI A(H5N2) virus infection, suggesting a new genotype provisionally classified as B3.14. The relationship of the virus with the severity of illness remains unknown.

This study investigated the hematological and serum biochemical responses of pregnant ewes administered Azadirachta indica leaf extract (NE) during late gestation. Twenty-four pregnant ewes were assigned in a Completely Randomized Design to a 2 × 3 factorial arrangement comprising two sampling days (Day 1 and Day 30) and three Neem extract doses: 0 mL (NE0), 20 mL (NE20), and 40 mL (NE40), with three replicates per treatment. Blood samples were collected through the jugular vein on Days 1 and 30 and analyzed using an automated hematology analyzer and spectrophotometric kits. Data were subjected to analysis of variance using SAS 9.4, and means were separated by the Duncan multiple range test. Significant treatment effects were detected from the results for erythrocytes (P = 0.0187), mean corpuscular volume (P = 0.0032), glucose (P = 0.0002), total blood protein (P = 0.0269), monocytes (P = 0.0261), and eosinophils (P = 0.0453). Treatment × day interactions occurred for monocytes (P = 0.0261) and GGT (P = 0.0101). By Day 30, NE20 and NE40 ewes exhibited higher erythrocyte counts, reduced mean corpuscular volume, improved glucose preservation, and increased total protein relative to NE0, while liver and kidney biomarkers remained within physiological limits. These findings demonstrate that weekly administration of A. indica leaf extract at 20 mL/ewe is a safe and effective phytogenic strategy that enhances erythropoiesis, mitigates gestational hypoglycemia, improves protein status, and supports immune function without eliciting toxicity during late pregnancy.

At the thresold of the 21st century, the Argentine writer Samanta Schweblin with the novel Distancia de rescate (2014) and her Uruguayan counterpart Fernanda Trías with Mugre rosa (2020) fictionalize stories, where the monstrous coexists with the human being and its environment. This article proposes a comparative hermeneutics of the selected novels as a counterpart to the rhetorical-naturalist discourses of the River Plate narrative of the previous century. Ecocritical and biopolitical theories seek to give a renewed theoretical framework to the new aesthetics of horror. The female voices that lead the respective stories expose a disturbing and apocalyptic world, in which a hopeful future is not foreseen.

Dengue is endemic throughout the tropical areas of the Americas, but little is known about its regional dynamics. We examined seasonal and multiannual dengue trends across the Americas and possible underlying mechanisms using monthly dengue surveillance data from 14 countries. We collected monthly dengue case data from 241 subnational locations in 14 countries, ranging from 1985 to 2018 (6 to 22 years), and used wavelet analysis to isolate seasonal (8 to 16 months) and multiannual (17+ months) patterns. For each location, we assessed seasonal and multiannual dynamics as well as coherence and differences in timing of dengue cycles between 22,578 location pairs. We assessed patterns in coherence over time and space and compared these patterns to variations in temperature, rainfall, and El Niño Southern Oscillation patterns. Strong synchrony in dengue dynamics was identified across the region at the seasonal and multiannual scales. Seasonal dengue dynamics were associated with local climate patterns and dengue dynamics in nearby locations. High synchrony at multiannual scales indicated that large dengue epidemics were shared across the region, with an average temporal lag of only 6 months at distances of up to 10,000 kilometers. Synchrony of these epidemics likely reflects both regional climate variability and human movement. Observed dengue dynamics were not unique to individual countries in the Americas but rather extended across the region reflecting climatic and nonclimatic drivers. These findings can support the development of better early warning tools to support epidemic preparedness and response and underscore the importance of working collaboratively across borders.

El presente artículo tiene como propósito principal analizar los procesos de enseñanza de la ortografía en el aula desde una perspectiva reflexiva, poniendo en primer plano la construcción de conocimientos por parte de las niñas y los niños en interacción con sus pares y docentes. A partir de investigaciones didácticas en curso realizadas con estudiantes de 2do y 4to de primaria, se describen y analizan episodios de interacciones en los que se abordan problemas ortográficos, identificando las estrategias utilizadas por las y los estudiantes y el rol de la intervención docente en situaciones que problematizan el sistema gráfico y ortográfico del español. Así, se registra que niñas y niños no se limitan a la memorización de reglas, sino que reflexionan coordinando diferentes planos de la lengua. Los análisis permiten reconocer la exploración y elaboración de hipótesis por parte de las y los estudiantes y el desarrollo de un saber-sobre el español, que les permite comprender mejor el sistema de escritura de su propia lengua al ser convertido en objeto de reflexión.

Background/Objectives: Healthcare workers (HCWs) faced elevated risks during the coronavirus disease 2019 (COVID-19) pandemic. Vaccination among HCWs was a key strategy to mitigate severe outcomes and maintain healthcare system functionality during the crisis. The aim of this study was to assess the distribution, severity, and clinical factors associated with COVID-19 among HCWs in a tertiary hospital across eight pandemic waves and evaluate the effectiveness of vaccination in reducing severe outcomes. Methods: A cross-sectional study analyzed data from HCWs at a high-specialty hospital in Mexico City from March 2020 to February 2024. Sociodemographic, clinical, and vaccination data were collected and analyzed via bivariate and multivariable logistic regression to identify the factors associated with infection and severity. Results: A total of 7049 cases were analyzed, and 2838 (40.26%) were confirmed COVID-19 cases. Severe outcomes, including hospitalizations and deaths, were most common during the early waves, with 83.3% of severe cases occurring among unvaccinated individuals. Vaccination significantly reduced infection risk, with individuals receiving two or more doses showing a lower likelihood of infection (OR 0.67; 95% CI 0.51-0.89; p = 0.005). Older age; comorbidities such as hypertension and obesity; and symptoms such as fever were associated with increased severity. Compared with earlier coverage, enhanced vaccination coverage significantly lowered the hospitalization risk during the later waves (OR 11.11; 95% CI 1.2-110.2; p = 0.040). Conclusions: Vaccination effectively reduced severe COVID-19 outcomes among HCWs, demonstrating its critical role in mitigating the disease burden despite the high risk of exposure. Strategies such as targeted vaccination campaigns and continuous surveillance are essential to protect HCWs and ensure healthcare system resilience.

La rabia es la zoonosis con mayor impacto sobre herbívoros domésticos, provocando en América Latina pérdidas económicas de aproximadamente 97 millones de dólares anuales. En esta región, el vampiro común (Desmodus rotundus) es un reservorio del virus de la rabia y se considera su principal transmisor al ganado. El objetivo de este estudio fue analizar la progresión de la rabia paralítica bovina (RPB) y su asociación con la presencia y distribución de D. rotundus en Tamaulipas, México, en función de factores ambientales (características ecológicas y geográficas) que lo favorecen. Se analizó la distribución anual de casos detectados de RPB en Tamaulipas por municipio durante 1999 a 2020. La distribución espacial del murciélago D. rotundus se estudió considerando las características biológicas de la especie, así como las de Tamaulipas. La RPB, asociada a D. rotundus mediante tipificación de la variante antigénica del virus, se presentó en 28 de los 43 municipios que comprende el estado, con marcada tendencia a expandirse desde el sur hacia el norte de la entidad. La ecorregión bosque húmedo veracruzano concentró el mayor número de casos de RPB y presencia del vampiro, ambos factores se vieron influenciados por diferentes tipos de vegetación como áreas agrícolas, pastizales y selvas. La tendencia observada en los últimos 10 años, de avanzar hacia el norte del estado de parte de D. rotundus y los brotes de casos de RPB en esas zonas, sugieren la posibilidad de que la especie expanda su distribución hacia los Estados Unidos de América, país actualmente considerado libre de la presencia del organismo, principalmente hacia el estado vecino de Texas, debido a que sus características geográficas y ecológicas son similares a las de la entidad analizada.

In this study, we present the complete annotated genome of a novel Salmonella phage, vB_SenS_ST1UNAM. This phage exhibits lytic activity against several Salmonella enterica serotypes, such as S. Typhi, S. Enteritidis, and S. Typhimurium strains, which are major causes of foodborne illness worldwide. Its genome consists of a linear, double-stranded DNA of 47,877 bp with an average G+C content of 46.6%. A total of 85 coding regions (CDS) were predicted, of which only 43 CDS were functionally assigned. Neither genes involved in the regulation of lysogeny, nor antibiotic resistance genes were identified. This phage harbors a lytic cassette that encodes a type II-holin and a Rz/Rz1-like spanin complex, along with a restriction-modification evasion system and a depolymerase that degrades Salmonella exopolysaccharide. Moreover, the comparative analysis with closely related phage genomes revealed that vB_SenS_ST1UNAM represents a novel genus, for which the genus “Gomezvirus” within the subfamily “ST1UNAM-like” is proposed.

Preterm birth is a worldwide problem with a high economic impact and morbimortality in children. Therefore, the literature has focused on finding modifiable factors associated with this entity, such as the study "Risk factors associated with preterm birth in a second level hospital," which concluded that "100% of risk factors associated with preterm birth are potentially preventable". Our team reanalyzed the results and found in the regression model that premature rupture of membranes was the only variable associated with preterm birth. This variable is not 100% preventable, so the results found are different from the authors' conclusions.

We analyze the relationship between uncertainty and economic growth expectations in Mexico through the Growth at Risk methodology. Our analysis consists of two stages: first, we estimate a quantile regression of annual output growth conditional on lagged values of a measure of macroeconomic uncertainty and other drivers. Second, based on the fitted values of the quantile regression, we estimate the parameters of a t-skewed distribution of expected economic growth. Our results show that an increase in macroeconomic uncertainty has a negative and statistically significant impact on the left tail of the growth distribution, leading to an increased probability of observing lower growth rates. These results remain robust to alternative measures of financial conditions, of economic policy uncertainty, and of risk exposure, as well as to alternative measurements of economic activity.