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BACKGROUND: Transfusion-transmitted viral infection (TTI) is a major problem in patients receiving blood products. Monitoring high-risk patients is essential for assessing the epidemiology of blood-borne infections. STUDY DESIGN AND METHODS: A 1-year, cross-sectional seroprevalence study in patients with a history of multiple transfusions was conducted. Peripheral blood samples were titered to detect serologic markers of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). The presence of these viruses and demographic, behavioral, and medical traits were assessed. RESULTS: A total of 300 male and female multiply transfused patients with a mean age of 30.7 (±17.5) years were studied. The prevalence was 13.7% for HCV, 7% for HBV, and 1.7% for HIV. Patients with hemophilia had the highest prevalence for HCV and HIV infections, and hemodialyzed patients, for HBV infection. The risk factors related to acquired HCV were hemophilia (odds ratio [OR], 5.6; 95% confidence interval [CI], 2.5-12.6), more than five hospitalizations (OR, 3.8; 95% CI, 1.6-8.9), and having received a transfusion before mandatory screening in 1993 (OR, 8.4; 95% CI, 2.0-34.6), and for HIV, having received a transfusion before 1987 (OR, 19.0; 95% CI, 2.0-177.7). The main risk factors for HBV were having end-stage renal disease and being treated with hemodialysis (OR, 3.7; 95% CI, 1.4-9.9) and transplantation (OR, 4.2; 95% CI, 1.4-12.1). CONCLUSIONS: This study showed that HCV infection was more frequently identified than HBV and HIV infections in multiply transfused Mexican patients. Additionally, several risk factors are associated with TTI such as mandatory screenings before 1987 and 1993, which were the most important for HIV and HCV infections but not for HBV. [ABSTRACT FROM AUTHOR]

One of the highest incidences of acute lymphoblastic leukemia (ALL) in the world has been reported in Mexico City. In the current study (26 cases), the frequencies of the most frequent genetic rearrangements TEL-AML1, MLL/AF4, BCR-ABL (major and minor) in ALL in children from Mexico City were determined. For the ALL, the frequency of MLL/AF4 was 65.4%, for TEL-AML1 and that of BCR/ABL was 3.8%. Only 6 of the 17 children with the MLL/AF4 rearrangement were less than 26 months old. The frequency reported for MLL/AF4 in Mexican children with ALL is one of the highest worldwide. These findings could potentially explain the higher frequency of ALL with poor prognosis for children in Mexico City. [ABSTRACT FROM AUTHOR]

Chikungunya virus (CHIKV) is an alphavirus transmitted by Aedes mosquitoes, which causes Chikungunya fever. Three CHIKV genotypes have been identified: West African, East-Central-South African and Asian. In 2014, CHIKV was detected for the first time in Mexico, accumulating 13,569 confirmed cases in the following three years. Studies on the molecular diversification of CHIKV in Mexico focused on limited geographic regions or investigated only one structural gene of the virus. To describe the dynamics of this outbreak, we analyzed 309 serum samples from CHIKV acute clinical cases from 15 Mexican states. Partial NSP3, E1, and E2 genes were sequenced, mutations were identified, and their genetic variability was estimated. The evolutionary relationship with CHIKV sequences sampled globally were analyzed. Our sequences grouped with the Asian genotype within the Caribbean lineage, suggesting that the Asian was the only circulating genotype during the outbreak. Three non-synonymous mutations (E2 S248F and NSP3 A437T and L451F) were present in our sequences, which were also identified in sequences of the Caribbean lineage and in one Philippine sequence. Based on the phylogeographic analysis, the viral spread was reconstructed, suggesting that after the introduction through the Mexican southern border (Chiapas), CHIKV dispersed to neighboring states before reaching the center and north of the country through the Pacific Ocean states and Quintana Roo. This is the first viral phylogeographic reconstruction in Mexico characterizing the CHIKV outbreak across the country. [ABSTRACT FROM AUTHOR]

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. • We document that hypervariable regions of DENV can recapitulate the full-CDS phylogeny. • DENV-1 genotype V and DENV-2 Asian-American were the only genotypes circulating. • Mutations in NS2A and NS5 were disseminated and suggest the emergence of new lineages. • Phylogeographic analysis showed viral spread from coastal and tourist destinations. [ABSTRACT FROM AUTHOR]

Background and Aims: A substantial recrudescent wave of pandemic influenza A/H1N1 affected the Mexican population from December 1, 2011–March 20, 2012 following a 2-year period of sporadic transmission. Methods: We analyzed demographic and geographic data on all hospitalizations with severe acute respiratory infection (SARI) and laboratory-confirmed A/H1N1 influenza, and inpatient deaths, from a large prospective surveillance system maintained by a Mexican social security medical system during April 1, 2009–March 20, 2012. We also estimated the reproduction number (R) based on the growth rate of the daily case incidence by date of symptoms onset. Results: A total of 7569 SARI hospitalizations and 443 in-patient deaths (5.9%) were reported between December 1, 2011, and March 20, 2012 (1115 A/H1N1-positive inpatients and 154 A/H1N1-positive deaths). The proportion of laboratory-confirmed A/H1N1 hospitalizations and deaths was higher among subjects ≥60 years of age (χ2 test, p <0.0001) and lower among younger age groups (χ2 test, p <0.04) for the 2011–2012 pandemic wave compared to the earlier waves in 2009. The reproduction number of the winter 2011–2012 wave in central Mexico was estimated at 1.2–1.3, similar to that reported for the fall 2009 wave, but lower than that of spring 2009. Conclusions: We documented a substantial increase in the number of SARI hospitalizations during the period December 2011–March 2012 and an older age distribution of laboratory-confirmed A/H1N1 influenza hospitalizations and deaths relative to 2009 A/H1N1 pandemic patterns. The gradual change in the age distribution of A/H1N1 infections in the post-pandemic period is consistent with a build-up of immunity among younger populations. [ABSTRACT FROM AUTHOR]

Chikungunya virus (CHIKV) is an alphavirus transmitted by Aedes mosquitoes, which causes Chikungunya fever. Three CHIKV genotypes have been identified: West African, East-Central-South African and Asian. In 2014, CHIKV was detected for the first time in Mexico, accumulating 13,569 confirmed cases in the following three years. Studies on the molecular diversification of CHIKV in Mexico focused on limited geographic regions or investigated only one structural gene of the virus. To describe the dynamics of this outbreak, we analyzed 309 serum samples from CHIKV acute clinical cases from 15 Mexican states. Partial NSP3, E1, and E2 genes were sequenced, mutations were identified, and their genetic variability was estimated. The evolutionary relationship with CHIKV sequences sampled globally were analyzed. Our sequences grouped with the Asian genotype within the Caribbean lineage, suggesting that the Asian was the only circulating genotype during the outbreak. Three non-synonymous mutations (E2 S248F and NSP3 A437T and L451F) were present in our sequences, which were also identified in sequences of the Caribbean lineage and in one Philippine sequence. Based on the phylogeographic analysis, the viral spread was reconstructed, suggesting that after the introduction through the Mexican southern border (Chiapas), CHIKV dispersed to neighboring states before reaching the center and north of the country through the Pacific Ocean states and Quintana Roo. This is the first viral phylogeographic reconstruction in Mexico characterizing the CHIKV outbreak across the country.

The Zika virus (ZIKV) epidemic in the Americas established ZIKV as a major public health threat and uncovered its association with severe diseases, including microcephaly. However, genetic epidemiology in some at-risk regions, particularly Central America and Mexico, remains limited. We report 61 ZIKV genomes from this region, generated using metagenomic sequencing with ZIKV-specific enrichment, and combine phylogenetic, epidemiological, and environmental data to reconstruct ZIKV transmission. These analyses revealed multiple independent ZIKV introductions to Central America and Mexico. One introduction, likely from Brazil via Honduras, led to most infections and the undetected spread of ZIKV through the region from late 2014. Multiple lines of evidence indicate biannual peaks of ZIKV transmission in the region, likely driven by varying local environmental conditions for mosquito vectors and herd immunity. The spatial and temporal heterogeneity of ZIKV transmission in Central America and Mexico challenges arbovirus surveillance and disease control measures., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

The working and living environments of farmworkers put them and their families at risk for pesticide exposure and, consequently, immediate and long-term health effects. In this study, visual materials for a pesticide toxicology safety and health curriculum were constructed by engaging farmworkers in various stages of symbol development. Twenty-seven farmworkers in two states participated in this descriptive case study through focused small group discussions and interviews. Our findings support the importance of vivid and realistic symbols, the effectiveness of a traffic-light symbol in communicating technical information to farmworkers, and the need to engage low-literacy end-users in the production of educational materials. This work informs the development of curricula for other vulnerable populations pertaining to a variety of health-related topics, as well as discussions surrounding regulatory proposals to revise the United States Worker Protection Standard.