Novel Rickettsia and host records for argasid ticks, including Alveonasus cooleyi, on wild mammals in Baja California, Mexico.

We conducted surveillance of mammals to investigate their associations with argasid ticks and tick-borne pathogens. During 2021, a total of 20 wild carnivores and 57 lagomorphs were sampled, and 39 argasid ticks belonging to two species were collected. All mammals and ticks were tested by molecular assays to detect Borrelia and Rickettsia infections. Nine ticks identified as Otobius megnini were collected from two coyotes (Canis latrans) and 30 Alveonasus cooleyi (McIvor 1941) were collected from six bobcats (Lynx rufus) and one rabbit (Sylvilagus auduboni). We detected Rickettsia spp. DNA in 21 of the 27 (77.8%) tested Av. cooleyi and none of the O. megnini. No ticks were PCR-positive for borreliae and all mammals were PCR-negative for both pathogen genera. Phylogenetic analysis based on gltA, htrA, and 16 S rRNA targets revealed that all rickettsiae from Av. cooleyi clustered with ancestral group rickettsiae, likely representing a novel species of possibly endosymbiotic Rickettsia. The significance of Av. cooleyi and the newly identified Rickettsia sp. to the health of wildlife is unknown, and further work is indicated to determine whether they may be relevant to public health or carnivore conservation.

Pleistocene-Holocene vicariance, not Anthropocene landscape change, explains the genetic structure of American black bear (Ursus americanus) populations in the American Southwest and northern Mexico.

The phylogeography of the American black bear (Ursus americanus) is characterized by isolation into glacial refugia, followed by population expansion and genetic admixture. Anthropogenic activities, including overharvest, habitat loss, and transportation infrastructure, have also influenced their landscape genetic structure. We describe the genetic structure of the American black bear in the American Southwest and northern Mexico and investigate how prehistoric and contemporary forces shaped genetic structure and influenced gene flow. Using a suite of microsatellites and a sample of 550 bears, we identified 14 subpopulations organized hierarchically following the distribution of ecoregions and mountain ranges containing black bear habitat. The pattern of subdivision we observed is more likely a product of postglacial habitat fragmentation during the Pleistocene and Holocene, rather than a consequence of contemporary anthropogenic barriers to movement during the Anthropocene. We used linear mixed-effects models to quantify the relationship between landscape resistance and genetic distance among individuals, which indicated that both isolation by resistance and geographic distance govern gene flow. Gene flow was highest among subpopulations occupying large tracts of contiguous habitat, was reduced among subpopulations in the Madrean Sky Island Archipelago, where montane habitat exists within a lowland matrix of arid lands, and was essentially nonexistent between two isolated subpopulations. We found significant asymmetric gene flow supporting the hypothesis that bears expanded northward from a Pleistocene refugium located in the American Southwest and northern Mexico and that major highways were not yet affecting gene flow. The potential vulnerability of the species to climate change, transportation infrastructure, and the US-Mexico border wall highlights conservation challenges and opportunities for binational collaboration.

Risk Factors and Clinical Phenotypes Associated with Severity in Patients with COVID-19 in Northeast Mexico.

Objective: The aim of this study is to describe the main clinical phenotypes, laboratory findings, and severity of coronavirus disease 2019 (COVID-19) in patients hospitalized at the High Specialty Medical Unit # 71 of the Mexican Social Security Institute. Methods: Prospective observational cohort study with a total of 105 patients hospitalized with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection at the High Specialty Medical Unit # 71 (Torreón, Coahuila, Mexico), from May 15th to August 15th, 2020. The cases were confirmed to be COVID-19 positive through an RT-qPCR test. Clinical phenotypes and laboratory tests were evaluated to determine the degree of severity of the disease and the most frequent comorbidities. Results: The clinical characteristics of a total of 105 hospitalized patients (47 females and 58 males; median age being 52 years) with confirmed COVID-19 diagnoses were studied. The severity of the disease was classified as moderate grade (62.7%), severe grade (21.5%), and critical grade (15.6%). Among the most frequent underlying pathologies coexisted overweight (n = 75, 78.12%), obesity (n = 21, 21.87%), diabetes (n = 10, 9.52%), and hypertension (n = 6, 5.71%), some of these patients present more than one pathology. This association was found with diabetes (odds ratio [OR]: 1.42; 95% confidence interval [CI]: 1.23-1.97; p = 0.021) and high levels of D-dimer (OR: 1.01; 95% CI: 1.00-1.08; p = 0.001). Conclusion: In this retrospective cohort study of patients with COVID-19 from a specialty hospital in the northeast region of Mexico, it was observed that clinical phenotypes and D-dimer elevation were compatible with an inflammatory state by degree of severity; it was found that the hospitalized patients with underlying chronic medical conditions such as diabetes and elevated D-dimer levels were significantly associated with increased mortality from COVID-19. Age and sex (males) were two factors highly associated with mortality.

Reconstrucción histórica de la precipitación en la Reserva de la Biosfera El Cielo, México, mediante anillos de crecimiento en Taxodium mucronatum (Cupressaceae) / Historical precipitation reconstruction of El Cielo Biosphere Reserve, Mexico, using Taxodium mucronatum (Cupressaceae) annual growth rings

Introducción: El conocimiento histórico del clima es fundamental para analizar su variabilidad en el tiempo y su impacto en los ecosistemas y poblaciones humanas. Objetivo: Analizar el crecimiento anual de los árboles de sabino, también conocido como ahuehuete (Taxodium mucronatum) del río Sabinas para reconstruir la variabilidad de precipitación histórica en la Reserva de la Biosfera El Cielo, Tamaulipas, México. Métodos: Se fecharon los crecimientos anuales de 116 muestras de sabino, a partir de las cuales se desarrolló una cronología de 544 años (1474-2017). El periodo que sustentó un número de muestras adecuado para el análisis climático se extiende de 1550 a 2017 (468 años). Resultados: Con base en el análisis de función respuesta se determinó que la precipitación de invierno-primavera (noviembre-mayo) influyó de manera significativa en el crecimiento de los sabinos en el área de estudio (r= 0.77, P < 0.001). La reconstrucción registró una variabilidad climática alta a nivel interanual y entre décadas, en la cual, se identificó la presencia de sequías a principios y finales de cada siglo, así como la presencia de sequías extremas cíclicas cada 50 años. Estas sequías destacaron por su impacto social y económico a nivel nacional y regional. Las sequías más importantes son el "Año Uno Conejo" de acuerdo con el calendario Azteca, en 1558; la sequía de1696 con un impacto fuerte en el noreste de México; "El Año del Hambre" en 1785-1786, en la Reserva de la Biosfera El Cielo desde 1784; la sequía de 1801 que trajo consigo la escasez de alimentos; la de 1951 dentro del periodo de "Migración masiva del sector rural"; y la sequía más reciente, registrada en 2011. Las lluvias extremas más representativas sucedieron en 1756 y 1816. Conclusiones: De seguir el patrón de precipitación registrado en la Reserva de la Biosfera El Cielo, es posible esperar la presencia de sequías extremas a mediados y finales del siglo XXI.

Introduction: Historical knowledge of climate is essential to analyze its variability over time, as well as its impact on natural ecosystems and human populations. Objective: To analyze the annual growth of the sabino trees, also known as ahuehuete trees (Taxodium mucronatum) from the Sabinas River to reconstruct the historical variability of precipitation in El Cielo Biosphere Reserve, Tamaulipas, Mexico. Methods: The annual growth of 116 sabino samples was dated to develop a chronology of 544 years (1474-2017). The period that admitted a series of samples suitable for climate analysis extends from 1550 to 2017 (468 years). Results: Based on the analysis of the response function, it was determined that the winter-spring precipitation (November-May) significantly influenced the radial growth of sabinos in the study area (R= 0.77, P < 0.001). The reconstruction recorded high climatic variability at interannual and interdecadal levels, in which the presence of droughts was identified at the beginning and end of each century, as well as the presence of extreme cyclical droughts every 50 years. These droughts stood out for their social and economic impact at the regional and national level. The most important droughts are the "Año Uno Conejo" ("Year One Rabbit") according to the Aztec calendar in 1558. In 1696 with a strong impact in Northern Mexico. "El Año del Hambre" ("The Year of Hunger") in 1785-1786. Also, the drought of 1801 that brought alongside food shortages. 1951 within the period of "Mass migration of the rural sector"; and the most recent drought, recorded in 2011. The most representative extreme rainfalls occurred in 1756 and 1816. Conclusions: If the precipitation pattern registered at El Cielo Biosphere Reserve continues, it is possible to expect the presence of extreme droughts in the mid and late 21st century.

Rattlesnake (Crotalus spp.) distribution and diversity in Zacatecas, Mexico.

Mexico is home to a large number of reptile species and has one of the greatest diversities of venomous snakes, among which the rattlesnakes pertaining to the Crotalus genus stand out. Out of more than 40 species in the country, nine are found in Zacatecas: C. aquilus, C. atrox, C. basiliscus, C. lepidus, C. molossus, C. polystictus, C. pricei, C. scutulatus and C. willardi. Although these reptiles are important, due to their relevance in terms of ecology, cultural use and public health, their conservation is impacted by multiple factors, such as habitat fragmentation and indiscriminate killing. Thus, most species within this genus are found in some type of risk category at both the national and international level. The purpose of this study was to determine the potential distribution and diversity of rattlesnakes at the municipal level in the understudied state of Zacatecas. To do this, we analyzed and described the global distribution of nine rattlesnake species by building species distribution models, which determined their potential distribution based on a set of ecological variables and presence records. The resulting models were used to assess the diversity of rattlesnake species potentially present in each municipality within the state. Thirty-nine (67.24 %) out of fifty-eight municipalities registered at least one rattlesnake species. Fresnillo, Sombrerete and Valparaíso were some of the municipalities showing greatest diversity. Moreover, C. atrox, C. lepidus, C. molossus and C. scutulatus were the most widely found species in the state. On the other hand, C. basiliscus, C. polystictus, C. pricei and C. willardi were rarely spotted and so, information on their distribution patterns within Zacatecas is limited. Finally, the areas having the largest potential for the distribution of these species were defined. These findings should make field work much more time- and cost-effective, facilitating the collection of in situ data that are useful for management and conservation plans of these species in Zacatecas.

Comparing risk environments for HIV among people who inject drugs from three cities in Northern Mexico.

BACKGROUND: A large body of research has investigated the rise of injection drug use and HIV transmission in Tijuana and Ciudad Juarez (CJ). However, little is known about the dynamics of injecting in Hermosillo. This study compares drug-related behaviors and risk environment for HIV of people who inject drugs (PWID) across Tijuana, CJ, and Hermosillo to identify factors that could explain differences in HIV prevalence. METHODS: Data from Tijuana belong to a prospective study (El Cuete IV). Data from Hermosillo and Ciudad Juarez belong to a cross-sectional study. Both studies collected data in places where PWID spend time. All participants completed quantitative behavioral and serological testing for HIV. Datasets were merged using only comparable variables. Descriptive statistics tests were used to compare sociodemographic and behavioral characteristics of people who inject drugs PWID sampled in each city. A logistic regression model was built to identify factors independently associated with the likelihood of reporting receptive syringe sharing in the past 6 months. RESULTS: A total of 1494 PWID provided data between March 2011 and May 2012. HIV prevalence differed significantly between participants in Tijuana (4.2%), CJ (7.7%), and Hermosillo (5.2%; p < 0.05). PWID from Hermosillo reported better living conditions, less frequency of drug injection, and lower prevalence of syringe sharing (p < 0.01). PWID from CJ reported a higher prevalence of syringe sharing and confiscation by police (p < 0.01). In a multivariable logistic regression model, living in Hermosillo compared to Tijuana (adjusted odds ratio [AOR] = 0.42, 95% confidence interval [CI] 0.29-0.61) and being female (AOR = 0.61, 95% CI 0.45-0.83) were protective against syringe sharing. Having used crystal meth (AOR = 1.62, 95% CI 1.24-2.13, p = 0.001), having experienced syringe confiscation by police in the last 6 months (AOR = 1.78, 95% CI 1.34-2.40), and lower perception of syringe availability (AOR = 2.15, 95% CI 1.59-2.91) were significantly associated with syringe sharing (p < 0.05). CONCLUSIONS: Differences in HIV prevalence across cities reflect mainly differences in risk environments experienced by PWID, shaped by police practices, access to injection equipment, and dynamics of drug markets. Findings highlight the importance of ensuring sterile syringe availability through harm reduction services and a human rights approach to drug harms in northern Mexico and to generate better understanding of local dynamics and contexts of drug use for designing proper harm reduction programs.

Arsenic methylation capacity in relation to nutrient intake and genetic polymorphisms in one-carbon metabolism.

BACKGROUND: Nutrients and genetic polymorphisms participating in one-carbon metabolism may explain interindividual differences in inorganic arsenic (iAs) methylation capacity, which in turn may account for variations in susceptibility to iAs-induced diseases. OBJECTIVES: 1) To evaluate the association between polymorphisms in five one-carbon metabolism genes (FOLH1 c.223 T > C, MTHFD1 c.1958 G > A, MTHFR c.665 C > T, MTR c.2756 A > G, and MTRR c.66 A > G) and iAs methylation capacity; 2) To assess if previously reported associations between nutrient intake and iAs methylation capacity are modified by those polymorphisms. METHODS: Women (n = 1027) exposed to iAs in Northern Mexico were interviewed. Blood and urine samples were collected. Nutrient dietary intake was estimated using a validated food frequency questionnaire. iAs methylation capacity was calculated from urinary iAs species (iAs, monomethylarsonic acid [MMA] and dimethylarsinic acid [DMA]) measured by high performance liquid chromatography (HPLC-ICP-MS). One polymorphism in each of the five genes evaluated was genotyped by allelic discrimination. Multivariable linear regression models were used to evaluate if genetic polymorphisms modified the associations between iAs methylation capacity parameters and nutrient intake. RESULTS: The median (min-max) concentration of total arsenic (TAs) was 20.2 (1.3-2776.0) µg/g creatinine in the study population. Significant interactions for iAs metabolism were only found with FOLH1 c.223 T > C polymorphism and vitamin B12 intake, so that CT and CC genotype carriers had significantly lower %iAs, and higher DMA/iAs with an increased vitamin B12 intake, as compared to carriers of wild-type TT. CONCLUSION: Differences in dietary nutrient intake and genetic variants in one-carbon metabolism may jointly influence iAs methylation capacity. Confirmation of these interactions in other populations is warranted.

Dietary micronutrient intake and its relationship with arsenic metabolism in Mexican women.

INTRODUCTION: Concentrations of inorganic arsenic (iAs) metabolites in urine present intra- and interindividual variations, which are determined not only by the magnitude of exposure to iAs, but also by differences in genetic, environmental and dietary factors. OBJECTIVE: To evaluate whether differences in dietary intake of selected micronutrients are associated with the metabolism of iAs. METHODS: The intake of 21 micronutrients was estimated for 1027 women living in northern Mexico using a food frequency questionnaire. Concentration of urinary metabolites of iAs was determined by high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and the proportion of iAs metabolites was calculated (%iAs, monomethylarsonic acid [%MMA] and dimethylarsinic acid [%DMA]), as well as ratios corresponding to the first (MMA/iAs), second (DMA/MMA) and total methylation (DMA/iAs). RESULTS: After adjustment for covariates, it was found that methionine, choline, folate, vitamin B12, Zn, Se and vitamin C favor elimination of iAs mainly by decreasing the %MMA and/or increasing %DMA in urine. CONCLUSIONS: Our results confirm that diet contributes to the efficiency of iAs elimination. Further studies are needed to assess the feasibility of dietary interventions that modulate the metabolism of iAs and the consequent risk of diseases related to its exposure.