Temperatures Influence Susceptibility to Insecticides in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) Mosquitoes

Aedes aegypti and Aedes albopictus (Diptera: Culicidae) are vectors for several arboviruses, including dengue, Zika virus and chikungunya virus. The primary method of controlling these diseases is controlling the vector population, often with insecticides. Insecticide resistance may impact the success of these efforts. We tested the effect of variable temperature exposures on susceptibility to insecticides by exposing adult A. aegypti and A. albopictus to different temperatures and tested their susceptibility to insecticides. We hypothesized that adults maintained at high temperatures would show increased susceptibility to insecticides relative to lower temperatures. Colony mosquitoes were hatched, reared to adulthood and then maintained in three temperature regimes that reflect average seasonal temperatures in the Rio Grande Valley, TX. Susceptibility to permethrin and deltamethrin was assessed using the CDC bottle bioassay method. Overall Aedes albopictus had higher susceptibility to all insecticides than Aedes aegypti. Mosquitoes kept at different temperatures exhibited differential susceptibility to insecticides. Low temperature exposed mosquitoes had decreased susceptibility while high temperature conditions resulted in increased mortality. Our results suggest public health officials must consider temperature effects when controlling mosquitoes with insecticides

Reevaluación del riesgo de extinción de cinco especies del género Polianthes l. (Agavaceae)

We reassessed the extinction risk of the species Polianthes densiflora, P. howardii, P. longiflora, P. palustris and P. platyphylla by applying the MER (method of evaluation of extinction risk of wild species for Mexico). These species are listed as rare by the International Union for Conservation of Nature (IUCN) and are considered to be in the category of special protection according to Mexican regulation. MER criterion A (geographic distribution) was assessed with three methods: area of occupancy, extent of ocurrence, and species distribution models. Criteria B (habitat conditions) and D (impact of human activity) were examined by superimposing the human footprint map of Sanderson et al., where values range from 0 to 100. In this map, 0-10 denote pristine areas and 100 indicates that the habitat has been completely transformed. Criterion C (intrinsic biological vulnerability) was assigned based on the geophytic nature of the species. According to our findings, Polianthes densiflora and P. longiflora are in danger of extinction, while P. howardii and P. platyphylla are endangered and P. palustris is likely extinct. None of the five species concerned occur in any Natural Protected Area. We propose in situ and ex situ strategies to maintain these species as well as the development of programs of sustainable use for Polianthes longiflora and P. platyphylla. These species could be cultivated and domesticated by means of vegetative propagation.Con base en el método de evaluación del riesgo de extinción de las especies silvestres en México (MER), se redefinió el de Polianthes densiflora, P. howardii, P. longiflora, P. palustris y P. platyphylla. Estas cinco plantas se encuentran listadas en la categoría de protección especial en la Norma Oficial Mexicana y fueron catalogadas como raras por la Unión Internacional para la Conservación de la Naturaleza (IUCN). El criterio A del MER (amplitud de la distribución geográfica) se estimó mediante tres métodos: área ocupada, extensión del área ocupada y mapas obtenidos a partir de modelos de distribución. Los criterios B (condición del hábitat natural) y D (impacto humano) fueron evaluados con base en el mapa de Influencia Humana de Sanderson et al., el cual asigna valores entre 0 y 100, en donde 0-10 indica áreas conservadas y 100 la total destrucción del hábitat. El criterio C (vulnerabilidad intrínseca), se asignó en función de la naturaleza geófila de las especies. Los resultados obtenidos sugieren que Polianthes densiflora y P. howardii están en peligro de extinción, P. longiflora y P. platyphylla se encuentran amenazadas y P. palustris está probablemente extinta. Ninguna de las cinco plantas se ha registrado en alguna Área Natural Protegida. Se proponen estrategias de conservación in situ y ex situ para las especies estudiadas, así como el desarrollo de programas de uso sustentable para P. longiflora y P. platyphylla, que podrían ser cultivadas y domesticadas mediante la propagación vegetativa

Towards Conserving Crop Wild Relatives along the Texas–Mexico Border: The Case of Manihot walkerae

Walker’s Manihot, Manihot walkerae, is an endangered species endemic to south Texas and northeastern Mexico and is a Crop Wild Relative (CWR) of the international and economically important crop cassava (M. esculenta). Manihot walkerae is globally endangered (IUCN’s Redlist, Texas list, USA); however, it is not recognized on the Mexican list of endangered species (NOM-059-SEMARNAT). We assessed the status of M. walkerae in Mexico and re-evaluated its global status. According to our analysis, M. walkerae should be considered an endangered species based on the IUCN’s assessment method and a threatened species in Mexico based on the Mexican criteria. Our findings encourage the establishment of sound conservation plans for M. walkerae along the Texas–Mexico border. View Full-Tex

Potential Effects of Climate Change on the Geographic Distribution of the Endangered Plant Species Manihot walkerae

Walker’s Manihot, Manihot walkerae, is an endangered plant that is endemic to the Tamaulipan thornscrub ecoregion of extreme southern Texas and northeastern Mexico. M. walkerae populations are highly fragmented and are found on both protected public lands and private property. Habitat loss and competition by invasive species are the most detrimental threats for M. walkerae; however, the effect of climate change on M. walkerae’s geographic distribution remains unexplored and could result in further range restrictions. Our objectives are to evaluate the potential effects of climate change on the distribution of M. walkerae and assess the usefulness of natural protected areas in future conservation. We predict current and future geographic distribution for M. walkerae (years 2050 and 2070) using three different general circulation models (CM3, CMIP5, and HADGEM) and two climate change scenarios (RCP 4.5 and 8.5). A total of nineteen spatially rarefied occurrences for M. walkerae and ten non-highly correlated bioclimatic variables were inputted to the maximum entropy algorithm (MaxEnt) to produce twenty replicates per scenario. The area under the curve (AUC) value for the consensus model was higher than 0.90 and the partial ROC value was higher than 1.80, indicating a high predictive ability. The potential reduction in geographic distribution for M. walkerae by the effect of climate change was variable throughout the models, but collectively they predict a restriction in distribution. The most severe reductions were 9% for the year 2050 with the CM3 model at an 8.5 RCP, and 14% for the year 2070 with the CMIP5 model at the 4.5 RCP. The future geographic distribution of M. walkerae was overlapped with protected lands in the U.S. and Mexico in order to identify areas that could be suitable for future conservation efforts. In the U.S. there are several protected areas that are potentially suitable for M. walkerae, whereas in Mexico no protected areas exist within M. walkerae suitable habitat

Pathogenic landscape of transboundary zoonotic diseases in the Mexico–US border along the Rio Grande

Transboundary zoonotic diseases, several of which are vector borne, can maintain a dynamic focus and have pathogens circulating in geographic regions encircling multiple geopolitical boundaries. Global change is intensifying transboundary problems, including the spatial variation of the risk and incidence of zoonotic diseases.The complexity of these challenges can be greater in areas where rivers delineate international boundaries and encompass transitions between ecozones.The Rio Grande serves as a natural border between the US State ofTexas and the Mexican States of Chihuahua, Coahuila, Nuevo León, andTamaulipas. Not only do millions of people live in this transboundary region, but also a substantial amount of goods and people pass through it everyday. Moreover, it occurs over a region that functions as a corridor for animal migrations, and thus links the Neotropic and Nearctic biogeographic zones, with the latter being a known foci of zoonotic diseases. However, the pathogenic landscape of important zoonotic diseases in the southTexas–Mexico transboundary region remains to be fully understood. An international perspective on the interplay between disease systems, ecosystem processes, land use, and human behaviors is applied here to analyze landscape and spatial features of Venezuelan equine encephalitis, Hantavirus disease, Lyme Borreliosis, Leptospirosis, Bartonellosis, Chagas disease, human Babesiosis, and Leishmaniasis. Surveillance systems following the One Health approach with a regional perspective will help identifying opportunities to mitigate the health burden of those diseases on human and animal populations. It is proposed that the Mexico–US border along the Rio Grande region be viewed as a continuum landscape where zoonotic pathogens circulate regardless of national borders

Predicting the Impact of Climate Change on the Distribution of Rhipicephalus sanguineus in the Americas

Climate change may influence the incidence of infectious diseases including those transmitted by ticks. Rhipicephalus sanguineus complex has a worldwide distribution and transmits Rickettsial infections that could cause high mortality rates if untreated. We assessed the potential effects of climate change on the distribution of R. sanguineus in the Americas in 2050 and 2070 using the general circulation model CanESM5 and two shared socioeconomic pathways (SSPs), SSP2-4.5 (moderate emissions) and SSP2-8.5 (high emissions). A total of 355 occurrence points of R. sanguineus and eight uncorrelated bioclimatic variables were entered into a maximum entropy algorithm (MaxEnt) to produce 50 replicates per scenario. The area under the curve (AUC) value for the consensus model (\u3e0.90) and the partial ROC value (\u3e1.28) indicated a high predictive capacity. The models showed that the geographic regions currently suitable for R. sanguineus will remain stable in the future, but also predicted increases in habitat suitability in the Western U.S., Venezuela, Brazil and Bolivia. Scenario 4.5 showed an increase in habitat suitability for R. sanguineus in tropical and subtropical regions in both 2050 and 2070. Habitat suitability is predicted to remain constant in moist broadleaf forests and deserts but is predicted to decrease in flooded grasslands and savannas. Using the high emissions SSP5-8.5 scenario, habitat suitability in tropical and subtropical coniferous forests and temperate grasslands, savannas, and shrublands was predicted to be constant in 2050. In 2070, however, habitat suitability was predicted to decrease in tropical and subtropical moist broadleaf forests and increase in tropical and subtropical dry broadleaf forests. Our findings suggest that the current and potential future geographic distributions can be used in evidence-based strategies in the design of control plans aimed at reducing the risk of exposure to zoonotic diseases transmitted by R. sanguineus

High-resolution melt (HRM) analysis for detection of SNPs associated with pyrethroid resistance in the southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

The southern cattle fever tick, Rhipicephalus (Boophilus) microplus, is the most economically important ectoparasite of cattle worldwide. A limitation for sustainable control and eradication is the emergence of acaricide resistance among tick populations. Molecular diagnostic tools offer the opportunity to detect resistance rapidly, which can be complemented with confirmatory bioassays with larvae and adult ticks that are more resource and time consuming to generate. Synthetic pyrethroid resistance is one of the most prevalent and well-studied forms of resistance in arthropods, being linked with target site alterations in the sodium ion channel gene. Here, we report research on a novel molecular method to detect mutations in the para-sodium channel gene of R. microplus associated with acaricide resistance that is based on quantitative PCR high-resolution melt (HRM) analysis. Genomic DNA fragments of domains II and III of the para-sodium channel gene were amplified by real-time PCR in the presence of EVA®Green dye to test resistant and susceptible reference ticks from the U.S., Brazil, and Mexico. Larval packet tests with discriminating doses and a modified lethal time analysis were performed to confirm resistance to permethrin, cypermethrin, deltamethrin, and flumethrin in laboratory strains. Tick specimens collected from cattle that were inspected at the United States Port-of-Entry at the Texas-Mexico border were also genotyped. Previously described mutations associated with pyrethroid resistance (T170C, C190A, G184C, and T2134A) were successfully detected by qPCR-HRM in different genotypes and confirmed by sequencing. A novel non-synonymous SNP located at domain III (C2136A) and the G215T mutation in domain II, previously described only in Asian R. microplus and R. australis, were also detected with the HRM and confirmed by sequencing. This technique could be adapted for high-throughput screening, detection, and discovery of allele-specific mutations in cattle tick outbreak populations to inform eradication strategies in the USA. This knowledge could also be applied to integrated control programs in other parts of the world where R. microplus is endemic and where similar SNPs have been identified associated with pyrethroid resistance. This study highlights the existence of several mutations in the para-sodium channel gene in different combinations in field populations of R. microplus from Mexico

A tale of two cities: Aedes Mosquito surveillance across the Texas-Mexico Border

Cross border situations complicate epidemiologic risk assessments in transboundary regions such as the US-Mexico border. Countries have different health policies, mosquito control policies, and mosquito surveillance systems. We established a binational Aedes mosquito surveillance program in Reynosa, Tamaulipas, and McAllen, Texas by replicating a part of the Mexican Integrated Vector Monitoring System (IVMS) across the international border. The entomologic surveillance of the IVMSs is based on ova collection cups (ovitraps) and for the binational project, the surveillance protocol was modified to include an Autocidal Gravid Ovitrap (AGO) in the center of every city-block (100 m2) distribution of four ovitraps. We measured the weekly abun-dance of Aedes eggs and adult females in 72 clusters (cluster = one AGO and four ovitraps) in Reynosa and 67 clusters in McAllen from Epidemiologic Week (EW) 17 to EW 36. The mean weekly egg counts were 34 and 22 in McAllen and Reynosa respectively. The female adult mosquito counts were more than 5 in 12 out of 20 (60%) weeks in McAllen, and in 5 out of 16 (31%) weeks in Reynosa. For every increase of one female mosquito, the egg counts in the corresponding ovitraps increased by 2.33% (95% HDI: 2.31%–-2.42%) in McAllen and by 0.6% (95% HDI: 0.5%–0.62%) in Reynosa. Counter knowledge, weekly increase of temperature had a negative influence in adult and egg counts in Reynosa and McAllen. Precipitation had a positive influence on egg counts in McAllen

Aprendizaje activo y pedagogía culturalmente relevante en STEM: Tres lecciones aprendidas dentro y fuera del aula

Uno de los mayores desafíos en la ciencia, la tecnología, la ingeniería y la educación matemática (STEM, por sus siglas en inglés) es mejorar el rendimiento y la retención de estudiantes de diversos orígenes. Existen grandes diferencias entre los logros académicos de los estudiantes de minorías subrepresentadas (EMS) con aquellos que no pertenecen a estas minorías. Las diferencias inician desde el kínder y continúan hasta los estudios de posgrado. El aprendizaje activo y la pedagogía culturalmente sensible/relevante han mostrado resultados exitosos minimizando estas diferencias educacionales. Desafortunadamente, el aprendizaje activo y la pedagogía culturalmente relevante no son métodos comunes de enseñanza en STEM. Este documento resume tres lecciones aprendidas utilizando el aprendizaje activo y la pedagogía culturalmente relevante dentro y fuera del aula en diferentes plataformas de enseñanza que incluyen servicios de aprendizaje, enseñanza bilingüe, participación comunitaria, estudios en el extranjero y aprendizaje cooperativo en línea como parte de cursos en STEM. Las lecciones incluyen: romper el hielo, incluir reflexiones en los cursos y socializar