Laboratory evaluation of stable isotope labeling of Culicoides (Diptera: Ceratopogonidae) for adult dispersal studies.

BackgroundStable isotope labeling is a promising method for use in insect mark-capture and dispersal studies. Culicoides biting midges, which transmit several important animal pathogens, including bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV), are small flies that develop in various semi-aquatic habitats. Previous Culicoides dispersal studies have suffered from the limitations of other labeling techniques, and an inability to definitively connect collected adult midges to specific immature development sites.ResultsAdult C. sonorensis were successfully labeled with 13C and 15N stable isotopes as larvae developing in a semi-aquatic mud substrate in the laboratory. High and low-dose isotope treatments for both elements significantly enriched midges above the background isotope levels of unenriched controls. Enrichment had no effect on C. sonorensis survival, though a slight (~ 5 day) delay in emergence was observed, and there was no significant effect of pool size on 13C or 15N enrichment levels.ConclusionsStable isotope labeling is life-long, and does not interfere with natural insect behaviors. Stable isotope enrichment using 13C or 15N shows promise for Culicoides dispersal studies in the field. This method can be used to identify adult dispersal from larval source habitat where a midge developed. It may be possible to detect a single enriched midge in a pool of unenriched individuals, though further testing is needed to confirm the sensitivity of this method

Quantitative synthesis of the role of birds in carrying ticks and tick-borne pathogens in North America

Birds play a central role in the ecology of tick-borne pathogens. They expand tick populations and pathogens across vast distances and serve as reservoirs that maintain and amplify transmission locally. Research into the role of birds for supporting ticks and tick-borne pathogens has largely been descriptive and focused in small areas. To expand inference beyond these studies, we conducted a quantitative review at the scale of North America to identify avian life history correlates of tick infestation and pathogen prevalence, calculate species-level indices of importance for carrying ticks, and identify research gaps limiting understanding of tick-borne pathogen transmission. Across studies, 78 of 162 bird species harbored ticks, yielding an infestation prevalence of 1981 of 38,929 birds (5.1�%). Avian foraging and migratory strategies interacted to influence infestation. Ground-foraging species, especially non-migratory ground foragers, were disproportionately likely to have high prevalence and intensity of tick infestation. Studies largely focused on Borrelia burgdorferi, the agent of Lyme disease, and non-migratory ground foragers were especially likely to carry B. burgdorferi-infected ticks, a finding that highlights the potential importance of resident birds in local pathogen transmission. Based on infestation indices, all 'super-carrier' bird species were passerines. Vast interior areas of North America, many bird and tick species, and most tick-borne pathogens, remain understudied, and research is needed to address these gaps. More studies are needed that quantify tick host preferences, host competence, and spatiotemporal variation in pathogen prevalence and vector and host abundance. This information is crucial for predicting pathogen transmission dynamics under future global change.Peer reviewedNatural Resource Ecology and ManagementEntomology and Plant Patholog

Coccidian Parasites and Conservation Implications for the Endangered Whooping Crane (Grus americana)

While the population of endangered whooping cranes (Grus americana) has grown from 15 individuals in 1941 to an estimated 304 birds today, the population growth is not sufficient to support a down-listing of the species to threatened status. The degree to which disease may be limiting the population growth of whooping cranes is unknown. One disease of potential concern is caused by two crane-associated Eimeria species: Eimeria gruis and E. reichenowi. Unlike most species of Eimeria, which are localized to the intestinal tract, these crane-associated species may multiply systemically and cause a potentially fatal disease. Using a non-invasive sampling approach, we assessed the prevalence and phenology of Eimeria oocysts in whooping crane fecal samples collected across two winter seasons (November 2012–April 2014) at the Aransas National Wildlife Refuge along the Texas Gulf coast. We also compared the ability of microscopy and PCR to detect Eimeria in fecal samples. Across both years, 26.5% (n = 328) of fecal samples were positive for Eimeria based on microscopy. Although the sensitivity of PCR for detecting Eimeria infections seemed to be less than that of microscopy in the first year of the study (8.9% vs. 29.3%, respectively), an improved DNA extraction protocol resulted in increased sensitivity of PCR relative to microscopy in the second year of the study (27.6% and 20.8%, respectively). The proportion of positive samples did not vary significantly between years or among sampling sites. The proportion of Eimeria positive fecal samples varied with date of collection, but there was no consistent pattern of parasite shedding between the two years. We demonstrate that non-invasive fecal collections combined with PCR and DNA sequencing techniques provides a useful tool for monitoring Eimeria infection in cranes. Understanding the epidemiology of coccidiosis is important for management efforts to increase population growth of the endangered whooping crane.The open access fee for this work was funded through the Texas A&M University Open Access to Knowledge (OAK) Fund

Programa piloto de ciencia ciudadana en México para vigilancia pasiva de triatominos y concientizar sobre la enfermedad de Chagas

Objective. To generate data about Chagas disease vectors through passive surveillance and inform the public using social media and community science. Materials and methods. We used social media to inform, raise awareness and to promote the public to report their triatomine encounters. We received pictures and specimens collected to be tested for Trypanosoma cruzi and to identify recent bloodmeal source through PCR. Results. Community scientists reported 44 triatomines from 15 states in Mexico and one triatomine from Nicaragua, including 9 species with Triatoma dimidiata sensu lato and T. gerstaeckeri being the most common. We received 12 collected specimens and T. cruzi was detected in 8 (67%) of the discrete typing unit TcI. We identified recent bloodmeal source in 6 triatomines including: human (Homo sapiens), dog (Canis lupus familiaris), wood rat (Neotoma sp.), dove (Columbidae) and amphibius (Bufonidae). Conclusion. The use of community science can be a complementary method to generate information about the ecology and epidemiology of Chagas disease vectors.Objetivo. Generar datos sobre vectores de la enfermedad de Chagas (EC) mediante vigilancia pasiva e informar a la población mediante redes sociales y ciencia ciudadana. Material y métodos. Utilizando redes sociales informamos, concientizamos y alentamos al público a reportarnos sus encuentros con triatominos. Recibimos reportes fotográficos y especímenes colectados a los que analizamos para detectar infección por Trypanosoma cruzi e identificar la fuente reciente de alimentación mediante PCR. Resultados. Nos reportaron 44 triatominos de 15 estados en México y uno de Nicaragua, incluyendo 9 especies siendo Triatoma dimidiata sensu lato y T. gerstaeckeri las más comunes. Recibimos 12 especímenes colectados y encontramos T. cruzi en 8 (67%) de la unidad taxonómica discreta TcI. Identificamos fuente reciente de alimentación en 6 triatominos incluyendo: humano (Homo sapiens), perro (Canis lupus familiaris), rata de campo (Neotoma sp.), paloma (Columbidae) y anfibio (Bufonidae). Conclusión. Ciencia ciudadana puede ser un método complementario para generar información sobre ecología y epidemiología de EC

Avian species diversity and transmission of West Nile virus in Atlanta, Georgia

BACKGROUND: The dilution effect is the reduction in vector-borne pathogen transmission associated with the presence of diverse potential host species, some of which are incompetent. It is popularized as the notion that increased biodiversity leads to decreased rates of disease. West Nile virus (WNV) is an endemic mosquito-borne virus in the United States that is maintained in a zoonotic cycle involving various avian host species. In Atlanta, Georgia, substantial WNV presence in the vector and host species has not translated into a high number of human cases. METHODS: To determine whether a dilution effect was contributing to this reduced transmission, we characterized the host species community composition and performed WNV surveillance of hosts and vectors in urban Atlanta between 2010 and 2011. We tested the relationship between host diversity and both host seroprevalence and vector infection rates using a negative binomial generalized linear mixed model. RESULTS: Regardless of how we measured host diversity or whether we considered host seroprevalence and vector infection rates as predictor variables or outcome variables, we did not detect a dilution effect. Rather, we detected an amplification effect, in which increased host diversity resulted in increased seroprevalence or infection rates; this is the first empirical evidence for this effect in a mosquito-borne system. CONCLUSIONS: We suggest that this effect may be driven by an over-abundance of moderately- to poorly-competent host species, such as northern cardinals and members of the Mimid family, which cause optimal hosts to become rarer and present primarily in species-rich areas. Our results support the notion that dilution or amplification effects depend more on the identities of the species comprising the host community than on the absolute diversity of hosts. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-017-1999-6) contains supplementary material, which is available to authorized users

Adaptation of a microbial detection array as a monitoring tool revealed the presence 2 of mosquito-borne viruses and insect-specific viruses in field-collected mosquitoes

Several mosquito-borne diseases affecting humans are emerging or re-emerging in the United States. The early detection of pathogens in mosquito populations is essential to prevent and control the spread of these diseases. In this study, we tested the potential applicability of the Lawrence Livermore Microbial Detection Array (LLMDA) to enhance bio-surveillance by detecting microbes present in Aedes aegypti, Aedes albopictus and Culex mosquitoes that are major vector species globally, including in Texas. The sensitivity and reproducibility of the LLMDA was tested in mosquito samples spiked with different concentrations of dengue virus (DENV) revealing a detection limit of \u3e100 but \u3c1000 pfu/mL. Additionally, field-collected mosquitoes from Chicago, Illinois and College Station, Texas of known infection status (West Nile virus (WNV) and Culex flavivirus (CxFLAV) positive) were tested on the LLMDA to confirm its efficiency. Mosquito field samples of unknown infection status, collected in San Antonio, TX and the Lower Rio Grande Valley (LRGV), TX were run on the LLMDA and further confirmed by PCR or qPCR. The analysis of the field samples with the LLMDA revealed the presence of cell fusing agent virus (CFAV) in Ae. aegypti populations. Wolbachia was also detected in several of the field samples (Ae. albopictus and Culex spp.) by the LLMDA. Our findings demonstrated that the LLMDA can be used to detect multiple arboviruses of public health importance including viruses that belong to the Flavivirus, Alphavirus and Orthobunyavirus genera. Additionally, insect-specific viruses and bacteria were also detected from field-collected mosquitoes. Another strength of this array is its ability to detect multiple viruses in the same mosquito pool allowing for the detection of co-circulating pathogens in an area, and the identification of potential ecological associations between different viruses. This array can aid in the bio-surveillance of mosquito borne viruses circulating in specific geographical areas

Local impact of temperature and precipitation on West Nile virus infection in Culex species mosquitoes in northeast Illinois, USA

<p>Abstract</p> <p>Background</p> <p>Models of the effects of environmental factors on West Nile virus disease risk have yielded conflicting outcomes. The role of precipitation has been especially difficult to discern from existing studies, due in part to habitat and behavior characteristics of specific vector species and because of differences in the temporal and spatial scales of the published studies. We used spatial and statistical modeling techniques to analyze and forecast fine scale spatial (2000 m grid) and temporal (weekly) patterns of West Nile virus mosquito infection relative to changing weather conditions in the urban landscape of the greater Chicago, Illinois, region for the years from 2004 to 2008.</p> <p>Results</p> <p>Increased air temperature was the strongest temporal predictor of increased infection in <it>Culex pipiens </it>and <it>Culex restuans </it>mosquitoes, with cumulative high temperature differences being a key factor distinguishing years with higher mosquito infection and higher human illness rates from those with lower rates. Drier conditions in the spring followed by wetter conditions just prior to an increase in infection were factors in some but not all years. Overall, 80% of the weekly variation in mosquito infection was explained by prior weather conditions. Spatially, lower precipitation was the most important variable predicting stronger mosquito infection; precipitation and temperature alone could explain the pattern of spatial variability better than could other environmental variables (79% explained in the best model). Variables related to impervious surfaces and elevation differences were of modest importance in the spatial model.</p> <p>Conclusion</p> <p>Finely grained temporal and spatial patterns of precipitation and air temperature have a consistent and significant impact on the timing and location of increased mosquito infection in the northeastern Illinois study area. The use of local weather data at multiple monitoring locations and the integration of mosquito infection data from numerous sources across several years are important to the strength of the models presented. The other spatial environmental factors that tended to be important, including impervious surfaces and elevation measures, would mediate the effect of rainfall on soils and in urban catch basins. Changes in weather patterns with global climate change make it especially important to improve our ability to predict how inter-related local weather and environmental factors affect vectors and vector-borne disease risk.</p> <p>Local impact of temperature and precipitation on West Nile virus infection in <it>Culex </it>species mosquitoes in northeast Illinois, USA.</p

Diel activity patterns of vector mosquito species in the urban environment: Implications for vector control strategies

Mathematical models have been widely used to study the population dynamics of mosquitoes as well as to test and validate the effectiveness of arbovirus outbreak responses and mosquito control strategies. The objective of this study is to assess the diel activity of mosquitoes in Miami-Dade, Florida, and Brownsville, Texas, the most affected areas during the Zika outbreak in 2016–2017, and to evaluate the effectiveness of simulated adulticide treatments on local mosquito populations. To assess variations in the diel activity patterns, mosquitoes were collected hourly for 96 hours once a month from May through November 2019 in Miami-Dade County, Florida, and Brownsville, Texas. We then performed a PERMANOVA followed by a SIMPER analysis to assess whether the abundance and species richness significantly varies at different hours of the day. Finally, we used a mathematical model to simulate the population dynamics of 5 mosquito vector species and evaluate the effectiveness of the simulated adulticide applications. A total of 14,502 mosquitoes comprising 17 species were collected in Brownsville and 10,948 mosquitoes comprising 19 species were collected in Miami-Dade County. Aedes aegypti was the most common mosquito species collected every hour in both cities and peaking in abundance in the morning and the evening. Our modeling results indicate that the effectiveness of adulticide applications varied greatly depending on the hour of the treatment. In both study locations, 9 PM was the best time for adulticide applications targeting all mosquito vector species; mornings/afternoons (9 AM– 5 PM) yielded low effectiveness, especially for Culex species, while at night (12 AM– 6 AM) the effectiveness was particularly low for Aedes species. Our results indicate that the timing of adulticide spraying interventions should be carefully considered by local authorities based on the ecology of the target mosquito species in the focus area

Hacer memoria de la vida religiosa

Los autores intentan hacer una síntesis del camino que ha recorrido la vida religiosa en América Latina destacando la complejidad y la riqueza que supone la vocación a la vida religiosa expresado por los autores de esta manera: “el martirologio de América Latina está lleno en estos últimos tiempos, de religiosos y religiosas que testimoniaron con su vida lo que creían y predicaban". En este artículo se analiza el origen misionero de la vida religiosa antes del Concilio Vaticano II, las transformaciones que ha tenido la vida religiosa después del concilio con la relectura del mismo en Medellín, Puebla, también se analizan los grandes cambios que han surgido al final del S. XX, así como las implicaciones para los religiosos(as) y lo que sucede en Santo Domingo, Conferencia en la que se reafirma la opción por los pobres, se plantea el reto de la inculturación, se tratan temas como la tierra, los laicos, los jóvenes y la mujer en la encrucijada del paso de la modernidad a la postmodernidad. Se señala en el primer párrafo de este escrito: “No resulta fácil hacer una apretada síntesis del camino recorrido por la vida religiosa en América Latina. La vida es mucha más rica que cualquier expresión de ella. Y ciertamente la vida religiosa en América Latina ha escrito páginas bellísimas, de fidelidad y de compromiso con los más desheredados de la tierra, de comunión y participación en las grandes luchas por la promoción y la dignidad de todo hombre, sobre todo de los más empobrecidos y marginados, esforzándose hasta el sacrificio de la vida por desterrar la injusticia y la pobreza que han marcado duramente a esta tierra generosa. Han sido páginas, cargadas de creatividad y coraje, refrendadas, a veces, con el testimonio irrefutable de la sangre. Ya desde el comienzo fueron «intrépidos luchadores por la justicia, evangelizadores de la paz» y lo han continuado siendo hasta nuestros días: el martirologio de América Latina está lleno en estos últimos tiempos, de religiosos y religiosas que testimoniaron con su vida lo qué creían y predicaban”

Diel activity patterns of two distinct populations of Aedes aegypti in Miami, FL and Brownsville, TX

The diel biting activity of Aedes (Stegomyia) aegypti (L) populations was extensively investigated in the early 1900s to gain more information on the biology of Ae. aegypti, and this information was used to devise effective approaches to controlling populations of this species and protect the human population from widespread arbovirus outbreaks. However, few contemporary studies are available regarding the diel activity patterns of Ae. aegypti. To assess the diel activity patterns of Ae. aegypti in southern Florida and Texas, we conducted 96-h uninterrupted mosquito collections once each month from May through November 2019 in Miami, Florida, and Brownsville, Texas, using BG-Sentinel 2 Traps. The overall diel activity pattern in both cities was bimodal with morning and evening peak activity between 7:00 and 8:00 and between 19:00 and 20:00. There were significant daily, monthly, seasonal, and site-specific differences in activity patterns, but these differences did not affect the overall peak activity times. These differences suggest daily, monthly, seasonal, and site-specific variations in human exposure to Ae. aegypti. Our observations can be used in planning and executing Ae. aegypti vector control activities in southern Florida and southern Texas, specifically those targeting the adult mosquito populations