RESUMEN
Mosquito-borne diseases constitute a significant global impact on public and animal health. Climatic variables are recognized as major drivers in the mosquitoes' life history, principally rainfall and temperature, which directly influence mosquito abundance. Likewise, urbanization changes environmental conditions, and understanding how environmental variables and urbanization influence mosquito dynamics is crucial for the integrated management of mosquito-borne diseases, especially in the context of climate change. In this study, our aim was to observe the effect of temperature, rainfall, and the percentage of impervious surface on the abundance of mosquito species over a temporal scale of one complete year of fortnightly samplings, spanning from June 2021 to June 2022 in Yucatan, Mexico. We selected nine localities along an urbanization gradient (three natural, three rural, and three urban) from Mérida City to Reserva de la Biosfera Ría Celestún. Using BG-traps, mosquitoes were collected biweekly at each locality. Additionally, we estimated the percentage of impervious surface. Daily data of the maximum, mean and minimum temperatures, diurnal temperature range and rainfall were accumulated weekly. We calculated the accumulated quantities of temperatures and rainfall and lagged from one to four weeks before sampling for each locality. Generalized linear mixed models were then performed to study the influence of environmental variables and percentage of impervious surfaces on each of the 15 most abundant species. A total of 131,525 mosquitoes belonging to 11 genera and 49 species were sampled with BG-Sentinel traps baited with BG-lure and dry ice. The most frequently significative variable is the accumulated precipitation four weeks before the sampling. We observed a positive relationship between Cx. quinquefasciatus and Cx. thriambus with the diurnal temperature range. For Ae. aegypti, we observed a positive relationship with minimum temperature. Conversely, the percentage of impervious surface serves as a proxy of anthropogenic influence and helped us to distinguishing species exhibiting habitat preference for urban and rural environments, versus those preferring natural habitats. Our results characterize the species-specific effects of environmental variables (temperature, rainfall and impervious surface) on mosquito abundance.
Asunto(s)
Culicidae , Estaciones del Año , Temperatura , Animales , México , Culicidae/fisiología , Culicidae/clasificación , Culicidae/crecimiento & desarrollo , Urbanización , Mosquitos Vectores/fisiología , Mosquitos Vectores/crecimiento & desarrollo , Dinámica Poblacional , Lluvia , Cambio ClimáticoRESUMEN
BACKGROUND: Aedes aegypti-borne diseases are becoming major public health problems in tropical and sub-tropical regions. While socioeconomic status has been associated with larval mosquito abundance, the drivers or possible factors mediating this association, such as environmental factors, are yet to be identified. We examined possible associations between proximity to houses and roads and immature mosquito abundance, and assessed whether these factors and mosquito prevention measures mediated any association between household environmental factors and immature mosquito abundance. METHODS: We conducted two cross-sectional household container surveys in February-March and November-December, 2017, in urban and rural areas of Quetzaltenango, Guatemala. We used principal components analysis to identify factors from 12 variables to represent the household environment. One factor which included number of rooms in house, electricity, running water, garbage service, cable, television, telephone, latrine, well, and sewer system, was termed "environmental capital." Environmental capital scores ranged from 0 to 5.5. Risk factors analyzed included environmental capital, and distance from nearest house/structure, paved road, and highway. We used Poisson regression to determine associations between distance to nearest house/structure, roads, and highways, and measures of immature mosquito abundance (total larvae, total pupae, and positive containers). Using cubic spline generalized additive models, we assessed non-linear associations between environmental capital and immature mosquito abundance. We then examined whether fumigation, cleaning containers, and distance from the nearest house, road, and highway mediated the relationship between environmental capital and larvae and pupae abundance. RESULTS: We completed 508 household surveys in February-March, and we revisited 469 households in November-December. Proximity to paved roads and other houses/structures was positively associated with larvae and pupae abundance and mediated the associations between environmental capital and total numbers of larvae/pupae (p ≤ 0.01). Distance to highways was not associated with larval/pupal abundance (p ≥ 0.48). Households with the lowest and highest environmental capital had fewer larvae/pupae than households in the middle range (p < 0.01). CONCLUSIONS: We found evidence that proximity to other houses and paved roads was associated with greater abundance of larvae and pupae. Understanding risk factors such as these can allow for improved targeting of surveillance and vector control measures in areas considered at higher risk for arbovirus transmission.
Asunto(s)
Aedes/crecimiento & desarrollo , Planificación Ambiental/estadística & datos numéricos , Vivienda , Larva , Pupa , Animales , Estudios Transversales , Guatemala , Humanos , Factores de Riesgo , Encuestas y CuestionariosRESUMEN
The markedly anthropophilic and endophilic behaviors of Aedes aegypti (L.) make it a very efficient vector of dengue, chikungunya, and Zika viruses. Although a large body of research has investigated the immature habitats and conditions for adult emergence, relatively few studies have focused on the indoor resting behavior and distribution of vectors within houses. We investigated the resting behavior of Ae. aegypti indoors in 979 houses of the city of Acapulco, Mexico, by performing exhaustive indoor mosquito collections to describe the rooms and height at which mosquitoes were found resting. In total, 1,403 adult and 747 female Ae. aegypti were collected, primarily indoors (98% adults and 99% females). Primary resting locations included bedrooms (44%), living rooms (25%), and bathrooms (20%), followed by kitchens (9%). Aedes aegypti significantly rested below 1.5 m of height (82% adults, 83% females, and 87% bloodfed females); the odds of finding adult Ae. aegypti mosquitoes below 1.5 m was 17 times higher than above 1.5 m. Our findings provide relevant information for the design of insecticide-based interventions selectively targeting the adult resting population, such as indoor residual spraying.
Asunto(s)
Aedes/fisiología , Animales , Conducta Animal , Femenino , Vivienda , Insectos Vectores/fisiología , Masculino , MéxicoRESUMEN
Urban parks are areas designated for human recreation but also serve as shelter and refuge for populations of several species of native fauna, both migratory and introduced. In Brazil, the effect of annual climate variations on Aedes aegypti and dengue epidemics in large cities like São Paulo is well known, but little is known about how such variations can affect the diversity of mosquito vectors in urban parks and the risk of disease transmission by these vectors. This study investigates the influence of larval habitats and seasonal factors on the diversity and abundance of Culicidae fauna in Anhanguera Park, one of the largest remaining green areas in the city of São Paulo. Species composition and richness and larval habitats were identified. Seasonality (cold-dry and hot-rainy periods) and year were considered as explanatory variables and the models selection approach was developed to investigate the relationship of these variables with mosquito diversity and abundance. A total of 11,036 specimens from 57 taxa distributed in 13 genera were collected. Culex nigripalpus, Cx. quinquefasciatus and Aedes albopictus were the most abundant species. Bamboo internodes and artificial breeding sites showed higher abundance, while ponds and puddles showed greater richness. Significant relationships were observed between abundance and seasonality, with a notable increase in the mosquitos abundance in the warm-rainy periods. The Shannon and Berger-Parker indices were related with interaction between seasonality and year, however separately these predictors showed no relationship with ones. The increased abundance of mosquitoes in warm-rainy months and the fact that some of the species are epidemiologically important increase not only the risk of pathogen transmission to people who frequent urban parks but also the nuisance represented by insect bites. The findings of this study highlight the importance of knowledge of culicid ecology in green areas in urban environments.