Journal of Vector Ecology最新文献

We investigated the abundance and distribution of Aedes aegypti and Aedes albopictus mosquitoes in urban parks in the eastern zone of the city of São Paulo, where the highest number of autochthonous dengue cases during the major 2015-2016 epidemic was reported. The association of climatic and environmental factors with the spatiotemporal distribution of species in relation to vegetation cover and human proximity was examined. Twelve geo-referenced ovitraps were randomly installed in each park, covering areas with varying degrees of vegetation and human activity from September, 2018 to February, 2020, during three weeks each season. A total of 57,604 Aedes aegypti or Aedes albopictus eggs were collected, identifying 10,228 Ae. aegypti and 23,764 Ae. albopictus larvae. Seasonal variations showed distinct patterns with higher mosquito abundances during warmer and rainier seasons. The association between abundance and climatic factors was more evident at the level of the aedini assemblies than at the level of the local populations. Aedes aegypti was predominantly found in peripheral and transitional areas with higher human activity during rainy and warmer seasons. In contrast, Ae. albopictus thrived in inner park areas with greater vegetation cover and lower human activity during drier and milder seasons. The abundance of Ae. aegypti and Ae. albopictus was influenced by climatic factors and park-specific microhabitats. These findings underscore the importance of targeted vector control strategies in urban park settings during seasons favorable for mosquito reproduction. Understanding the interaction between ecological factors and these mosquitoes in urban environments is critical for effective public health interventions.

This field study describes the abundance of ticks and the prevalence of tick-borne pathogens in two hiking areas, Stebbins Cold Canyon (SCC) and Skyline Wilderness Park (SKY), in northern California. These areas have experienced extreme weather events, including wildfire, drought, and heavy rainfall, which have changed the environment. Questing ticks were collected over nine months, identified to species, and screened for tick-borne pathogens using qPCR. Four hundred and fifty-nine ticks were collected, including 54 adults from SCC and 405 from SKY, consisting of 279 (68.9%) larvae, 2 (0.5%) nymphs, and 124 (30.6%) adults. At SCC, Ixodes pacificus and Dermacentor occidentalis accounted for 92.6% (50/54) and 7.4% (4/54), respectively. At SKY, I. pacificus (16.8%, 68/405), D. occidentalis (12.3%, 50/405), D. similis (0.7%, 3/405), and D. albipictus (70.4%, 285/405) were collected. Overall, the prevalence of tick-borne pathogens was low in the collected ticks. Borrelia burgdorferi sl (0.8%, 1/121) and Rickettsia rhipicephali (1.7%, 2/121) were found at SKY. Rickettsia tillamookensis was identified at SCC and SKY with a prevalence of 3.7% (2/54) and 1.7% (2/121), respectively. Babesia duncani was identified in 3.7% (2/54) and 1.2% (5/405) of ticks at SCC and SKY, respectively. These findings suggest that multiple tick species can withstand extreme weather events, providing further data regarding the effects of weather extremes and climate change on tick populations and pathogen prevalence. This study is one of the first to report B. duncani in I. pacificus ticks in California, particularly in Solano County.

We investigated the association between water physicochemical parameters and polarized light patterns with mosquito oviposition in central coast urban areas of Peru. Water samples from diverse locations were analyzed, assessing key parameters, including conductivity, total dissolved solids, hardness, pH, alkalinity, phosphate, and nitrate levels. Principal component analysis revealed that conductivity, total dissolved solids, and hardness were significantly associated with the presence of mosquito oviposition. These findings were corroborated by generalized linear mixed models, which highlighted location-specific effects and seasonal variations in physicochemical parameters associated with oviposition. Our study also explored polarized light as a potential oviposition cue. While a direct causal link between polarized light patterns and oviposition requires further investigation, a positive correlation between pH levels and circularly polarized light patterns suggests a potential interaction between water chemistry and this optical cue. These findings underscore the complex interplay of environmental factors associated with mosquito oviposition. Our results suggest an association between physicochemical cues, particularly conductivity, total dissolved solids, and hardness, and the presence of mosquito oviposition, with polarized light potentially playing a role.

Knowledge of the utilization by mosquito species of different habitats is critical for determining risk for the transmission of mosquito-borne pathogens. The Great Plains region of the United States is experiencing a biome-level change as grasslands are being converted to forests through the process of woody plant encroachment by eastern redcedar (ERC). There is a need to evaluate how mosquitoes respond to fine scale habitat characteristics within areas experiencing ERC encroachment. This study examined the influence of fine-scale vegetation differences on mosquito abundance, bloodmeal hosts, and infection with West Nile virus (WNV) in eight ERC-encroached sites across Oklahoma. Mosquito traps were placed in three unique habitats in ERC-encroached sites. Ae. albopictus, Ae. vexans, An. punctipennis, Cx. erraticus, and Cx. tarsalis were most abundant in the ecotone and/or forested areas of ERC trees compared with grass. Ps. columbiae was more abundant in grassland than in forest. Blood meal analysis indicated that mosquitoes fed primarily on mammals, and we detected Anaplasma species in several blood meals. These results suggest that important mosquito vectors may occur throughout much of ERC-encroached areas, a finding that has consequences for blood meal acquisition, pathogen transmission, and thus public health and land management programs throughout the Great Plains.

The increasing prevalence of insecticide resistance in Aedes mosquitoes necessitates development of alternative control methods. This study evaluated adulticidal efficacy of essential oils from Litsea cubeba, Syzygium aromaticum, and Cinnamomum porrectum against laboratory and field populations of Aedes aegypti and Aedes albopictus. Discriminating concentrations (DCs) were established using WHO tube tests. L. cubeba showed the lowest DCs (6.21% v/v for Ae. aegypti, 9.68% v/v for Ae. albopictus), followed by C. porrectum (9.70%, 15.55%) and S. aromaticum (19.40%, 24.33%). At these DCs, all oils demonstrated 98-100% knockdown and 99-100% mortality against field populations. Aedes albopictus required higher DCs than Ae. aegypti, suggesting species-specific susceptibility differences. Essential oils showed superior efficacy against field-collected Ae. aegypti compared to cypermethrin. Results indicate potential of these oils as effective botanical insecticides, particularly where conventional insecticide resistance occurs.

This study examined the presence and characteristics of microplastics (MPs) in water collected from potential mosquito oviposition habitats in Lubbock, TX. Water samples ranging from 10 to 1000 mL were collected from 36 suspected artificial and natural oviposition habitats, and sites were categorized as artificial containers, tires, or natural sites. Samples were filtered through a series of stainless-steel sieves and isopore membrane filters, and MPs were imaged and counted using a stereo microscope. MPs were classified by shape into fragments, fibers, films, spheres, and foams. Scanning Electron Microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA)were employed to characterize the size, morphology, and polymer type of MPs collected from a subset of oviposition habitats. Results suggest MPs are commonly found in artificial containers and tires, and at higher concentrations than natural sites. Furthermore, MPs found in all potential oviposition sites were predominantly fragments and fibers. SEM analysis revealed diverse morphologies and indicated potential microbial colonization on MP surfaces. Ultimately, this study provides insights into the distribution and characteristics of MPs in mosquito oviposition habitats, highlighting the potential impact of MP pollution and the potential effects on mosquito biology, and serves as a foundation for further research on the ecological implications of MPs in mosquito oviposition habitats.

Spatial and temporal differences in the relative abundance of arthropod vectors are important factors that influence the risk of disease for mammalian hosts. Seasonal changes in the diversity and abundance of fleas (Siphonaptera) in Richardson's ground squirrel (Urocitellus richardsonii) burrows were studied at two sites in central Saskatchewan. A total of 225 fleas (151 at an urban site and 74 at a rural site) were collected. Flea prevalence differed among seasons at the urban site but not at the rural site. Of the nine flea species detected (eight at the urban site and six at the rural site), Oropsylla rupestris, O. bruneri, O. labis, O. tuberculata, and Aetheca wagneri are vectors of Yersinia pestis, the causative agent of plague. The presence and abundance of some fleas differed between sites and seasons. Neopsylla inopina and O. rupestris were the most abundant species at the urban site during the spring and summer, respectively, while O. bruneri was the most abundant species at the rural site. Our findings may have implications for the management of the black-tailed prairie dogs (Cynomys ludovicianus) in southwestern Saskatchewan because they coexist with U. richardsonii, are hosts for Oropsylla, and are at great risk of plague exposure/infection.