Potential Larval Habitats Research Articles

The impact of Bacillus thuringiensis var. israelensis (Vectobac® WDG) larvicide sprayed with drones on the bio-control of malaria vectors in rice fields of sub-urban Kigali, Rwanda

BackgroundThe core vector control tools used to reduce malaria prevalence are currently long-lasting insecticidal nets (LLINs), and indoor residual spraying (IRS). These interventions are hindered by insecticide resistance and behavioural adaptation by malaria vectors. Thus, for effective interruption of malaria transmission, there is a need to develop novel vector control interventions and technologies to address the above challenges. Larviciding using drones was experimented as an innovative tool that could complement existing indoor interventions to control malaria.MethodsA non-randomized larviciding trial was carried out in irrigated rice fields in sub-urban Kigali, Rwanda. Potential mosquito larval habitats in study sites were mapped and subsequently sprayed using multirotor drones. Application of Bacillus thuringiensis var. israelensis (Bti) (Vectobac® WDG) was followed by entomological surveys that were performed every two weeks over a ten-month period. Sampling of mosquito larvae was done with dippers while adult mosquitoes were collected using CDC miniature light traps (CDC-LT) and pyrethrum spraying collection (PSC) methods. Malaria cases were routinely monitored through community health workers in villages surrounding the study sites.ResultsThe abundance of all-species mosquito larvae, Anopheles larvae and all-species pupae declined by 68.1%, 74.6% and 99.6%, respectively. Larval density was reduced by 93.3% for total larvae, 95.3% for the Anopheles larvae and 61.9% for pupae. The total adult mosquitoes and Anopheles gambiae sensu lato collected using CDC-Light trap declined by 60.6% and 80% respectively. Malaria incidence also declined significantly between intervention and control sites (U = 20, z = − 2.268, p = 0.023).ConclusionsThe larviciding using drone technology implemented in Rwanda demonstrated a substantial reduction in abundance and density of mosquito larvae and, concomitant decline in adult mosquito populations and malaria incidences in villages contingent to the treatment sites. The scaling up of larval source management (LSM) has to be integrated in malaria programmes in targeted areas of malaria transmission in order to enhance the gains in malaria control.

Coupling of potential habitat models with particle tracking experiments to examine larval fish dispersal and connectivity in deep water regions.

Computing Lagrangian trajectories with ocean circulation models is a powerful way to infer larval dispersal pathways and connectivity. Defining release areas and timing of particles to represent larval habitat realistically is critical to obtaining representative dispersal pathways. However, it is challenging due to spatial and temporal variability in larval density. Forward-tracking particle experiments were conducted to study larval connectivity of four species (neritic or mesopelagic) in the Gulf of Mexico's (GoM) deep-water region. A seasonal climatology coupled with predicted potential larval habitat models based on generalized additive models was used to delimit the particle dispersal origin. Two contrasting mesoscale circulation patterns were examined: (1) high Loop Current (LC) intrusion, absence of recently detached LC anticyclonic eddies (LC-ACE), and no interaction between LC-ACEs and the semi-permanent cyclonic eddy (CE) in the Bay of Campeche (BoC), and (2) limited LC intrusion, a recently detached LC-ACE, and interaction between LC-ACEs and the BoC's CE. To simulate larval transport, virtual larvae were randomly released in the potential habitats and advected for 30 days with the velocity fields of the HYbrid Coordinate Ocean Model with hourly-resolution assimilation. Potential habitat location and size played a major role in dispersal and connectivity. A greater percentage of particles were retained in potential habitats restricted to the southern BoC, suggesting lower connectivity with other GoM regions than those encompassing most of the BoC or the central Gulf. Mesoscale feature interactions in the western GoM and BoC led to greater dispersion along the western basin. By contrast, the absence of ACE-CE interaction in the BoC led to greater retention and less connectivity between the southern and northern GoM. Under high LC intrusion, particles seeded north of the Yucatan Shelf were advected through the Florida Straits and dispersed within the GoM. Coupling potential habitat models with particle experiments can help characterize the dispersal and connectivity of fish larvae in oceanic systems.

Where does Aedes albopictus (Diptera: Culicidae) really breed in a Mediterranean residential area? Results from a field study in Valencia, Eastern Spain.

Since its introduction in Spain in 2004, Aedes albopictus has rapidly spread across the country. Its aggressive biting behaviour causes nuisance, limiting outdoor activities. Also, its role as a vector of several arboviruses implies a major public health risk, with several cases of autochthonous dengue having been reported nationwide over the past few years. Control strategies usually focus on interventions in breeding sites. As such, accurate knowledge of the main larval habitats becomes a major priority in infested areas. A detailed identification of breeding sites of Ae. albopictus was carried out in the outdoors of 60 residential properties during July-August 2022 in El Vedat de Torrent (Valencia, Eastern Spain), an area recently colonised by this species. A total of 1444 real and potential breeding sites were examined. The most abundant potential larval habitat were plant pot plates (6.48 units/house), although a low infestation level was found, both for larvae (2.06% positivity, x̄ = 30.5 larvae/container), and pupae (0.51%, x̄ = 2.5 pupae/container). A total of 7715 larvae and 205 pupae were found in a disused flooded water pool depuration system. Animal drinkers, buckets and irrigation water containers were found to be the most common positive containers. No statistical difference was observed among the different container materials. A general statistical increase of 1 larva per 11.7 ml of water in breeding sites was detected. Breeding sites of other species such as Culex pipiens (n = 2) and Culex modestus (n = 1) were also rarely found in this residential area. To our knowledge, this is the first aedic index study carried out in Europe, and it provides valuable information about the main domestic breeding habitats of Ae. albopictus, which can greatly improve control programmes.

Species composition of Culicoides (Diptera: Ceratopogonidae) in the Ridge and Valley region of Tennessee, USA.

Biting midges in the genus Culicoides Latreille (Diptera: Ceratopogonidae) are known to transmit many pathogens of veterinary and medical concern. Although much work has been done globally and in certain regions of North America, Culicoides spp. research in rural Appalachia is limited. To begin characterizing the distribution and community structure of Culicoides spp. in Appalachia, we surveyed 2 distinct sites in the Ridge and Valley ecoregion of northeastern Tennessee, USA, from April 2021-September 2021. Culicoides spp. were sampled using 2 methods: Centers for Disease Control ultraviolet LED light traps and potential larval habitat substrate collection (coupled with water chemistry values). Site 1 was dominated by natural features, and Site 2 was a beef cattle operation. During 96 trap nights, a total of 1,568 Culicoides were collected, representing 24 species. Site 1 yielded the highest diversity, with 24 species, while Site 2 yielded 12 species. Overall, the most abundant species in light traps were C. stellifer Coquillett (44%), C. bergi Cochrane (18%), C. haematopotus Malloch (12%), and C. debilipalpis Lutz (11%). From substrate sampling, 8 species were identified. Culicoides haematopotus was the most abundant and was collected during each sampling period. Water chemistry values taken at the time of substrate collection were not significantly related to which Culicoides spp. emerged from a given substrate. Our results indicate a diverse community of Culicoides spp. in our study area, however, further work is needed to identify Culicoides species composition across a variety of landscapes in Appalachia and inform research on vector presence and associated vector disease dynamics.

Mapping Potential Malaria Vector Larval Habitats for Larval Source Management in Western Kenya: Introduction to Multimodel Ensembling Approaches.

Identification and mapping of larval sources are a prerequisite for effective planning and implementing mosquito larval source management (LSM). Ensemble modeling is increasingly used for prediction modeling, but it lacks standard procedures. We proposed a detailed framework to predict potential malaria vector larval habitats by using multimodel ensemble modeling, which includes selection of models, ensembling method, and predictors, evaluation of variable importance, prediction of potential larval habitats, and assessment of prediction uncertainty. The models were built and validated based on multisite, multiyear field observations and climatic/environmental variables. Model performance was tested using independent field observations. Overall, we found that the ensembled model predicted larval habitats with about 20% more accuracy than the average of the individual models ensembled. Key larval habitat predictors in western Kenya were elevation, geomorphon class, and precipitation for the 2 months prior. Additional predictors may be required to increase the predictive accuracy of the larva-positive habitats. This is the first study to provide a detailed framework for the process of multimodel ensemble modeling for malaria vector habitats. Mapping of potential habitats will be helpful in LSM planning.

Species diversity pattern of mosquitoes (Diptera: Culicidae) breeding in different permanent, temporary and natural container habitats of Peshawar, KP Pakistan.

To determine the species composition, relative abundance and seasonal variation of different mosquitoes Genera (Aedes, Anopheles, Armigeres, Culex, and Culiseta) in different habitats the present research work was carried out in Entomology Research Laboratory of The University of Peshawar. Sampling performed from variety of permanent and temporary breeding habitats was carried out on monthly basis from targeted breeding sites for two consecutive years through dipping method. Species diversity in the survey sites was noted. Collection from these seventeen various types of potential larval habitats, yielded a total of 42,430 immature constituting 41,556 larvae and 874 pupae. Among these only 19,651 adult mosquitoes emerged comprising 11,512 female and 8,139 male mosquitoes. 78% (n= 15333) of mosquito larvae were from permanent and 22% (n=4318) were from temporary breeding sites. This study showed that Peshawar valley harbours 15 species from the genera Aedes, Anopheles, Armigeres, Culex and Culiseta. When the density of each species was examined, Culex quinquifasciatus was found to be dominant (79%) and constant in distribution. Among the temporary habitats Aedes albopictus was found as the most prevalent species particularly from tree holes and water cisterns. The highest intensity of mosquitoes was in June (2243 emerged adults) and November (2667 emerged adults) while the lowest was in January (203 emerged adults). A perfect positive correlation (r = +0.8) was found between temperature and population of mosquitoes (df 10 and α 0.05). The species diversity index for mosquitoes remained between 0.12 and 1.76. The Margalef's richness components was noticeably low for bamboo traps (0.2) and fairly high for rice fields, Percolating water and Animal tracks (1.3) which shows the abundance of mosquito species in these habitats. Similarly Pielou's Evenness was highest for bamboo traps (E=1) showing species uniform distribution. Animal tracks were presumed not only the diverse habitat rather also possessed high value for species richness and species evenness. Temperature, rainfall, humidity and other related attributes responsible for species variation and abundance need to be analysed further to pave way for controlling vector species in their oviposition targeted sites.

Larval habitat stability and productivity in two sites in Southern Ghana

BackgroundMosquito larval source management (LSM) is a valuable additional tool for malaria vector control. Understanding the characteristics of mosquito larval habitats and its ecology in different land use types can give valuable insight for an effective larval control strategy. This study determined the stability and productivity of potential anopheline larval habitats in two different ecological sites: Anyakpor and Dodowa in southern Ghana.MethodsA total of 59 aquatic habitats positive for anopheline larvae were identified, and sampled every two weeks for a period of 30 weeks using a standard dipping method. Larvae were collected using standard dippers and were raised in the insectary for identification. Sibling species of the Anopheles gambiae sensu lato (s.l.) were further identified by polymerase chain reaction. The presence of larval habitats, their stability and larvae positive habitats were compared between the two sites using Mann–Whitney U and the Kruskal–Wallis test. Factors affecting the presence of An. gambiae larvae and physicochemical properties at the sites were determined using multiple logistic regression analysis and Spearman’s correlation.ResultsOut of a total of 13,681 mosquito immatures collected, 22.6% (3095) were anophelines and 77.38% (10,586) were culicines. Out of the 3095 anophelines collected, An. gambiae s.l. was predominant (99.48%, n = 3079), followed by Anopheles rufipes (0.45%, n = 14), and Anopheles pharoensis (0.064%, n = 2). Sibling species of the An. gambiae consisted of Anopheles coluzzii (71%), followed by An. gambiae s.s. (23%), and Anopheles melas (6%). Anopheles mean larval density was highest in wells [6.44 (95% CI 5.0–8.31) larvae/dip], lowest in furrows [4.18 (95% CI 2.75–6.36) larvae/dip] and man-made ponds [1.20 (95% CI 0.671–2.131) larvae/dip].The results also revealed habitat stability was highly dependent on rainfall intensity, and Anopheles larval densities were also dependent on elevated levels of pH, conductivity and TDS.ConclusionThe presence of larvae in the habitats was dependent on rainfall intensity and proximity to human settlements. To optimize the vector control measures of malaria interventions in southern Ghana, larval control should be focused on larval habitats that are fed by underground water, as these are more productive habitats.Graphical

Habitat type and host grazing regimen influence the soil microbial diversity and communities within potential biting midge larval habitats

BackgroundBiting midges (Culicoides spp.) are important vectors of diverse microbes such as viruses, protozoa, and nematodes that cause diseases in wild and domestic animals. However, little is known about the role of microbial communities in midge larval habitat utilization in the wild. In this study, we characterized microbial communities (bacterial, protistan, fungal and metazoan) in soils from disturbed (bison and cattle grazed) and undisturbed (non-grazed) pond and spring potential midge larval habitats. We evaluated the influence of habitat and grazing disturbance and their interaction on microbial communities, diversity, presence of midges, and soil properties.ResultsBacterial, protistan, fungal and metazoan community compositions were significantly influenced by habitat and grazing type. Irrespective of habitat and grazing type, soil communities were dominated by phyla Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Proteobacteria (Bacteria); Apicomplexa, Cercozoa, Ciliophora, Ochrophyta (Protists); Chytridiomycota, Cryptomycota (Fungi) and Nematoda, Arthropoda (Metazoa). The relative abundance of Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Proteobacteria, Verrucomicrobia (Bacteria); Apicomplexa, Lobosa (Protists); Ascomycota, Blastomycotina, Cryptomycota (Fungi); and Platyhelminthes (Metazoa) were significantly affected by grazing type. Of note, midge prevalence was higher in grazed sites (67–100%) than non-grazed (25%). Presence of midges in the soil was negatively correlated with bacterial, protistan, fungal and metazoan beta diversities and metazoan species richness but positively correlated with protistan and fungal species richness. Moreover, total carbon (TC), nitrogen (TN) and organic matter (OM) were negatively correlated with the presence of midges and relative abundances of unclassified Solirubrobacterales (Bacteria) and Chlamydomonadales (Protists) but positively with Proteobacteria and unclassified Burkholderiales (Bacteria).ConclusionsHabitat and grazing type shaped the soil bacterial, protistan, fungal and metazoan communities, their compositions and diversities, as well as presence of midges. Soil properties (TN, TC, OM) also influenced soil microbial communities, diversities and the presence of midges. Prevalence of midges mainly in grazed sites indicates that midges prefer to breed and shelter in a habitat with abundant hosts, probably due to greater accessibility of food (blood meals). These results provide a first glimpse into the microbial communities, soil properties and prevalence of midges in suspected midge larval habitats at a protected natural prairie site.

Altitude, not potential larval habitat availability, explains pronounced variation in Plasmodium falciparum infection prevalence in the western Kenya highlands

Progress in malaria control has stalled over the recent years. Knowledge on main drivers of transmission explaining small-scale variation in prevalence can inform targeted control measures. We collected finger-prick blood samples from 3061 individuals irrespective of clinical symptoms in 20 clusters in Busia in western Kenya and screened for Plasmodium falciparum parasites using qPCR and microscopy. Clusters spanned an altitude range of 207 meters (1077-1284 m). We mapped potential mosquito larval habitats and determined their number within 250 m of a household and distances to households using ArcMap. Across all clusters, P. falciparum parasites were detected in 49.8% (1524/3061) of individuals by qPCR and 19.5% (596/3061) by microscopy. Across the clusters, prevalence ranged from 26% to 70% by qPCR. Three to 34 larval habitats per cluster and 0-17 habitats within a 250m radius around households were observed. Using a generalized linear mixed effect model (GLMM), a 5% decrease in the odds of getting infected per each 10m increase in altitude was observed, while the number of larval habitats and their proximity to households were not statistically significant predictors for prevalence. Kitchen located indoors, open eaves, a lower level of education of the household head, older age, and being male were significantly associated with higher prevalence. Pronounced variation in prevalence at small scales was observed and needs to be taken into account for malaria surveillance and control. Potential larval habitat frequency had no direct impact on prevalence.

Improved Use of Drone Imagery for Malaria Vector Control through Technology-Assisted Digitizing (TAD)

Drones have the potential to revolutionize malaria vector control initiatives through rapid and accurate mapping of potential malarial mosquito larval habitats to help direct field Larval Source Management (LSM) efforts. However, there are no clear recommendations on how these habitats can be extracted from drone imagery in an operational context. This paper compares the results of two mapping approaches: supervised image classification using machine learning and Technology-Assisted Digitising (TAD) mapping that employs a new region growing tool suitable for non-experts. These approaches were applied concurrently to drone imagery acquired at seven sites in Zanzibar, United Republic of Tanzania. Whilst the two approaches were similar in processing time, the TAD approach significantly outperformed the supervised classification approach at all sites (t = 5.1, p < 0.01). Overall accuracy scores (mean overall accuracy 62%) suggest that a supervised classification approach is unsuitable for mapping potential malarial mosquito larval habitats in Zanzibar, whereas the TAD approach offers a simple and accurate (mean overall accuracy 96%) means of mapping these complex features. We recommend that this approach be used alongside targeted ground-based surveying (i.e., in areas inappropriate for drone surveying) for generating precise and accurate spatial intelligence to support operational LSM programmes.

GLOBE Mosquito Habitat Mapper Citizen Science Data 2017-2020.

The GLOBE Program's GLOBE Observer application is a free citizen science mobile data collection and visualization tool compatible with iOS and Android operating systems. Citizen scientists armed with the app can report the mosquito larval habitats they identify using the GLOBE Mosquito Habitat Mapper tool. This data can complement the climate, weather, and land cover data obtained from satellite measurements by scientists who develop risk models for mosquito‐borne diseases. Public participation in mosquito surveillance research provides the opportunity to obtain the volume, velocity and variety of data needed to fight the threat of vector‐borne diseases, especially in under‐resourced communities with minimal to no municipal surveillance and mitigation services. GLOBE Mosquito Habitat Mappers document and describe potential and active mosquito larval habitats in and around their homes and communities. An easy‐to‐use pictorial interface enables users to geolocate and describe oviposition sites encountered, count and identify mosquito larvae, and when appropriate, eliminate the larval habitats. During Mosquito Habitat Mapper's first 3 years of use, over 24,000 data observations have been reported throughout the world. This technical report summarizes GLOBE Mosquito Habitat Mapper data reported by GLOBE citizen scientists from three regions: Africa, Asia and the Pacific Islands, and Latin America and the Caribbean. Localized mosquito larvae distribution patterns were examined by comparing data collected in three cities in Senegal–Dakar, Touba, and Thilmakha. The Senegal data show habitat and genera differences among mosquitoes identified by citizen scientists in the cities and illustrates the potential of the app for community‐based surveillance and research.

Status of the invasive mosquito species Aedes aegypti (L., 1762) and Aedes albopictus (Skuse, 1895) (Diptera: Culicidae) in Turkey

Aedes aegypti (L., 1762) and Aedes albopictus (Skuse, 1895) (Diptera: Culicidae) are important vectors of arboviruses. In Turkey, Ae. albopictus eggs were detected in the Thrace area of northwestern Turkey for the first time in 2011. In 2015, studies revealed the spread of Ae. albopictus and the first detection of Ae. aegypti within northeastern Turkey was reported. This paper reports the results of a survey of the presence and distribution of Ae. albopictus and Ae. aegypti in Turkey conducted over 5 years. As of 2019, monitoring studies were conducted on the presence of Ae. albopictus and Ae. aegypti in five geographical regions (Black Sea, Central Anatolia, Marmara, Mediterranean and Aegean Regions). A comprehensive range of potential larval habitats, such as tires, artificial containers, cemeteries, water bottles and natural breeding habitats, were assessed. In addition, standard ovitraps and adults’ traps were used in some localities. This study showed that Ae. albopictus , in particular, expanded its distribution each year and has the potential to extend its range throughout Turkey over the next few years. In Turkey, the distribution of Ae. aegypti is currently limited to northeastern Turkey. Future work focused on determining more effective surveillance and control studies is discussed.

Environmental and spatial risk factors for the larval habitats of Plasmodium knowlesi vectors in Sabah, Malaysian Borneo

Land-use changes, such as deforestation and agriculture, can influence mosquito vector populations and malaria transmission. These land-use changes have been linked to increased incidence in human cases of the zoonotic malaria Plasmodium knowlesi in Sabah, Malaysian Borneo. This study investigates whether these associations are partially driven by fine-scale land-use changes creating more favourable aquatic breeding habitats for P. knowlesi anopheline vectors. Using aerial remote sensing data, we developed a sampling frame representative of all land use types within a major focus of P. knowlesi transmission. From 2015 to 2016 monthly longitudinal surveys of larval habitats were collected in randomly selected areas stratified by land use type. Additional remote sensing data on environmental variables, land cover and landscape configuration were assembled for the study site. Risk factor analyses were performed over multiple spatial scales to determine associations between environmental and spatial variables and anopheline larval presence. Habitat fragmentation (300 m), aspect (350 m), distance to rubber plantations (100 m) and Culex larval presence were identified as risk factors for Anopheles breeding. Additionally, models were fit to determine the presence of potential larval habitats within the areas surveyed and used to generate a time-series of monthly predictive maps. These results indicate that land-use change and topography influence the suitability of larval habitats, and may partially explain the link between P. knowlesi incidence and deforestation. The predictive maps, and identification of the spatial scales at which risk factors are most influential may aid spatio-temporally targeted vector control interventions.

Predicting distribution of malaria vector larval habitats in Ethiopia by integrating distributed hydrologic modeling with remotely sensed data

Larval source management has gained renewed interest as a malaria control strategy in Africa but the widespread and transient nature of larval breeding sites poses a challenge to its implementation. To address this problem, we propose combining an integrated high resolution (50 m) distributed hydrological model and remotely sensed data to simulate potential malaria vector aquatic habitats. The novelty of our approach lies in its consideration of irrigation practices and its ability to resolve complex ponding processes that contribute to potential larval habitats. The simulation was performed for the year of 2018 using ParFlow-Common Land Model (CLM) in a sugarcane plantation in the Oromia region, Ethiopia to examine the effects of rainfall and irrigation. The model was calibrated using field observations of larval habitats to successfully predict ponding at all surveyed locations from the validation dataset. Results show that without irrigation, at least half of the area inside the farms had a 40% probability of potential larval habitat occurrence. With irrigation, the probability increased to 56%. Irrigation dampened the seasonality of the potential larval habitats such that the peak larval habitat occurrence window during the rainy season was extended into the dry season. Furthermore, the stability of the habitats was prolonged, with a significant shift from semi-permanent to permanent habitats. Our study provides a hydrological perspective on the impact of environmental modification on malaria vector ecology, which can potentially inform malaria control strategies through better water management.

Geographically extensive larval surveys reveal an unexpected scarcity of primary vector mosquitoes in a region of persistent malaria transmission in western Zambia

BackgroundThe Barotse floodplains of the upper Zambezi River and its tributaries are a highly dynamic environment, with seasonal flooding and transhumance presenting a shifting mosaic of potential larval habitat and human and livestock blood meals for malaria vector mosquitoes. However, limited entomological surveillance has been undertaken to characterize the vector community in these floodplains and their environs. Such information is necessary as, despite substantial deployment of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) against Anopheles vectors, malaria transmission persists across Barotseland in Zambia’s Western Province.MethodsGeographically extensive larval surveys were undertaken in two health districts along 102 km of transects, at fine spatial resolution, during a dry season and following the peak of the successive wet season. Larvae were sampled within typical Anopheles flight range of human settlements and identified through genetic sequencing of cytochrome c oxidase I and internal transcribed spacer two regions of mitochondrial and nuclear DNA. This facilitated detailed comparison of taxon-specific abundance patterns between ecological zones differentiated by hydrological controls.ResultsAn unexpected paucity of primary vectors was revealed, with An. gambiae s.l. and An. funestus representing < 2% of 995 sequenced anophelines. Potential secondary vectors predominated in the vector community, primarily An. coustani group species and An. squamosus. While the distribution of An. gambiae s.l. in the study area was highly clustered, secondary vector species were ubiquitous across the landscape in both dry and wet seasons, with some taxon-specific relationships between abundance and ecological zones by season.ConclusionsThe diversity of candidate vector species and their high relative abundance observed across diverse hydro-ecosystems indicate a highly adaptable transmission system, resilient to environmental variation and, potentially, interventions that target only part of the vector community. Larval survey results imply that residual transmission of malaria in Barotseland is being mediated predominantly by secondary vector species, whose known tendencies for crepuscular and outdoor biting renders them largely insensitive to prevalent vector control methods.Graphical

Container Mosquito Habitat Community Cleanup: A How-To Guide for Event Organization

&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Being bitten by the container mosquitoes Aedes aegypti and Ae. albopictus means a higher risk of becoming infected with Zika, dengue, or chikungunya virus. Container mosquitoes develop in the water that collects in discarded tires, jars, cans, buckets, and boats. The best way to prevent irritating bites and dangerous mosquito-transmitted illnesses is to get rid of all trash that holds water. This 6-page fact sheet written by Amy Hallock, Eva A. Buckner, Ricky W. Telg, and Alena R. Poulin and published by the UF/IFAS Entomology and Nematology Department is packed with recommendations that will help you to successfully develop and host a cleanup event to reduce potential mosquito larval habitats in your community and keep yourself and your neighbors safe.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D;

Larval ecology and infestation indices of two major arbovirus vectors, Aedes aegypti and Aedes albopictus (Diptera: Culicidae), in Brazzaville, the capital city of the Republic of the Congo

BackgroundInvasive mosquito species, such as Aedes albopictus in Congo can affect the distribution of native species, changing the vector composition and pattern of disease transmission. Here, we comparatively establish the geographical distribution and larval habitat preference of Ae. aegypti and Ae. albopictus and the risk of arbovirus disease outbreaks using Stegomyia indices in the city of Brazzaville, the capital of the Republic of the Congo.MethodsHuman dwelling surveys of water-holding containers for immature stages of Aedes was carried out in December 2017 in Brazzaville through a random cluster sampling method. A total of 268 human dwellings distributed in 9 boroughs and 27 neighbourhoods were surveyed across the city.ResultsOverall, 455 potential larval habitats were surveyed. Both Ae. aegypti and Ae. albopictus were collected across the city with an overall high prevalence of Ae. aegypti (53.1%) compared to Ae. albopictus (46.9%). Geographical distribution analysis showed that Ae. aegypti was more abundant (mean = 6.6 ± 1.4) in neighbourhoods located in downtown, while the abundance of Ae. albopictus was low (mean = 3.5 ± 0.6) in suburbs. Peridomestic containers, especially discarded tanks, were the most strongly colonized productive larval habitat for both mosquito species with the prevalence of 56.4% and 53.1% for Ae. aegypti and Ae. albopictus, respectively. Globally, the house index (HI), Breteau index (BI) and container index (CI) were high for Ae. aegypti (26.6%, 38.4% and 22.6%) and Ae. albopictus (33.3%, 49.6% and 26.6%) compared to the transmission risk threshold (5%, 5% and 20%) established by the WHO/PAHO. Overall, pupae-based indices (the pupae index and the pupae per person index) were not significantly different between Ae. aegypti (273.4% and 23.2%) and Ae. albopictus (228.8% and 19.5%).ConclusionsThe findings of this study suggest a high risk for transmission of arbovirus diseases in Brazzaville and call for an urgent need to implement vector control strategies against these vectors in the Republic of the Congo.

The First Record of Aedes vittatus (Diptera: Culicidae) in the Dominican Republic: Public Health Implications of a Potential Invasive Mosquito Species in the Americas.

Aedes vittatus Bigot is distributed throughout Africa, tropical Asia, and southern Europe and occurs in sylvatic as well as peridomestic environments where it readily feeds on humans. Although the vectorial capacity of Ae. vittatus is not well understood, this species is known to play a role in the maintenance and transmission of yellow fever, Zika, chikungunya, and dengue virus within its native range. In October 2019, after a routine inspection of mosquito-breeding containers in Jarabacoa, Dominican Republic, two Ae. vittatus females were captured via human landing catch method. After this finding, a CDC miniature light trap was deployed at the point of initial detection from 18:00 to 08:00 h, 2 d/wk from 3 to 31 October 2019. Potential larval habitats were also sampled via traditional dip method once per week spanning a 150 m radius from point of initial detection. In addition to the 2 adult females, 10 female and 2 male Ae. vittatus were captured. One Ae. vittatus larva also was found in a small puddle formed by an animal hoof print. Conventional PCR and Sanger sequencing were used to confirm morphological identification of collected specimens. This is the first detection of Ae. vittatus in the Dominican Republic as well as the Americas. Therefore, enhanced surveillance is needed to better understand the range and public health risks this potential invasive mosquito species may pose in the Dominican Republic, other Caribbean Islands, and/or the Americas.

English

The purpose of this research is to design, deploy and validate artificial intelligence (AI) algorithms operating on drone videos to enable a real time methodology for optimizing predictive mapping&nbsp; unknown, geographic locations (henceforth, geolocation)&nbsp; of potential, seasonal, Anopheles (gambiae, and funestus)&nbsp; larval habitats in an agro-village, epi-entomological, intervention site (Akonyibedo village) in Gulu District, Northern Uganda. Formulae are developed for classifying the drone swath, capture point, land cover in Akonyibedo agro-village. An AI algorithm is designed for constructing a smartphone application (app) in order to enable automatic detection of potential larval habitats from drone videos. The aim of this work is to enable scaling up to larger intervention sites (e.g., district level, sub-county) and then throughout entire Uganda. We demonstrate how capture point, stratifiable, drone swath coverage in Akonyibedo village can be accomplished employing temporal series of re-centered, real time, imaged, Anopheline, larval habitat, seasonal, map projections. We also define a remote methodology for detecting unknown, georeferenceable, capture point geolocations of potential, seasonal, breeding sites employing multispectral, wavelength, signature, reflux emissivities in a drone spectral library. Our results show that high-resolution&nbsp; drone&nbsp; imagery when processed employing state of the art AI algorithms can discriminate a profile of water bodies where Anopheles mosquitoes are most likely to breed (overall ground truth accuracy of 100%). Live, high definition, Anopheline larval habitat signature maps can be generated in real-time drone AI app on a smartphone or Apple device while the image is being captured or larvicidal application is taking place. Key words: Anopheles, larval habitat, drones, artificial intelligence (AI), malaria, Uganda. &nbsp;

Environmental influences on Aedes aegypti catches in Biogents Sentinel traps during a Californian "rear and release" program: Implications for designing surveillance programs.

As Aedes aegypti continues to expand its global distribution, the diseases it vectors (dengue, Zika, chikungunya and yellow fever) are of increasing concern. Modern efforts to control this species include “rear and release” strategies where lab-reared mosquitoes are distributed throughout the landscape to replace or suppress invasive populations. These programs require intensive surveillance efforts to monitor their success, and the Biogents Sentinel (BGS) trap is one of the most effective tools for sampling adult Ae. aegypti. BGS trap catches can be highly variable throughout landscapes, so we investigated the potential impacts of environmental factors on adult Ae. aegypti capture rates during a “rear and release” program in California to better understand the relative contributions of true variability in population density across a landscape and trap context. We recorded male and female Ae. aegypti catches from BGS traps, with and without CO2, throughout control sites where no mosquitoes were released and in treatment sites where males infected with Wolbachia were released. BGS trap catches were positively influenced by higher proportions of shade or bushes in the front yard of the premises as well as the presence of potential larval habitats such as subterranean vaults. In contrast, an increase in residential habitat within a 100 m radius of trap locations negatively influenced BGS trap catches. For male Ae. aegypti, increased visual complexity of the trap location positively influenced capture rates, and the presence of yard drains negatively affected catch rates in control sites. Lastly, for BGS traps using CO2, higher catch rates were noted from traps placed greater than one meter from walls or fences for both male and female mosquitoes. These results have important implications for surveillance programs of Ae. aegypti throughout the Californian urban environment including adult monitoring during “rear and release” programs.