Larval Surveys Research Articles

List of the larval survey and fauna of mosquitoes in Japanese archipelago

List of the larval survey and fauna of mosquitoes in Japanese archipelago

Larval habitat diversity, physicochemical characterization and their effect on the density of larval malaria vectors in the city of Accra, Ghana.

Malaria is more prevalent in rural areas due to fewer mosquito breeding habitats in urban settings. However, urban factors such as irrigated farming, open sewers, and discarded containers create mosquito breeding sites. This study investigates the diversity and distribution of larval habitats and the impact of physicochemical characteristics on the presence and density of Anopheles gambiae s.l. larvae in Accra, Ghana. Larval surveys and collections were conducted at fifteen locations in Accra, divided into five categories: Irrigated Urban Farming (IUF), Lower Socioeconomic Status (LS), Middle Socioeconomic Status (MS), High Socioeconomic Status (HS), and Peri-urban (PU) areas. Physicochemical parameters were measured, and species identification was performed using morphological and molecular methods. A total of 727 breeding habitats were identified, with 65.34% (475/727) positive for Anopheles larvae. Drainage ditches were the most common habitat type (48.21%, 229/475). The highest abundance of An. gambiae s.l. was found in IUF sites (6,244/22,919), especially during the rainy season (77.01%, 17,650/22,919; R2 = 3.46, P = 0.000). Polluted habitats, including household effluents, had higher ammonium levels (3.4 mg/L NH -N) compared to unpolluted ones (1.3 mg/L NH -N). Other distinguishing parameters included dissolved oxygen (34% vs 52.9%), conductivity (5106 μS/cm vs 2049 μS/cm), and total dissolved solids (3181 mg/L vs 1255 mg/L). The predominant malaria vector was An. coluzzii(54.4%, 368/677). Additionally, the invasive An. stephensi, previously unreported in Ghana, was detected. Malaria vectors breed in diverse and often polluted urban habitats, with high larval densities in urban agricultural areas. The detection of the invasive An. Stephensi highlights the need for continuous monitoring and vector control strategies in urban settings.

Kajian Angka Bebas Jentik (ABJ) pada Dataran Tinggi di Kelurahan Kemiling Bandar Lampung

Dengue Fever is caused by the dengue virus transmitted by humans through the bite of Aedes aegypti and Aedes albopictus mosquitoes previously infected with dengue virus from other dengue fever patients. The problem is that there is no vaccine or anti-viral drug for dengue hemorrhagic fever, an extraordinary event of dengue hemorrhagic fever if in the community: someone dies or the mortality rate is fifty percent of the previous one and in one month the number of dengue cases doubles from the previous year. Epidemiological control of the presence of mosquitoes through the 3M movement and the larva-free rate (ABJ) ≥ 95% of the national target. Alternative Fogging is carried out if three or more patients with unexplained fever are found and more than or equal to five percent of larvae are found. Therefore, it is necessary to observe the larval stage of DHF vectors to determine the distribution, mosquito density, the main habitat of larvae, and the alleged risk of transmission. The purpose of this study was to determine the House Index, Container Index, Bruteau Index, Density Figure and ABJ through a larval survey. The sampling technique used proportional random sampling. Research instruments: questionnaires, observation sheets, flashlight equipment to check for the presence of larvae. Results HI, BI and CI Habitat Index > 5%. The larva free rate in Sumberejo Prosperous Village was 87%, indicating a moderate density of potential dengue transmission, because it was below > 95%.

A regional One Health approach to the risk of invasion by Anopheles stephensi in Mauritius.

Anopheles stephensi is an invasive malaria vector in Africa that threatens to put an additional 126 million people at risk of malaria if it continues to spread. The island nation of Mauritius is highly connected to Asia and Africa and is at risk of introduction due to this connectivity. For early detection of An. stephensi, the Vector Biology and Control Division under the Ministry of Health in Mauritius, leveraged a well-established Aedes program, as An. stephensi is known to share Aedes habitats. These efforts triggered multisectoral coordination and cascading benefits of integrated vector and One Health approaches. Beginning June 2021, entomological surveys were conducted at points of entry (seaport, airport) and on ships transporting livestock in collaboration with the Civil Aviation Department, the Mauritian Port Authority and National Veterinary Services. A total of 18, 39, 723 mosquito larval surveys were respectively conducted in the airport, seaport, and other localities in Mauritius while two, 20, and 26 adult mosquito surveys were respectively conducted in the airport, seaport, and twenty-six animal assembly points. Alongside adult mosquito surveys, surveillance of vectors of veterinary importance (e.g.- Culicoides spp.) was also carried out in collaboration with National Parks and Conservation Service and land owners. A total of 8,428 adult mosquitoes were collected and 1,844 larval habitats were positive for mosquitoes. All collected mosquitoes were morphologically identified and 151 Anopheles and 339 Aedes mosquitoes were also molecularly characterized. Mosquito species detected were Aedes albopictus, Anopheles arabiensis, An. coustani, An. merus, Culex quinquefasciatus, Cx. thalassius and Lutzia tigripes. Anopheles stephensi was not detected. The One Health approach was shared with the French Agricultural Research Centre for International Development (CIRAD), strengthening collaboration between Mauritius and Réunion Island on vector surveillance at entry points and insecticide resistance monitoring. The Indian Ocean Commission (IOC) was also alerted to the risk of An. stephensi, leading to regional efforts supporting trainings and development of a response strategy to An. stephensi bringing together stakeholders from Comoros, Madagascar, Mauritius, Réunion Island and Seychelles. Mauritius is a model system showing how existing public health entomology capabilities can be used to enhance vector surveillance and control and create multisectoral networks to respond to any emerging public and veterinary health vector-borne disease threat.

Survey Indeks Entomologi dan Identifikasi Larva Aedes Aegypti di Kelurahan Pampang Kecamatan Panakukkang Kota Makassar

One effort to control Aedes aedes. mosquitoes is by knowing the entomological index. The entomological index is an indicator of the density of Aedes aegypti larvae in a particular settlement which is an important consideration in determining effective vector control efforts. The success of larva monitoring is seen from the House Index (HI), Container Index (CI), Breteau Index (BI) and Larval Free Rate (ABJ), because these entomological indices are used to monitor the population density of Aedes spp in the spread of the dengue virus. The problem in this service is how to reduce the high number of dengue fever cases. This community service is to determine the larval density of the House Index, Container Index, and Breteau Index. The service methods used are surveys and observations. The results of the larval survey in Pampang subdistrict showed that the HI, CI and BI values ​​in Pampang subdistrict were respectively 26% (DF=4), 14.36% (DF=4) and 27.45 (DF=4) in the density category. moderate, while the larvae free rate (ABJ) is 79%, which still does not meet the Environmental Health Quality Standards standards in an area described as having an ABJ of less than 95%.

Identifying villages and breeding habitats for dengue transmission in Thailand: insights from long-term larval surveys

BackgroundIn Thailand, the Department of Disease Control (DDC) regularly performs visual larval surveys throughout the country to monitor dengue fever outbreaks. Since 2016, the DDC switched from a paper-based to a digital-based larval survey process. The significant amount of larval survey data collected digitally presents a valuable opportunity to precisely identify the villages and breeding habitats that are vulnerable to dengue transmission.MethodsThe study used digitally collected larval survey data from 2017 to 2019. It employed larval indices to evaluate the risk of dengue transmission in villages based on seasonal, regional, and categorical perspectives. Furthermore, the study comprehensively scrutinized each container category by employing different measures to determine its breeding preference ratio.ResultsThe result showed that villages with a very high-risk of dengue transmission were present year-round in all regions, with the highest proportion during the rainy season. The Southern region had more high-risk villages during the winter season due to rainfall. Slums and residential communities were more vulnerable to dengue than commercial areas. All container categories could potentially serve as breeding habitats for dengue-carrying mosquitoes, with abandoned containers being the most significant breeding sites.ConclusionsThe risk of dengue transmission was present year-round throughout Thailand. This underscores the importance of community and government initiatives, along with sustained public awareness campaigns and active community engagement, to efficiently and permanently eradicate mosquito breeding habitats. It should be noted that larval indices may not strongly correlate with dengue cases, as indicated by the preliminary analysis. However, they offer valuable insights into potential breeding sites for targeted preventive measures.

Species composition of larval mosquitoes (Diptera: Culicidae) in bamboo stumps in mid-western Nepal

ABSTRACT Bamboo stumps serve as important phytotelmata in which mosquitoes breed. The physiochemical parameters of water in the bamboo stumps influence the species composition and larval abundance of mosquito species. Bamboo stumps were scanned in monsoon season of 2022 by adopting a larval survey method in mid-western Nepal. Supplementary data such as water volume, temperature and pH were also recorded. The linear relationship between different physiochemical parameters with mosquito larval population and larval abundance of different mosquito species was analysed in RStudio-1.0.44 and Past software version 4.07. Altogether, 120 larval mosquitoes belonging to 7 species and 3 genera were recorded from 26 bamboo stumps. The larval abundance of immature mosquito shows positive correlation with water temperature, pH and volume of the water. The coexistence of larvae of dengue vectors (Aedes aegypti and Aedes albopictus) and vector of Lymphatic Filariasis (Culex quinquefasciatus) as well the coexistence of different larval mosquito species were recorded. This established bamboo stumps as important mosquito breeding habitats including vector species in mid-western Nepal.

Broad scale community-level larval fish survey of southern Lake Erie

Abstract The early-life history stages of fish are sensitive to environmental change and therefore can indicate habitat quality as well as help predict recruitment of resident and transient fishes. In 2019, as part of the Lake Erie Cooperative Science and Monitoring Initiative, we conducted a lake-wide assessment of the ichthyoplankton community in U.S. nearshore waters and international offshore waters. The goal of this work was to characterize the larval fish community across the lake and assess species composition, phenology, and distribution of larvae. Ichthyoplankton were sampled weekly using bongo nets at ports beginning at the Detroit River and along the southern shore of Lake Erie to Dunkirk, NY, and less frequently in the Niagara River and offshore areas. Larval fish were present from March 26 through August 29, 2019. The first taxon to emerge was Lake Whitefish in all basins, followed by Walleye, Yellow Perch, and catostomids, depending on port. Mean total density peaked in mid-June due to high catches of Gizzard Shad, Morone spp., and Freshwater Drum in the western basin. Few fish were collected in the offshore sites. Taxa richness, diversity, and larval density were higher in the western basin and lower in the central and eastern basins, generally following the productivity gradient. This was the first study to provide a comprehensive community assessment of the ichthyoplankton community of Lake Erie and can provide a baseline to assess future change, especially in community composition or phenology, of larvae which are likely to respond to climate and habitat change.

Environmental Vulnerability against the Presence of Anopheles spp. with Malaria Cases in North Jakarta

There are several locations in DKI Jakarta which have the potential become breeding places for Anopheles spp larvae. The aim of this study was to analyze environmental vulnerability to the presence of Anopheles spp. larvae with malaria cases using a geographic information system approach. This study was an observational study with a cross sectional design. This study was carried out in March – June 2023 in North Jakarta City, DKI Jakarta. The sample consists of data from all malaria patients from 2020-2023 in North Jakarta. The global positioning system coordinates were taken at the addresses of malaria patients. In addition, data on the presence of Anopheles spp. obtained from larval surveys conducted in Cilincing and Penjaringan Sub-Districts and the coordinates for the habitat of Anopheles spp. larvae. The GPS points obtained were then used for spatial analysis. The distribution of malaria cases was random, while the distribution of Anopheles larvae was dispersed. Buffering zone >1000 m from the breeding site indicated that it does not have the potential in malaria transmission due to malaria patients were at a long distance from the breeding site of Anopheles spp. and flight distance of Anopheles spp. not exceeding 1000 m

Tuberculosis Health Education, Larval Survey, and Rat Identification in the Community on Satangnga Island, Takalar Regency

Tuberculosis disease is a direct infectious disease caused by Mycobacterium Tuberculosis bacteria or known as pulmonary TB, has a very fast transmission rate and is also very contagious. The method used in this activity is a quantitative pre-experimental method with a one group pretest-posttest design. This community service was carried out as a government effort in controlling the risk of tuberculosis disease and enlivening the tri dharma objectives of Hasanuddin University, namely carrying out community service. The community service activities were carried out with health counseling on tuberculosis disease which was held on October 7, 2023 at SMP 3 Mappakasunggu Satangnga Hamlet, Mattirobaji Village, Tanakeke Islands Sub-District, Takalar Regency in 2023. The number of counseling participants was 19 people and this activity was accompanied by the principal and 4 teachers. The community service activities that have been carried out show that there are differences before and after health counseling on tuberculosis disease at SMP Negeri 3 Mappakasunggu Satangnga Hamlet, Mattirobaji Village, Kec. Tanakeke Islands, Takalar Regency. This can be seen in the p-value (0.000) <0.05. For rat identification, the type of rat obtained was the rattus-rattus diardii type as many as 2 rats. Then the survey of larvae that were found were aedes aegepty larvae in 15 community houses. It is hoped that the people of Satanngga Hamlet will always adopt clean and healthy living habits and maintain a clean environment around their homes.
 Abstrak
 Penyakit tuberkulosis adalah penyakit menular langsung yang disebabkan oleh bakteri Mycobacterium Tuberculosis atau dikenal dengan TB paru, memiliki tingkat penularan yang sangat cepat dan juga sangat mudah menular. Metode yang digunakan dalam kegiatan ini adalah metode kuantitatif pre-experimental dengan desain one group pretest-posttest. Pengabdian masyarakat ini dilaksanakan sebagai upaya pemerintah dalam mengendalikan risiko penyakit tuberkulosis dan menyemarakkan tujuan tri dharma perguruan tinggi Universitas Hasanuddin yaitu melaksanakan pengabdian masyarakat. Kegiatan pengabdian dilakukan dengan penyuluhan Kesehatan mengenai penyakit tuberkulosis yang dilaksanakan pada tanggal 7 Oktober 2023 di SMP 3 Mappakasunggu Dusun Satangnga, Desa Mattirobaji, Kec. Kepulauan Tanakeke, Kabupaten Takalar Tahun 2023. Jumlah peserta penyuluhan sebanyak 19 orang dan kegiatan ini di damping oleh kepala sekolah dan 4 orang guru. Kegiatan pengabdian kepada masyarakat yang telah dilakukan menunjukkan bahwa terdapat perbedaan sebelum dan sesudah penyuluhan kesehatan penyakit tuberkulosis di SMP Negeri 3 Mappakasunggu Dusun Satangnga, Desa Mattirobaji, Kec. Kepulauan Tanakeke, Kabupaten Takalar. Hal ini dapat dilihat pada nilai p-value (0.000) < 0.05. Untuk identidikasi tikus, jenis tikus yang didapatkan adalah jenis rattus-rattus diardii sebanyak 2 ekor. Kemudian survey jentik yang banyak ditemukan adalah jentik aedes aegepty di 15 rumah masyarakat. Diharapkan masyarakat Dusun Satangnga agar selalu menerapkan perilaku hidup bersih dan sehat dan menjaga lingkungan kebersihan lingkungan sekitar rumah.

Dendrochronological reconstruction of arborvitae leafminer (Argyresthia spp.) outbreaks on northern white-cedar (Thuja occidentalis) in Maine, USA

Although northern white-cedar ( Thuja occidentalis; henceforth cedar) is thought to have few insect pests, arborvitae leafminers (primarily Argyresthia thuiella) have been known to cause leaf necrosis. Yet, historical evidence for leafminer outbreaks is limited. We combined leafminer larval surveys conducted between 1950 and 1992 with tree-ring analyses from eight cedar stands to reconstruct a history of leafminer outbreaks in Maine, USA. Our tree-ring data show distinctive 2- to 3-year growth reductions that we attribute to leafminers. Several such growth reductions correspond to peak leafminer larval abundances, providing evidence that the reductions are reliable indicators of leafminer activity. Outbreak severity within a site was unrelated to cedar abundance. Outbreak periods thus identified (beginning ca. 1919, 1937, 1950, 1962, mid-1970s, but not at all sites) suggest that leafminer damage may have been more prevalent (albeit patchy) than previously thought. This historical information is relevant given current outbreaks in Maine and elsewhere.

The Key Associated Factor of the Emergence of the Dengue Vector in Peri-Urban and Rural Settlements

Introduction: The population density of Aedes mosquitoes is a risk factor for dengue in endemic areas. Therefore, it is necessary to understand the risk factors for mosquito vector emergence in settlements. This study aimed to determine the key factors associated with the occurrence and population density of dengue vectors in peri-urban and rural settlements. Methods: A cross-sectional study was conducted in two dengue-endemic villages, Bergas-Kidul and Gebugan, representing peri-urban and rural settlements, respectively. A cluster-based larval survey was conducted in the dengue-case house and in 18–20 houses around a radius of 100 m. All water containers and their characteristics and mosquito larvae emergence were recorded in each house to calculate Aedes indices. The geographic coordinates, altitude, air temperature, and humidity were mapped and analyzed using GIS and SPSS software. Results and Discussion: Dengue vectors were found in peri-urban and rural with HI, CI, BI, and DF indices of 29.3%, 32.2%, 35.4, 6.0; then 12.2%, 14.3%, 14.6, and 3.0, respectively. In peri-urban areas, larval occurrence was associated with air temperature, air humidity, container type, and open microhabitat, whereas in rural areas, it was associated with only open microhabitat. Conclusion: The Aedes indices represent a high density of mosquito populations, and the existence of open microhabitats is the key factor for larval occurrence in both peri-urban and rural settlements. Community participation in vector control needs to be increased in addition to studying the resistance of Aedes mosquitoes to a number of insecticide groups.

Assessing the bioefficacy of a commercial temephos formulation (Temebate®) for controlling Aedes albopictus larvae in different land use localities in Malaysia

Temephos is the World Health Organization (WHO) recommended larvicide and is still being utilized worldwide to control larvae of dengue vectors; Aedes aegypti and Aedes albopictus. The efficacy of a commercial temephos product; Temebate® to exterminate the local populations of Ae. albopictus larvae originated from different land use particularly dengue-risk and dengue-free housing localities as well as agrarian localities including oil palm plantations, rubber estates and paddy fields was assessed to verify its bioefficacy in these localities. Field populations of Ae. albopictus larvae were attained via a larval survey at each study locality. Each Ae. albopictus larval population was subjected to a 24-h larval bioassay using Temebate® at operational dosage of 1 mg/L. Almost all Ae. albopictus larval populations demonstrated mortalities between 7.00% and 100.00% by the end of the first 4 h of Temebate® exposure with the resistance ratios between 0.94 and 8.33. After 24 h of Temebate® exposure, all sixteen Ae. albopictus larval populations exhibited increased mortalities with ten of them showing 100% mortalities. These results confirmed the relevance of Temebate® to be continuously used by the residents of these localities as their control efforts against dengue vectors. Nevertheless, Temebate® application by consumers in dengue-risk localities need to be carefully monitored to prevent further development of temephos resistance among Ae. albopictus populations and substantiated with other vector control approaches.

More than mesolectic: Characterizing the nutritional niche of Osmia cornifrons.

Characterizing the nutritional needs of wild bee species is an essential step to better understanding bee biology and providing suitable supplemental forage for at-risk species. Here, we aim to characterize the nutritional needs of a model solitary bee species, Osmia cornifrons (Radoszkowski), by using dietary protein-to-lipid ratio (P:L ratio) as a proxy for nutritional niche and niche breadth. We first identified the mean target P:L ratio (~3.02:1) and P:L collection range (0.75-6.26:1) from pollen provisions collected across a variety of sites and time points. We then investigated the P:L tolerance range of larvae by rearing bees invitro on a variety of diets. Multifloral and single-source pollen diets with P:L ratios within the range of surveyed provisions did not always support larval development, indicating that other dietary components such as plant secondary compounds and micronutrients must also be considered in bee nutritional experiments. Finally, we used pollen metabarcoding to identify pollen from whole larval provisions to understand how much pollen bees used from plants outside of their host plant families to meet their nutritional needs, as well as pollen from individual forager bouts, to observe if bees maintained strict floral constancy or visited multiple plant genera per foraging bout. Whole larval provision surveys revealed a surprising range of host plant pollen use, ranging from ~5% to 70% of host plant pollen per provision. Samples from individual foraging trips contained pollen from multiple genera, suggesting that bees are using some form of foraging decision making. Overall, these results suggest that O. cornifrons have a wide nutritional niche breadth, but while pollen P:L ratio tolerance is broad, a tolerable P:L ratio alone is not enough to create a quality diet for O. cornifrons, and the plant species that make up these diets must also be carefully considered.

Aedes aegypti container preference for oviposition and its possible implications for dengue vector surveillance in Delhi, India.

Dengue is a mosquito-borne viral disease globally transmitted by Aedes aegypti. The most effective method to prevent the transmission of the disease is proficient vector control. Understanding the breeding behaviour of the responsible vectors is very pertinent in this regard; therefore, the present study was conducted to understand Ae. aegypti behaviour regarding the selection of containers for oviposition in the megacity of Delhi. A household survey in different localities within Delhi was carried out during 2018-2019. All available containers were inspected for the presence of immature Ae. aegypti. In entomological surveillance, the ovipositional preference of Aedes was computed using the breeding preference ratio, container index in the field, and laboratory settings, and associations of dengue cases with monthly variation in environmental factors and container type were also calculated. The household larval survey in 40 localities showed that 40% of 27,776 water-holding containers in 3,400 houses were plastic, followed by overhead tanks (26.2%), and coolers (12.1%). The most preferred breeding habitat was clay pots (9.3%), followed by metallic containers (8.5%) and solid waste (7.1%). A laboratory-based study showed that Aedes preferred clay containers (81.8%) over 4 other types of containers (plastic, paper, metal, and glass). The present study provides a rationale for using clay containers as a possible surveillance tool (ovitraps) or as a vector control tool. This information might aid researchers in developing novel traps and targeting preferred containers for larval control activities during transmission and non-transmission seasons.

Towards the invasion of wild and rural forested areas in Gabon (Central Africa) by the Asian tiger mosquito Aedes albopictus: Potential risks from the one health perspective.

Since its first record in urban areas of Central-Africa in the 2000s, the invasive mosquito, Aedes albopictus, has spread throughout the region, including in remote villages in forested areas, causing outbreaks of Aedes-borne diseases, such as dengue and chikungunya. Such invasion might enhance Ae. albopictus interactions with wild animals in forest ecosystems and favor the spillover of zoonotic arboviruses to humans. The aim of this study was to monitor Ae. albopictus spread in the wildlife reserve of La Lopé National Park (Gabon), and evaluate the magnitude of the rainforest ecosystem colonization. From 2014 to 2018, we used ovitraps, larval surveys, BG-Sentinel traps, and human landing catches along an anthropization gradient from La Lopé village to the natural forest in the Park. We detected Ae. albopictus in gallery forest up to 15 km away from La Lopé village. However, Ae. albopictus was significantly more abundant at anthropogenic sites than in less anthropized areas. The number of eggs laid by Ae. albopictus decreased progressively with the distance from the forest fringe up to 200m inside the forest. Our results suggested that in forest ecosystems, high Ae. albopictus density is mainly observed at interfaces between anthropized and natural forested environments. Additionally, our data suggested that Ae. albopictus may act as a bridge vector of zoonotic pathogens between wild and anthropogenic compartments.

Combining modeling with novel field observations yields new insights into wintertime food limitation of larval fish

AbstractRecruitment success of marine fishes is generally considered to be highly dependent on larval growth and survival. In temperate ecosystems, fish larvae are sensitive to food limitation during the low productivity seasons, particularly if water temperatures and concomitant larval metabolic costs increase due to climate change. We combined 7 years of in situ sampling of larval fish, novel observations on zooplankton via automated image analyses, and larval physiological modeling to explore feeding conditions of Atlantic herring larvae (Clupea harengus) in the North Sea. The observed plankton size‐structure was close to the theoretical optimum for larval foraging, but not the biomass. Our results for autumn larvae supported Hjort's critical period hypothesis: small first‐feeding larvae were predicted to have a high probability of starvation, whereas larvae > 13 mm were able to reach their maximal growth capacity. In winter, the majority of herring larvae of all tested sizes (5–27 cm) experienced food‐limitation with over 35% probability of starvation. Sensitivity analysis suggested that young herring larvae improve their growth performance and probability of survival if feed not only on copepods and their life‐stages but include other microplankters in their diet. Given projected warming of the North Sea, our model predicts that herring larvae would require 28% (35%) more prey biomass in autumn (winter) to sustain their growth and survival in the future. This finding together with the ongoing low recruitment of North Sea herring underscore the importance of future micro‐ and mesoplankton monitoring within a scope of wintertime larval fish surveys.

Comparative efficacy of eDNA and conventional methods for monitoring wetland anuran communities

Documenting biodiversity, species occurrence, and species status require reliable monitoring techniques, but the complex life history and cryptic behavior of many anurans create challenges for conventional monitoring approaches. Environmental DNA (eDNA) surveys are a promising alternative (or complement) to conventional anuran monitoring, but their relative success has not been fully tested. We assessed the comparative efficacy of targeted eDNA detection via quantitative PCR (qPCR) and three conventional amphibian survey methods (visual encounter, breeding call, and larval dipnet surveys) for detecting nine anuran species in natural wetlands in southern Ontario, Canada. Our analyses revealed that all assessment methods yielded imperfect detection, with visual encounter and eDNA surveys detecting the greatest species richness and eDNA surveys requiring the fewest sampling events. Amphibian community composition results differed among survey methods and sampling events, and detection efficacy was markedly variable, with some species requiring two to three methods to maximize detection success. Notably, two relatively terrestrial species (Anaxyrus americanusandHyla versicolor) had relatively low and seasonally variable eDNA detection rates, suggesting that species-specific ecology likely affects eDNA presence or detection. These findings suggest that optimized monitoring for complex anuran communities may require application of multiple monitoring methods, which may need to be tailored to individual target species or communities.

Entomological surveillance on Aedes aegypti during covid 19 period in Cape Coast, Ghana: Risk of arboviral outbreaks, multiple insecticide resistance and distribution of F1534C, V410L and V1016I kdr mutations.

The study assessed the risk of transmission of Aedes-borne arboviruses in a community at Cape Coast during the Covid-19 restriction period in 2020 based on entomological indices. The spatial distribution of insecticide resistance was also assessed in Ae. aegypti population from Cape Coast. Three larval indices were calculated from a household larval survey in 100 randomly selected houses. WHO susceptibility bioassay was performed on female adult Ae. aegypti that were reared from the larvae collected from household containers and other receptacles located outside houses against four insecticides. The mosquitoes were also screened for F1534C, V1016I, and V410L kdr mutations. The estimated larval indices in the study community were House index- 34%, Container index- 22.35%, and Breteau index- 2.02. The mosquito population was resistant to Deltamethrin (0.05%), DDT (4%), Fenitrothion (1%), and Bendiocarb (0.1%). A triple kdr mutation, F1534C, V410L and V1016I were detected in the mosquito population. The study found the risk of an outbreak of Aedes-borne diseases lower in the covid-19 lockdown period than before the pandemic period. The low risk was related to frequent clean-up exercises in the community during the Covid-19 restriction period. Multiple insecticide resistance couple with three kdr mutations detected in the study population could affect the effectiveness of control measures, especially in emergency situations. The study supports sanitation improvement as a tool to control Ae. aegypti and could complement insecticide-based tools in controlling this vector.

Effectiveness of dengue training programmes on prevention and control among high school students in the Yangon region, Myanmar

BackgroundDengue is one of the health problems in Myanmar. Thus, health promotion in schools is considered a key approach for reducing risk-taking behaviours related to dengue. ObjectivesThe study aimed to evaluate a dengue training programme for high school students to measure changes in knowledge, attitude and practices (KAP) towards dengue; evaluate the effectiveness of the programme in improving prevention and control practices among families and determining changes in larval indices in their dwelling places. MethodologyThe dengue school training programme was conducted for Grades 9 and 10 students in Yangon. In total, 300 students in the intervention school received training and were compared with 300 students as control. KAP was assessed using a self-administered questionnaire, whereas larval and control practice surveys were conducted at the homes of both groups 3 months before and after the programme. ResultsThe KAP scores of the intervention group increased after the programme. Moreover, the programme improved prevention and control practices and decreased the larval indices in the intervention group. Students from the same group with high scores in knowledge and self-reported practices were less likely to exhibit Aedes larval positivity in their residential areas. ConclusionThis study demonstrated the impact of the dengue training programme on the KAP of students and short-term family larval control practices, which influenced household larval indices.