Mosquito Larvae Research Articles

Evaluating Mosquito Biocontrol Effectiveness by Isolating and Characterizing Some Fungi Against Culex Pipiens and Anopheles Stephensi in Sothern Part of Iraq

Objectives: Isolation Aspergillus tamarii, Cladosporium herbarum, and Verticillium lecanii fungi from naturally infected Culex pipiens and Anopheles stephensi insects were morphologically and molecularly identified. Methods: In this study, populations of mosquitoes were cultured and examined to determine fungal infection and evaluated as potential agents against C. pipiens and A. stephensi. Results: A variety of fungal isolates demonstrated differing degrees of pathogenicity 24 hours after treatment against C. pipiens and A. stephensi eggs, four-instar mosquito larvae, and adults. and as a biological control, it was found that the fungal suspension of each of the used fungi affected the life roles of the two mosquitoes. as it was more than the fungus suspension A. tamarii, Cl. herbarum on V. lecanii. The highest percentage of eggs mortality were (36.72, 48.97) %, (29.14, 42.25) %, and (24.45, 35.70) % of C. pipiens and A. stephensi when using the highest concentration of 1*105 spore/ml, 3*105 spore/ml and 2*105 spore/ml of fungicide A. tamarii, C. herbarum, V.lecanii and respectively after 24 hours. The highest mortality rate was for the fourth larval stages, and the mosquito A. stephensi is more sensitive to type C. pipiens infection., as, in order (75.6, 67.19, 56.8) %, (74.18, 59.81, 50) %, and (65, 52,42.71) %. Conclusions: Results highlight the significance of a mosquito's natural fungal opponent. All isolates had an impact on adults and larvae, although they were less successful against eggs. Both have the potential to develop, particularly against the larvae of the primary arbovirus, malaria, and lymphatic filariasis vectors, A. stephensi, and C. pipiens.

Update on the composition and distribution of the mosquito fauna (Diptera: Culicidae) in Cabo Verde, a country at risk for mosquito-borne diseases.

Mosquitoes play a critical role as vectors of pathogens affecting both humans and animals. Therefore, understanding their biodiversity and distribution is crucial to developing evidence-based vector control strategies. The current study updated the composition and distribution of mosquito species through a comprehensive survey of all municipalities of Cabo Verde. From October 2017 to September 2018, mosquito larvae and pupae were collected from 814 aquatic habitats. Anopheles gambiae (Giles, 1902) and Culex pipiens (Linnaeus, 1758) complexes were subjected to PCR-based techniques for sibling species identification. Ten mosquito species from 5 genera were identified: Aedes aegypti (Linnaeus, 1762), Aedes caspius (Pallas, 1771), Anopheles arabiensis (Patton, 1905), Anopheles pretoriensis (Theobald, 1903), Culex bitaeniorhynchus (Giles, 1901), Cx. pipiens, Culex quinquefasciatus (Say, 1823), Culex tritaeniorhynchus (Giles, 1901), Culiseta longiareolata (Macquart, 1838), and Lutzia tigripes (de Grandpre & de Charmoy, 1901). Santiago Island reported the highest number of species (n = 8). Ae. aegypti and Cx. quinquefasciatus were the most widely distributed species across the country. An. arabiensis was the sole species identified within the An. gambiae complex. The findings from our study will help guide health policy decisions to effectively control mosquito-borne diseases.

Ammonia transport in the excretory system of mosquito larvae (Aedes aegypti): Rh protein expression and the transcriptome of the rectum

The role of the mosquito excretory organs (Malpighian tubules, MT and hindgut, HG) in ammonia transport as well as expression and function of the Rhesus (Rh protein) ammonia transporters within these organs was examined in Aedes aegypti larvae and adult females. Immunohistological examination revealed that the Rh proteins are co-localized with V-type H+-ATPase (VA) to the apical membranes of MT and HG epithelia of both larvae and adult females. Of the two Rh transporter genes present in A. aegypti, AeRh50-1 and AeRh50-2, we show using quantitative real-time PCR (qPCR) and an RNA in-situ hybridization (ISH) assay that AeRh50-1 is the predominant Rh protein expressed in the excretory organs of larvae and adult females. Further assessment of AeRh50-1 function in larvae and adults using RNAi (i.e. dsRNA-mediated knockdown) revealed significantly decreased [NH4+] (mmoll-1) levels in the secreted fluid of larval MT which does not affect overall NH4+ transport rates, as well as significantly decreased NH4+ flux rates across the HG (haemolymph to lumen) of adult females. We also used RNA sequencing to identify the expression of ion transporters and enzymes within the rectum of larvae, of which limited information currently exists for this important osmoregulatory organ. Of the ammonia transporters in A. aegypti, AeRh50-1 transcript is most abundant in the rectum thus validating our immunohistochemical and RNA ISH findings. In addition to enriched VA transcript (subunits A and d1) in the rectum, we also identified high Na+-K+-ATPase transcript (α subunit) expression which becomes significantly elevated in response to HEA, and we also found enriched carbonic anhydrase 9, inwardly rectifying K+ channel Kir2a, and Na+-coupled cation-chloride (Cl-) co-transporter CCC2 transcripts. Finally, the modulation in excretory organ function and/or Rh protein expression was examined in relation to high ammonia challenge, specifically high environmental ammonia (HEA) rearing of larvae. NH4+ flux measurements using the scanning-ion selective electrode (SIET) technique revealed no significant differences in NH4+ transport across organs comprising the alimentary canal of larvae reared in HEA vs freshwater. Further, significantly increased VA activity, but not NKA, was observed in the MT of HEA-reared larvae. Relatively high Rh protein immunostaining persists within the hindgut epithelium, as well as the ovary, of females at 24-48h post blood meal corresponding with previously demonstrated peak levels of ammonia formation. These data provide new insight into the role of the excretory organs in ammonia transport physiology and the contribution of Rh proteins in mediating ammonia movement across the epithelia of the MT and HG, and the first comprehensive examination of ion transporter and channel expression in the mosquito rectum.

Investigation of the Diversity of Fauna and Larval Habitat Characteristics of Culex Mosquitoes, the Potential Arboviruses Vectors in South East of Iran

Introduction: Arboviruses have been a persistent public health challenge in Iran for the past 50 years. Culex mosquitoes are the main vectors of these viruses. Different aspects of these vectors, including their phenotypic characteristics, insecticide resistance, and the potential for infection transmission, were regularly reported from different parts of the world. The present study aimed to determine the fauna and prevalence of the Culex larval stage in four sites in Kerman province, Iran from March to September 2019. Method: In total, 450 samples of Culex mosquito larvae were collected and identified using valid taxonomic keys. Physical and biological characteristics data of the larval habitats, including water situation, sunlight situation, and habitat kind, were recorded. Results: Two Culex species, Culiseta longiareolata and Culex quinquefasciatus, were detected with prevalence rates of 88.8% and 11.2%, respectively. The recorded temperatures in larval habitats ranged from 16 to 28 ◦C. Kerman City, Iran exhibited the highest prevalence of detected Culex mosquito larvae among the studied areas. Moreover, Rayen City and Sirjan City in Iran had the lowest and highest temperature rates, respectively. The temporary habitats were the most prevalent sites for larvae collection. Conclusion: This study provided a snapshot of the predominant Culex mosquito fauna in Kerman, serving as a foundation for future molecular studies, identification of insecticide-resistant fauna, and exploration of the potential for initial transmission and continuation of zoonotic infections.

The Influence of Environmental Factors on the Incidence of Malaria on the Coast of Malacca Regency

Environmental conditions that support malaria transmission include the physical environment such as temperature, air humidity, rainfall, wind speed, altitude of a place or location and sunlight. The biological environment which is the environment of flora and fauna such as: mangroves, mosses and algae can affect the life of mosquito larvae. The presence of plants can protect larvae from sunlight and attacks from other living things. The mosquito population in an area is also determined by the presence of various types of larva-eating fish such as tin head fish, tilapia and tilapia. The presence of large livestock such as cows and buffaloes can reduce the number of mosquito bites in humans if the cage is located close to the house. The purpose of this study is to determine and analyze the Influence of Environmental Factors on the Incidence of Malaria on the Coast of Malacca Regency. The type of research used is quantitative research with Case Control design. The population in the study was all people living in coastal areas covering the working areas of the Weoe and Lamea health centers who carried out microscopic and RDT thick drops blood preparation examinations based on malaria register data at the Puskesmas in 2020. The case sampling technique in this study was to use a total sampling technique saturated with a total of 73 local positive malaria cases (indigenus) recorded in 2020 at the Weoe and Alkani health centers, while the control sample was set at a ratio of 1: 1, so that a large sample of 73 people was obtained. So the total sample number is 146 people. The data was then analyzed using a simple logistic regression test. The results showed that there was an influence of mosquito breeding sites, mosquito breeding sites on the incidence of malaria on the coast of Malacca Regency with a p.value value<α (0.05). While the variables Temperature, Humidity, Large livestock ownership had no influence on the incidence of Malaria (p > 0.05).

Comparative biotoxicity study for identifying better alternative insecticide especially green nano-emulsion which used as mosquitocides

This research work was planned to test biosafety of different nanomaterials on the different animals models. These nanoparticles were previously used as potential insecticides of mosquito larvae. The biosafety of these nanoproducts were evaluated on certain organs of non target animals that associated with mosquito breeding sites in Egypt. Animal organs such as the kidneys of rats, toads, and the fish’s spleen were used as models to study the biological toxicity of these nanomaterials. After 30 days of the animals receiving the nanomaterials in their water supply, different cell mediated immune cells were assessed in these tissues. Both TNF-α and BAX immuno-expression were also used as immunohistochemical markers. Histopathology was conducted to detect the effect of the tested nanoproducts at the tissue level of the liver and kidneys of both the rats and toads. Green nanoemulsion of the lavender essential oil was relatively more effective, safe, and biodegradable to be used as insecticides against mosquito larvae than the metal-based nanomaterials.

Habitat suitability modeling of mosquito species in Faiyum Governorate, Egypt, using GIS

BackgroundThe life cycle and geographic range of mosquitoes are profoundly influenced by weather conditions. In Faiyum Governorate, Egypt, researchers looked at over 42 different mosquito breeding areas in the wild. Culex pipiens, Culex antennatus, Culex perexiguus, Culex theileri, Anopheles multicolor, Anopheles sergentii, Ochlerotatus caspius, Culiseta longiareolata, and Uranotaenia unguiculata, were all represented among the collected mosquito larvae. Using Maxent, we identified the most important bioclimatic factors affecting habitat appropriateness for each species. In order to determine the link between a species’ habitat appropriateness and bioclimatic factors, the computer builds response curves for each bioclimatic factor. All species risk maps, species richness maps, and individual species maps were generated with a Software that build interactive web maps (ArcGIS 10.3).ResultsEach mosquito species’ range was impacted by four bioclimatic factors. The most influential factors were those linked to temperature and precipitation. Culex antennatus, Culex perexiguus, Culex pipiens, and Ochlerotatus caspius responded best to temperature-related factors. Precipitation of wettest month (bio 13) was effective in four species (Anopheles multicolor, Culex antennatus, Culex perexiguus, and Culex pipiens).ConclusionAreas in the north and west of El-Fayoum district (Zawyat El-Karadsah, Beni-Saleh, and Monshat Abd-Allah), in Tamiya in Kafr Mahfouz, in the south of Abshway, especially in Tobhar, in the north of Atssa, in the south and center of Sinnuris have been identified as high-risk areas and more susceptible to mosquito-borne diseases.

Larval mosquito predation: evaluation of the effectiveness of five aquatic arthropod species against larvae of Culex pipiens Linnaeus, 1758 (Diptera: Culicidae)

ABSTRACT Mosquitoes are insects of medical interest. They contribute to the transmission and spread of many viral and parasitic diseases. Various methods have been used to control mosquitoes such as conventional insecticides, which are widely used throughout the world and have a negative impact on the environment and targeted species. Predatory insects are significant for the biocontrol of various pests, including the important potential against the larval instars of mosquitoes. In this study, we tested the efficacy of five species Piona uncata Koenike, 1888; Notonecta glauca Linnaeus, 1758; Corixa punctata Illiger, 1807, Ilyocoris cimicoide Linnaeus, 1758; and Sympetrum striolatum Charpentier, 1840 against the fourth instars larvae of Culex pipiens Linnaeus, 1758, according to two exposure phases (Light phase, Twilight phase). The predation assays show a significant effect of tested species against mosquito larvae with the following decreasing order of efficacy: S. striolatum> N. gluca> P. uncata> I. cimicoides> C. pinctata. The early larval instars are the most favourable trophic choice of the five predatory species. On the other hand, we noticed a difference in the predation rate for each species during the two experimental periods. The light phase exhibits the highest predatory efficacy than the twilight phase.

Terrestrial subsidies and light affect an aquatic micro‐ecosystem in unexpected ways

Abstract The effects of resource subsidies on a recipient ecosystem depends on a variety of factors. Firstly, increasing the supply of limiting nutrients tends to increase the accumulation of biomass across different compartments of the recipient food web. Secondly, in the case of aquatic microorganisms, this accumulation may also be contingent on inputs of energy through light, mediating interactions between heterotrophic bacteria and autotrophic algae. Thirdly, macroscopic consumers feed upon microorganisms and recycle nutrients through excretion and egestion, profoundly affecting nutrient cycling. In order to examine the context‐dependency of nutrient cycling in aquatic systems, we performed an experiment in mesocosms where we followed the responses of dissolved nutrients, microorganisms, and larvae of the cosmopolitan mosquito Culex quinquefasciatus (Diptera: Culicidae) to two terrestrial subsidies differing in carbon (C):nutrient, in combination with two light intensities. We found that the interactions amongst bacteria and algae themselves remained generally unimportant after accounting for treatment effects, and that light did mediate some of the effects of nutrient subsidies on microorganisms. We also found that the presence of mosquito larvae was associated with altered concentrations of nitrogen (N) in some treatments, ultimately benefitting algae. Finally, we found that low C:nutrient subsidies generally increased the development rate of mosquito larvae, and that increased light exposure led to higher mosquito survival. Overall, these patterns may be explained by strong nitrogen limitation in our system, causing both group of microorganisms to respond similarly to variations in nutrient supply without direct covariation, and to the key role of N recycling by mosquito larvae in sustaining algal densities in exposed treatments. The context‐dependency in our study may reflect elemental or molecular constraints other than phosphorus. Our experiment thus calls for greater synthesis amongst ecological theories.

Bioluminescence - The Vibrant Glow of Nature and its Chemical Mechanisms.

Bioluminescence, the mesmerizing natural phenomenon where living organisms produce light through chemical reactions, has long captivated scientists and laypersons alike, offering a rich tapestry of insights into biological function, ecology, evolution as well as the underlying chemistry. This comprehensive introductory review systematically explores the phenomenon of bioluminescence, addressing its historical context, geographic dispersion, and ecological significance with a focus on their chemical mechanisms. Our examination begins with terrestrial bioluminescence, discussing organisms from different habitats. We analyze thefireflies of Central Europe's meadows and the fungi in the Atlantic rainforest of Brazil. Additionally, we inspect bioluminescent species in New Zealand, specifically river-dwelling snails and mosquito larvae found in Waitomo Caves. Our exploration concludes in the Siberian Steppes, highlighting the area's luminescent insects and annelids. Transitioning to the marine realm, the second part of this review examines marine bioluminescent organisms. We explore this phenomenon in deep-sea jellyfish and their role in the ecosystem. We then move to Toyama Bay, Japan, where seasonal bioluminescence of dinoflagellates and ostracods present a unique case study. We also delve into the bacterial world, discussing how bioluminescent bacteria contribute to symbiotic relationships. For each organism, we contextualize its bioluminescence, providing details about its discovery, ecological function, and geographical distribution. A special focus lies on the examination of the underlying chemical mechanisms that enables these biological light displays. Concluding this review, we present a series of practical bioluminescence and chemiluminescence experiments, providing a resource for educational demonstrations and student research projects. Our goal with this review is to provide a summary of bioluminescence across the diverse ecological contexts, contributing to the broader understanding of this unique biological phenomenon and its chemical mechanisms serving researchers new to the field, educators and students alike.

Variable gut pH as a potential mechanism of tolerance to Bacillus thuringiensis subsp. israelensis toxins in the biting midge Culicoides sonorensis.

Toxins of Bacillus thuringiensis subsp. israelensis (Bti) are safer alternatives for controlling dipteran pests such as black flies and mosquitoes. The biting midge Culicoides sonorensis (Diptera: Ceratopogonidae) is an important pest of livestock in much of the United States and larval midges utilize semi-aquatic habitats which are permissive for Bti product application. Reports suggest that Bti products are ineffective at killing biting midges despite their taxonomic relation to black flies and mosquitoes. Here, we investigate the toxicity of a Bti-based commercial insecticide and its active ingredient in larval Culicoides sonorensis. A suspected mechanism of Bti tolerance is an acidic larval gut, and we used a pH indicator dye to examine larval Culicoides sonorensis gut pH after exposure to Bti. The lethal concentration to kill 90% (LC90) of larvae ofthe commercial product (386 mg/L) was determined to be almost 10 000 times more than that of some mosquito species, and no concentration of active ingredient tested achieved 50% larval mortality. The larval gut was found to be more acidic after exposure to Bti which inhibits Bti toxin activity. By comparison, 100% mortality was achieved in larval Aedes aegypti at the product's label rate for this species and mosquito larvae had alkaline guts regardless of treatment. Altering the larval rearing water to alkaline conditions enhanced Bti efficacy when using the active ingredient. We conclude that Bti is not practical for larval Culicoides sonorensis control at the same rates as mosquitos but show that alterations or additives to the environment could make the products more effective. © 2024 Society of Chemical Industry.

Larvicidal and Ovicidal Properties of Essential Oils Derived from Origanum minutiflorum and Salvia dorystoechas against the Aedes aegypti

This study assessed the larvicidal and ovicidal effects of essential oils extracted from the above ground of Origanum minutiflorum and Salvia dorystoechas, belonging to the Lamiaceae plant family, on Aedes aegypti mosquito larvae and eggs. The research utilized essential oil concentrations ranging from 1 to 100 ppm. Larvicidal activity was evaluated 6 hours post-exposure and subsequently at 24-hour intervals over a period of 5 days while ovicidal activity was monitored every 2 days for a total of 10 days. Findings indicated that both essential oils demonstrated significant larvicidal effects at 50 and 100 ppm concentrations against Ae. aegypti larvae. In contrast, ovicidal effects were not observed to be statistically significant. Throughout the experiment, O. minutiflorum essential oil consistently showed higher larvicidal potency compared to S. dorystoechas. Therefore, while essential oils from both O. minutiflorum and S. dorystoechas effectively target Ae. aegypti larvae, especially at elevated concentrations, they did not exhibit ovicidal properties.

Diversity and Distribution of Culicidian Fauna in Urban and Rural Areas of Setif Region (North-East Algeria).

Objective: The study explored larval mosquito breeding sites in urban and rural areas from March 2021 to February 2022 in the North-East region of Algeria to provide information on larval biology and ecology of different mosquito species. Methodology: It focused on the effect of the physicochemical characteristics of the breeding sites (pH and water temperature), area, and months on the larval mosquito abundance. Diversity index and equitability were calculated for the registered mosquito species in both areas. Results: Months significantly affected the larval mosquito abundances, with a clear abundance increase from March to August 2021, and then, a clear decrease to February 2022. The interactions between rural and urban areas, water pH, and water temperature as well affected the mosquito abundance. Twelve species of Culicidae were identified and distributed in three genera: Culex, Culiseta, and Aedes. Culex pipiens was the most dominant species in rural and urban sites, with a rate of 69% and 48%, respectively. In rural site, Aedes caspius and Aedes vexans occupied the second position with value of 7-8% each. In urban sites, the second position was occupied by Culiseta longiareolata (36%) and then by Culex theileri (10%). In terms of site diversity, only one site was highly diversified in rural sites, El Hchichia (H' = 1.12 bits). In urban sites, Setif Center, Guellel an Ain Trick, had almost similar diversity with values between 1.03 and 1.04 bits. Equitability values were 0.48 in rural sites and 0.55 in urban sites. Therefore, the Culicidae species presented in these study sites are moderately balanced. Conclusion: The present study provides key tools for planning a better vector control through the information on the effect of some factors on the proliferation of mosquitoes in the urban and rural sites of the Setif region and on the Culicidae diversity and abundance.

IJCM_292A: Chikungunya Outbreak Investigation at Village Bolasa, Petlawat, Jhabua, Madhya Pradesh, India, September 2023

Background: Chikungunya, a resurging vector-borne disease caused by chikungunya virus, remains a global health challenge. In 2023, globally 4.4 lakhs suspected cases and 365 fatalities were estimated; India accounting for 21% of the global burden. On 5 September 2023, suspected outbreak of chikungunya was reported at Bolasa village, Jhabua, Madhya Pradesh by local newspaper. Objective: We investigated to confirm the outbreak, describe the epidemiology and provide evidence-based recommendations. Methodology: We compared past three years Integrated Disease Surveillance System (IDSP) data to confirm the outbreak. We defined a suspect case as fever with arthralgia in a resident of Bolasa village, during 20 August-30 October 2023, searched cases by reviewing patients register from health-care-facilities and house-to-house in Bolasa village. Cases were interviewed using semi- structured questionnaire prepared by modifying WHO chikungunya toolbox and data analyzed using Microsoft-Excel. We conducted environmental survey at domestic and peri-domestic areas and serum samples collected for laboratory confirmation. Results: No chikungunya case was reported in the last three years. We identified 117 suspected cases (56% females) with median age of 40 years (range 27-52 years). Other than fever and arthralgia, the other symptoms included bodyache (78%) and headache (67%). Overall attack rate (AR) was 8%; highest AR in Tadvifaliya of 18% followed by Harijan and Patidar faliya with 12% each. Among the cases, 76% stored water in containers without cover, mosquito larvae were found in the containers in the house or nearby place of 60% cases. Of the 20 serum samples tested, nine were positive for chikungunya IgM-antibody. Conclusion: We detected a confirmed chikungunya outbreak in a rural setting with vector breeding sites identified in a community. Outbreak investigation led to vector control by eliminating breeding sites and community sensitization on water storage practices. We recommended early case reporting, periodic entomological surveys and source reduction.

Bamboo stumps that are artificially in use put pressure on dengue and chikungunya vector control in Dhaka city, Bangladesh.

Aedes aegypti and Ae. albopictus mosquitoes breed in natural and artificial containers, and they transmit dengue and chikungunya. A study was conducted to identify the contribution of bamboo stumps to these disease vectors that were used in the flower garden as pillars to hold the bamboo flex fence. Two sizes of whole bamboo were used to hold fences around gardens at Dhaka University, Bangladesh, and were painted red and green. Mosquito larvae and pupae were collected from bamboo stumps between July and August, and vectors were identified up to the species level. The data were analyzed using the STATA/MP 14.2 version. 83.5% and 0.2% were Ae. albopictus and Ae. aegypti, respectively, and the remaining were Culex and Ar-migeres species. Ae. albopictus, Ae. aegypti, and both species-positive bamboo stumps were 46.9, 0.7, and 47.1%, respectively. 54.5% of the bamboo stumps had at least one mosquito species. The average stump depth for Aedes positive stumps (mean=11.7 cm, SE = 0.5) was significantly (p <0.001) higher than the Aedes negative stumps (mean = 9.5 cm, SE = 0.4). 53.8% and 38.0% stumps were found Aedes positive on the ground and upper sides of fences, respectively, and found significant (p<0.01) differences between both sides. A zero-inflated negative binomial count model is significant at a 5% level of significance, χ2(4) = 11.8, p = 0.019 (<0.05) for Ae. albopictus. Stump depth is found to have a significant positive effect on the number of Aedes-positive stumps. Artificially used natural containers are adding pressure to current mosquito control activities as mosquitoes are breeding on them, which needs additional attention.

PH, suhu air, dan perilaku pemberantasan sarang nyamuk terhadap keberadaan jentik nyamuk Aedes sp di Tembesi Lama, Kota Batam

Dengue hemorrhagic fever (DHF) is a disease caused by a virus spread by Aedes aegypti and Aedes albopictus mosquitoes that have been infected with the dengue virus. Dengue Hemorrhagic Fever (DHF) continues to be a health concern in Riau Islands Province, especially in Batam City. This study aimed to investigate the relationship between container condition and Eradication of Mosquito Den behavior (PSN) with the presence of larvae. A significant association was found between container type, water pH, container water temperature, and the existence of larvae in Tembesi Lama (p value &lt;0.05). Location and container closing conditions variables were not statistically associated with the presence of larvae (p value &gt;0.05). The study discovered that non-disposable containers within the house had the greatest number of Aedes sp. mosquito larvae. Additionally, mosquito larvae were identified in containers without a lid, with a water pH greater than 7.8, and a temperature between 27-30˚C. When measuring PSN behavior, the majority of respondents in Tembesi Lama RT.01-02 RW. 02 had engaged in various PSN activities at their residences. Respondents have not effectively implemented certain PSN actions.

Evaluation of Alchornea cordifolia Extracts for Larvicidal Activity against Anopheles Mosquitoes: Implications for Malaria Control

Alchornea cordifolia is a botanical specimen renowned for its medicinal benefits. The phytochemicals present in this plant boast antioxidant, anti-inflammatory, antimicrobial, and analgesic properties, making it a versatile and effective remedy. This plant has been utilized for several decades in treating various ailments like; malaria, diarrhea, and respiratory infections. To evaluate its efficacy in eradicating mosquito larvae, extractions from both the plant's bark and leaves were obtained using various methods, including crude methods, hot water, and ethanol. The plant was macerated in alcohol and hot water, while the bioassay was carried out using a static non-renewal test. The results of the bioassay indicated that the LC50 values for the various extracts of the plant. The ethanol extract was the most active against the mosquito larvae, with an LC50 value of 8.37 ppm. It was followed by the crude stem-bark extract, which had an LC50 value of 13.18 ppm, and the hot water extract, which had an LC50 value of 110.00 ppm. The plant's diverse range of phytochemicals may have played a role in its potency in eliminating mosquito larvae. This activity of the plant strongly suggests that Alchornea cordifolia has insecticidal properties as a larvicide against malaria.

Battle of the Bites: The Effect of Sewage Effluent Exposure on Mosquitofish Biocontrol of Mosquitoes in Residential Louisiana.

Mosquitofish, Gambusia affinis, are eponymous larval mosquito predators. Their ability to colonize and survive in habitats that are uninhabitable by other potential predators allows them to naturally manage larval mosquito populations in most ground pools they are present in. However, effluent from residential onsite wastewater treatment systems (OWTSs) appears to limit the presence of fish predators. This is especially problematic in Louisiana, where regulations allow the discharge of OWTS effluent into open drainage conveyances. To determine the effect of effluent on the capacity of mosquitofish for biocontrol in contaminated areas, we assessed the body condition metrics of populations from two effluent-exposed sites and two sites not exposed to effluent, determined the lethal effect of effluent-contaminated drainage water on fish, and measured the prey consumption rates in the presence of effluent. Female fish collected from effluent-impacted sites had a reduced somatic body condition and most females examined displayed masculinized anal fins resembling the male gonopodium structure. This trait was not seen in fish collected from the control sites and has not yet been documented in association with OWTSs or in the state of Louisiana. Fish from the control sites survived at effluent-contaminated water levels < 70%, and the prey clearance rates increased with dilution. Onsite wastewater treatment system effluent has significant effects on both the short- and long-term persistence of mosquitofish, their body composition, reproductive health, and larval mosquito consumption. These effects likely release mosquito larvae from suppression and may increase the threat of mosquito-transmitted pathogens in effluent-contaminated locations.

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.

Preparation of a long-lasting tablet of spinosad microspheres and its residual insecticidal efficacy against the yellow fever mosquito, Aedes aegypti (Diptera: Culicidae) larvae.

In order to provide a long-lasting formulation for spinosad (SP) targeting larval stages of Aedes aegypti (Linnaeus) and others alike, a SP tablet was developed based on microspheres, using polylactic acid as inside coating material. The microspheres were encapsulated using polyethylene glycol and 1-hexadecanol to form a sustained-release SP tablet. Micromorphology, active ingredient loading, structure identification, photolysis resistance and biological activity were evaluated in this report. (i) The SP microspheres had an average particle size of 6.16 ± 2.28 μm, low adhesion and good dispersion as evaluated by scanning electron microscopy and morphology. (ii) The average active ingredient loading and encapsulation of SP microspheres were 32.80 ± 0.74% and 78.41 ± 2.22%, respectively. (iii) The chemical structure of encapsulated SP was confirmed by Fourier transform infrared and 1H-nuclear magnetic resonance. (iv) The photostability of the microspheres and the tablets were evaluated. The results showed that DT50 (time required to dissipate 50% of the mass originally present) of SP was 0.95 days in microspheres and 6.94 days in tablets. (v) The long-term insecticidal activity of SP tablets was investigated, and the tablet had a long-lasting activity against the mosquito larvae, showing 100% larval mortality for 63 days. The study provided a new long-lasting formulation of SP, which displayed good efficacy in the control of Ae. aegypti larvae. © 2024 Society of Chemical Industry.