Culex Species Research Articles

Larvicidal Activity of Solvent Extracts of Nicotiana tabacum L, and Datura metel L, (Solanales: Solanaceae) Against Larvae of Three Mosquito Species

Mosquitoes are insects that vector many of the life threatening diseases. Control of these insects is one of the major problems of the world today. Leaves and seed kernel extracts of Tobacco; Nicotiana tabacum (L.) and Thorn-Apple; Datura metel (L.) were assayed for larvicidal activity against three mosquito species of Aedes, Anopheles and Culex respectively. Samples of the three species were collected from mosquito breeding sites and reared in the laboratory for continued source of larvae following standard procedures. The plants parts used were extracted with hexane, chloroform and methanol in increasing order of polarity. Each extract was formulated into 0.9, 1.6, 2.4, 3.5 and 4.0mg/mL concentrations, and tested for larvicidal activity against 25 larvae of each genus in three replicates, alongside the controls over 12 to 72 hrs periods. The extracts that exhibited highest larvicidal activity were subjected to phytochemical screenings for searching active ingredients. Data were analyzed using Analysis of Variance, treatment means separated through DNMRT and lethal concentrations of the extracts were determined. Among the extracts tested, hexane extract of D. metel and methanol extract of N. tabacum caused highest larvicidal activity with more than 70% mortality on Aedes and Anopheles larvae when 4.0mg/mL was applied after 72 hrs (LC50 2.94±0.1 and LC502.58±0.1 mg/mL respectively). Culex larvae were less susceptible to all concentrations of the extracts. Though, larvicidal activity was observed to be directly proportional to concentrations and larval exposure periods, significant differences (p< 0.05) in the means of larval death were observed. The active extracts were found to contain alkaloids, saponins steroids, flavonoids and glycosides from moderate to high quantity which could be responsible for larvicidal activity. Future formulation studies, toxicity profile and possible mechanism of action may lead to the development of potential insecticidal products.

The Distribution and Composition of Vector Abundance in Hanoi City, Vietnam: Association with Livestock Keeping and Flavivirus Detection.

Background: Dengue virus and Japanese encephalitis virus are two common flaviviruses that are spread widely by Aedes and Culex mosquitoes. Livestock keeping is vital for cities; however, it can pose the risk of increasing the mosquito population. Our study explored how livestock keeping in and around a large city is associated with the presence of mosquitoes and the risk of them spreading flaviviruses. Methods: An entomological study was conducted in 6 districts with 233 households with livestock, and 280 households without livestock, in Hanoi city. BG-Sentinel traps and CDC light traps were used to collect mosquitoes close to animal farms and human habitats. Adult mosquitoes were counted, identified to species level, and grouped into 385 pools, which were screened for flaviviruses using a pan-flavivirus qPCR protocol and sequencing. Results: A total of 12,861 adult mosquitoes were collected at the 513 households, with 5 different genera collected, of which the Culex genus was the most abundant. Our study found that there was a positive association between livestock keeping and the size of the mosquito population—most predominantly between pig rearing and Culex species (p < 0.001). One pool of Cx. tritaeniorhynchus, collected in a peri-urban district, was found to be positive for Japanese encephalitis virus. Conclusions: The risk of flavivirus transmission in urban areas of Hanoi city due to the spread of Culex and Aedes mosquitoes could be facilitated by livestock keeping.

Molecular characterization and phylogenetic analysis of collected mosquitoes (Diptera: Culicidae) from Northcentral Nigeria using mitochondrial COI and ribosomal IGS gene regions

BackgroundMosquitoes are important vectors of disease-causing organisms such as filarial worms, malaria parasites, and arboviruses endemic to sub-Saharan Africa including Nigeria. Malaria is a disease caused by a plasmodium parasite, transmitted by the bite of infected mosquitoes and is no doubt a public health concern. There is limited information on the genetic diversity of mosquitoes in Nigeria. This is necessary because information about the genetic diversity of mosquitoes is a very important step towards vector control and management with the aim to mitigate or eliminate burden resulting from malaria and other diseases caused by mosquitoes. In the present study, we investigated the genetic variability and relatedness of mosquitoes based on the DNA sequences of the mitochondrial cytochrome oxidase subunit I (COI) and ribosomal intergenic non-coding spacer gene regions (IGS). Mosquitoes were collected from five different states in Northcentral Nigeria, they were morphologically identified using standard keys and genomic DNA was extracted. The specific regions of interests were amplified, and the PCR products were then sequenced.ResultsPCR was able to successfully amplify the expected amplicon sizes of COI and IGS sequences (710 and 169) base pairs, respectively. For COI sequence, pairwise genetic distance between mosquito species ranged from 0.00 to 0.17 in the COI sequences. The pairwise genetic distance among Culex, Aedes and Anopheles species in the IGS sequences ranged from 0.000 to 0.118. Phylogenetic analysis of the sequences of the mitochondrial cytochrome oxidase subunit showed that there was genetic diversity amongst the different mosquito species sampled. It effectively showed marked differences between Culicine and Anopheline mosquitoes.ConclusionsThe ribosomal IGS primers used for this study only amplified Anopheles spp. However, it revealed that there is diversity among the Anopheles gambiae and Anopheles arabiensis samples collected. This study concludes that the mitochondrial COI and ribosomal IGS gene regions are reliable markers for mosquito genetic diversity study and will surely yield a reliable result for molecular diversity assessment of mosquito species.

Chemical Composition, Insecticidal and Mosquito Larvicidal Activities of Allspice (Pimenta dioica) Essential Oil.

Essential oils are biologically and environmentally safe pesticidal compounds yielded from aromatic plants. Spices are important sources of essential oils, and they are widely used in the medicine, food, and various other industries. Among the different spices, Allspice (Pimenta dioica) is underexplored in terms of its biological efficacy and a limited number of studies are available on the chemical composition of Allspice essential oil (AEO); thus, the present study evaluated the larvicidal property, the repellency, and the fumigant toxicity against common pests of stored products of AEO. AEO was found to inhibit the survival of larvae of such vectors as Aedis, Culex, and Armigeres species. Further, AEO was found to exert repellant effects against the pests of such stored products as Sitophilus, Callosobruchus, and Tribolium. Similarly, the fumigant toxicity was found to be high for AEO against these species. The contact toxicity of AEO was high against Sitophilus and Callosobruchus. Apart from that, the essential oil was found to be safe against a non-target organism (guppy fishes) and was found to be non-genotoxic in an Allium cepa model. Overall, the results of the present study indicate that the essential oil from Allspice could be used as an environmentally safe larvicidal and biopesticidal compound.

SURVEY OF MOSQUITO SPECIES, COMPOSITION AND BREEDING HABITATS IN FOUR COMMUNITIES OF KADUNA METROPOLIS, NIGERIA

A survey on the species composition and breeding habitats of mosquitoes was conducted in four communities of Kaduna metropolis (Nariya, Tudun Wada, Kabala Doki and Sabon Tasha) through intensive bi-weekly sampling collection of larvae for a period of three months. All the randomly selected sampling points were categorized into three habitat types; Domestic Container (DC), Temporary Ground Pool (TGP) and Man-made Reservoir (MMR). All 3rd and 4th instar larvae were harvested and identified using taxonomic keys by Gillies and Coetzee. A total of 6,803 larvae samples were encountered and identified across the four communities. There were thirteen species which fall within the three common genera comprised of Culex species (94.19%), Aedes species (4.8%) and Anopheles (0.10%). Of the thirteen species identified, Culex quinquefasciatus Say, 1823 (72.8%) was significantly high (p&lt;0.05), then Culex toroensis Edwards(12.05%) and Aedes aegypti Linnaeus (4.8%). Temporary ground pool (61.7%) harbored more mosquito larvae; however there was no significant difference (p&gt;0.05) in distribution of mosquitoes among the three habitat types sampled; The study identified medically important mosquito species in the four communities and recommends integrated control measures for these vectors especially in line with National Malaria Control strategy 2016 - 2030 for global reduction of malaria disease

Detection of Insect-Specific Flaviviruses in Mosquitoes (Diptera: Culicidae) in Northeastern Regions of South Africa.

Mosquitoes in the Aedes and Culex genera are considered the main vectors of pathogenic flaviviruses worldwide. Entomological surveillance using universal flavivirus sets of primers in mosquitoes can detect not only pathogenic viruses but also insect-specific ones. It is hypothesized that insect-specific flaviviruses, which naturally infect these mosquitoes, may influence their vector competence for zoonotic arboviruses. Here, entomological surveillance was performed between January 2014 and May 2018 in five different provinces in the northeastern parts of South Africa, with the aim of identifying circulating flaviviruses. Mosquitoes were sampled using different carbon dioxide trap types. Overall, 64,603 adult mosquitoes were collected, which were screened by RT-PCR and sequencing. In total, 17 pools were found positive for insect-specific Flaviviruses in the mosquito genera Aedes (12/17, 70.59%) and Anopheles (5/17, 29.41%). No insect-specific viruses were detected in Culex species. Cell-fusing agent viruses were detected in Aedes aegypti and Aedes caballus. A range of anopheline mosquitoes, including Anopheles coustani, An. squamosus and An. maculipalpis, were positive for Culex flavivirus-like and Anopheles flaviviruses. These results confirm the presence of insect-specific flaviviruses in mosquito populations in South Africa, expands their geographical range and indicates potential mosquito species as vector species.

Surveillance of Culex mosquitoes in Jiangsu Province from 2018 to 2019

To investigate the distribution and density of Culex mosquito populations and the resistance of Culex pipiens pallens to insecticides in Jiangsu Province in 2018 and 2019. During the period from June to October in 2018 and 2019, six counties (districts, cities) were sampled in southern, northern and central Jiangsu Province as surveillance sites. The density of Culex mosquitoes was measured overnight using the light trapping technique. In addition, Culex pipiens pallens mosquitoes were collected from Hai'an of Nantong City and Yandu District of Yancheng City, central Jiangsu Province, and the sensitivity of female first filial generations to dichlorodiphenyltrichloroethane (DDT), malation, proposur, beta cypermethrin and deltamethrin was tested using the standard WHO insecticide susceptibility test assay. A total of 104 423 Culex mosquitoes were captured in six surveillance sites of Jiangsu Province in 2018 and 2019, and Culex quinquefasciatus (49.11%), Culex pipiens pallens (28.38%), and Culex tritaeniorhynchus (21.04%) were predominant species. The density of Culex mosquitoes started to increase since early June, peaked in July and tended to be low in late October. Culex pipiens pallens mosquitoes captured from Hai'an was susceptible to malation, while those from Yandu District were moderately resistant to malation. Culex pipiens pallens mosquitoes from both Yandu and Hai'an were moderately resistant to proposur, and were resistant to DDT, beta cypermethrin and deltamethrin. Culex quinquefasciatus, Culex pipiens pallens and Culex tritaeniorhynchus are predominant Culex species in Jiangsu Province. Culex pipiens pallens is resistant to DT, beta cypermethrin and deltamethrin in central Jiangsu Province.

Updated distribution maps of predominant Culex mosquitoes across the Americas

BackgroundEstimates of the geographical distribution of Culex mosquitoes in the Americas have been limited to state and provincial levels in the United States and Canada and based on data from the 1980s. Since these estimates were made, there have been many more documented observations of mosquitoes and new methods have been developed for species distribution modeling. Moreover, mosquito distributions are affected by environmental conditions, which have changed since the 1980s. This calls for updated estimates of these distributions to understand the risk of emerging and re-emerging mosquito-borne diseases.MethodsWe used contemporary mosquito data, environmental drivers, and a machine learning ecological niche model to create updated estimates of the geographical range of seven predominant Culex species across North America and South America: Culex erraticus, Culex nigripalpus, Culex pipiens, Culex quinquefasciatus, Culex restuans, Culex salinarius, and Culex tarsalis.ResultsWe found that Culex mosquito species differ in their geographical range. Each Culex species is sensitive to both natural and human-influenced environmental factors, especially climate and land cover type. Some prefer urban environments instead of rural ones, and some are limited to tropical or humid areas. Many are found throughout the Central Plains of the USA.ConclusionsOur updated contemporary Culex distribution maps may be used to assess mosquito-borne disease risk. It is critical to understand the current geographical distributions of these important disease vectors and the key environmental predictors structuring their distributions not only to assess current risk, but also to understand how they will respond to climate change. Since the environmental predictors structuring the geographical distribution of mosquito species varied, we hypothesize that each species may have a different response to climate change.Graphical abstract

Insecticidal efficacy of &lt;i&gt;Rubus steudneri&lt;/i&gt; and &lt;i&gt;Rubus apetalus&lt;/i&gt; against &lt;i&gt;Aedes&lt;/i&gt; (Diptera: Culicidae) and &lt;i&gt;Culex&lt;/i&gt; (Diptera: Culicidae) mosquitoes

Introduction and Aim: Rubus steudneri Schweinf. and Rubus apetalus Poir. belonging to the family Rosaceae is one of the ethnomedicinal plants used widely in Ethiopia as food, for construction and as medicine. To the best of our knowledge, insecticidal activity of R. steudneri and R. apetalus has not been investigated so far. In this study, we report insecticidal efficacy of R. steudneri and R. apetalus in terms of larvicidal effect against II and III instar larvae of Aedes and Culex mosquitoes.&#x0D; Materials and Methods: The shade-dried and powdered leaves were extracted using methanol by maceration process. Insecticidal activity of leaf extract was determined by larvicidal assay against II and III instar larvae of Aedes and Culex species. LC50 and LC90 values were calculated.&#x0D; Results: The leaf extract of both Rubus species exhibited concentration dependent larvicidal effect. II instar larvae were shown to be highly susceptible than III instar larvae. Among leaf extracts, extract of R. steudneri exhibited marked insecticidal activity when compared to extract of R. apetalus as revealed by lower LC50 and LC90 values. Culex larvae displayed marked susceptibility to leaf extracts when compared to Aedes larvae.&#x0D; Conclusion: Marked larvicidal effect was observed against larvae of Culex species when compared to Aedes species as indicated by lower LC50 and LC90 values. It is evident that the leaf extracts of both Rubus contain insecticidal principles.

Transmitted Light as Attractant with Mechanical Traps for Collecting Nocturnal Mosquitoes in Urban Bangkok, Thailand.

Mosquito surveillance is the cornerstone for determining abundance, species diversity, pathogen infection rates, and temporal and spatial distribution of different life stages in an area. Various methods are available for assessing adult mosquito populations, including mechanical trap devices using different forms of attractant cues (chemical and visual) to lure mosquitoes to the trap. So-called "light traps" use various electromagnetic wavelengths to produce a variety of visible spectral colors to attract adult mosquitoes. However, this type of trapping technology has not been widely used in Thailand. This study compared the efficacy of 4 light-emitting diodes (LEDs) (blue, green, yellow, and red) and 2 fluorescent (ultraviolet [UV] and white) lights for collecting mosquitoes in urban Bangkok. Using a Latin square experimental design, 6 light traps equipped with different lights were rotated between 6 trap site locations within the Kasetsart University (KU) campus. Each location received 6 replicate collections (6 consecutive trap-nights represented 1 replicate) over 36 collection nights for a total of 216 trap-nights. Traps were operated simultaneously (1800 to 0600 h), with captured mosquitoes removed at 3-h intervals. In total, 2,387 mosquitoes consisting of 11 species across 5 genera (Aedes, Anopheles, Armigeres, Culex, and Mansonia) were captured. Collectively, Culex species represented the predominant group sampled (2,252; 94.4%). The UV light source captured 1,544 (64.7%) of the total mosquitoes collected, followed by white 389 (16.3%), with the 4 LED sources collecting between 6.8% (blue) and 1.9% (yellow). Traps equipped with UV light were clearly the most effective for capturing nocturnally active mosquito species on the KU campus.

Mosquito-Borne Viral Pathogens Detected in Zambia: A Systematic Review

Emerging and re-emerging mosquito-borne viral diseases are a threat to global health. This systematic review aimed to investigate the available evidence of mosquito-borne viral pathogens reported in Zambia. A search of literature was conducted in PubMed and Google Scholar for articles published from 1 January 1930 to 30 June 2020 using a combination of keywords. Eight mosquito-borne viruses belonging to three families, Togaviridae, Flaviviridae and Phenuiviridae were reported. Three viruses (Chikungunya virus, Mayaro virus, Mwinilunga virus) were reported among the togaviruses whilst four (dengue virus, West Nile virus, yellow fever virus, Zika virus) were among the flavivirus and only one virus, Rift Valley fever virus, was reported in the Phenuiviridae family. The majority of these mosquito-borne viruses were reported in Western and North-Western provinces. Aedes and Culex species were the main mosquito-borne viral vectors reported. Farming, fishing, movement of people and rain patterns were among factors associated with mosquito-borne viral infection in Zambia. Better diagnostic methods, such as the use of molecular tools, to detect the viruses in potential vectors, humans, and animals, including the recognition of arboviral risk zones and how the viruses circulate, are important for improved surveillance and design of effective prevention and control measures.

Composition, seasonal abundance, and public health importance of mosquito species in the regional unit of Thessaloniki, Northern Greece.

Mosquitoes (Diptera: Culicidae) are the largest group of blood-feeding insects that disturb not only humans but also other mammals and birds. This study reports the presence of native mosquito species in the regional unit of Thessaloniki and the monitoring of their population. In total, 13 mosquito species belonging to four genera were identified. The most dominant species was Culex pipiens, followed by Aedes caspius. In the present study, we report for the first time the presence of Ae. vittatus in Greece and of Anopheles plumbeus in the regional unit of Thessaloniki. Regarding the seasonal variation, species of the genus Aedes were the ones that first appeared in late March, followed by Culex species at the end of April and finally species of the genus Anopheles in July. Species of the Aedes genus were found to be the most abundant in the first quarter of the year (late March to early April). Population of Cx. pipiens remained at high levels from late April to late September. Species of the genus Anopheles were found in high densities from early August to October. The current study contributes to the knowledge of the mosquito species composition and their relative abundance in an area where West Nile virus caused severe epidemic outbreaks.

Dragonflies as an Important Aquatic Predator Insect and Their Potential for Control of Vectors of Different Diseases

Mosquitoes belong to order of Diptera. The main important vectors are genus Aedes, Culex and Anopheles. They transmit different agents such bacteria, viruses, and parasites. According to the latest information around 7 hundred million people around the world are suffering from mosquitoborne illness resulting over one million deaths. The main important disease transmitted by Anopheles is malaria. Other genus of mosquitoes including Aedes and Culex species transmit different arboviral disease to human. According to guideline of World Health Organization, the mina control of disease is vectors control. The main important vector control is using different insecticides. Using chemical insecticides for controlling mosquitoes is limited because they develop resistance against these insecticides. So, efforts have been made to control the mosquito vectors by eco-friendly techniques. In this research all, the relevant information regarding the topic of research is research through the internet and used in this paper. An intensive search of scientific literature was done in “PubMed”, “Web of Knowledge”, “Scopus”, “Google Scholar”, “SID”, etc Results shows that one of important environmental friendly vector control is biological control, using different predators and other microorganisms for vector and pest control. Dragonflies do eat mosquitos and serve as mosquito predators. They feed on mosquitos and reduce their number in outdoor areas. The dragonflies are scary biters, but they are dangerous to mosquitos. Worldwide results showed that dragonflies are able to control Aedes, Culex and Anopheles mosquito species. The artificial rearing of these predators and releasing for biological control is an appropriate measure for vector control worldwide.

Mango ginger (Curcuma amada Roxb.) rhizome essential oils as source of environmental friendly biocides: Comparison of the chemical composition, antibacterial, insecticidal and larvicidal properties of essential oils extracted by different methods

The essential oil isolated from plants is widely utilized as eco-friendly biocides and antibacterial agents. Curcuma amada, commonly known as mango ginger, is well-known for its applications in the food and aromatics industry for its significant mango-like aroma. The present study compared the different C. amada essential oils prepared by hydrodistillation (CHD), steam distillation (CSD), microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE), for their chemical composition, antibacterial, larvicidal and insecticidal properties. GC/MS analysis indicated the presence of compounds including α-pinene, β-myrcene, p-cymene, (Z)-β-ocimene, Camphor, linalyl acetate, safrole, ar-curcumene, and β-curcumene in the different C. amada essential oils. The antibacterial activity was observed against different strains of microbes, with a higher efficacy in the essential oils prepared by UAE and MAE methods. Apart from these, the MAE, UAE, CSD, and CHD were also shown to have significantly higher larvicidal activity against Aedes, Culex, and Armigeres species; however, no toxic effect was observed in non-targeted species like fishes and Allium cepa model of genotoxicity. Further, these essential oils were also found to have significant contact and fumigant toxicity as well as repellency against pests of stored grains (Sitophilus and Tribolium). Considering these results, the present study assumes that Curcuma amada essential oils may be a source of ecofriendly insecticides and antibacterial agents.

Host-Feeding Patterns of the Mosquito Assemblage at Lomas Barbudal Biological Reserve, Guanacaste, Costa Rica.

Mosquito-borne pathogens have spread throughout tropical regions of the Western Hemisphere causing increased burden of disease in the region. Outbreaks of dengue fever, yellow fever, chikungunya, West Nile, and Zika have occurred over the past several years. Mosquito blood-feeding patterns need to be assayed to assist in determining which vertebrates could act as hosts of these mosquito-borne pathogens and which mosquito species could act as vectors. We conducted bloodmeal analyses of mosquitoes collected at Lomas Barbudal Biological Reserve, a dry tropical forest reserve in Costa Rica. Mosquitoes were collected using backpack aspirators and light, gravid, and resting traps, and then identified morphologically. Blood-fed mosquitoes underwent DNA extraction, PCR amplification, and sequencing of the vertebrate cytochrome b and cytochrome c oxidase 1 genes to identify vertebrate bloodmeal hosts. Several mosquitoes known to vector pathogens were found including Culex (Melanoconion) erraticus Dyar & Knab (Diptera: Culicidae), Cx. (Mel.) pedroi Sirivanakarn & Belkin, Aedes (Stegomyia) albopictus Skuse, Ae. (Ochlerotatus) scapularis Rondani, Ae. (Och.) serratus Theobald, and Ae. (Och.) taeniorhynchus Wiedemann. The most common bloodmeal hosts were basilisk lizards (Basiliscus vittatus) Wiegmann (Squamata: Corytophanidae) in Culex (Linnaeus) species and white-tailed deer (Odocoileus virginianus) Zimmermann (Artiodactyla: Cervidae) in Aedes (Meigen) species. These results show the diversity of mosquito species in a tropical dry deciduous forest and identify associations between mosquito vectors and potential pathogen reservoir hosts. Our study highlights the importance of understanding interactions between vector species and their hosts that could serve as predictors for the potential emergence or resurgence of mosquito-borne pathogens in Costa Rica.

Aedes species (Diptera: Culicidae) ecological and host feeding patterns in the north-eastern parts of South Africa, 2014\u20132018

BackgroundThere is a paucity of recent data and knowledge on mosquito diversity and potential vectors of arboviruses in South Africa, with most of the available data dating back to the 1950s–1970s. Aedes and Culex species are the major vectors of some of the principal arboviruses which have emerged and re-emerged in the past few decades.MethodsIn this study we used entomological surveillance in selected areas in the north-eastern parts of South Africa from 2014 to 2018 to assess mosquito diversity, with special emphasis on the Aedes species. The impact of trap types and environmental conditions was also investigated. Identification of the blood meal sources of engorged females collected during the study period was carried out, and DNA barcodes were generated for selected species.ResultsOverall, 18.5% of the total Culicidae mosquitoes collected belonged to the genus Aedes, with 14 species recognised or suspected vectors of arboviruses. Species belonging to the Neomelaniconion subgenus were commonly collected in the Bushveld savanna at conservation areas, especially Aedes mcintoshi and Aedes circumluteolus. Aedes aegypti was present in all sites, albeit in low numbers. Temperature was a limiting factor for the Aedes population, and they were almost exclusively collected at temperatures between 18 °C and 27 °C. The cytochrome oxidase subunit I (COI) barcode fragment was amplified for 21 Aedes species, and for nine of these species it was the first sequence information uploaded on GenBank.ConclusionThis study provides a better understanding of the diversity and relative abundance of Aedes species in the north-east of South Africa. The information provided here will contribute to future arboviral research and implementation of efficient vector control and prevention strategies.Graphical abstract

Temporal Distribution and Abundance of Mosquito Vectors in Dhaka City

Species of Anopheles, Aedes and Culex mosquitoes showed that Anopheles gambiae s.s had the highest number (43.5%) out of the three malaria vectors (viz. Anopheles gambiae, An. arabiensis and An. funestus). For Aedes and Culex species, Aedes aegypti (37.6%) and Culex fatigans (37.1%) had the highest prevalence out of their sibling species. Temperature and rainfall were highly correlated with the abundance of mosquito vectors. It was observed that the rainy season (March to October) recorded the highest number (Total 11 specie) of mosquito vectors collected with the peak (Aedes aegypty, 140) in the months of July (932) and August (976) while the lowest (333) collection was in the dry season (November to February) with lowest (333) in the month of February when there was little or no rains.&#x0D; Asiat. Soc. Bangladesh, Sci. 46(1): 27-35, June 2020

Monitoring and Mapping of Insecticide Resistance in Medically Important Mosquitoes (Diptera: Culicidae) in Iran (2000-2020): A Review.

Background:Mosquitos due to their role in the transmission of different pathogens to humans are considered as an important group in the phylum Arthropoda. According to the WHO and FAO guideline different groups of insecticide applied for controlling pests in both the agricultural and public health sectors.Methods:All the data published about resistant status of the mosquitoes Anopheles, Culex, Aedes and Culiseta species were searched on PubMed, Elsevier, Web of Science, Magiran and google scholar. The objectives of this study was to review the trend of resistance to insecticides during 2000–2020 in medically important mosquitoes in Iran. The criteria for resistant are followed according to WHO guideline.Results:The Results showed that there are widespread, multiple resistances in the country to different organochlorine, organophosphates, carbamate and pyrethroids insecticides in the mosquitoes.Conclusion:The effect of pesticide residues on the environment could be a cause for selection pressure on mosquitos and lead to insecticides resistance to them. Insecticides resistance is main challenge of the vector control program. Also result will provide a guideline for control of the mosquito-borne diseases in the country as well as the world.

Impact of underground storm drain systems on larval ecology of Culex and Aedes species in urban environments of Southern California

An extensive network of storm water conveyance systems in urban areas, often referred to as the “underground storm drain system” (USDS), serves as significant production habitats for mosquitoes. Knowledge of whether USDS habitats are suitable for newly introduced dengue vectors Aedes aegypti and Ae. albopictus will help guide surveillance and control efforts. To determine whether the USDS functions as a suitable larval habitat for Culex, Ae. aegypti and Ae. albopictus in southern California, we examined mosquito habitat utilization and larval survivorship using laboratory microcosm studies. The data showed that USDS constituted 4.1% of sampled larval habitats for Ae. aegypti and Ae. albopictus, and 22.0% for Cx. quinquefasciatus. Furthermore, USDS water collected in the summer completely inhibited Aedes larval development, but yielded a 15.0% pupation rate for Cx. quinquefasciatus. Food supplementation in the microcosms suggests that nutrient deficiency, toxins and other factors in the USDS water led to low success or complete failure of larval development. These results suggest that USDS habitats are currently not major productive larval habitats for Aedes mosquitoes in southern California. Our findings prompt inclusion of assessments of pupal productivity in USDS habitats and adult mosquito resting sites in the mosquito surveillance program.

Lack of Zika Virus and Other Recognized Flaviviruses among the Mosquito Vectors during and Post the Hajj Mass Gathering.

Makkah city, Kingdom of Saudi Arabia (KSA), contains many of the world’s mosquito vectors of parasitic and arboviral disease and is the site of the Hajj mass gathering. As such there is a risk of exportation and globalization of vector-borne viruses, including the re-emerging Zika virus (ZIKV). There was international concern regarding the introduction of ZIKV to KSA and potential international spread of the virus following the 2016 Hajj which took place few days after the Rio summer Olympics at the height of the ZIKV pandemic. We aimed to detect flaviviruses, including ZIKV, circulating among mosquito hosts in the city of Makkah during and post the 2016 Hajj pilgrimage. Mosquitos (adults and larvae) were sampled from 15 sites in Makkah city during and post the 2016 Hajj and identified to species by morphological keys. Mosquitos were pooled according to date of collection, location, and species. A Pan-Flaviviruses RT-PCR assay that enables identification of 51 flaviviruses species and three tentative species was used to detect flavivirus RNA directly from mosquito homogenates. Between the 10 September and 6 October 2016, 9412 female mosquitos were collected. Of these, 81.3% were Aedes aegypti, 18.6% were Culex species, and 0.1% were Anopheles species. Of the total 493 mosquito pools generated, 242 (49%) were positive by the Pan-Flaviviruses primer set. Sequence analysis revealed that none of the mosquitos carried a pathogenic flavivirus, including ZIKV, but were infected with a novel insect-specific flavivirus. We found no pathogenic flaviviruses circulating in Makkah city during and post the 2016 Hajj and no evidence of introduction of ZIKV through the pilgrimage. Enhanced vector-borne diseases surveillance, prevention, and control are crucial in KSA especially during international mass gatherings such as the annual Hajj to prevent outbreaks and the spread of viruses with epidemic and pandemic potentials.