Search

Copyright of Environmental & Social Management Journal / Revista de Gestão Social e Ambiental is the property of Environmental & Social Management Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Plant-based insecticides have an increasing demand in mosquito control programs due to the eco-friendly nature of botanical products. We examined the ovicidal and oviposition deterrent properties of ethanol extracts of Tabernaemontana divaricata leaves against Aedes albopictus and Culex quinquefasciatus mosquitoes. Ovicidal bioassays were conducted to determine the lethal concentrations required to kill 50% and 90% of mosquito eggs (LC50 and LC90). Oviposition deterrent activity of leaf extracts was evaluated using 1% treatment solutions (2 g leaf powder: 200 ml distilled water). The number of eggs laid in treatments and controls was recorded for 7 days. LC50 and LC90 for Ae. albopictus were 626.6 and 892.5 ppm, respectively. For Cx. quinquefasciatus, LC50 and LC90 were 553.2 and 621.1 ppm, respectively. A strong positive correlation was reported between egg mortalities and concentrations (Aedes albopictus r = 0.993, p = 0.001; Culex quinquefasciatus, r = 0.992, p = 0.001). Eggs of Cx. quinquefasciatus were more susceptible to leaf extracts compared to those of Ae. albopictus. The deterrent properties of the plant extracts were relatively high during the first few days of the treatment (99.8% for Ae. albopictus and 100% for Cx. quinquefasciatus). The gradual reduction of the deterrent properties was observed after the second day of treatment for Ae. albopictus and the third day for Cx. quinquefasciatus. The oviposition activity index (OAI) ranged from − 0.968 to -0.120 for Ae. albopictus and − 1 to -0.53 for Cx. quinquefasciatus. The results reveal the ovicidal and oviposition deterrent properties of the leaf extracts of Ta. divaricata against Ae. albopictus and Cx. quinquefasciatus. [ABSTRACT FROM AUTHOR]

Simple Summary: Aedes, Culex, and Anopheles mosquitoes are the most prolific arthropod vectors of viral and parasitic agents of debilitating and lethal diseases in humans and animals. Despite some success in integrated pest management programs to control vectors, mosquito-borne diseases, such as dengue and dengue hemorrhagic fever, yellow fever, chikungunya, West Nile, and Zika, and parasitic diseases, such as malaria, lymphatic filariasis, and river blindness, continue to threaten the health and well-being of half the world's population, many of whom live in economically and medically challenged societies. The perpetual problem inflicted by vector-borne diseases is compounded by the selection for resistance to synthetic pesticides, globalization, and climate change. The latter appears to be the most significant factor implicated in the geographic expansion of mosquitoes. Here, we present a review of these challenges and highlight traditional vector control strategies that employ synthetic pesticides, and "green" eco-friendly technologies that include SIT, IIT, RIDL, CRISPR/Cas9/Cas13 gene drive systems, and biological control, with an emphasis on Lysinibacillus sphaericus and Bacillus thuringiensis subsp. israelensis (Bti). Mosquitoes are the most notorious arthropod vectors of viral and parasitic diseases for which approximately half the world's population, ~4,000,000,000, is at risk. Integrated pest management programs (IPMPs) have achieved some success in mitigating the regional transmission and persistence of these diseases. However, as many vector-borne diseases remain pervasive, it is obvious that IPMP successes have not been absolute in eradicating the threat imposed by mosquitoes. Moreover, the expanding mosquito geographic ranges caused by factors related to climate change and globalization (travel, trade, and migration), and the evolution of resistance to synthetic pesticides, present ongoing challenges to reducing or eliminating the local and global burden of these diseases, especially in economically and medically disadvantaged societies. Abatement strategies include the control of vector populations with synthetic pesticides and eco-friendly technologies. These "green" technologies include SIT, IIT, RIDL, CRISPR/Cas9 gene drive, and biological control that specifically targets the aquatic larval stages of mosquitoes. Regarding the latter, the most effective continues to be the widespread use of Lysinibacillus sphaericus (Ls) and Bacillus thuringiensis subsp. israelensis (Bti). Here, we present a review of the health issues elicited by vector mosquitoes, control strategies, and lastly, focus on the biology of Ls and Bti, with an emphasis on the latter, to which no resistance has been observed in the field. [ABSTRACT FROM AUTHOR]

Abstract Background A total of 290 mosquito species are recorded in Cambodia among which 43 are known vectors of pathogens. As Cambodia is heavily affected by deforestation, a potential change in the dynamic of vector-borne diseases (VDBs) could occur through alteration of the diversity and density of sylvatic vector mosquitoes and induce an increase in their interactions with humans. Understanding mosquito diversity is therefore critical, providing valuable data for risk assessments concerning the (re)emergence of local VBDs. Consequently, this study mainly aimed to understand the spatial and temporal distribution of sylvatic mosquito populations of Cambodia by determining which factors impact on their relative abundance and presence. Methods A study was conducted in 12 sites from four forests in Cambodia. All mosquitoes, collected during the dry and rainy seasons, were morphologically identified. The diversity and relative density of mosquito species in each site were calculated along with the influence of meteorological and geographical factors using a quasi-Poisson generalized linear model. Results A total of 9392 mosquitoes were collected belonging to 13 genera and 85 species. The most represented genera were Culex, accounting for 46% of collected mosquitoes, and Aedes (42%). Besides being the most abundant species, Culex pseudovishnui and Aedes albopictus, which are known vectors of numerous arboviruses, were present in all sites during both dry and rainy seasons. The presence of mosquito species reported to be zoo-anthropophilic feeders was also observed in both forested and urban areas. Finally, this study demonstrated that altitude, temperature and precipitation impacted the abundance of mosquitoes but also influenced species community composition. Conclusion The results indicate an important diversity of mosquitoes in the four forests and an influence of meteorological and geographical factors on their community. Additionally, this work highlights in parallel the abundance of species considered to be of medical importance and therefore underlines the high risk of pathogen emergence/re-emergence in the region. Graphical Abstract

Healthcare systems worldwide are burdened by mosquitoes transmitting dangerous diseases. Conventional mosquito surveillance methods to alleviate these diseases are based on expert entomologists’ manual examination of the morphological characteristics, which is time-consuming and unscalable. The lack of professional experts brings a high necessity for cheap and accurate automated alternatives for mosquito classification. This paper proposes an end-to-end deep Convolutional Neural Network (CNN) for mosquito species classification by taking advantage of both dropout layers and transfer learning to enhance performance accuracy. Dropout layers randomly disable the neurons of the neural network, mitigating co-adaptation and data overfitting. Transfer learning efficiently applies the extracted features from one dataset to others. Furthermore, a Region of Interest (ROI) visualization component is adopted to gain insight into the model learning. The generalization ability and feasibility of the proposed model are validated on four publicly available mosquito datasets. Experimental results on these datasets with an accuracy of 98.82%, 98.92%, 94.66%, and 98.40% demonstrate the superiority of our proposed system over the recent state-of-the-art approaches. The effectiveness of different numbers of dropout layers, their positions in the network, and their values are all investigated through ablation studies. Visualizing the model attention confirms that useful mosquito features are learned from insect legs and thorax through our model leading to optimistic predictions.

Background: A total of 290 mosquito species are recorded in Cambodia among which 43 are known vectors of pathogens. As Cambodia is heavily affected by deforestation, a potential change in the dynamic of vector-borne diseases (VDBs) could occur through alteration of the diversity and density of sylvatic vector mosquitoes and induce an increase in their interactions with humans. Understanding mosquito diversity is therefore critical, providing valuable data for risk assessments concerning the (re)emergence of local VBDs. Consequently, this study mainly aimed to understand the spatial and temporal distribution of sylvatic mosquito populations of Cambodia by determining which factors impact on their relative abundance and presence. Methods: A study was conducted in 12 sites from four forests in Cambodia. All mosquitoes, collected during the dry and rainy seasons, were morphologically identified. The diversity and relative density of mosquito species in each site were calculated along with the influence of meteorological and geographical factors using a quasi-Poisson generalized linear model. Results: A total of 9392 mosquitoes were collected belonging to 13 genera and 85 species. The most represented genera were Culex, accounting for 46% of collected mosquitoes, and Aedes (42%). Besides being the most abundant species, Culex pseudovishnui and Aedes albopictus, which are known vectors of numerous arboviruses, were present in all sites during both dry and rainy seasons. The presence of mosquito species reported to be zoo-anthropophilic feeders was also observed in both forested and urban areas. Finally, this study demonstrated that altitude, temperature and precipitation impacted the abundance of mosquitoes but also influenced species community composition. Conclusion: The results indicate an important diversity of mosquitoes in the four forests and an influence of meteorological and geographical factors on their community. Additionally, this work highlights in parallel the abundance of species considered to be of medical importance and therefore underlines the high risk of pathogen emergence/re-emergence in the region. [ABSTRACT FROM AUTHOR]

Mosquitoes are a major cause of lethal vector-borne diseases like dengue, malaria, filariasis, chikungunya, and Japanese encephalitis, among other diseases. In a developing country like India, mosquito-borne diseases are significant threats to familiar people as in certain places, there remains low sanitation. Larval and pupal life stages of mosquitoes are mostly confined to tropical and temperate waterbodies and often form a significant proportion of biomass waterbodies. Due to rebound vectorial capacity, resistance to chemical insecticides, and harmful environmental effects, the vector control program has shifted to using biological control agents. These methods are target-specific, eco-friendly, cost-effective, and can be easily deployed. So, the present review is focused on collating and updating the information on the use of aquatic predators, bacterial strains such as Bacillus sp. and actinobacterial, algae, and fungi, which are widely used for control of adult mosquitoes in their variety of natural habitats. This review also covers the predation of larvivorous fish and botanical insecticides.

Key aspects of 36 mosquito-borne arboviruses indigenous to Africa are summarized, including lesser or poorly-known viruses which, like Zika, may have the potential to escape current sylvatic cycling to achieve greater geographical distribution and medical importance. Major vectors are indicated as well as reservoir hosts, where known. A series of current and future risk factors is addressed. It is apparent that Africa has been the source of most of the major mosquito-borne viruses of medical importance that currently constitute serious global public health threats, but that there are several other viruses with potential for international challenge. The conclusion reached is that increased human population growth in decades ahead coupled with increased international travel and trade is likely to sustain and increase the threat of further geographical spread of current and new arboviral disease.

Mosquitoes breed by feeding on the blood of vertebrates to obtain the nutrients necessary to oviposition. In the process of feeding on human blood, mosquitoes can transmit a variety of serious human diseases and pose a great risk to human health. With the rapid development of globalization and the intensification of global climate change, the distribution of arboviruses represented by the dengue virus (DENV) and the Zika virus (ZIKV) has also presents globalization. China has a large geographical span and abundant local pathogens and vectors. With the growth of population, the expansion of urbanization, the frequent international trade and the increase of international tourism, there are more and more imported mosquito-borne diseases, and the public health problems caused by these diseases have also been paid more and more attention. In this paper, we systematically introduce the mosquito-borne diseases (dengue fever, Japanese encephalitis, malaria, yellow fever, West Nile fever, Zika fever, Chikungunya fever, and Sindbis disease) and their vectors, their distribution and characteristics, in order to provide theoretical basis for the systematic research and comprehensive control of mosquitoes and mosquito-borne diseases in China. [ABSTRACT FROM AUTHOR]

Background & objectives: Although, the number of considerable cases of dengue and lymphatic filariasis have been reported from Galle District, Sri Lanka in the past several years, contribution of abandoned boats to spread vector mosquitoes of Aedes and Culex in the coast is not well studied. Our aim was to assess the positive composition of different types of abandoned boats by larval vector mosquitoes to investigate their occurrence and habitat preference, and the monsoonal and co-existence variation of Aedes mosquitoes. Methods: The 4th instar larvae of Aedes and Culex species from three different abandoned boat types in nine subsampling sites at three municipal areas in Galle District were collected during 2017–2019. In total, 15 sampling rounds were conducted in each site for three years duration as five sample rounds per year. Larval collections and identifications were carried out using standard techniques and identification keys according to WHO guidelines. The occurrence of mosquito larvae was analysed by boat type, locations within area and year. Further, the average infestation variation of Aedes mosquitoes were compared with monsoonal and co-existence changers. Results; Out of the total abandoned boats, majority (51%) were engine boats and, 32.7%, 16.35% were troller boats and canoe boats, respectively. Troller boats were highly infested boat type for vector mosquitoes. Aedes albopictus was the dominant vector in abandoned boats other than recorded Ae. aegypti and Culex quinquefasciatus. Culex quinquefasciatus showed comparatively low infestation percentages. The average infestation of Ae. albopictus showed a consistent pattern with monsoon variation. A competitive rapid invasion of Aedes aegypti was observed with the suppressing Ae. albopictus in abandoned boats after 2018. Interpretation & conclusion: Abandoned boats contribute noteworthy to spread of Aedes and Culex vector mosquitoes in coastal belt, Galle District. These study findings would be helpful for researchers and health authorities to design appropriate vector control measures and to mitigate future dengue and filariasis outbreaks.

Abstract The use of semiochemicals in odour-based traps for surveillance and control of vector mosquitoes is deemed a new and viable component for integrated vector management programmes. Over 114 semiochemicals have been identified, yet implementation of these for management of infectious diseases such as malaria, dengue, chikungunya and Rift Valley fever is still a major challenge. The difficulties arise due to variation in how different mosquito species respond to not only single chemical compounds but also complex chemical blends. Additionally, mosquitoes respond to different volatile blends when they are looking for a mating partner, oviposition sites or a meal. Analytically the challenge lies not only in correctly identifying these semiochemical signals and cues but also in developing formulations that effectively mimic blend ratios that different mosquito species respond to. Only then can the formulations be used to enhance the selectivity and efficacy of odour-based traps. Understanding how mosquitoes use semiochemical cues and signals to survive may be key to unravelling these complex interactions. An overview of the current studies of these chemical messages and the chemical ecology involved in complex behavioural patterns is given. This includes an updated list of the semiochemicals which can be used for integrated vector control management programmes. A thorough understanding of these semiochemical cues is of importance for the development of new vector control methods that can be integrated into established control strategies.

Aedes aegypti mosquitoes are vectors for arboviruses of medical importance such as dengue (DENV) and Zika (ZIKV) viruses. Different innate immune pathways contribute to the control of arboviruses in the mosquito vector including RNA interference, Toll and Jak-STAT pathways. However, the role of cellular responses mediated by circulating macrophage-like cells known as hemocytes remains unclear. Here we show that hemocytes are recruited to the midgut of Ae. aegypti mosquitoes in response to DENV or ZIKV. Blockade of the phagocytic function of hemocytes using latex beads induced increased accumulation of hemocytes in the midgut and a reduction in virus infection levels in this organ. In contrast, inhibition of phagocytosis by hemocytes led to increased systemic dissemination and replication of DENV and ZIKV. Hence, our work reveals a dual role for hemocytes in Ae. aegypti mosquitoes, whereby phagocytosis is not required to control viral infection in the midgut but is essential to restrict systemic dissemination. Further understanding of the mechanism behind this duality could help the design of vector-based strategies to prevent transmission of arboviruses.

Aedes aegypti mosquitoes are vectors for arboviruses of medical importance such as dengue (DENV) and Zika (ZIKV) viruses. Different innate immune pathways contribute to the control of arboviruses in the mosquito vector including RNA interference, Toll and Jak-STAT pathways. However, the role of cellular responses mediated by circulating macrophage-like cells known as hemocytes remains unclear. Here we show that hemocytes are recruited to the midgut of Ae. aegypti mosquitoes in response to DENV or ZIKV. Blockade of the phagocytic function of hemocytes using latex beads induced increased accumulation of hemocytes in the midgut and a reduction in virus infection levels in this organ. In contrast, inhibition of phagocytosis by hemocytes led to increased systemic dissemination and replication of DENV and ZIKV. Hence, our work reveals a dual role for hemocytes in Ae. aegypti mosquitoes, whereby phagocytosis is not required to control viral infection in the midgut but is essential to restrict systemic dissemination. Further understanding of the mechanism behind this duality could help the design of vector-based strategies to prevent transmission of arboviruses. [ABSTRACT FROM AUTHOR]

Abstract Key aspects of 36 mosquito-borne arboviruses indigenous to Africa are summarized, including lesser or poorly-known viruses which, like Zika, may have the potential to escape current sylvatic cycling to achieve greater geographical distribution and medical importance. Major vectors are indicated as well as reservoir hosts, where known. A series of current and future risk factors is addressed. It is apparent that Africa has been the source of most of the major mosquito-borne viruses of medical importance that currently constitute serious global public health threats, but that there are several other viruses with potential for international challenge. The conclusion reached is that increased human population growth in decades ahead coupled with increased international travel and trade is likely to sustain and increase the threat of further geographical spread of current and new arboviral disease.

Vector mosquitoes contribute significantly to the global burden of diseases in humans, livestock and wildlife. As such, the spatial distribution and abundance of mosquito species and their surveillance cannot be ignored. Here, we surveyed mosquito species across major tourism hotspots in semi-arid Botswana, including, for the first time, the Central Kalahari Game Reserve. Our results reported several mosquito species across seven genera, belonging to Aedes, Anopheles, Culex, Mansonia, Mimomyia, Coquillettidia and Uranotaenia. These results document a significant species inventory that may inform early warning vector-borne disease control systems and likely help manage the risk of emerging and re-emerging mosquito-borne infections.

The use of semiochemicals in odour-based traps for surveillance and control of vector mosquitoes is deemed a new and viable component for integrated vector management programmes. Over 114 semiochemicals have been identified, yet implementation of these for management of infectious diseases such as malaria, dengue, chikungunya and Rift Valley fever is still a major challenge. The difficulties arise due to variation in how different mosquito species respond to not only single chemical compounds but also complex chemical blends. Additionally, mosquitoes respond to different volatile blends when they are looking for a mating partner, oviposition sites or a meal. Analytically the challenge lies not only in correctly identifying these semiochemical signals and cues but also in developing formulations that effectively mimic blend ratios that different mosquito species respond to. Only then can the formulations be used to enhance the selectivity and efficacy of odour-based traps. Understanding how mosquitoes use semiochemical cues and signals to survive may be key to unravelling these complex interactions. An overview of the current studies of these chemical messages and the chemical ecology involved in complex behavioural patterns is given. This includes an updated list of the semiochemicals which can be used for integrated vector control management programmes. A thorough understanding of these semiochemical cues is of importance for the development of new vector control methods that can be integrated into established control strategies. [ABSTRACT FROM AUTHOR]

The construction industry employs millions of workers in the USA. However, little is known about how environmental disturbances caused by the construction industry impacts vector mosquito ecology and behavior, and whether it is responsible for increasing the abundance of mosquitoes. There is a major scientific gap on how to assess the occupational exposure risk of mosquito biting and arbovirus transmission among outdoor worker populations who spend a disproportionate amount of time working outdoors. In our opinion, it is critical to address how construction workers and the surrounding communities may be geographically and seasonally exposed to vector mosquitoes. Research should identify modifiable worker- and organizational-level factors that improve worksite mosquito-control practices to give insights into future vector-control strategies in urban environments. Recent studies have shown that the proliferation of vector mosquitoes is partially attributable to construction sites. Very little is known about how environmental disturbances caused by construction sites impact vector mosquito ecology and behavior. There is a significant scientific gap on how to assess the risk of mosquito biting and arbovirus transmission in construction sites. In our opinion, it is critical to address how construction sites may be geographically and seasonally exposed to vector mosquitoes and their effect on the transmission of arboviruses in the surrounding communities and in the population as a whole. Research should also identify modifiable worker- and organizational-level factors that improve mosquito-control practices to guide future vector-control strategies in urban environments. [ABSTRACT FROM AUTHOR]

Mosquitoes are widely despised for their exasperating buzzing and irritating bites, and more poignantly because, during blood-feeding, females may transmit pathogens that cause devastating diseases. However, the ability to transmit such viruses, filarial worms, or malaria parasites varies greatly amongst the ∼3500 recognised mosquito species. Applying omics technologies to sample this diversity and explore the biology underlying these variations is bringing increasingly greater resolution that enhances our understanding of mosquito evolution. Here we review the current status of mosquito omics, or 'mozomics', resources and recent advances in their applications to characterise mosquito biology and evolution, with a focus on the intersection of evolutionary and functional genomics to understand the putative links between gene and genome dynamism and mosquito diversity. Highlights Genomic sampling of mosquito diversity has greatly improved in recent years and looks set to take advantage of emerging technologies to explore even further. Evolutionary genomics analyses have unveiled dynamic patterns of gene and genome evolution likely linked to mosquito adaptability that will guide future research and control efforts. Functional genomics assays have helped to characterise biological roles of thousands of genes, albeit with condition-patchy and species-biased coverage that is now starting to be remedied. Comparative genomics approaches are increasingly being applied to contextualise and enhance the interpretation of results from multispecies studies with an evolutionary perspective. These trends mean that effective data sharing will be critical to facilitate future integrative meta-analyses and fully harness the benefits of combined evolutionary and functional analyses. [ABSTRACT FROM AUTHOR]

Background: Studies that improve and/or assess the ability of traps in vector detection, facilitate the control of diseases caused by these vectors. Objective: The objective of this study was to compare four types of traps for A. aegypti capture and collection under field conditions, and to evaluate the influences of temperature and precipitation on the efficiency of these traps. Method: Ovitraps (filter paper and palette), "mosquitéricas" and MosquiTRAP® were installed in 10 city blocks, which received on each face, one type of trap. Qualitative and quantitative entomological indices were calculated for all traps. Results: The "mosquitéricas" trap had the lowest positivity index (3%). Only the IPAaegypti and IDAaegypti indices showed a positive relationship with temperature and precipitation, respectively. The ovitraps had up to 6.6 times more chances of positivity for A. aegypti when compared to MosquiTRAP®, with no significant difference between the filter paper and the palette substrates. Conclusion: The ovitraps presented the best indices to be used in the surveillance of A. aegypti. The recommendation to use filter paper as a substrate for oviposition is imperative because of its lower cost, easier manufacturing, transport and storage, as well as better visibility of the deposited eggs. [ABSTRACT FROM AUTHOR]

Mosquitoes act as key vector for transmission of devastating parasites and pathogens which affect millions of people globally. In this research, the green synthesis of silver nanoparticles of Cassia fistula fruit pulp as an innovative and operative tool against vector mosquitoes is presented. Silver nanoparticles were characterized by a series of techniques including Fourier transform infrared spectroscopy, Transmission Electron Microscope and confirmed by Scanning Electron Microscope, UV-Vis spectrophotometry and X-ray diffraction. Silver nanoparticles were highly effective against the larvae (I-IV instar) and pupae of Aedes albopictus and Culex pipiens pallens after 24, 48 and 72 h of treatment. Ae. albopictus had LC50 values ranging from 8.3 mg/L (I instar) to 17.3 mg/L (pupae) and LC50 ranging from 1.1 mg/L (I instar) to 19.0 mg/L (pupae) against Cx. pipiens pallens. The systemic effect of AgNPs was further assessed in the fourth instar larvae of Ae. albopictus and Cx. pipiens pallens by measuring the levels of total proteins and activity of two important marker enzymes: Acetylcholinesterase and α- and β-carboxylesterase. Overall, the findings of the study suggest that the use of Cassia fistula-fruit pulp extract mediated synthesis of silver nanoparticles can be used for controlling vector mosquitoes. This is the first report on the mosquito larvicidal and pupicidal activity of AgNPs synthesized by Cassia fistula fruit pulp and its possible mechanism of action. [ABSTRACT FROM AUTHOR]

The power and ease of Drosophila genetics and the medical relevance of mosquitotransmitted viruses have made dipterans important model organisms in antiviral immunology. Studies of virus-host interactions at the molecular and population levels have illuminated determinants of resistance to virus infection. Here, we review the sources and nature of variation in antiviral immunity and virus susceptibility in model dipteran insects, specifically the fruit fly Drosophila melanogaster and vector mosquitoes of the genera Aedes and Culex. We first discuss antiviral immune mechanisms and describe the virus-specificity of these responses. In the following sections, we review genetic and microbiota-dependent variation in antiviral immunity. In the final sections, we explore less well-studied sources of variation, including abiotic factors, sexual dimorphism, infection history, and endogenous viral elements. We borrow from work on other pathogen types and non-dipteran species when it parallels or complements studies in dipterans. Understanding natural variation in virus-host interactions may lead to the identification of novel restriction factors and immune mechanisms and shed light on the molecular determinants of vector competence. [ABSTRACT FROM AUTHOR]

In this paper, a reaction-diffusion system is proposed to model the spatial spreading of West Nile virus in vector mosquitoes and host birds in North America. Transmission dynamics are based on a simplified model involving mosquitoes and birds, and the free boundary is introduced to model and explore the expanding front of the infected region. The spatial-temporal risk index $$R_0^F(t)$$ , which involves regional characteristic and time, is defined for the simplified reaction-diffusion model with the free boundary to compare with other related threshold values, including the usual basic reproduction number $$R_0$$ . Sufficient conditions for the virus to vanish or to spread are given. Our results suggest that the virus will be in a scenario of vanishing if $$R_0\le 1$$ , and will spread to the whole region if $$R_{0}^F(t_0)\ge 1$$ for some $$t_0\ge 0$$ , while if $$R^F_0(0)<1

Objectives To evaluate the ovicidal and oviposition deterrent activities of five medicinal plant extracts namely Aegle marmelos (Linn.), Limonia acidissima (Linn.), Sphaeranthus indicus (Linn.), Sphaeranthus amaranthoides (burm.f), and Chromolaena odorata (Linn.) against Culex quinquefasciatus and Aedes aegypti mosquitoes. Three solvents, namely hexane, ethyl acetate, and methanol, were used for the preparation of extracts from each plant. Methods Four different concentrations—62.5 parts per million (ppm), 125 ppm, 250 ppm, and 500 ppm—were prepared using acetone and tested for ovicidal and oviposition deterrent activities. One-way analysis of variance (ANOVA) was used to determine the significance of the treatments and means were separated by Tukey's test of comparison. Results Among the different extracts of the five plants screened, the hexane extract of L. acidissima recorded the highest ovicidal activity of 79.2% and 60% at 500 ppm concentration against the eggs of Cx. quinquefasciatus and Ae. aegypti , respectively. Similarly, the same hexane extract of L. acidissima showed 100% oviposition deterrent activity at all the tested concentrations against Cx. quinquefasciatus and Ae. aegypti adult females. Conclusion It is concluded that the hexane extract of L. acidissima could be used in an integrated mosquito management program. [ABSTRACT FROM AUTHOR]

Abstract: The biased usage of synonymous codons affects translational efficiency of genes. We studied codon usage patterns of genes that are perfectly conserved at the amino acid level among three important mosquito vector species: Aedes aegypti (vector of dengue virus), Anopheles gambiae (vector of malaria) and Culex quinquefasciatus (vector of lymphatic filariasis and West Nile Virus). Although these proteins have the same amino acid sequences, non-random usage of synonymous codons is evident among the orthologous genes. The coding sequences of these genes were simulated to generate random mutation sites to be further investigated for patterns of codon bias. It was found that codon usage bias is significantly higher in genes that represented perfectly conserved proteins than genes where variation was apparent at the amino acid sequence. Our results suggest that genes coding for perfectly conserved proteins are highly biased with optimized codons and may be under stringent translational selection in these vector species. [Copyright &y& Elsevier]

Abstract: Objectives: Until the early 2000s, lymphatic filariasis would commonly break out in the coastal areas in Korea. Through steady efforts combining investigation and treatment, filariasis was officially declared eradicated in 2008. This study surveyed the density of vector species of filariasis in past endemic areas, and inspected filariasis DNA from collected mosquitoes for protection against the reemergence of filariasis. Methods: Between May and October 2009, mosquitoes were caught using the black night trap in past endemic coastal areas: Gyeongsangnam-do, Jeollanam-do, and Jeju-do. The collected mosquitoes were identified, and the extracted DNA from the collected vector mosquitoes was tested by polymerase chain reaction for Brugia malayi filariasis. Results: Ochletotatus togoi, Anophel es (Hyrcanus) group and Culex pipiens were most frequently caught in Jeollanam-do (Geomun Island, Bogil Island, Heuksan Island), Jeju-do (Namone-ri, Wimi-ri). and Gyeongsangnam-do (Maemul Island). DNA of B malayi was not found in Och Togoi and An (Hyrcanus) group as main vectors of filariasis. Conclusion: Lymphatic filariasis was not found in the vector mosquitoes collected in past endemic areas. However, considering that the proportion of vector species is quite high, there is a potential risk that filariasis could be reemerging through overseas travel or trade. Thus, there is a need to continuously monitor vector mosquitoes of lymphatic filariasis. [Copyright &y& Elsevier]

Because of their special behaviour, physiology and close relationship with humans, mosquitoes act as one of the most important vectors of human diseases, such as filariasis, Japanese encephalitis, dengue and malaria. The major vector mosquitoes are members of the Culex, Aedes and Anopheles genera. Insecticides play important roles in agricultural production and public health, especially in a country with a huge human population, like China. Large quantities of four classes of insecticides, organochlorines, organophosphates, carbamates and pyrethroids, are applied annually to fields or indoors in China, directly or indirectly bringing heavy selection pressure on vector populations. The seven major species of vector mosquito in China are the Culex pipiens L. complex, C. tritaeniorhynchus Giles, Anopheles sinensis Wied., A. minimus Theobald, A. anthropophagus Xu & Feng, Aedes albopictus (Skuse) and Ae. aegypti L., and all have evolved resistance to all the above types of insecticide except the carbamates. The degree of resistance varies among mosquito species, insecticide classes and regions. This review summarizes the resistance status of these important vector mosquitoes, according to data reported since the 1990s, in order to improve resistance management and epidemic disease control, and to communicate this information from China to the wider community. [ABSTRACT FROM AUTHOR]

Simple Summary: Mosquitoes vector pathogens that cause burdening diseases in humans, livestock and wildlife worldwide. Spatially and temporally, mosquito diversity varies considerably in response to bio-physical environments. As such, there is a need for mosquito diversity and distribution studies, as well as monitoring programmes, to inform on the risk of associated diseases. This survey assessed mosquito species in three major touristic areas of Botswana that are likely to harbour pathogens across prevailing hosts. The results revealed that all regions surveyed had important mosquito groups (Anopheles, Aedes and Culex) that are threats to public, wildlife and livestock health globally, including the arid Central Kalahari Game Reserve. The findings represent useful species inventories for future surveys and monitoring programmes. Vector mosquitoes contribute significantly to the global burden of diseases in humans, livestock and wildlife. As such, the spatial distribution and abundance of mosquito species and their surveillance cannot be ignored. Here, we surveyed mosquito species across major tourism hotspots in semi-arid Botswana, including, for the first time, the Central Kalahari Game Reserve. Our results reported several mosquito species across seven genera, belonging to Aedes, Anopheles, Culex, Mansonia, Mimomyia, Coquillettidia and Uranotaenia. These results document a significant species inventory that may inform early warning vector-borne disease control systems and likely help manage the risk of emerging and re-emerging mosquito-borne infections. [ABSTRACT FROM AUTHOR]

The mosquito community from remote locations toward the southern border of the Brazilian State of Amazonas, in four localities along the Liberdade and Gregório Rivers, was sampled using CDC and Malaise traps, complemented with net sweeping and immature collections. During May 2011, 190 collections yielded 13,012 mosquitoes, from 15 genera and 112 different species, together with 10 morphospecies, which may represent new undescribed taxa. Among the species collected, there are two new geographical distribution records for the State of Amazonas. Culex, the most abundant genus, also had the highest number of species. Both Aedes and Uranotaenia had the second highest number of species, although they were the second and seventh most abundant, respectively. The most abundant species were Aedes (Ochlerotatus) fulvus (Wiedemann), Aedes (Ochlerotatus) nubilus (Theobald), Culex (Culex) mollis Dyar & Knab, Nyssorhynchus (Nyssorhynchus) oswaldoi sensu lato, Culex (Melanoconion) pedroi Sirivanakarn & Belkin, and Culex (Melanoconion) gnomatos Sallum, Hutchings & Ferreira. The epidemiological implications of mosquito species are discussed and compared with other mosquito inventories from the Amazon region. These results represent the first standardized mosquito inventories of the Liberdade and Gregório Rivers, with the identification of 112 species and 10 morphospecies, within the municipalities of Ipixuna and Eirunepé, from which we have only few records in the published literature., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America.All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)