Genomic and evolutionary analyses of Tango transposons in Aedes aegypti, Anopheles gambiae and other mosquito species

The CH2Cl2-MeOH (30:70 v/v) extracts of the seeds of Mangifera indica (Mango), Persea americana (Avocado) and Dacryodes edulis (African plum) were evaluated for potential mosquito larvicidal activity against 3rd and 4th instar larvae of Aedes aegypti, Culex quinquefasciatus and Anopheles gambiae. Extracts were diluted with 1 mL of methanol and concentrations ranging from 1000 to 125 mg/L in 4 replicates each, were prepared in the volume of 100 mL in the plastic cups (250 mL). A volume of 1 mL of methanol added to 99 mL of tap water was prepared as negative control and Bi-one (1000 mg/L) constituted a positive control. In each test solution, 25 larvae of each mosquito species were separately transferred and larval mortality was recorded after 24 h post-treatment. As results, the three plant seed extracts applied at 1000 mg/L caused for at least 79% mortality of each mosquito species larvae assessed. The seed extract of P. americana (LC50 of 98.31, 129.24 and 136.26 mg/L, respectively against An. gambiae, Ae. aegypti and Cx. quiquefasciatus larvae) was the most potent followed by D. edulis (LC50 of 176.87 mg/L for An. gambiae, 198.68 mg/L for Ae. aegypti and 201.70 mg/L for Cx. quinquefasciatus) and M. indica (LC50 of 258.98 mg/L for An. gambiae, 297.35 mg/L for Ae. aegypti and 435.45 mg/L for Cx. quinquefasciatus). Globally, all the seed extracts were more toxic against An. gambiae larvae compared to other mosquito species and need further exploration for the development of a new botanical larvicide to reduce mosquito densities.

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Programmable CRISPR interference for gene silencing using Cas13a in mosquitoes

10.1101/846055 ◽

2019 ◽

Author(s):

Aditi Kulkarni ◽

Wanqin Yu ◽

Alex Moon ◽

Ashmita Pandey ◽

Kathryn A. Hanley ◽

...

Keyword(s):

Aedes Aegypti ◽

Gene Silencing ◽

Anopheles Gambiae ◽

Blood Meal ◽

Egg Production ◽

Mosquito Species ◽

Single Strand ◽

Crispr Interference ◽

Target Mrna

AbstractIn the CRISPR-Cas systems, Cas13a is an RNA-guided RNA nuclease specifically targeting single strand RNA. We developed a Cas13a mediated CRISPR interference tool to target mRNA for gene silencing in mosquitoes. The machinery was tested in two mosquito species. A Cas13a expressing plasmid was delivered to mosquitoes by intrathoracic injection, and Cas13a transcripts were detectable at least10 days post-delivery. In Anopheles gambiae, vitellogenin gene was silenced by Vg-crRNA injection two hours post-blood meal, which was accompanied by a significant reduction in egg production. In Aedes aegypti, the α- and δ-subunits of COPI genes were silenced by a post-blood meal crRNA injection, which resulted in mortality and fragile midguts, reproducing a phenotype reported previously. Co-silencing genes simultaneously is achievable when a cocktail of target crRNAs is given. No detectable collateral cleavages of non-target transcripts were observed in the study. This study adds a programmable CRISPR tool to manipulate RNA in mosquitoes.

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Video Recording Can Conveniently Assay Mosquito Locomotor Activity

10.1101/2020.02.28.970566 ◽

2020 ◽

Author(s):

Maisa da Silva Araujo ◽

Fang Guo ◽

Michael Rosbash

Keyword(s):

Locomotor Activity ◽

Aedes Aegypti ◽

Anopheles Gambiae ◽

Tracking System ◽

Mosquito Species ◽

Activity Patterns ◽

Video Recording ◽

Constant Darkness ◽

Daily Rhythms ◽

Wide Range

AbstractAnopheles gambiae and Aedes aegypti are perhaps the best studied mosquito species and important carriers of human malaria and arbovirus, respectively. Mosquitoes have daily rhythms in behaviors and show a wide range of activity patterns. Although Anopheles is known to be principally nocturnal and Aedes principally diurnal, details of mosquito activity are not easily assayed in the laboratory. We recently described FlyBox, a simple tracking system for assaying Drosophila locomotor activity rhythms and thought that it might also be applicable to monitoring mosquito activity. Indeed, we show here that FlyBox can easily, conveniently, affordably and accurately measure the activity of Anopheles as well as Aedes over several days. The resulting profiles under light-dark as well as constant darkness conditions are compatible with results in the literature, indicating that this or similar systems will be useful in the future for more detailed studies on a range of insect species and under more diverse laboratory conditions.

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A Simple PCR Assay for Discrimination of Dengue Vectors from Nsukka LGA, Nigeria

International Annals of Science ◽

10.21467/ias.10.1.67-77 ◽

2020 ◽

Vol 10 (1) ◽

pp. 67-77

Author(s):

Amos Watentena ◽

Ikem Chris Okoye ◽

Ikechukwu Eugene Onah ◽

Onwude Cosmas Ogbonnaya ◽

Emmanuel Ogudu

Keyword(s):

Aedes Aegypti ◽

Aedes Albopictus ◽

Mosquito Species ◽

Public Health Problem ◽

Major Public Health Problem ◽

Mosquito Vector ◽

Aedes Mosquitoes ◽

Allele Specific ◽

Arboviral Diseases ◽

Dengue Vectors

Mosquitoes of Aedes species are vectors of several arboviral diseases which continue to be a major public health problem in Nigeria. This study among other things, morphologically identified Aedes mosquitoes collected from Nsukka LGA and used an allele specific PCR amplification for discrimination of dengue vectors. Larval sampling, BG-sentinel traps and modified human landing catches were used for mosquito sampling in two selected autonomous communities of Nsukka LGA (Nsukka and Obimo). A total of 124 Aedes mosquitoes consisting of five (5) different species were collected from April to June, 2019 in a cross-sectional study that covered 126 households, under 76 distinct geographical coordinates. Larvae was mainly collected from plastic containers 73% (n=224), metallic containers 14% (n=43), earthen pots 9% (n=29) and used car tyres 3% (n=9), reared to adult stage 69.35% (n=86), and all mosquitoes were identified using standard morphological keys. Five (5) Aedes mosquito species were captured; Aedes aegypti 83(66.94%), Aedes albopictus 33(26.61%), Aedes simpsoni (4.48%), Aedes luteocephalus (≤1%) and Aedes vittatus (≤1%). Nsukka autonomous community had higher species diversity than Obimo. Allele specific amplification confirmed dengue vectors, Aedes aegypti and Aedes albopictus species on a 2% agarose gel. Since the most recent re-emergence of arboviral diseases is closely associated with Aedes species, findings of this study, therefore, give further evidence about the presence of potential arboviral vectors in Nigeria and describe the role of a simple PCR in discriminating some. Further entomological studies should integrate PCR assays in mosquito vector surveillance.

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Transmission Potential of Zika Virus by Aedes aegypti (Diptera: Culicidae) and Ae. mediovittatus (Diptera: Culicidae) Populations From Puerto Rico

Journal of Medical Entomology ◽

10.1093/jme/tjaa286 ◽

2021 ◽

Author(s):

Rebecca A Zimler ◽

Donald A Yee ◽

Barry W Alto

Keyword(s):

Puerto Rico ◽

Aedes Aegypti ◽

Zika Virus ◽

Mosquito Species ◽

The United States ◽

Infection Rates ◽

Transmission Potential ◽

Transmission Rates ◽

Higher Doses ◽

Local Transmission

Abstract Recurrence of local transmission of Zika virus in Puerto Rico is a major public health risk to the United States, where mosquitoes Aedes aegypti (Linnaeus) and Aedes mediovittatus (Coquillett) are abundant. To determine the extent to which Ae. mediovittatus are capable of transmitting Zika virus and the influence of viremia, we evaluated infection and transmission in Ae. mediovittatus and Ae. aegypti from Puerto Rico using serial dilutions of infectious blood. Higher doses of infectious blood resulted in greater infection rates in both mosquitoes. Aedes aegypti females were up to twice as susceptible to infection than Ae. mediovittatus, indicating a more effective midgut infection barrier in the latter mosquito species. Aedes aegypti exhibited higher disseminated infection (40–95%) than Ae. mediovittatus (<5%), suggesting a substantial midgut escape barrier in Ae. mediovittatus. For Ae. aegypti, transmission rates were low over a range of doses of Zika virus ingested, suggesting substantial salivary gland barriers.

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Unravelling population structure heterogeneity within the genome of the malaria vector Anopheles gambiae

BMC Genomics ◽

10.1186/s12864-021-07722-y ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Melina Campos ◽

Luisa D. P. Rona ◽

Katie Willis ◽

George K. Christophides ◽

Robert M. MacCallum

Keyword(s):

Population Structure ◽

Anopheles Gambiae ◽

Malaria Vector ◽

Mosquito Species ◽

Gene Clusters ◽

Selective Sweeps ◽

Structure Heterogeneity ◽

Genomic Studies ◽

Time Required ◽

Genomic Regions

Abstract Background Whole genome re-sequencing provides powerful data for population genomic studies, allowing robust inferences of population structure, gene flow and evolutionary history. For the major malaria vector in Africa, Anopheles gambiae, other genetic aspects such as selection and adaptation are also important. In the present study, we explore population genetic variation from genome-wide sequencing of 765 An. gambiae and An. coluzzii specimens collected from across Africa. We used t-SNE, a recently popularized dimensionality reduction method, to create a 2D-map of An. gambiae and An. coluzzii genes that reflect their population structure similarities. Results The map allows intuitive navigation among genes distributed throughout the so-called “mainland” and numerous surrounding “island-like” gene clusters. These gene clusters of various sizes correspond predominantly to low recombination genomic regions such as inversions and centromeres, and also to recent selective sweeps. Because this mosquito species complex has been studied extensively, we were able to support our interpretations with previously published findings. Several novel observations and hypotheses are also made, including selective sweeps and a multi-locus selection event in Guinea-Bissau, a known intense hybridization zone between An. gambiae and An. coluzzii. Conclusions Our results present a rich dataset that could be utilized in functional investigations aiming to shed light onto An. gambiae s.l genome evolution and eventual speciation. In addition, the methodology presented here can be used to further characterize other species not so well studied as An. gambiae, shortening the time required to progress from field sampling to the identification of genes and genomic regions under unique evolutionary processes.

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Behavioural response of mosquito vectors Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus to synthetic pyrethroid and organophosphorus-based slow-release insecticidal paint

Parasites & Vectors ◽

10.1186/s13071-021-04746-x ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Sunil Dhiman ◽

Kavita Yadav ◽

B. N. Acharya ◽

Raj Kumar Ahirwar ◽

D. Sukumaran

Keyword(s):

Aedes Aegypti ◽

Culex Quinquefasciatus ◽

Anopheles Stephensi ◽

Slow Release ◽

Disease Risk ◽

Mosquito Species ◽

Escape Time ◽

Behavioural Avoidance ◽

Vector Mosquito ◽

Contact Exposure

Abstract Background The direct toxicological impact of insecticides on vector mosquitoes has been well emphasized; however, behavioural responses such as excito-repellency and physical avoidance as a result of insecticide exposure have not been much studied. We have demonstrated the excito-repellency and behavioural avoidance in certain vector mosquito species on exposure to a slow-release insecticidal paint (SRIP) formulation in addition to direct toxicity. Methods A SRIP formulation developed by the Defence Research and Development Establishment, Gwalior, contains chlorpyriphos, deltamethrin and pyriproxyfen as active insecticides. Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti mosquitoes were used to study the excito-repellency response of the formulation. The experiments were performed in a specially designed dual-choice exposure and escape chamber made of transparent polymethyl methacrylate. For the experiments, the SRIP formulation was applied undiluted at a rate of 8 m2 per kg on 15 cm2 metallic surfaces. Mosquitoes were introduced into the exposure chamber, and observations of the movement of mosquitoes into the escape chamber through the exit portal were taken at 1-min intervals for up to 30 min. Results The evaluated formulation displayed strong excito-repellency against all three tested vector mosquito species. Results showed that the ET50 (escape time 50%) for Ae. aegypti, An. stephensi and Cx. quinquefasciatus was 20.9 min, 14.5 min and 17.9 min for contact exposure (CE) respectively. Altogether in CE, the escape rates were stronger in An. stephensi mosquitoes at different time intervals compared to Ae. aegypti and Cx. quinquefasciatus mosquitoes. The probit analysis revealed that the determined ET did not deviate from linearity for both non-contact exposure (NCE) and placebo exposure (PE) (χ2 ≤ 7.9; p = 1.0) for Ae. aegypti mosquitoes and for NCE (χ2 = 8.3; p = 1.0) and PE (χ2 = 1.7; p = 1.0) treatments in Cx. quinquefasciatus. Mortality (24 h) was found to be statistically higher (F = 6.4; p = 0.02) in An. stephensi for CE but did not vary for NCE (p ≥ 0.3) and PE (p = 0.6) treatments among the tested mosquito species. Survival probability response suggested that all the three tested species displayed similar survival responses for similar exposures (χ2 ≤ 2.3; p ≥ 0.1). Conclusion The study demonstrates the toxicity and strong behavioural avoidance in known vector mosquito species on exposure to an insecticide-based paint formulation. The combination of insecticides in the present formulation will broaden the overall impact spectrum for protecting users from mosquito bites. The efficacy data generated in the study provide crucial information on the effectiveness of the tested formulation and could be useful in reducing the transmission intensity and disease risk in endemic countries.

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Single blinded semi-field evaluation of MAÏA® topical repellent ointment compared to unformulated 20% DEET against Anopheles gambiae, Anopheles arabiensis and Aedes aegypti in Tanzania

Malaria Journal ◽

10.1186/s12936-020-03461-9 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Emmanuel Mbuba ◽

Olukayode G. Odufuwa ◽

Frank C. Tenywa ◽

Rose Philipo ◽

Mgeni M. Tambwe ◽

...

Keyword(s):

Aedes Aegypti ◽

Anopheles Gambiae ◽

Anopheles Arabiensis ◽

Protective Efficacy ◽

Latin Square ◽

Field Evaluation ◽

Sensu Stricto ◽

Lower Limbs ◽

Complete Protection ◽

Regular User

Abstract Background N,N-Diethyl-3-methylbenzamide (DEET) topical mosquito repellents are effective personal protection tools. However, DEET-based repellents tend to have low consumer acceptability because they are cosmetically unappealing. More attractive formulations are needed to encourage regular user compliance. This study evaluated the protective efficacy and protection duration of a new topical repellent ointment containing 15% DEET, MAÏA® compared to 20% DEET in ethanol using malaria and dengue mosquito vectors in Bagamoyo Tanzania. Methods Fully balanced 3 × 3 Latin square design studies were conducted in large semi-field chambers using laboratory strains of Anopheles gambiae sensu stricto, Anopheles arabiensis and Aedes aegypti. Human volunteers applied either MAÏA® ointment, 20% DEET or ethanol to their lower limbs 6 h before the start of tests. Approximately 100 mosquitoes per strain per replicate were released inside each chamber, with 25 mosquitoes released at regular intervals during the collection period to maintain adequate biting pressure throughout the test. Volunteers recaptured mosquitoes landing on their lower limbs for 6 h over a period of 6 to 12-h post-application of repellents. Data analysis was conducted using mixed-effects logistic regression. Results The protective efficacy of MAÏA® and 20% DEET was not statistically different for each of the mosquito strains: 95.9% vs. 97.4% against An. gambiae (OR = 1.53 [95% CI 0.93–2.51] p = 0.091); 96.8% vs 97.2% against An. arabiensis (OR = 1.08 [95% CI 0.66–1.77] p = 0.757); 93.1% vs 94.6% against Ae. aegypti (OR = 0.76 [95% CI 0.20–2.80] p = 0.675). Average complete protection time (CPT) in minutes of MAÏA® and that of DEET was similar for each of the mosquito strains: 571.6 min (95% CI 558.3–584.8) vs 575.0 min (95% CI 562.1–587.9) against An. gambiae; 585.6 min (95% CI 571.4–599.8) vs 580.9 min (95% CI 571.1–590.7) against An. arabiensis; 444.1 min (95% CI 401.8–486.5) vs 436.9 min (95% CI 405.2–468.5) against Ae. aegypti. Conclusions MAÏA® repellent ointment provides complete protection for 9 h against both An. gambiae and An. arabiensis, and 7 h against Ae. aegypti similar to 20% DEET (in ethanol). MAÏA® repellent ointment can be recommended as a tool for prevention against outdoor biting mosquitoes in tropical locations where the majority of the people spend an ample time outdoor before going to bed.

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Chikungunya: epidemiology

F1000Research ◽

10.12688/f1000research.7171.1 ◽

2016 ◽

Vol 5 ◽

pp. 82 ◽

Cited By ~ 56

Author(s):

Lyle R. Petersen ◽

Ann M. Powers

Keyword(s):

Public Health ◽

Aedes Aegypti ◽

Aedes Albopictus ◽

Chikungunya Virus ◽

Mosquito Species ◽

Febrile Illness ◽

Current Understanding ◽

Global Public Health ◽

Temperate Climates

Chikungunya virus is a mosquito-borne alphavirus that causes fever and debilitating joint pains in humans. Joint pains may last months or years. It is vectored primarily by the tropical and sub-tropical mosquito, Aedes aegypti, but is also found to be transmitted by Aedes albopictus, a mosquito species that can also be found in more temperate climates. In recent years, the virus has risen from relative obscurity to become a global public health menace affecting millions of persons throughout the tropical and sub-tropical world and, as such, has also become a frequent cause of travel-associated febrile illness. In this review, we discuss our current understanding of the biological and sociological underpinnings of its emergence and its future global outlook.

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Wolbachia strain wAu efficiently blocks arbovirus transmission in Aedes albopictus

10.1101/844670 ◽

2019 ◽

Author(s):

Maria Vittoria Mancini ◽

Christie S. Herd ◽

Thomas H. Ant ◽

Shivan M. Murdochy ◽

Steven P. Sinkins

Keyword(s):

Aedes Aegypti ◽

Aedes Albopictus ◽

Mosquito Species ◽

Field Trials ◽

Asian Tiger Mosquito ◽

Native Strain ◽

Promising Tool ◽

Novel Approach ◽

Asian Tiger ◽

Tiger Mosquito

AbstractThe global incidence of arboviral diseases transmitted by Aedes mosquitoes, including dengue, chikungunya, yellow fever, and Zika, has increased dramatically in recent decades. The release of Aedes aegypti carrying the maternally inherited symbiont Wolbachia as an intervention to control arboviruses is being trialled in several countries. However, these efforts are compromised in many endemic regions due to the co-localization of the secondary vector Aedes albopictus, the Asian tiger mosquito. Ae. albopictus has an expanding global distribution following incursions into a number of new territories. To date, only the wMel and wPip strains of Wolbachia have been reported to be transferred into and characterized in this vector. A Wolbachia strain naturally infecting Drosophila simulans, wAu, was selected for transfer into a Malaysian Ae. albopictus line to create a novel triple-strain infection. The newly generated line showed self-compatibility, moderate fitness cost and complete resistance to Zika and dengue infections.Author summaryAedes albopictus, the invasive Asian tiger mosquito, is responsible for numerous outbreaks of important viruses such as dengue and Zika in various regions of the world. The need for alterative control interventions propelled the development of a novel approach that exploits a natural insect symbiont, Wolbachia; when transferred into non-native hosts, these maternally-inherited bacteria are able to interfere with the transmission of mosquito-borne viruses, and also provide reproductive advantages to the host, offering a promising tool for self-sustaining field applications. Currently, several field trials are ongoing for the primary vector of dengue and several other arboviruses, Aedes aegypti, providing encouraging results. In this study, Ae. albopictus has been targeted for a similar approach: this mosquito species naturally carries two strains of Wolbachia. The artificial introduction of a third, non-native strain made this line less able to transmit dengue and Zika viruses and had an impact on its fitness.

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