scholarly journals Transgenic expression of Nix converts genetic females into males and allows automated sex sorting in Aedes albopictus

2021 ◽  
Author(s):  
Célia Lutrat ◽  
Roenick Proveti Olmo ◽  
Thierry Baldet ◽  
Jérémy Bouyer ◽  
Eric Marois
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Mosquito Control ◽  
Flight Performance ◽  
Genetic Sexing ◽  
Transgenic Expression ◽  
Fluorescence Marker ◽  
Transgenic Lines ◽  
Genetic Sexing Strains ◽  
Primary Gene

Aedes albopictus is a major vector of arboviruses. Better understanding of its sex determination is crucial for developing mosquito control tools, especially genetic sexing strains. In Aedes aegypti, Nix is the primary gene responsible for masculinization and Nix-expressing genetic females develop into fertile, albeit flightless, males. In Ae. albopictus, Nix has also been implicated in masculinization but its role remains to be further characterized. In this work, we established Ae. albopictus transgenic lines ectopically expressing Nix. Several were composed exclusively of genetic females, with transgenic individuals being phenotypic and functional males due to the expression of the Nix transgene. Their reproductive fitness was marginally impaired, while their flight performance was similar to controls. Overall, our results show that Nix is sufficient for full masculinization in Ae. albopictus. Moreover, the transgene construct contains a fluorescence marker allowing efficient automated sex sorting. Consequently, such strains constitute valuable sexing strains for genetic control.

Spinosyns Delivered in Sugar Meals to Aedes aegypti and Aedes albopictus (Diptera: Culicidae): Acute Toxicity and Subacute Effects on Survival, Fecundity, and Fertility

2022 ◽  
Author(s):  
Abdullah A Alomar ◽  
Barry W Alto ◽  
Edward D Walker
Keyword(s):  
Acute Toxicity ◽  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Nutritive Value ◽  
Mosquito Control ◽  
Environmental Safety ◽  
Adult Mosquito ◽  
Hatch Rate ◽  
Median Lethal Concentrations ◽  
Males And Females

Abstract Sugar is an essential source of nutrition for adult mosquitoes to acquire energy. Toxic sugar bait (TSB) provides a promising method for mosquito control by incorporating toxins into artificial sources of sugar (i.e., toxic baits) presented to wild populations. Spinosyns comprise a family of bacterial secondary metabolites with a unique mode of action against the insect nervous system, an appealing environmental safety profile, and potential for incorporation into sugar baits. This research evaluated acute and subacute effects of spinosad (spinosyns A and D) and spinetoram (spinosyns J and L) in sugar meals on survival, fecundity, and fertility of Aedes aegypti and Aedes albopictus. Acute toxicity of spinosyns doubled from 24 to 48 h of assessment, revealing a relatively slow and cumulative action of the formulated spinosyns. Median lethal concentrations at 48 h were lower for spinetoram than for spinosad, lower for Ae. albopictus than Ae. aegypti, and lower for males than females. When exposed to subacute LC50 concentrations of spinosad and spinetoram for 24 h, survival of males and females of both species was diminished compared with controls, fecundity of females was increased, but fertility as measured by hatch rate of eggs was decreased. The formulations may have increased the nutritive value of the sugar meals thereby boosting fecundity, while toxifying embryos, reducing fertility. The inclusion of subacute effects of spinosyns allows assessment of the broader consequences of TSB for adult mosquito control.

scholarly journals Irradiation induced inversions suppress recombination between the M locus and morphological markers in Aedes aegypti

BMC Genetics ◽  
2020 ◽  
Vol 21 (S2) ◽  
Author(s):  
Antonios A. Augustinos ◽  
Muhammad Misbah-ul-Haq ◽  
Danilo O. Carvalho ◽  
Lucia Duran de la Fuente ◽  
Panagiota Koskinioti ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Genetic Stability ◽  
Genetic Recombination ◽  
Substantial Reduction ◽  
Wild Type ◽  
Genetic Sexing ◽  
Red Eye ◽  
Naturally Occurring ◽  
Genetic Sexing Strains ◽  
Classical Genetics

Abstract Background Aedes aegypti is the primary vector of arthropod-borne viruses and one of the most widespread and invasive mosquito species. Due to the lack of efficient specific drugs or vaccination strategies, vector population control methods, such as the sterile insect technique, are receiving renewed interest. However, availability of a reliable genetic sexing strategy is crucial, since there is almost zero tolerance for accidentally released females. Development of genetic sexing strains through classical genetics is hindered by genetic recombination that is not suppressed in males as is the case in many Diptera. Isolation of naturally-occurring or irradiation-induced inversions can enhance the genetic stability of genetic sexing strains developed through genetically linking desirable phenotypes with the male determining region. Results For the induction and isolation of inversions through irradiation, 200 male pupae of the ‘BRA’ wild type strain were irradiated at 30 Gy and 100 isomale lines were set up by crossing with homozygous ‘red-eye’ (re) mutant females. Recombination between re and the M locus and the white (w) gene (causing a recessive white eye phenotype when mutated) and the M locus was tested in 45 and 32 lines, respectively. One inversion (Inv35) reduced recombination between both re and the M locus, and wand the M locus, consistent with the presence of a rather extended inversion between the two morphological mutations, that includes the M locus. Another inversion (Inv5) reduced recombination only between w and the M locus. In search of naturally-occurring, recombination-suppressing inversions, homozygous females from the red eye and the white eye strains were crossed with seventeen and fourteen wild type strains collected worldwide, representing either recently colonized or long-established laboratory populations. Despite evidence of varying frequencies of recombination, no combination led to the elimination or substantial reduction of recombination. Conclusion Inducing inversions through irradiation is a feasible strategy to isolate recombination suppressors either on the M or the m chromosome for Aedes aegypti. Such inversions can be incorporated in genetic sexing strains developed through classical genetics to enhance their genetic stability and support SIT or other approaches that aim to population suppression through male-delivered sterility.

scholarly journals Assessment of mosquito insecticidal activity of bacterial extracts produced by Colombian strains

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Manuela Agudelo-Restrepo ◽  
Martha Lucia Hernández‐Quesada ◽  
Edinson Yonny Sanabria-Duran ◽  
Sandra Inés Uribe-Soto ◽  
Adriana Ortiz-Reyes ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Serratia Marcescens ◽  
Aedes Albopictus ◽  
Insecticidal Activity ◽  
Mosquito Control ◽  
World Health ◽  
Identification System ◽  
Control Disease ◽  
Health Organization ◽  
Emergence Of Resistance

Aedes aegypti and Aedes albopictus are the major vectors for the transmission of more than 30 disease-causing viruses as dengue fever, dengue hemorragic fever, zika, yellow fever and chikungunya. Vector control is one of the important strategies used in order to fight these diseases in tropical and subtropical countries. However, mosquito control is facing a threat because of the emergence of resistance to synthetic insecticides. The aim of this study was to identify larvicidal and adulticidal activity of secondary metabolites in extracts produced by bacteria isolated from different sources in Colombia. A total of 105 extracts produced from the same number of bacteria were evaluated for their activity against fourth instar larvae and adults of A. aegypti and A. albopictus using standard protocols defined for the WHO (World Health Organization) and CDC (Control Disease Centre, USA). Six extracts showed relevant activity (more than 50% of mosquito larvae were killed after 48 hours), two of them showed to be actives against larvae of Aedes aegypti and four against larvae of Aedes albopictus. None of the extracts showed activity against the mosquitoes in adult stage. The bacteria producing active extracts were identified using the biolog ® identification system as Serratia marcescens ss marcescens, Escherichia hermannii, Serratia marcescens ss marcescens, Bacillus marisflavi, Bacillus atropheus/subtilis and Pseudomonas chlororaphis subsp. aurantiaca. In conclusion, bacterial extracts are a good source for the search of new strategies in the control of mosquitoes. Further studies to determine the compound responsible for the insecticidal activity are in progress.

scholarly journals Baseline Susceptibility Status of Florida Populations of Aedes aegypti (Diptera: Culicidae) and Aedes albopictus

2020 ◽  
Vol 57 (5) ◽  
pp. 1550-1559 ◽  
Author(s):  
Casey Parker ◽  
Daviela Ramirez ◽  
Carol Thomas ◽  
C Roxanne Connelly
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Mosquito Control ◽  
Pyrethroid Resistance ◽  
Mosquito Species ◽  
Mosquito Vectors ◽  
Product Selection ◽  
Lambda Cyhalothrin ◽  
Susceptibility Status ◽  
Methods Of Control

Abstract Resistance to insecticides used to control mosquito vectors threatens the ability of mosquito-control organizations to protect public health. Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) are invasive species widely distributed throughout Florida and have been implicated in recent epidemics of Zika, dengue, and chikungunya viruses. Knowledge of the susceptibility status of these mosquito species to pyrethroid and organophosphate active ingredients (AIs) is needed to inform product selection and treatment decisions. The susceptibility of 37 Ae. aegypti and 42 Ae. albopictus populations from Florida was assessed in response to six pyrethroid and three organophosphate AIs using the CDC bottle bioassay method. Of all bioassays completed with a pyrethroid AI, 95% for Ae. aegypti and 30% for Ae. albopictus resulted in a resistant outcome. For organophosphate AIs, ~31% of assays conducted for both species were classified as resistant. The highest frequency of susceptibility for both species was observed in response to the organophosphate AI, naled. Lambda-cyhalothrin was the only pyrethroid to result in a susceptible status for Ae. aegypti and also had the highest frequency of susceptibility for Ae. albopictus. Resistance was detected to every AI tested for both Ae. aegypti and Ae. albopictus, but there was a pronounced trend of pyrethroid resistance in Florida populations of Ae. aegypti. The results of this work provide evidence for the need to decrease reliance on pyrethroids and to implement different methods of control of Ae. aegypti in Florida.

scholarly journals Genetic sexing strains for the population suppression of the mosquito vector Aedes aegypti

2020 ◽  
Vol 376 (1818) ◽  
pp. 20190808 ◽  
Author(s):  
Panagiota Koskinioti ◽  
Antonios A. Augustinos ◽  
Danilo O. Carvalho ◽  
Muhammad Misbah-ul-Haq ◽  
Gulizar Pillwax ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Disease Transmission ◽  
Large Scale ◽  
Mosquito Vector ◽  
Control Analysis ◽  
Genetic Sexing ◽  
Red Eye ◽  
Eye Colour ◽  
Population Suppression ◽  
Genetic Sexing Strains

Aedes aegypti is the primary vector of arthropod-borne viruses including dengue, chikungunya and Zika. Vector population control methods are reviving to impede disease transmission. An efficient sex separation for male-only releases is crucial for area-wide mosquito population suppression strategies. Here, we report on the construction of two genetic sexing strains using red- and white-eye colour mutations as selectable markers. Quality control analysis showed that the Red-eye genetic sexing strains (GSS) is better and more genetically stable than the White-eye GSS. The introduction of an irradiation-induced inversion (Inv35) increases genetic stability and reduces the probability of female contamination of the male release batches. Bi-weekly releases of irradiated males of both the Red-eye GSS and the Red-eye GSS/Inv35 fully suppressed target laboratory cage populations within six and nine weeks, respectively. An image analysis algorithm allowing sex determination based on eye colour identification at the pupal stage was developed. The next step is to automate the Red-eye-based genetic sexing and validate it in pilot trials prior to its integration in large-scale population suppression programmes. This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases’.

Distribution of Aedes aegypti and Aedes albopictus in different eco zones of Thiruvananthapuram city with special reference to dengue viremia in humans

ENTOMON ◽  
2018 ◽  
Vol 43 (4) ◽  
pp. 223-230
Author(s):  
S. Sunil Kumar ◽  
D.A. Evans ◽  
K. Muthulakshmi ◽  
T. DilipKumar ◽  
R. Heera Pillai ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Dengue Shock Syndrome ◽  
Single Step ◽  
Equal Distribution ◽  
Distribution Study ◽  
Urban Zone ◽  
High Prevalence ◽  
Vector Management ◽  
Efficient Vector

Mosquito index study of three ecologically different ecozones of the Thiruvananthapuram district, Kerala showed sharp difference on the proportionate distribution of Aedes aegypti and Aedes albopictus. Human dengue viremia (HDV) was very high in those ecozones where A.aegypti density was high and HDV was low where A.albopictus was high. In a coastal zone of Thiruvananthapuram city, A. aegypti was the most abundant vector and in a hilly, arid suburban zone, A.albopictus was the abundant vector. In the urban zone both species of mosquitoes showed equal distribution. Study on the circulating serotypes in the serum of HDV by Single step single tube Multiplex PCR showed all the four serotypes viz DENV1, DENV2, DENV3 and DENV4 in patients of Thiruvananthapuram city, which indicated the possibility of Dengue Shock Syndrome, unless there is efficient vector management. Among the four dengue serotypes, Type 1 was the most abundant virus. Abundance of microhabitats in Thiruvananthapuram city, which support A. aegypti may be the reason for high prevalence of dengue fever in the urban zone.

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

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.

RELAÇÃO DE CAUSALIDADE ENTRE A FEBRE DA ZIKA E MICROCEFALIA NO BRASIL: REVISÃO INTEGRATIVA

2020 ◽  
Vol 42 (3) ◽  
Author(s):  
André Emanuel Dantas Mercês ◽  
Angela de Souza Cajuhi ◽  
Lorena Conceição Souza dos Santos ◽  
Rudval Souza da Silva ◽  
Cleuma Sueli Santos Suto ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Zika Virus ◽  
Electronic Library

O Zika vírus é um arbovírus transmitido pela picada dos mosquitos Aedes aegypti e Aedes albopictus infectados e apresentam como principais manifestações clínicas: febre aguda, exantema, prurido e conjuntivite. Em 2015 causou uma epidemia no Brasil, desencadeando casos de microcefalia em bebês cujas gestantes tiveram a febre da Zika. O Nordeste notificou o maior número de casos. Objetivou-se identificar, a partir de uma revisão integrativa, a relação entre a febre da Zika e a microcefalia. Trata-se de revisão integrativa, realizada a partir de buscas desenvolvidas nas bases de dados da Biblioteca Virtual em Saúde (BVS) e da Scientific Electronic Library Online (SciELO) com publicações dos anos de 2015 e 2016, idiomas português e inglês. Foram encontradas 191 publicações, as quais passaram por um processo de leitura e análise quanto ao atendimento do objetivo e aplicação dos critérios de inclusão. Restaram oito publicações que integraram o corpus desta revisão. Os resultados apontam para uma relação de causa e efeito entre o contato das gestantes com o Zika vírus e o desenvolvimento de microcefalia em seus bebês. Necessita-se de maiores evidências que demonstrem os reais fatores envolvidos nesse processo, como os genéticos, ambientais e até mesmo interferência de outras infecções. Palavras-chave: Zika vírus. Microcefalia. Aplicações da epidemiologia.

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