#Phylogeography and #invasion #history of #Aedes aegypti, the #Dengue and #Zika #mosquito vector in Cape Verde islands (West Africa) (Evol Appl., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Evol Appl. 2019 Aug 3;12(9):1797-1811. doi: 10.1111/eva.12834. eCollection 2019 Oct.

Phylogeography and invasion history of Aedes aegypti, the Dengue and Zika mosquito vector in Cape Verde islands (West Africa).

Salgueiro P1, Serrano C1, Gomes B1,2, Alves J3, Sousa CA1, Abecasis A1, Pinto J1.

Author information: 1 Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT) Universidade Nova de Lisboa (UNL) Lisboa Portugal. 2 Oswaldo Cruz Institute (IOC) Fundação Oswaldo Cruz (FIOCRUZ) Rio de Janeiro Brasil. 3 Direção Geral de Saúde/Instituto Nacional de Saúde Pública, Ministério da Saúde de Cabo Verde Praia Cabo Verde.

 

Abstract

Aedes-borne arboviruses have spread globally with outbreaks of vast impact on human populations and health systems. The West African archipelago of Cape Verde had its first outbreak of Dengue in 2009, at the time the largest recorded in Africa, and was one of the few African countries affected by the Zika virus epidemic. Aedes aegypti was the mosquito vector involved in both outbreaks. We performed a phylogeographic and population genetics study of A. aegypti in Cape Verde in order to infer the geographic origin and evolutionary history of this mosquito. These results are discussed with respect to the implications for vector control and prevention of future outbreaks. Mosquitoes captured before and after the Dengue outbreak on the islands of Santiago, Brava, and Fogo were analyzed with two mitochondrial genes COI and ND4, 14 microsatellite loci and five kdr mutations. Genetic variability was comparable to other African populations. Our results suggest that A. aegypti invaded Cape Verde at the beginning of the Holocene from West Africa. Given the historic importance of Cape Verde in the transatlantic trade of the 16th-17th centuries, a possible contribution to the genetic pool of the founding populations in the New World cannot be fully discarded. However, contemporary gene flow with the Americas is likely to be infrequent. No kdr mutations associated with pyrethroid resistance were detected. The implications for vector control and prevention of future outbreaks are discussed.

KEYWORDS: Aedes aegypti; Africa; Cape Verde; Dengue; Zika; phylogeography; population genetics; vector control

PMID: 31548858 PMCID: PMC6752157 DOI: 10.1111/eva.12834

Keywords: Mosquitoes; Aedes aegypti; Zika virus; Dengue fever; Cape Verde.

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#Vector #Competence: What Has #Zika Virus Taught Us? (Viruses, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Viruses. 2019 Sep 17;11(9). pii: E867. doi: 10.3390/v11090867.

Vector Competence: What Has Zika Virus Taught Us?

Azar SR1,2,3, Weaver SC4,5,6.

Author information: 1 Department of Microbiology and Immunology, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. srazar@utmb.edu. 2 Institute for Translational Sciences, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. srazar@utmb.edu. 3 Institute for Human Infections and Immunity, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. srazar@utmb.edu. 4 Department of Microbiology and Immunology, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. sweaver@utmb.edu. 5 Institute for Translational Sciences, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. sweaver@utmb.edu. 6 Institute for Human Infections and Immunity, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. sweaver@utmb.edu.

 

Abstract

The unprecedented outbreak of Zika virus (ZIKV) infection in the Americas from 2015 to 2017 prompted the publication of a large body of vector competence data in a relatively short period of time. Although differences in vector competence as a result of disparities in mosquito populations and viral strains are to be expected, the limited competence of many populations of the urban mosquito vector, Aedes aegypti, from the Americas (when its susceptibility is viewed relative to other circulating/reemerging mosquito-borne viruses such as dengue (DENV), yellow fever (YFV), and chikungunya viruses (CHIKV)) has proven a paradox for the field. This has been further complicated by the lack of standardization in the methodologies utilized in laboratory vector competence experiments, precluding meta-analyses of this large data set. As the calls for the standardization of such studies continue to grow in number, it is critical to examine the elements of vector competence experimental design. Herein, we review the various techniques and considerations intrinsic to vector competence studies, with respect to contemporary findings for ZIKV, as well as historical findings for other arboviruses, and discuss potential avenues of standardization going forward.

KEYWORDS: Aedes aegypti; Flaviviruses; Zika virus; arbovirus; mosquitoes; vector competence

PMID: 31533267 DOI: 10.3390/v11090867

Keywords: Mosquitoes; Aedes aegypti; Flavivirus; Zika Virus.

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#Transgenic #Aedes aegypti #Mosquitoes Transfer #Genes into a Natural #Population (Sci Rep., abstract)

[Source: Scientific Reports, full page: (LINK). Abstract, edited.]

Transgenic Aedes aegypti Mosquitoes Transfer Genes into a Natural Population

Benjamin R. Evans, Panayiota Kotsakiozi, Andre Luis Costa-da-Silva, Rafaella Sayuri Ioshino, Luiza Garziera, Michele C. Pedrosa, Aldo Malavasi, Jair F. Virginio, Margareth L. Capurro & Jeffrey R. Powell

Scientific Reports, volume 9, Article number: 13047 (2019)

 

Abstract

In an attempt to control the mosquito-borne diseases yellow fever, dengue, chikungunya, and Zika fevers, a strain of transgenically modified Aedes aegypti mosquitoes containing a dominant lethal gene has been developed by a commercial company, Oxitec Ltd. If lethality is complete, releasing this strain should only reduce population size and not affect the genetics of the target populations. Approximately 450 thousand males of this strain were released each week for 27 months in Jacobina, Bahia, Brazil. We genotyped the release strain and the target Jacobina population before releases began for >21,000 single nucleotide polymorphisms (SNPs). Genetic sampling from the target population six, 12, and 27–30 months after releases commenced provides clear evidence that portions of the transgenic strain genome have been incorporated into the target population. Evidently, rare viable hybrid offspring between the release strain and the Jacobina population are sufficiently robust to be able to reproduce in nature. The release strain was developed using a strain originally from Cuba, then outcrossed to a Mexican population. Thus, Jacobina Ae. aegypti are now a mix of three populations. It is unclear how this may affect disease transmission or affect other efforts to control these dangerous vectors. These results highlight the importance of having in place a genetic monitoring program during such releases to detect un-anticipated outcomes.

Keywords: Genetics; Aedes aegypti; Brazil; GMOs.

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First report on the #transmission of #Zika virus by #Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae) during the 2018 Zika #outbreak in #India (Acta Trop., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Acta Trop. 2019 Aug 20:105114. doi: 10.1016/j.actatropica.2019.105114. [Epub ahead of print]

First report on the transmission of Zika virus by Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae) during the 2018 Zika outbreak in India.

Singh H1, Singh OP2, Akhtar N3, Sharma G4, Sindhania A5, Gupta N6, Valecha N7.

Author information: 1 National Institute of Malaria Research, Sector 8 Dwarka, New Delhi 110077, India. Electronic address: hspawar@rediffmail.com. 2 National Institute of Malaria Research, Sector 8 Dwarka, New Delhi 110077, India. Electronic address: singh@nimr.org.in. 3 National Institute of Malaria Research, Sector 8 Dwarka, New Delhi 110077, India. Electronic address: nasreen84akhtar@gmail.com. 4 National Institute of Malaria Research, Sector 8 Dwarka, New Delhi 110077, India. Electronic address: gunjan.sharma@gmail.com. 5 National Institute of Malaria Research, Sector 8 Dwarka, New Delhi 110077, India. Electronic address: ankita@mrcindia.org. 6 Indian Council of Medical Research, Ansari Nagar, New Delhi, 110029, India. Electronic address: ngupta@icmr.org.in. 7 National Institute of Malaria Research, Sector 8 Dwarka, New Delhi 110077, India. Electronic address: neenavalecha@gmail.com.

 

Abstract

In a recent outbreak of Zika virus (ZIKV) infection in Jaipur city (Rajasthan, India), a total of 159 cases were reported in September 2018. In order to identify vector responsible for Zika transmission, mosquitoes were collected from houses with reported Zika cases and nearby houses. A total of 108 pools containing 522 mosquitoes were tested for presence of ZIKV virus using RT-PCR and Real Time RT-PCR. We detected presence of ZIKV in three pools of Aedes (Stegomyia) aegypti (L.), out of a total of 79 pools with 383 Ae. aegypti through RT-PCR as well as real-time RT-PCR. The presence of ZIKV in Ae. aegypti was further confirmed by DNA sequencing of the partial envelope region of ZIKV. Homology search of DNA sequence revealed highest identity (100%) with a ZIKV isolate from human from the study area which support the role of Ae. aegypti acting as a ZIKV vector. All other mosquitoes (Aedes vittatus and Culex quinquefasciatus) were negative for ZIKV. None of the F1 generation mosquito pools (276 mosquitoes in 43 pools) were found positive. This is the first report of presence of ZIKV in Ae. aegypti from the Indian subcontinent.

Copyright © 2019. Published by Elsevier B.V.

KEYWORDS: Entomological surveillance; Outbreak; RT-PCR; Transmission risk

PMID: 31442386 DOI: 10.1016/j.actatropica.2019.105114

Keywords: Zika Virus; Aedes aegypti; India; Mosquitoes.

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No #evidence of #Zika, #dengue, or #chikungunya virus #infection in field-caught #mosquitoes from the Recife Metropolitan Region, #Brazil, 2015 (Wellcome Open Res., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Wellcome Open Res. 2019 Jun 10;4:93. doi: 10.12688/wellcomeopenres.15295.1. eCollection 2019.

No evidence of Zika, dengue, or chikungunya virus infection in field-caught mosquitoes from the Recife Metropolitan Region, Brazil, 2015.

Ramesh A#1,2, Jeffries CL#3, Castanha P4,5, Oliveira PAS1, Alexander N2, Cameron M3, Braga C1, Walker T3.

Author information: 1 Department of Parasitology, Instituto Aggeu Magalhães(IAM/FIOCRUZ Pernambuco), Recife, Brazil. 2 Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK. 3 Department of Disease Control, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK. 4 Department of Virology, Instituto Aggeu Magalhães(IAM/FIOCRUZ Pernambuco), Recife, Brazil. 5 Universidade Estadual de Pernambuco (UPE), Recife, Brazil. #Contributed equally

 

Abstract

Background:

The Recife Metropolitan Region (RMR), north-eastern Brazil, was the epicentre of the 2015 Zika virus (ZIKV) epidemic, which was followed by a 2016 chikungunya virus (CHIKV) epidemic. It historically has amongst the highest incidence of dengue virus (DENV) infections and is the only remaining focus of lymphatic filariasis (LF) in Brazil. In early 2015, a molecular xenomonitoring surveillance project focused on Culex (Cx.) quinquefasciatus commenced to inform LF elimination activities. Aedes (Ae.) aegypti mosquitoes were also collected, concurrent with the first microcephaly cases detected in the RMR. In terms of the 2015 ZIKV epidemic, these are the earliest known field-collected mosquitoes, preserved for potential RNA virus detection, when ZIKV was known to be circulating locally.

Methods:

Adult mosquitoes were collected in two sites (0.4 km 2) of Sítio Novo, Olinda, RMR, from July 22 to August 21, 2015. Mosquitoes were morphologically identified, sorted by physiological status, and pooled (up to 10 mosquitoes per house per day or week). RNA was extracted, reverse transcribed and the cDNA tested by real-time PCR.

Results:

A total of 10,139 adult female Cx. quinquefasciatus and 939 adult female Ae. aegypti were captured. All female Ae. aegypti specimens were included within 156 pools and screened for ZIKV, DENV and CHIKV. In addition, a sub-set of 1,556 Cx. quinquefasciatus adult females in 182 pools were screened for ZIKV. No evidence of infection with any of the three arboviruses was found.

Conclusions:

The absence of arbovirus detection may have been expected given the extremely restricted geographic area and collection of mosquitoes during a very short time period of peak mosquito abundance (July-September), but low arbovirus circulation (November-March).  However, this study demonstrates the potential to retrospectively screen for additional unexpected pathogens in situations of rapid emergence, such as occurred during the outbreak of ZIKV in the RMR.

KEYWORDS: Aedes aegypti; Culex quinquefasciatus; Zika virus; arboviruses; chikungunya virus; dengue virus; disease surveillance; molecular xenomonitoring; neglected tropical diseases; urban areas

PMID: 31363498 PMCID: PMC6644828 DOI: 10.12688/wellcomeopenres.15295.1

Keywords: Arbovirus; Zika virus; Chikungunya fever; Dengue fever; Mosquitoes; Culex quinquefasciatus; Aedes aegypti; Brazil.

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#Autocidal gravid #ovitraps protect humans from #chikungunya virus infection by reducing #Aedes aegypti #mosquito populations (PLoS Negl Trop Dis., abstract)

[Source: PLoS Neglected Tropical Diseases, full page: (LINK). Abstract, edited.]

OPEN ACCESS /  PEER-REVIEWED / RESEARCH ARTICLE

Autocidal gravid ovitraps protect humans from chikungunya virus infection by reducing Aedes aegypti mosquito populations

Tyler M. Sharp , Olga Lorenzi, Brenda Torres-Velásquez, Veronica Acevedo, Janice Pérez-Padilla, Aidsa Rivera, Jorge Muñoz-Jordán, Harold S. Margolis, Stephen H. Waterman, Brad J. Biggerstaff, Gabriela Paz-Bailey, Roberto Barrera

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Published: July 25, 2019 / DOI: https://doi.org/10.1371/journal.pntd.0007538

 

Abstract

Background

Public health responses to outbreaks of dengue, chikungunya, and Zika virus have been stymied by the inability to control the primary vector, Aedes aegypti mosquitos. Consequently, the need for novel approaches to Aedes vector control is urgent. Placement of three autocidal gravid ovitraps (AGO traps) in ~85% of homes in a community was previously shown to sustainably reduce the density of female Ae. aegypti by >80%. Following the introduction of chikungunya virus (CHIKV) to Puerto Rico, we conducted a seroprevalence survey to estimate the prevalence of CHIKV infection in communities with and without AGO traps and evaluate their effect on reducing CHIKV transmission.

Methods and findings

Multivariate models that calculated adjusted prevalence ratios (aPR) showed that among 175 and 152 residents of communities with and without AGO traps, respectively, an estimated 26.1% and 43.8% had been infected with CHIKV (aPR = 0.50, 95% CI: 0.37–0.91). After stratification by time spent in their community, protection from CHIKV infection was strongest among residents who reported spending many or all weekly daytime hours in their community:10.3% seropositive in communities with AGO traps vs. 48.7% in communities without (PR = 0.21, 95% CI: 0.11–0.41). The age-adjusted rate of fever with arthralgia attributable to CHIKV infection was 58% (95% CI: 46–66%). The monthly number of CHIKV-infected mosquitos and symptomatic residents were diminished in communities with AGO traps compared to those without.

Conclusions

These findings indicate that AGO traps are an effective tool that protects humans from infection with a virus transmitted by Ae. aegypti mosquitos. Future studies should evaluate their protective effectiveness in large, urban communities.

 

Author summary

Aedes species mosquitos transmit pathogens of public health importance, including dengue, Zika, and chikungunya viruses. No tools exist to control these mosquitos that sustainably and effectively prevent human infections. Autocidal gravid ovitraps (AGO traps) have been shown to sustainably reduce Aedes populations by >80%. After chikungunya virus was introduced into Puerto Rico, we conducted serosurveys in communities with and without AGO traps. We observed a two-fold lower prevalence of chikungunya virus infection among residents of communities with AGO traps compared to communities without. Among infected residents of communities with traps, a significant proportion likely had been infected while outside their community. These findings indicate that AGO traps are an effective tool that protects humans from infection with pathogens transmitted by Aedes mosquitos.

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Citation: Sharp TM, Lorenzi O, Torres-Velásquez B, Acevedo V, Pérez-Padilla J, Rivera A, et al. (2019) Autocidal gravid ovitraps protect humans from chikungunya virus infection by reducing Aedes aegypti mosquito populations. PLoS Negl Trop Dis 13(7): e0007538. https://doi.org/10.1371/journal.pntd.0007538

Editor: Paulo Pimenta, Fundaçao Oswaldo Cruz, BRAZIL

Received: March 15, 2019; Accepted: June 10, 2019; Published: July 25, 2019

This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

Data Availability: All relevant data will be submitted within Supporting Information files.

Funding: The authors received no specific funding for this work.

Competing interests: The authors have declared that no competing interests exist. Autocidal gravid ovitraps (AGO traps) used in this study were developed and constructed by CDC personnel (RB). Rights for the AGO trap patent (US 9.237,741 B2) were transferred to the US Government (Executive Order 10096). Eventual royalties derived from trap sales by licensed companies follow 15 U.S.C. 3710c.

Keywords: Arbovirus; Chikungunya fever; Aedes aegypti; Mosquitoes; Ovitraps.

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#Vertical #Transmission of #Zika Virus (Flaviviridae, #Flavivirus) in #Amazonian #Aedes aegypti (Diptera: Culicidae) Delays Egg Hatching and Larval Development of Progeny (J Med Entomol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

J Med Entomol. 2019 Jul 6. pii: tjz110. doi: 10.1093/jme/tjz110. [Epub ahead of print]

Vertical Transmission of Zika Virus (Flaviviridae, Flavivirus) in Amazonian Aedes aegypti (Diptera: Culicidae) Delays Egg Hatching and Larval Development of Progeny.

Chaves BA1,2, Junior ABV1, Silveira KRD3, Paz ADC1, Vaz EBDC1, Araujo RGP3, Rodrigues NB3, Campolina TB3, Orfano ADS3, Nacif-Pimenta R3, Villegas LEM3, Melo FF4, Silva BM5, Monteiro WM1,2, Guerra MDGVB1,2, Lacerda MVG1,6, Norris DE7, Secundino NFC3, Pimenta PFP1,3.

Author information: 1 Tropical Medicine Foundation Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil. 2 Amazonas State University, Minas Gerais, Belo Horizonte, Brazil. 3 Laboratory of Medical Entomology, Rene Rachou Research Institute – FIOCRUZ, Minas Gerais, Belo Horizonte, Brazil. 4 Multidisciplinary Health Institute, Federal University of Bahia, Bahia, Brazil. 5 Department of Biological Sciences, Federal University of Ouro Preto, Minas Gerais, Ouro Preto, Brazil. 6 Leonidas and Maria Deane Research institute – FIOCRUZ, Amazonas, Brazil. 7 The Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD.

 

Abstract

Zika virus (ZIKV) has emerged as a globally important arbovirus and has been reported from all states of Brazil. The virus is primarily transmitted to humans through the bite of an infective Aedes aegypti (Linnaeus, 1762) or Aedes albopictus (Skuse, 1895). However, it is important to know if ZIKV transmission also occurs from Ae. aegypti through infected eggs to her offspring. Therefore, a ZIKV and dengue virus (DENV) free colony was established from eggs collected in Manaus and maintained until the third-fourth generation in order to conduct ZIKV vertical transmission (VT) experiments which used an infectious bloodmeal as the route of virus exposure. The eggs from ZIKV-infected females were allowed to hatch. The resulting F1 progeny (larvae, pupae, and adults) were quantitative polymerase chain reaction (qPCR) assayed for ZIKV. The viability of ZIKV vertically transmitted to F1 progeny was evaluated by cultivation in C6/36 cells. The effects of ZIKV on immature development of Ae. aegypti was assessed and compared with noninfected mosquitoes. AmazonianAe. aegypti were highly susceptible to ZIKV infection (96.7%), and viable virus passed to their progeny via VT. Moreover, eggs from the ZIKV-infected mosquitoes had a significantly lower hatch rate and the slowest hatching. In addition, the larval development period was slower when compared to noninfected, control mosquitoes. This is the first study to illustrate VT initiated by oral infection of the parental population by using mosquitoes, which originated from the field and a ZIKV strain that is naturally circulating in-country. Additionally, this study suggests that ZIKV present in the Ae. aegypti can modify the mosquito life cycle. The data reported here suggest that VT of ZIKV to progeny from naturally infected females may have a critical epidemiological role in the dissemination and maintenance of the virus circulating in the vector.

© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America.

KEYWORDS: Aedes aegypti ; Zika virus; fitness cost; vertical transmission

PMID: 31278737 DOI: 10.1093/jme/tjz110

Keywords: Flavivirus; Zika Virus; Aedes aegypti.

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