#Vector #Competence and #Vertical #Transmission of #Zika Virus in #Aedes albopictus (Diptera: Culicidae) (Vector Borne Zoo Dis., abstract)

[Source: Vector Borne and Zoonotic Diseases, full page: (LINK). Abstract, edited.]

Vector Competence and Vertical Transmission of Zika Virus in Aedes albopictus (Diptera: Culicidae)

Xiaoxia Guo, Chunxiao Li, Yongqiang Deng, Yuting Jiang, Aijuan Sun, Qinmei Liu, Yande Dong, Dan Xing, Wuchun Cao, Chengfeng Qin, and Tongyan Zhao

Published Online: 14 Jan 2020 / DOI: https://doi.org/10.1089/vbz.2019.2492

 

Abstract

Zika virus (ZIKV) is an emerging mosquito-borne pathogen belonging to the genus Flavivirus of the family Flaviviridae. Aedes albopictus is widely distributed in China. However, little is known about the vector competence of Ae. albopictus in China. The present study presents the oral susceptibility and vector competence of Ae. albopictus Guangzhou strain to ZIKV. Additionally, vertical transmission of ZIKV is described. The results demonstrated the susceptibility of local Ae. albopictus mosquitoes to ZIKV with an extrinsic incubation period of 6 days. Disseminated infection was observed in Ae. albopictus starting on day 2 postinfection (PI). Starting on day 6 PI, the saliva of Ae. albopictus exhibited ZIKV infection, and the transmission rate was 36.4%. Vertical transmission was observed during the first gonotrophic cycle. The minimum infection rate was observed in third-to-fourth instar larvae.

Keywords: Zika Virus; Mosquitoes; Aedes albopictus; China.

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#Sequencing of #ZIKV #genomes directly from Ae. aegypti and Cx. quinquefasciatus #mosquitoes collected during the 2015-16 #epidemics in #Recife (Infect Genet Evol., abstract)

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

Infect Genet Evol. 2020 Jan 6:104180. doi: 10.1016/j.meegid.2020.104180. [Epub ahead of print]

Sequencing of ZIKV genomes directly from Ae. aegypti and Cx. quinquefasciatus mosquitoes collected during the 2015-16 epidemics in Recife.

Paiva MHS1, Guedes DRD2, Krokovsky L2, Machado LC2, Rezende TMT2, de Morais Sobral MC2, Ayres CFJ2, Wallau GL3.

Author information: 1 Universidade Federal de Pernambuco, Caruaru, Brazil. 2 Entomology Department of the Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil. 3 Entomology Department of the Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil. Electronic address: gabriel.wallau@cpqam.fiocruz.br.

 

Abstract

Zika virus (ZIKV) is a negative sense RNA virus from the Flaviviridae family, which was relatively unknown until the first human epidemic in Micronesia, in 2007. Since its spread to French Polynesia and the Americas. Recife, the capital of Pernambuco state and epicenter of the Zika epidemic in Brazil, experienced a large number of microcephaly cases and other congenital abnormalities associated to the ZIKV infection from, 2015 to 16. Evidences suggest that both Aedes aegypti and Culex quinquefasciatus mosquitoes from Recife are capable of replicating and transmitting the virus. Here, we conducted high throughput sequencing of ZIKV genomes directly from Ae. aegypti and Cx. quinquefasciatus mosquitoes collected during the ZIKV epidemics in Recife, in order to investigate the variability and evolution of the virus. We obtained 11 draft ZIKV genomes derived from 5 pools from each Ae. aegypti and Cx. quinquefasciatus species. Genome coverage breadth ranged from 16 to 100% and average depth from 45 to 46,584×. Two of these genomes were obtained from pools of unfed Cx. quinquefasciatus females. Amino acid substitutions found here were not species-specific, which could indicate species specific virus adaptation. In addition, molecular clock dating estimated that ZIKV draft genomes obtained here were co-circulating in the region during the epidemics. Overall results highlight that viral mutations and even minor variants can be detected in genomes directly sequenced from mosquito samples and insights about natural viral genomic variability and viral evolution can be useful when designing tools for mosquito control programs.

Copyright © 2019. Published by Elsevier B.V.

KEYWORDS: Aedes aegypti; Arboviruses; Culex quinquefasciatus; Surveillance; ZIKV

PMID: 31918041 DOI: 10.1016/j.meegid.2020.104180

Keywords: Zika Virus; Aedes aegypti; Culex quinquefascitus; Mosquitoes; Brazil.

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#Surveillance for #Zika in #Mexico: naturally infected #mosquitoes in #urban and semi-urban areas (Pathog Glob Health, abstract)

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

Pathog Glob Health. 2020 Jan 5:1-6. doi: 10.1080/20477724.2019.1706291. [Epub ahead of print]

Surveillance for Zika in Mexico: naturally infected mosquitoes in urban and semi-urban areas.

Correa-Morales F1, González-Acosta C2, Mejía-Zúñiga D3, Huerta H4, Pérez-Rentería C4, Vazquez-Pichardo M4, Ortega-Morales AI5, Hernández-Triana LM6, Salazar-Bueyes VM1, Moreno-García M7.

Author information: 1 Subdirección del Programa de Enfermedades Transmitidas por Vectores, Centro Nacional de Programas Preventivos y Control de Enfermedades, Ciudad de México, México. 2 Coordinación de Enfermedades Transmitidas por Vector y Zoonosis, Servicios de Salud de Morelos, Cuernavaca, México. 3 Unidad de Investigación Entomológica y Bioensayos-Servicios de Salud de Chihuahua, Chihuahua, México. 4 Laboratorio de Entomología, Instituto de Diagnóstico y Referencia Epidemiológicos ‘Dr. Manuel Martínez Báez’, Ciudad de México, México. 5 Departamento de Parasitología, Universidad Autónoma Agraria Antonio Narro Unidad Laguna, Torreón, México. 6 Animal and Plant Health Agency, Virology Department, Wildlife Zoonoses and Vector-Borne Diseases Research Group, Addlestone, UK. 7 Unidad de Investigación Entomológica y Bioensayos-Centro Regional de Control de Vectores Panchimalco-Servicios de Salud de Morelos, Jojutla, México.

 

Abstract

Zika cases have been reported in 29 out of the 32 states of Mexico. Information regarding which mosquito species might be driving Zika virus transmission/maintenance in nature must be regularly updated. From January 2017 to November 2018, mosquitoes were collected indoors and outdoors using the CDC backpack aspirator in urban and semi-urban areas with evidence of mosquito-borne disease transmission. 3873 mosquito pools were tested for Zika infection using the CDC Trioplex real-time RT-PCR. For each collected specie, maximum likelihood estimator of infection rate (MLE) was estimated. Results showed 492 mosquito pools positive for Zika virus RNA. The majority of the positive pools were Aedes (Stegomyia) aegypti (Linnaeus) (54.6%, MLE = 19) (males and females) and Culex (Culex) quinquefasciatus (Say) (19.5%, MLE = 16.8). For the first time, ZIKV infection was detected in Ae. (Georgecraigius) epactius (Dyar and Knab) (MLE = 17.1), Cx. (Melanoconion) erraticus (Dyar and Knab) (MLE = non-estimable), Culiseta (Culiseta) inornata (Williston) (MLE = non estimable), and Cs (Cs.) particeps (Adams) (MLE = 369.5). Other detected species were: Ae. (Stg.) albopictus (Skuse) (MLE = 90.5), Cx. (Cx.) coronator s.l. (Dyar and Knab) (MLE = 102.8) and Cx. (Cx.) tarsalis (Coquillett) (MLE = 117.2). However, our results do not allow for the incrimination of these species as vectors of ZIKV. Routine surveillance should start to consider other mosquito species across the taxonomic spectrum of the Culicidae.

KEYWORDS: Arbovirus; Culicidae; mosquito-borne diseases; vector control

PMID: 31902313 DOI: 10.1080/20477724.2019.1706291

Keywords: Zika Virus; Mosquitoes; Aedes spp.; Mexico.

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A quantitative #comparison of #WNV #incidence from 2013 to 2018 in Emilia-Romagna, #Italy (PLOS Negl Trop Dis., abstract)

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

OPEN ACCESS /  PEER-REVIEWED / RESEARCH ARTICLE

A quantitative comparison of West Nile virus incidence from 2013 to 2018 in Emilia-Romagna, Italy

Giovanni Marini , Mattia Calzolari, Paola Angelini, Romeo Bellini, Silvia Bellini, Luca Bolzoni, Deborah Torri, Francesco Defilippo, Ilaria Dorigatti, Birgit Nikolay, Andrea Pugliese, Roberto Rosà, Marco Tamba

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Published: January 2, 2020 / DOI: https://doi.org/10.1371/journal.pntd.0007953

 

Abstract

Background

West Nile virus (WNV) transmission was much greater in 2018 than in previous seasons in Europe. Focusing on Emilia-Romagna region (northern Italy), we analyzed detailed entomological and epidemiological data collected in 2013–2018 to quantitatively assess environmental drivers of transmission and explore hypotheses to better understand why the 2018 epidemiological season was substantially different than the previous seasons. In particular, in 2018 WNV was detected at least two weeks before the observed circulation in 2013–2017 and in a larger number of mosquito pools. Transmission resulted in 100 neuroinvasive human cases in the region, more than the total number of cases recorded between 2013 and 2017.

Methodology

We used temperature-driven mathematical models calibrated through a Bayesian approach to simulate mosquito population dynamics and WNV infection rates in the avian population. We then estimated the human transmission risk as the probability, for a person living in the study area, of being bitten by an infectious mosquito in a given week. Finally, we translated such risk into reported WNV human infections.

Principal findings

The estimated prevalence of WNV in the mosquito and avian populations were significantly higher in 2018 with respect to 2013–2017 seasons, especially in the eastern part of the region. Furthermore, peak avian prevalence was estimated to have occurred earlier, corresponding to a steeper decline towards the end of summer. The high mosquito prevalence resulted in a much greater predicted risk for human transmission in 2018, which was estimated to be up to eight times higher than previous seasons. We hypothesized, on the basis of our modelling results, that such greater WNV circulation might be partially explained by exceptionally high spring temperatures, which have likely helped to amplify WNV transmission at the beginning of the 2018 season.

 

Author summary

West Nile virus (WNV) is one of the most recent emerging mosquito-borne diseases in Europe and North America. While most human infections are asymptomatic, about 1% of them can result in severe neurological diseases which might be fatal. WNV transmission was unusually greater in 2018 than in previous years in many European countries, resulting in a large number of human infections. Focusing on Emilia-Romagna region (Italy), we developed an epidemiological model informed by entomological data; through that we found that exceptionally high spring temperatures might have contributed at amplifying WNV transmission at the beginning of the season, causing greater WNV prevalence in mosquito and avian populations during the summer, which resulted in a higher estimated risk for human transmission. Thus, weather anomalies at the beginning of the mosquito breeding season, which are likely to become more common under the projected scenarios of climate change, might act as an early warning signal for public health authorities, enabling them to design efficient surveillance and prevention strategies.

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Citation: Marini G, Calzolari M, Angelini P, Bellini R, Bellini S, Bolzoni L, et al. (2020) A quantitative comparison of West Nile virus incidence from 2013 to 2018 in Emilia-Romagna, Italy. PLoS Negl Trop Dis 14(1): e0007953. https://doi.org/10.1371/journal.pntd.0007953

Editor: Waleed Saleh Al-Salem, Saudi Ministry of Health, SAUDI ARABIA

Received: July 10, 2019; Accepted: November 20, 2019; Published: January 2, 2020

Copyright: © 2020 Marini et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the manuscript and its Supporting Information files.

Funding: Data used in this study was collected in the frame of “Regional Surveillance of Arboviral Diseases” financed by the Emilia-Romagna Region. I.D. acknowledges research funding from the Imperial College Junior Research Fellowship and joint Centre funding from the UK Medical Research Council and Department for International Development. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Keywords: WNV; Wild Birds; Mosquitoes; Global Warming; Italy.

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#Risk of #dengue in Central #Africa: #Vector competence studies with #Aedes aegypti and Aedes albopictus (Diptera: Culicidae) populations and dengue 2 virus (PLOS Negl Trop Dis., abstract)

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

OPEN ACCESS /  PEER-REVIEWED / RESEARCH ARTICLE

Risk of dengue in Central Africa: Vector competence studies with Aedes aegypti and Aedes albopictus (Diptera: Culicidae) populations and dengue 2 virus

Basile Kamgang , Marie Vazeille, Armel N. Tedjou, Theodel A. Wilson-Bahun, Aurélie P. Yougang, Laurence Mousson, Charles S. Wondji , Anna-Bella Failloux

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Published: December 30, 2019 / DOI: https://doi.org/10.1371/journal.pntd.0007985 / This is an uncorrected proof.

 

Abstract

Introduction

Dengue is the most important mosquito-borne diseases worldwide but was considered scarce in West-Central Africa. During the last decade, dengue outbreaks have increasingly been reported in urban foci in this region suggesting major epidemiological changes. However, in Central Africa where both vectors, Aedes aegypti and Aedes albopictus are well established, the role of each species in dengue transmission remains poorly investigated.

Methodology/Principal findings

Field-collected strains of Ae. aegypti and Ae. albopictus from different ecological settings in Central Africa were experimentally challenged with dengue 2 virus (DENV-2). Mosquitoes were analysed at 14- and 21-days post-infection. Analysis provide evidence that both Ae. aegypti and Ae. albopictus in Central Africa were able to transmit dengue virus with Ae. aegypti exhibiting a higher transmission rate. Unexpectedly, two Ae. aegypti populations from Bénoué and Maroua, in northern Cameroon, were not able to transmit DENV-2.

Conclusions/Significance

We conclude that both Ae. aegypti and Ae. albopictus are susceptible to DENV-2 and may intervene as active dengue vectors. These findings highlight the urgent need to plan a vector surveillance program and control methods against dengue vectors in Central Africa in order to prevent future outbreaks.

 

Author summary

Dengue virus (DENV) is a flavivirus mainly transmitted to humans through the bite of infected mosquitoes notably Aedes aegypti and Aedes albopictus. In Central Africa where both vectors, Ae. aegypti and Ae. albopictus are well established, the role of each species in dengue transmission remains poorly investigated. Here, we assessed the vector competence of Ae. aegypti and Ae. albopictus collected in different ecological settings in Central Africa to transmit dengue 2 virus (DENV-2). We provide evidence that both Ae. aegypti and Ae. albopictus in Central Africa were able to transmit dengue virus with Ae. aegypti exhibiting a higher transmission rate. These findings could increase the risk of dengue outbreak in the region and emphasize the need for a comprehensive vector surveillance program to prevent and preparedness for an intervention in case of outbreaks.

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Citation: Kamgang B, Vazeille M, Tedjou AN, Wilson-Bahun TA, Yougang AP, Mousson L, et al. (2019) Risk of dengue in Central Africa: Vector competence studies with Aedes aegypti and Aedes albopictus (Diptera: Culicidae) populations and dengue 2 virus. PLoS Negl Trop Dis 13(12): e0007985. https://doi.org/10.1371/journal.pntd.0007985

Editor: Duane J. Gubler, Duke-NUS GMS, SINGAPORE

Received: September 9, 2019; Accepted: December 10, 2019; Published: December 30, 2019

Copyright: © 2019 Kamgang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the manuscript.

Funding: BK was funded by the Wellcome Trust, 204862/Z/16/Z (https://wellcome.ac.uk). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Keywords: Flavivirus; Dengue fever; Africa region; Mosquitoes; Aedes aegypti; Aedes albopictus.

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#Patterns, #Drivers, and #Challenges of #Vector-Borne #Disease Emergence (Vector Borne Zoo Dis., abstract)

[Source: Vector Borne and Zoonotic Diseases, full page: (LINK). Abstract, edited.]

Patterns, Drivers, and Challenges of Vector-Borne Disease Emergence

Andrea Swei, Lisa I. Couper, Lark L. Coffey, Durrell Kapan, and Shannon Bennett

Published Online: 3 Dec 2019 / DOI: https://doi.org/10.1089/vbz.2018.2432

 

Abstract

Vector-borne diseases are emerging at an increasing rate and comprise a disproportionate share of all emerging infectious diseases. Yet, the key ecological and evolutionary dimensions of vector-borne disease that facilitate their emergence have not been thoroughly explored. This study reviews and synthesizes the existing literature to explore global patterns of emerging vector-borne zoonotic diseases (VBZDs) under changing global conditions. We find that the vast majority of emerging VBZDs are transmitted by ticks (Ixodidae) and mosquitoes (Culicidae) and the pathogens transmitted are dominated by Rickettsiaceae bacteria and RNA viruses (Flaviviridae, Bunyaviridae, and Togaviridae). The most common potential driver of these emerging zoonoses is land use change, but for many diseases, the driver is unknown, revealing a critical research gap. While most reported VBZDs are emerging in the northern latitudes, after correcting for sampling bias, Africa is clearly a region with the greatest share of emerging VBZD. We highlight critical gaps in our understanding of VBZD emergence and emphasize the importance of interdisciplinary research and consideration of deeper evolutionary processes to improve our capacity for anticipating where and how such diseases have and will continue to emerge.

Keywords: Infectious Diseases; Mosquitoes; Emerging Diseases.

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Infected #Mosquitoes Have Altered #Behavior to #Repellents: A Systematic Review and Meta-analysis (J Med Entomol., abstract)

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

J Med Entomol. 2019 Nov 22. pii: tjz209. doi: 10.1093/jme/tjz209. [Epub ahead of print]

Infected Mosquitoes Have Altered Behavior to Repellents: A Systematic Review and Meta-analysis.

Lajeunesse MJ1, Avello DA1, Behrmann MS1, Buschbacher TJ1, Carey K1, Carroll J1, Chafin TJ1, Elkott F1, Faust AM1, Fauver H1, Figueroa GD1, Flaig LL1, Gauta SA1, Gonzalez C1, Graham RM1, Hamdan K1, Hanlon T1, Hashami SN1, Huynh D1, Knaffl JL1, Lanzas M1, Libell NM1, McCabe C1, Metzger J1, Mitchell I1, Morales MA1, Nayyar YR1, Perkins A1, Phan TA1, Pidgeon NT1, Ritter CL1, Rosales VC1, Santiago O1, Stephens R1, Taylor EJ1, Thomas AJ1, Yanez NE1.

Author information: 1 Department of Integrative Biology, University of South Florida, Tampa, FL.

 

Abstract

Here we conducted a systematic review and meta-analysis to reach a consensus on whether infected and uninfected mosquitoes respond differently to repellents. After screening 2,316 published studies, theses, and conference abstracts, we identified 18 studies that tested whether infection status modulated the effectiveness of repellents. Thirteen of these studies had outcomes available for meta-analysis, and overall, seven repellents were tested (typically DEET with 62% of outcomes), six mosquito species had repellence behaviors measured (typically Aedes aegypti (L.) (Diptera: Culicidae) mosquitoes with 71% of outcomes), and a broad diversity of infections were tested including Sindbis virus (Togaviridae: Alphavirus) (33% of outcomes), Dengue (Flaviviridae: Flavivirus) (31%), malaria (Plasmodium berghei Vincke & Lips (Haemospororida: Plasmodiidae) or P. falciparum Welch (Haemospororida: Plasmodiidae); 25%), Zika (Flaviviridae: Flavivirus) (7%), and microsporidia (4%). Pooling all outcomes with meta-analysis, we found that repellents were less effective against infected mosquitoes-marking an average 62% reduction in protective efficacy relative to uninfected mosquitoes (pooled odds ratio = 0.38, 95% confidence interval = 0.22-0.66; k = 96). Older infected mosquitoes were also more likely to show altered responses and loss of sensitivity to repellents, emphasizing the challenge of distinguishing between age or incubation period effects. Plasmodium- or Dengue-infected mosquitoes also did not show altered responses to repellents; however, Dengue-mosquito systems used inoculation practices that can introduce variability in repellency responses. Given our findings that repellents offer less protection against infected mosquitoes and that these vectors are the most dangerous in terms of disease transmission, then trials on repellent effectiveness should incorporate infected mosquitoes to improve predictability in blocking vector-human contact.

© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

KEYWORDS: feeding behavior; malaria; mosquito repellent and attractant; mosquito-borne disease

PMID: 31755530 DOI: 10.1093/jme/tjz209

Keywords: Arbovirus; Mosquitoes; Mosquitoe repellents.

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