#Transmission #potential of African, Asian and American #Zika virus #strains by #Aedes aegypti and #Culex quinquefasciatus from #Guadeloupe (French West Indies) (Emerg Microbes Infect., abstract)

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

Emerg Microbes Infect. 2019;8(1):699-706. doi: 10.1080/22221751.2019.1615849.

Transmission potential of African, Asian and American Zika virus strains by Aedes aegypti and Culex quinquefasciatus from Guadeloupe (French West Indies).

Hery L1, Boullis A1, Delannay C1, Vega-Rúa A1.

Author information: 1a Institute Pasteur of Guadeloupe, Laboratory of Vector Control research, Unit Transmission Reservoir and Pathogens Diversity , Les Abymes , France.



Zika virus (ZIKV) is an arbovirus that has dramatically spread in South America and the Caribbean regions since 2015. The majority of vector incrimination studies available for ZIKV showed that Aedes aegypti mosquitoes are important vectors for this virus. However, several reports suggest that Culex quinquefasciatus mosquitoes may be implicated in ZIKV transmission in certain urban settings. In the present study, we evaluated the vector competence for ZIKV of Cx. quinquefasciatus and Ae. aegypti mosquitoes from Guadeloupe using African, American and Asian strains. The results demonstrated that Cx. quinquefasciatus is refractory to ZIKV infection whatever the strain tested at 7, 14 or 21 days post-infection (dpi), while ZIKV transmission was recorded in Ae. aegypti for all the three strains. The African ZIKV strain was better transmitted by Ae. aegypti (∼ 50% mean transmission efficiency) and with a shorter incubation period (7 dpi) when compared to the Asian and American strains (<14% transmission efficiency; incubation period of 14-21 dpi). Taken together, these results suggest that only Ae. aegypti mosquitoes are involved in urban ZIKV transmission in Guadeloupe and highlight a higher infectiousness of the African ZIKV strain in this mosquito species when compared to the Asian and American ones.

KEYWORDS: Guadeloupe; Zika virus; vector competence

PMID: 31109248 DOI: 10.1080/22221751.2019.1615849

Keywords: Zika Virus; Mosquitoes; Culex quinquefasciatus; Aedes aegypti; Guadeloupe.



#Pathogen blocking in #Wolbachia-infected #Aedes aegypti is not affected by #Zika and #dengue virus co-infection (PLoS Negl Trop Dis., abstract)

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


Pathogen blocking in Wolbachia-infected Aedes aegypti is not affected by Zika and dengue virus co-infection

Eric P. Caragata , Marcele N. Rocha , Thiago N. Pereira, Simone B. Mansur, Heverton L. C. Dutra, Luciano A. Moreira

Published: May 20, 2019 / DOI: https://doi.org/10.1371/journal.pntd.0007443 / This is an uncorrected proof.




Wolbachia’s ability to restrict arbovirus transmission makes it a promising tool to combat mosquito-transmitted diseases. Wolbachia-infected Aedes aegypti are currently being released in locations such as Brazil, which regularly experience concurrent outbreaks of different arboviruses. A. aegypti can become co-infected with, and transmit multiple arboviruses with one bite, which can complicate patient diagnosis and treatment.

Methodology/principle findings

Using experimental oral infection of A. aegypti and then RT-qPCR, we examined ZIKV/DENV-1 and ZIKV/DENV-3 co-infection in Wolbachia-infected A. aegypti and observed that Wolbachia-infected mosquitoes experienced lower prevalence of infection and viral load than wildtype mosquitoes, even with an extra infecting virus. Critically, ZIKV/DENV co-infection had no significant impact on Wolbachia’s ability to reduce viral transmission. Wolbachia infection also strongly altered expression levels of key immune genes Defensin C and Transferrin 1, in a virus-dependent manner.


Our results suggest that pathogen interference in Wolbachia-infected A. aegypti is not adversely affected by ZIKV/DENV co-infection, which suggests that Wolbachia-infected A. aegypti will likely prove suitable for controlling mosquito-borne diseases in environments with complex patterns of arbovirus transmission.


Author summary

Wolbachia is an endosymbiotic bacterium that infects insects. It has been artificially transferred into Aedes aegypti, a mosquito species that can transmit medically important viruses including dengue, chikungunya, and Zika. Wolbachia in A. aegypti limits infection with these viruses, making the mosquitoes much less capable of transmitting them to people. In tropical areas, where these viral pathogens are commonly found, it is not unusual for outbreaks of different viruses to occur at the same time, which can complicate diagnosis and treatment for those afflicted. Mosquitoes with Wolbachia are currently being released into these areas to reduce transmission of these diseases. In our study, we assessed whether Wolbachia infection in A. aegypti mosquitoes could still effectively inhibit the dengue and Zika viruses if the mosquitoes were fed both viruses at the same time. We found that Wolbachia was still very effective at inhibiting the replication of both viruses in the mosquito, and likewise still greatly reduced the chance of transmission of either virus. Our results suggest that Wolbachia-infected mosquitoes should be able to limit infection with more than one virus, should they encounter them in the field.


Citation: Caragata EP, Rocha MN, Pereira TN, Mansur SB, Dutra HLC, Moreira LA (2019) Pathogen blocking in Wolbachia-infected Aedes aegypti is not affected by Zika and dengue virus co-infection. PLoS Negl Trop Dis 13(5): e0007443. https://doi.org/10.1371/journal.pntd.0007443

Editor: Sujatha Sunil, International Centre for Genetic Engineering and Biotechnology, INDIA

Received: December 27, 2018; Accepted: May 7, 2019; Published: May 20, 2019

Copyright: © 2019 Caragata 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: This work was supported by FAPEMIG, CNPq, CAPES, the Brazilian Ministry of Health (DECIT/SVS), and a grant to Monash University from the Foundation for the National Institutes of Health through the Vector-Based Transmission of Control: Discovery Research (VCTR) program of the Grand Challenges in Global Health Initiatives of the Bill and Melinda Gates Foundation. 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: Zika Virus; Dengue Fever; Aedes aegypti; Wolbachia; Mosquitoes.


Evidence for #infection but not #transmission of #Zika virus by #Aedes albopictus (Diptera: Culicidae) from #Spain (Parasit Vectors., abstract)

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

Parasit Vectors. 2019 May 3;12(1):204. doi: 10.1186/s13071-019-3467-y.

Evidence for infection but not transmission of Zika virus by Aedes albopictus (Diptera: Culicidae) from Spain.

Hernández-Triana LM1, Barrero E2, Delacour-Estrella S3, Ruiz-Arrondo I4, Lucientes J3, Fernández de Marco MDM2, Thorne L2, Lumley S5, Johnson N2,6, Mansfield KL2, Fooks AR2,7.

Author information: 1 Wildlife Zoonoses and Vector-borne Diseases Research Group, Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey, KT15 3NB, UK. luis.hernandez-triana@apha.gov.uk. 2 Wildlife Zoonoses and Vector-borne Diseases Research Group, Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey, KT15 3NB, UK. 3 Department of Animal Pathology, Faculty of Veterinary Medicine, University of Zaragoza, Zaragoza, Spain. 4 Center for Rickettsiosis and Vector-Borne Diseases Group, Hospital Universitario San Pedro-CIBIR, Logroño, Spain. 5 Public Health England, Porton Down, Salisbury, SP4 0JG, UK. 6 Faculty of Health and Medicine, University of Surrey, Guildford, Surrey, GU27XH, UK. 7 Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK.




A number of mosquito-borne viruses such as dengue virus (DENV), Usutu virus (USUV), West Nile virus (WNV) are autochthonously transmitted in Europe and six invasive mosquito species have been detected in this temperate region. This has increased the risk for the emergence of further mosquito-borne diseases. However, there is a paucity of information on whether European populations of invasive mosquito species are competent to transmit arboviruses. In this study, the susceptibility of Aedes albopictus originating from Spain and a laboratory-adapted colony of Aedes aegypti, was assessed for infection with, and transmission of Zika virus (ZIKV). Vertical transmission in both species was also assessed.


Aedes albopictus colonised from eggs collected in Spain and an existing colony of Ae. aegypti were fed infectious blood meals containing ZIKV (Polynesian strain) at 1.6 × 107 PFU/ml. Blood-fed mosquitoes were separated and maintained at 20 °C or 25 °C. Legs, saliva and bodies were sampled from specimens at 7, 14 and 21 days post-infection (dpi) in order to determine infection, dissemination and transmission rates. All samples were analysed by real-time RT-PCR using primers targeting the ZIKV NS1 gene.


At 14 dpi and 21 dpi, ZIKV RNA was detected in the bodies of both species at both temperatures. However, live virus only was detected in the saliva of Ae. aegypti at 25 °C with a transmission rate of 44%. No evidence for virus expectoration was obtained for Ae. albopictus under any condition. Notably, ZIKV RNA was not detectable in the saliva of Ae. aegypti at 20 °C after 21 days. No vertical transmission of ZIKV was detected in this study.


Experimental infection of Ae. albopictus colonized from Spain with ZIKV did not result in expectoration of virus in saliva in contrast to results for Ae. aegypti. No evidence of vertical transmission of virus was observed in this study. This suggests that this strain of Ae. albopictus is not competent for ZIKV transmission under the conditions tested.

KEYWORDS: Aedes aegypti; Aedes albopictus; Spain; Vector competence; Zika virus

PMID: 31053164 DOI: 10.1186/s13071-019-3467-y

Keywords: Zika Virus; Mosquitoes; Aedes aegytpi; Aedes albopictus; Spain.


#Aedes aegypti NeSt1 #protein enhances #Zika virus #pathogenesis by activating neutrophils (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

Aedes aegypti NeSt1 protein enhances Zika virus pathogenesis by activating neutrophils

Andrew K Hastings, Ryuta Uraki, Hallie Gaitsch, Khushwant Dhaliwal, Sydney Stanley, Hannah Sproch, Eric Williamson, Tyler MacNeil, Alejandro Marin-Lopez, Jesse Hwang, Yuchen Wang,Jonathan R. Grover, Erol Fikrig

DOI: 10.1128/JVI.00395-19



Saliva from the mosquito vector of flaviviruses is capable of changing the local immune environment, leading to an increase of flavivirus-susceptible cells at the infected bite site. Additionally, an antibody response towards specific salivary gland (SG) components changes the pathogenesis of flavivirus in human populations. To investigate if antigenic SG proteins are capable of enhancing Zika virus (ZIKV) infection, a re-emerging flavivirus primarily transmitted by the Aedes aegypti mosquito, we screened for antigenic SG proteins using a yeast display library, and demonstrate a previously undescribed SG protein, we term neutrophil stimulating factor 1 (NeSt1), activates primary mouse neutrophils ex vivo. Passive immunization against NeSt1 decreases pro-IL-1β and CXCL2 expression, prevents macrophages from infiltrating into the bite site, protects susceptible IFNAR-/-IFNGR-/- (AG129) mice from early ZIKV replication, and ameliorates viral-induced pathogenesis. These findings indicate that NeSt1 stimulates neutrophils at the mosquito bite site to change the immune microenviroment, allowing higher early viral replication and enhancing ZIKV pathogenesis.



When a Zika virus infected mosquito bites a person, mosquito saliva is injected into the skin along with the virus. Molecules in this saliva can make virus infection more severe by changing the immune system to make the skin a better place for the virus to replicate. We identify a molecule in this paper that activates immune cells, called neutrophils, to recruit other immune cells, called macrophages, that the virus can infect. We name this molecule neutrophil stimulating factor 1 (NeSt1). When we use antibodies to block NeSt1 in a mouse and then allow Zika virus infected mosquitoes to feed on these mice, they survive much better than mice that do not have antibodies against NeSt1. These findings give us more information about how mosquito saliva enhances virus infection, and it is possible that a vaccine against NeSt1 might protect people against severe Zika virus infection.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Zika Virus; Aedes aegypti; Mosquitoes.


Lack of #Evidence of #Sylvatic #Transmission of #Dengue Viruses in the #Amazon #Rainforest Near Iquitos, #Peru (Vector Borne Zoo Dis., abstract)

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

Lack of Evidence of Sylvatic Transmission of Dengue Viruses in the Amazon Rainforest Near Iquitos, Peru

Michael J. Turell, Alfonso S. Gozalo, Carolina Guevara, George B. Schoeler, Faustino Carbajal, Victor M. López-Sifuentes, and Douglas M. Watts

Published Online: 9 Apr 2019 / DOI: https://doi.org/10.1089/vbz.2018.2408



Dengue viruses (DENV) are currently responsible for more human morbidity and mortality than any other known arbovirus, and all four DENV are known to exist in sylvatic cycles that might allow these viruses to persist if the urban (Aedes aegypti) cycle could be controlled. To determine whether DENV were being maintained in a sylvatic cycle in a forested area about 14 km southwest of Iquitos, Peru, a city in which all 4 serotypes of DENV circulate, we placed 20 DENV seronegative Aotus monkeys in cages either in the canopy or near ground level for a total of 125.6 months. Despite capturing >66,000 mosquitoes in traps that collected some of the mosquitoes attracted to these monkeys, blood samples obtained once a month from each animal were tested and found to be negative by an enzyme-linked immunosorbent assay for IgM and IgG antibodies to dengue, yellow fever, Venezuelan equine encephalitis, Oropouche, and Mayaro viruses. Although all four DENV serotypes were endemic in nearby Iquitos, the findings of this study did not support a DENV sylvatic maintenance and transmission cycle in a selected area of the Amazon rainforest in northeastern Peru.

Keywords: Arbovirus; Dengue fever; Monkeys; Aedes aegypti; Mosquitoes; Brazil.


#Vector #competence of #Australian #Aedes aegypti and Aedes albopictus for an #epidemic strain of #Zika virus (PLoS Negl Trop Dis., abstract)

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


Vector competence of Australian Aedes aegypti and Aedes albopictus for an epidemic strain of Zika virus

R. Leon E. Hugo , Liesel Stassen , Jessica La, Edward Gosden, O’mezie Ekwudu, Clay Winterford, Elvina Viennet, Helen M. Faddy, Gregor J. Devine, Francesca D. Frentiu

Published: April 4, 2019 / DOI: https://doi.org/10.1371/journal.pntd.0007281 / This is an uncorrected proof.




Recent epidemics of Zika virus (ZIKV) in the Pacific and the Americas have highlighted its potential as an emerging pathogen of global importance. Both Aedes (Ae.) aegypti and Ae. albopictus are known to transmit ZIKV but variable vector competence has been observed between mosquito populations from different geographical regions and different virus strains. Since Australia remains at risk of ZIKV introduction, we evaluated the vector competence of local Ae. aegypti and Ae. albopictus for a Brazilian epidemic ZIKV strain. In addition, we evaluated the impact of daily temperature fluctuations around a mean of 28°C on ZIKV transmission and extrinsic incubation period.

Methodology/Principal findings

Mosquitoes were orally challenged with a Brazilian ZIKV strain (8.8 log CCID50/ml) and maintained at either 28°C constant or fluctuating temperature conditions. At 3, 7 and 14 days post-infection (dpi), ZIKV RNA copies were quantified in mosquito bodies, as well as wings and legs, using qRT-PCR, while virus antigen in saliva (a proxy for transmission) was detected using a cell culture ELISA. Despite high body and disseminated infection rates in both vectors, the transmission rates of ZIKV in saliva of Ae. aegypti (50–60%) were significantly higher than in Ae. albopictus (10%) at 14 dpi. Both species supported a high viral load in bodies, with no significant differences between constant and fluctuating temperature conditions. However, a significant difference in viral load in wings and legs between species was observed, with higher titres in Ae. aegypti maintained at constant temperature conditions. For ZIKV transmission to occur in Ae. aegypti, a disseminated virus load threshold of 7.59 log10 copies had to be reached.


Australian Ae. aegypti are better able to transmit a Brazilian ZIKV strain than Ae. albopictus. The results are in agreement with the global consensus that Ae. aegypti is the major vector of ZIKV.


Author summary

Zika virus (ZIKV) is a mosquito-borne pathogen that generally causes a mild febrile illness but mostly remains asymptomatic in 50–80% of infections. Infection during pregnancy can cause congenital malformations, notably microcephaly. In adults, it can cause Guillain-Barré syndrome. The recent ZIKV epidemic in the Americas has been linked to the urban vector Aedes aegypti. The presence of the species in Australia makes the region vulnerable to emerging mosquito-borne viruses. A mosquito’s competence to transmit a pathogen will depend on both the virus and vector strains. Here, we determine the vector competence of Australian Ae. aegypti and Ae. albopictus mosquitoes for a ZIKV epidemic strain, originating from the epicentre of the Brazilian outbreak, under constant and fluctuating temperatures that simulate field environments in Australia. Our results demonstrate that, although both species were susceptible to ZIKV infection, Ae. aegypti is more likely to transmit virus. Our results may aid in the formulation of public health strategies to mitigate the threat of ZIKV.


Citation: Hugo RLE, Stassen L, La J, Gosden E, Ekwudu O, Winterford C, et al. (2019) Vector competence of Australian Aedes aegypti and Aedes albopictus for an epidemic strain of Zika virus. PLoS Negl Trop Dis 13(4): e0007281. https://doi.org/10.1371/journal.pntd.0007281

Editor: Lyric C. Bartholomay, University of Wisconsin Madison, UNITED STATES

Received: October 22, 2018; Accepted: March 5, 2019; Published: April 4, 2019

Copyright: © 2019 Hugo 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: Funding was provided by the Australia National Health and Medical Research Council (NHMRC) grant number APP1125317 to FDF and GJD, an Australian Infectious Diseases seed grant “Zika virus vector biology, diagnostics and vaccines” (Pls Young, Hall and Devine), and a donation from John and Elizabeth Hunter. Australian governments fund the Australian Red Cross Blood Service to provide blood, blood products and services to the Australian community. 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: Zika Virus; Mosquitoes; Aedes aegypti; Aedes albopictus; Australia.


Local #Transmission of #Zika Virus in #Miami-Dade County: The #Florida Department of Health Rises to the Challenge (J Public Health Manag Pract., abstract)

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

J Public Health Manag Pract. 2019 May/Jun;25(3):277-287. doi: 10.1097/PHH.0000000000000990.

Local Transmission of Zika Virus in Miami-Dade County: The Florida Department of Health Rises to the Challenge.

Philip C1, Novick CG, Novick LF.

Author information: 1 Stamford, Connecticut (Ms Novick); Department of Public Health, East Carolina School of Medicine, Greenville, North Carolina (Dr Novick). Dr Philip is Former Surgeon General, State of Florida, Tallahassee, Florida.



As early as 2015, Florida and Centers for Disease Control and Prevention (CDC) public health officials recognized the potential danger of Zika for US residents and visitors. The Zika virus, a mosquito-borne flavivirus, is transmitted through the bite of the Aedes aegypti mosquito. A physician in Miami-Dade notified the Florida Department of Health (DOH) of the first non-travel-related Zika case in the United States. A 23-year old pregnant woman had presented on July 7, 2016, at 23 weeks of gestation, with a 3-day history of fever, widespread pruritic rash, and sore throat. Three more cases, involving men, were reported in Dade and Broward counties. These notifications set into motion additional activities from the DOH’s Zika Playbook: increased mosquito surveillance; collaboration with the CDC on recommendations for mosquito abatement techniques; and increased awareness of the risks of Zika. In August, the department reported that active transmission of Zika virus was occurring in one small area in Miami-Dade County known as Wynwood. Mosquito trapping in the area with local transmission identified large numbers of the Zika vector, Aedes aegypti females and a large number of mosquito larval sites. Control efforts included larviciding, eliminating standing water, and backpack and truck spraying of insecticides. A communication strategy was developed that addressed risk mitigation, public concerns over application of noxious pesticides, loss of tourist revenue, and reproductive issues. It was reported on December 28, 2016, that there had been 256 locally acquired cases of infection of Zika, 1011 travel-related cases, and 208 pregnant women with laboratory evidence of Zika. At the end of 2018, 2 years after active Zika virus transmission was controlled in Florida, there have been 101 reported cases of Zika during 2018 but none have been linked to local transmission.

PMID: 30933006 DOI: 10.1097/PHH.0000000000000990

Keywords: Zika Virus; Aedes aegypti; Moquitoes; Florida; USA.