#Virus #evolution in #Wolbachia-infected Drosophila (Proc Roy Soc B., abstract)

[Source: Proceedings of the Royal Society, Biological Sciences, full page: (LINK). Abstract, edited.]

Virus evolution in Wolbachia-infected Drosophila

Julien Martinez†, Gaspar Bruner-Montero, Ramesh Arunkumar, Sophia C. L. Smith, Jonathan P. Day, Ben Longdon and Francis M. Jiggins

Published: 30 October 2019 / DOI: https://doi.org/10.1098/rspb.2019.2117



Wolbachia, a common vertically transmitted symbiont, can protect insects against viral infection and prevent mosquitoes from transmitting viral pathogens. For this reason, Wolbachia-infected mosquitoes are being released to prevent the transmission of dengue and other arboviruses. An important question for the long-term success of these programmes is whether viruses can evolve to escape the antiviral effects of Wolbachia. We have found that Wolbachia altered the outcome of competition between strains of the DCV virus in Drosophila. However, Wolbachia still effectively blocked the virus genotypes that were favoured in the presence of the symbiont. We conclude that Wolbachia did cause an evolutionary response in viruses, but this has little or no impact on the effectiveness of virus blocking.



† Present address: MRC-University of Glasgow Centre for Virus Research, University of Glasgow, Glasgow G61 1QH, UK.

Electronic supplementary material is available online at https://doi.org/10.6084/m9.figshare.c.4698191

Keywords: Arbovirus; Wolbachia spp.


#Wolbachia pipientis occurs in #Aedes aegypti populations in #NM and #Florida, #USA (Ecol Evol., abstract)

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

Ecol Evol. 2019 Apr 26;9(10):6148-6156. doi: 10.1002/ece3.5198. eCollection 2019 May.

Wolbachia pipientis occurs in Aedes aegypti populations in New Mexico and Florida, USA.

Kulkarni A1, Yu W1, Jiang J1, Sanchez C1, Karna AK1, Martinez KJL1, Hanley KA1, Buenemann M2, Hansen IA1, Xue RD3, Ettestad P4, Melman S4, Duguma D5, Debboun M5, Xu J1.

Author information: 1 Biology Department New Mexico State University Las Cruces New Mexico. 2 Department of Geography New Mexico State University Las Cruces New Mexico. 3 Anastasia Mosquito Control District St. Augustine Florida. 4 New Mexico Department of Health Santa Fe New Mexico. 5 Harris County Public Health Mosquito and Vector Control Division Houston Texas.



The mosquitoes Aedes aegypti (L.) and Ae. albopictus Skuse are the major vectors of dengue, Zika, yellow fever, and chikungunya viruses worldwide. Wolbachia, an endosymbiotic bacterium present in many insects, is being utilized in novel vector control strategies to manipulate mosquito life history and vector competence to curb virus transmission. Earlier studies have found that Wolbachia is commonly detected in Ae. albopictus but rarely detected in Ae. aegypti. In this study, we used a two-step PCR assay to detect Wolbachia in wild-collected samples of Ae. aegypti. The PCR products were sequenced to validate amplicons and identify Wolbachia strains. A loop-mediated isothermal amplification (LAMP) assay was developed and used for detecting Wolbachia in selected mosquito specimens as well. We found Wolbachiain 85/148 (57.4%) wild Ae. aegypti specimens from various cities in New Mexico, and in 2/46 (4.3%) from St. Augustine, Florida. Wolbachiawas not detected in 94 samples of Ae. aegypti from Deer Park, Harris County, Texas. Wolbachia detected in Ae. aegypti from both New Mexico and Florida was the wAlbB strain of Wolbachia pipientis. A Wolbachia-positive colony of Ae. aegypti was established from pupae collected in Las Cruces, New Mexico, in 2018. The infected females of this strain transmitted Wolbachia to their progeny when crossed with males of Rockefeller strain of Ae. aegypti, which does not carry Wolbachia. In contrast, none of the progeny of Las Cruces males mated to Rockefeller females were infected with Wolbachia.

KEYWORDS: Aedes aegypti; Aedes albopictus; Florida; New Mexico; Texas; Wolbachia; wAlbB

PMID: 31161026 PMCID: PMC6540660 DOI: 10.1002/ece3.5198

Keywords: Arbovirus; Mosquitoes; Aedes aegypti; Aedes albopictus; New Mexico; Florida; USA.


#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.


#Wolbachia significantly impacts the #vector competence of #Aedes aegypti for #Mayaro virus (Sci Rep., abstract)

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

Sci Rep. 2018 May 2;8(1):6889. doi: 10.1038/s41598-018-25236-8.

Wolbachia significantly impacts the vector competence of Aedes aegypti for Mayaro virus.

Pereira TN1, Rocha MN1, Sucupira PHF1, Carvalho FD1, Moreira LA2.

Author information: 1 Centro de Pesquisas René Rachou- Fiocruz, Endossimbiontes e Interação Patógeno-Vetor, Belo Horizonte, Minas Gerais, 30190-002, Brazil. 2 Centro de Pesquisas René Rachou- Fiocruz, Endossimbiontes e Interação Patógeno-Vetor, Belo Horizonte, Minas Gerais, 30190-002, Brazil. luciano@minas.fiocruz.br.



Wolbachia, an intracellular endosymbiont present in up to 70% of all insect species, has been suggested as a sustainable strategy for the control of arboviruses such as Dengue, Zika and Chikungunya. As Mayaro virus outbreaks have also been reported in Latin American countries, the objective of this study was to evaluate the vector competence of Brazilian field-collected Ae. aegypti and the impact of Wolbachia (wMel strain) upon this virus. Our in vitro studies with Aag2 cells showed that Mayaro virus can rapidly multiply, whereas in wMel-infected Aag2 cells, viral growth was significantly impaired. In addition, C6/36 cells seem to have alterations when infected by Mayaro virus. In vivo experiments showed that field-collected Ae. aegypti mosquitoes are highly permissive to Mayaro virus infection, and high viral prevalence was observed in the saliva. On the other hand, Wolbachia-harboring mosquitoes showed significantly impaired capability to transmit Mayaro virus. Our results suggest that the use of Wolbachia-harboring mosquitoes may represent an effective mechanism for the reduction of Mayaro virus transmission throughout Latin America.

PMID: 29720714 DOI: 10.1038/s41598-018-25236-8

Keywords: Mayaro Virus; Mosquitoes; Aedes Aegypti; Wolbachia.


#Field- and clinically derived estimates of #Wolbachia-mediated blocking of #dengue virus #transmission potential in #Aedes aegypti #mosquitoes (Proc Natl Acad Sci USA, abstract)

[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]

Field- and clinically derived estimates of Wolbachia-mediated blocking of dengue virus transmission potential in Aedes aegypti mosquitoes

Lauren B. Carrington a,b,1, Bich Chau Nguyen Tran a, Nhat Thanh Hoang Le a, Tai Thi Hue Luong c, Truong Thanh Nguyen c, Phong Thanh Nguyen c, Chau Van Vinh Nguyen c, Huong Thi Cam Nguyen c, Trung Tuan Vu a,  Long Thi Vo a, Dui Thi Le a, Nhu Tuyet Vu a, Giang Thi Nguyen a, Hung Quoc Luu d, Anh Duc Dang d, Timothy P. Hurst e, Scott L. O’Neill e, Vi Thuy Tran a, Duong Thi Hue Kien a, Nguyet Minh Nguyen a, Marcel Wolbers a, Bridget Wills a, and Cameron P. Simmons a,b,e

Author Affiliations: a Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, District 5, Ho Chi Minh City, Vietnam; b Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Melbourne, VIC 3010, Australia; c Hospital for Tropical Diseases, District 5, Ho Chi Minh City, Vietnam; d National Institute of Hygiene and Epidemiology, Hai Ba Trung District, Hanoi, Vietnam; e Institute for Vector Borne Disease, Monash University, Clayton, Melbourne, VIC 3168, Australia

Edited by Anthony A. James, University of California, Irvine, CA, and approved November 29, 2017 (received for review September 11, 2017)



In laboratory experiments, Wolbachia (wMel strain)-infected Aedes aegypti are refractory to disseminated arboviral infections. Yet previous characterizations of wMel-mediated blocking have not considered several biologically and ecologically important factors likely to influence the virus–mosquito interaction. After direct feeding on 141 viremic dengue patients, we demonstrate wMel lowers dengue virus (DENV) transmission potential and lengthens the extrinsic incubation period. Subsequently, using established field populations of wild-type and wMel-infected Ae. aegypti, we compared field- versus laboratory-rearing conditions on mosquito susceptibility to disseminated DENV infection. The magnitude of wMel-mediated virus blocking was even greater when mosquitoes developed under field conditions. These clinically and ecologically relevant findings support Wolbachia introgression into Ae. aegypti populations as a biocontrol method to reduce the transmission of DENV and other arboviruses.



The wMel strain of Wolbachia can reduce the permissiveness of Aedes aegypti mosquitoes to disseminated arboviral infections. Here, we report that wMel-infected Ae. aegypti (Ho Chi Minh City background), when directly blood-fed on 141 viremic dengue patients, have lower dengue virus (DENV) transmission potential and have a longer extrinsic incubation period than their wild-type counterparts. The wMel-infected mosquitoes that are field-reared have even greater relative resistance to DENV infection when fed on patient-derived viremic blood meals. This is explained by an increased susceptibility of field-reared wild-type mosquitoes to infection than laboratory-reared counterparts. Collectively, these field- and clinically relevant findings support the continued careful field-testing of wMel introgression for the biocontrol of Ae. aegypti-born arboviruses.

wMel Wolbachia –  dengue virus –  Aedes aegypti mosquito –  extrinsic incubation period –  virus transmission



1 To whom correspondence should be addressed. Email: lbcarrington@gmail.com.

Author contributions: L.B.C., B.C.N.T., T.T.H.L., T.T.N., P.T.N., C.V.V.N., A.D.D., S.L.O., M.W., B.W., and C.P.S. designed research; B.C.N.T., T.T.H.L., T.T.N., P.T.N., H.T.C.N., and N.M.N. coordinated patient enrollment and sample collection; L.B.C., B.C.N.T., H.T.C.N., T.T.V., L.T.V., D.T.L., N.T.V., G.T.N., H.Q.L., T.P.H., V.T.T., D.T.H.K., and N.M.N. performed research; C.P.S. contributed new reagents/analytic tools; L.B.C., N.T.H.L., and M.W. analyzed data; and L.B.C. and C.P.S. wrote the paper.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1715788115/-/DCSupplemental.

This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0

Keywords: Dengue Fever; Mosquitoes; Aedes Aegypti; Wolbachia.


Novel #Wolbachia-transinfected #Aedes aegypti #mosquitoes possess diverse fitness and #vector competence phenotypes (PLoS Pathog., abstract)

[Source: PLoS Pathogens, full page: (LINK). Abstract, edited.]

Open Access / Peer-reviewed / Research Article

Novel Wolbachia-transinfected Aedes aegypti mosquitoes possess diverse fitness and vector competence phenotypes

Johanna E. Fraser , Jyotika Taneja De Bruyne , Iñaki Iturbe-Ormaetxe,  Justin Stepnell, Rhiannon L. Burns, Heather A. Flores, Scott L. O’Neill

Published: December 7, 2017 / DOI:  https://doi.org/10.1371/journal.ppat.1006751 /  This is an uncorrected proof.



Wolbachia pipientis from Drosophila melanogaster (wMel) is an endosymbiotic bacterium that restricts transmission of human pathogenic flaviviruses and alphaviruses, including dengue, Zika, and chikungunya viruses, when introduced into the mosquito vector Aedes aegypti. To date, wMel-infected Ae. aegypti have been released in field trials in 5 countries to evaluate the effectiveness of this strategy for disease control. Despite the success in establishing wMel-infected mosquitoes in wild populations, and the well-characterized antiviral capabilities of wMel, transinfecting different or additional Wolbachia strains into Ae. aegypti may improve disease impact, and perhaps more importantly, could provide a strategy to account for the possible evolution of resistant arboviruses. Here, we report the successful transinfection of Ae. aegypti with the Wolbachia strains wMelCS (D. melanogaster), wRi (D. simulans) and wPip (Culex quinquefasciatus) and assess the effects on Ae. aegypti fitness, cytoplasmic incompatibility, tissue tropism and pathogen blocking in a laboratory setting. The results demonstrate that wMelCS provides a similar degree of protection against dengue virus as wMel following an infectious blood meal, and significantly reduces viral RNA levels beyond that of wMel following a direct challenge with infectious virus in mosquitoes, with no additional fitness cost to the host. The protection provided by wRi is markedly weaker than that of wMelCS, consistent with previous characterisations of these lines in Drosophila, while wPip was found to substantially reduce the fitness of Ae. aegypti. Thus, we determine wMelCS as a key candidate for further testing in field-relevant fitness tests and viremic blood feeding challenges in a clinical setting to determine if it may represent an alternative Wolbachia strain with more desirable attributes than wMel for future field testing.


Author summary

Dengue viruses are transmitted by the Aedes aegypti mosquito, with an estimated 390 million human infections occurring per year worldwide. There is no approved antiviral therapeutic, and vaccines described so far have had limited efficacy. Recently, the endosymbiotic bacterium Wolbachia from Drosophila melanogaster (wMel) has been used to infect Ae. aegypti populations as a novel technology for reducing dengue virus transmission. Here we report the generation of three new mosquito lines infected with the Wolbachia strains wMelCS, wRi and wPip. Each line induced cytoplasmic incompatibility and was effectively maternally transmitted, as required for rapid spread through uninfected mosquito populations. Each Wolbachia strain was also found to reside in the salivary glands; a key tissue involved in viral transmission. Perhaps most importantly, wMelCS inhibited dengue virus replication and dissemination in mosquitoes following an infectious blood meal or intrathoracic injection, providing a similar level of protection as that described for wMel. wMelCS therefore warrants further investigation as a potential release strain in future field trials.


Citation: Fraser JE, De Bruyne JT, Iturbe-Ormaetxe I, Stepnell J, Burns RL, Flores HA, et al. (2017) Novel Wolbachia-transinfected Aedes aegypti mosquitoes possess diverse fitness and vector competence phenotypes. PLoS Pathog 13(12): e1006751. https://doi.org/10.1371/journal.ppat.1006751

Editor: Adler Dillman, University of California Riverside, UNITED STATES

Received: July 6, 2017; Accepted: November 13, 2017; Published: December 7, 2017

Copyright: © 2017 Fraser 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 raw data has been uploaded as a Supplemental Data Set.

Funding: This work was funded in part by a grant from the Foundation for the National Institutes of Health through the Grand Challenges in Global Health initiative of the Bill & Melinda Gates Foundation and by a Wellcome Trust Award No.102591. 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: Arbovirus; Aedes Aegypti; Wolbachia.


#Wolbachia effects on #RVF virus #infection in #Culex tarsalis #mosquitoes (PLoS Negl Trop Dis., abstract)

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


Wolbachia effects on Rift Valley fever virus infection in Culex tarsalis mosquitoes

Brittany L. Dodson , Elizabeth S. Andrews , Michael J. Turell, Jason L. Rasgon

Published: October 30, 2017 / DOI: https://doi.org/10.1371/journal.pntd.0006050 / This is an uncorrected proof.



Innovative tools are needed to alleviate the burden of mosquito-borne diseases, and strategies that target the pathogen are being considered. A possible tactic is the use of Wolbachia, a maternally inherited, endosymbiotic bacterium that can (but does not always) suppress diverse pathogens when introduced to naive mosquito species. We investigated effects of somatic Wolbachia (strain wAlbB) infection on Rift Valley fever virus (RVFV) in Culex tarsalismosquitoes. When compared to Wolbachia-uninfected mosquitoes, there was no significant effect of Wolbachia infection on RVFV infection, dissemination, or transmission frequencies, nor on viral body or saliva titers. Within Wolbachia-infected mosquitoes, there was a modest negative correlation between RVFV body titers and Wolbachia density, suggesting that Wolbachia may slightly suppress RVFV in a density-dependent manner in this mosquito species. These results are contrary to previous work in the same mosquito species, showing Wolbachia-induced enhancement of West Nile virus infection rates. Taken together, these results highlight the importance of exploring the breadth of pathogen modulations induced by Wolbachia.


Author summary

An integrated vector management program utilizes several practices, including pesticide application and source reduction, to reduce mosquito populations. However, mosquitoes are developing resistance to some of these methods and new control approaches are needed. A novel technique involves the bacterium Wolbachia that lives naturally in many insects. Wolbachia can be transferred to uninfected mosquitoes and can block pathogen transmission to humans, although in some circumstances pathogen enhancement has been observed. Additionally, Wolbachia is maternally inherited, allowing it to spread quickly through uninfected field populations of mosquitoes. We studied the impacts of Wolbachia on Rift Valley fever virus (RVFV) in the naturally uninfected mosquito, Culex tarsalis. Wolbachia had no effect on the frequencies at which Culex tarsalis became infected with or transmitted RVFV. However, when we analyzed the relationship between Wolbachia densities and RVFV titers, we determined that high densities of Wolbachia were associated with no virus infection or low levels of virus, suggesting that Wolbachia might suppress RVFV at high densities. These results contrast with our previous study that showed Wolbachia enhances West Nile virus infection in Culex tarsalis. Together, these studies highlight the importance of studying Wolbachia effects on a variety of pathogens so that control methods that use Wolbachia are not impeded by unintended or off-target effects.


Citation: Dodson BL, Andrews ES, Turell MJ, Rasgon JL (2017) Wolbachia effects on Rift Valley fever virus infection in Culex tarsalis mosquitoes. PLoS Negl Trop Dis11(10): e0006050. https://doi.org/10.1371/journal.pntd.0006050

Editor: Rhoel Ramos Dinglasan, University of Florida, UNITED STATES

Received: May 19, 2017; Accepted: October 18, 2017; Published: October 30, 2017

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 are within the paper and its Supporting Information files.

Funding: This study was funded by NIH grants R01AI116636 and R21AI128918 to JLR. 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: Mosquitoes; Culex spp.; RVF.