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Gallichotte EN, Fitzmeyer EA, Williams L, Spangler MC, Bosco-Lauth AM, Ebel GD. WNV and SLEV coinfection in avian and mosquito hosts: impact on viremia, antibody responses, and vector competence. J Virol 2024; 98:e0104124. [PMID: 39324792 PMCID: PMC11495067 DOI: 10.1128/jvi.01041-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2024] [Accepted: 09/08/2024] [Indexed: 09/27/2024] Open
Abstract
West Nile virus (WNV) and St. Louis encephalitis virus (SLEV) are closely related flaviviruses that can cause encephalitis in humans and related diseases in animals. In nature, both are transmitted by Culex, with wild birds, including jays, sparrows, and robins, serving as vertebrate hosts. WNV and SLEV circulate in the same environments and have recently caused concurrent disease outbreaks in humans. The extent that coinfection of mosquitoes or birds may alter transmission dynamics, however, is not well characterized. We therefore sought to determine if coinfection alters infection kinetics and virus levels in birds and infection rates in mosquitoes. Accordingly, American robins (Turdus migratorius), two species of mosquitoes, and vertebrate and invertebrate cells were infected with WNV and/or SLEV to assess how simultaneous exposure may alter infection outcomes. There was variable impact of coinfection in vertebrate cells, with some evidence that SLEV can suppress WNV replication. However, robins had comparable viremia and antibody responses regardless of coinfection. Conversely, in Culex cells and mosquitoes, we saw a minimal impact of simultaneous exposure to both viruses on replication, with comparable infection, dissemination, and transmission rates in singly infected and coinfected mosquitoes. Importantly, while WNV and SLEV levels in coinfected mosquito midguts were positively correlated, we saw no correlation between them in salivary glands and saliva. These results reveal that while coinfection can occur in both avian and mosquito hosts, the viruses minimally impact one another. The potential for coinfection to alter virus population structure or the likelihood of rare genotypes emerging remains unknown.IMPORTANCEWest Nile virus (WNV) and St. Louis encephalitis virus (SLEV) are closely related viruses that are transmitted by the same mosquitoes and infect the same birds in nature. Both viruses circulate in the same regions and have caused concurrent outbreaks in humans. It is possible that mosquitoes, birds, and/or humans could be infected with both WNV and SLEV simultaneously, as has been observed with Zika, chikungunya, and dengue viruses. To study the impact of coinfection, we experimentally infected vertebrate and invertebrate cells, American robins, and two Culex species with WNV and/or SLEV. Robins were efficiently coinfected, with no impact of coinfection on virus levels or immune response. Similarly, in mosquitoes, coinfection did not impact infection rates, and mosquitoes could transmit both WNV and SLEV together. These results reveal that WNV and SLEV coinfection in birds and mosquitoes can occur in nature, which may impact public health and human disease risk.
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Affiliation(s)
- Emily N. Gallichotte
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Emily A. Fitzmeyer
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Landon Williams
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Mark Cole Spangler
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Angela M. Bosco-Lauth
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Gregory D. Ebel
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
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Kuchinsky SC, Duggal NK. Usutu virus, an emerging arbovirus with One Health importance. Adv Virus Res 2024; 120:39-75. [PMID: 39455168 DOI: 10.1016/bs.aivir.2024.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2024]
Abstract
Usutu virus (USUV, Flaviviridae) is an emerging arbovirus that has led to epizootic outbreaks in birds and numerous human neuroinvasive disease cases in Europe. It is maintained in an enzootic cycle with Culex mosquitoes and passerine birds, a transmission cycle that is shared by West Nile virus (WNV) and St. Louis encephalitis virus (SLEV), two flaviviruses that are endemic in the United States. USUV and WNV co-circulate in Africa and Europe, and SLEV and WNV co-circulate in North America. These three viruses are prime examples of One Health issues, in which the interactions between humans, animals, and the environments they reside in can have important health impacts. The three facets of One Health are interwoven throughout this article as we discuss the mechanisms of flavivirus transmission and emergence. We explore the possibility of USUV emergence in the United States by analyzing the shared characteristics among USUV, WNV, and SLEV, including the role that flavivirus co-infections and sequential exposures may play in viral emergence. Finally, we provide insights on the importance of integrated surveillance programs as One Health tools that can be used to mitigate USUV emergence and spread.
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Affiliation(s)
- Sarah C Kuchinsky
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Nisha K Duggal
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States.
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Peng J, Zhang M, Wang G, Zhang D, Zheng X, Li Y. Biased virus transmission following sequential coinfection of Aedes aegypti with dengue and Zika viruses. PLoS Negl Trop Dis 2024; 18:e0012053. [PMID: 38557981 PMCID: PMC10984552 DOI: 10.1371/journal.pntd.0012053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 03/07/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Mosquito-borne arboviruses are expanding their territory and elevating their infection prevalence due to the rapid climate change, urbanization, and increased international travel and global trade. Various significant arboviruses, including the dengue virus, Zika virus, Chikungunya virus, and yellow fever virus, are all reliant on the same primary vector, Aedes aegypti. Consequently, the occurrence of arbovirus coinfection in mosquitoes is anticipated. Arbovirus coinfection in mosquitoes has two patterns: simultaneous and sequential. Numerous studies have demonstrated that simultaneous coinfection of arboviruses in mosquitoes is unlikely to exert mutual developmental influence on these viruses. However, the viruses' interplay within a mosquito after the sequential coinfection seems intricated and not well understood. METHODOLOGY/PRINCIPAL FINDINGS We conducted experiments aimed at examining the phenomenon of arbovirus sequential coinfection in both mosquito cell line (C6/36) and A. aegypti, specifically focusing on dengue virus (DENV, serotype 2) and Zika virus (ZIKV). We firstly observed that DENV and ZIKV can sequentially infect mosquito C6/36 cell line, but the replication level of the subsequently infected ZIKV was significantly suppressed. Similarly, A. aegypti mosquitoes can be sequentially coinfected by these two arboviruses, regardless of the order of virus exposure. However, the replication, dissemination, and the transmission potential of the secondary virus were significantly inhibited. We preliminarily explored the underlying mechanisms, revealing that arbovirus-infected mosquitoes exhibited activated innate immunity, disrupted lipid metabolism, and enhanced RNAi pathway, leading to reduced susceptibility to the secondary arbovirus infections. CONCLUSIONS/SIGNIFICANCE Our findings suggest that, in contrast to simultaneous arbovirus coinfection in mosquitoes that can promote the transmission and co-circulation of these viruses, sequential coinfection appears to have limited influence on arbovirus transmission dynamics. However, it is important to note that more experimental investigations are needed to refine and expand upon this conclusion.
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Affiliation(s)
- Jiameng Peng
- Department of Pathogen Biology, School of Medicine, Jinan University, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
| | - Meichun Zhang
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
| | - Gang Wang
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
| | - Dongjing Zhang
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
| | - Xiaoying Zheng
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
| | - Yongjun Li
- Department of Pathogen Biology, School of Medicine, Jinan University, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
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Reis LAM, Pampolha ABO, Dias DD, Santos MM, Pantoja JADS, Araújo PADS, da Silva FS, do Nascimento BLS, Carvalho VL, da Silva EVP, Nunes Neto JP. Ilheus Virus (ILHV) Resistance in Culex quinquefasciatus from the Northern Region of Brazil. Life (Basel) 2024; 14:427. [PMID: 38672699 PMCID: PMC11051376 DOI: 10.3390/life14040427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/04/2023] [Accepted: 12/26/2023] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Orthoflavivirus ilheusense (ILHV) is a member of the Flaviviridae family. It was first isolated in 1944 from pools of Aedes serratus and Psorophora ferox mosquitoes; however, it has also been detected in species of the genus Culex, such as Cx. portesi and Cx. coronator. The objective of this study was to examine the vector competence of Cx. quinquefasciatus mosquitoes to ILHV infection and the subsequent transmission of the virus through their saliva during feeding on blood. METHODS F1 generation females of Cx. quinquefasciatus (Ananindeua/PA) were orally infected with goose blood infected with strain BeH7445, and body, head and saliva samples were analyzed at 7, 14, and 21 dpi using the techniques of virus isolation in cells and indirect immunofluorescence. RESULTS The presence of ILHV was not detected in the body and head samples of Cx. quinquefasciatus females at any of the three dpi's analyzed, indicating that the lineage of mosquitoes analyzed was resistant to ILHV. CONCLUSIONS According to the results obtained in this study, the species Cx. quinquefasciatus proved resistant to ILHV, regardless of the virus titers to which it was exposed, which suggests the possibility that this species does not act as a vector in the ILHV transmission cycle.
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Affiliation(s)
- Lúcia Aline Moura Reis
- Graduate Program in Parasitary Biology in the Amazon Region, Center of Biological and Health Sciences, State University of Pará, Belém 66095-663, Brazil
| | - Ana Beatriz Oliveira Pampolha
- Institute of Biological Sciences, Faculty of Biological Sciences, Federal University of Pará (UFPA), Belém 66075-110, Brazil
| | - Daniel Damous Dias
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil (E.V.P.d.S.)
| | - Maissa Maia Santos
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil (E.V.P.d.S.)
| | - Jamilla Augusta de Sousa Pantoja
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil (E.V.P.d.S.)
| | - Pedro Arthur da Silva Araújo
- Graduate Program in Biology of Infectious and Parasitary Agents, Institute of Biological Sciences, Federal University of Pará (UFPA), Belém 66077-830, Brazil
| | - Fábio Silva da Silva
- Graduate Program in Parasitary Biology in the Amazon Region, Center of Biological and Health Sciences, State University of Pará, Belém 66095-663, Brazil
| | - Bruna Lais Sena do Nascimento
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil (E.V.P.d.S.)
| | - Valéria Lima Carvalho
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil (E.V.P.d.S.)
| | - Eliana Vieira Pinto da Silva
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil (E.V.P.d.S.)
| | - Joaquim Pinto Nunes Neto
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil (E.V.P.d.S.)
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Souza SSD, Gomes AR, Guimarães ATB, Rodrigues ASDL, de Matos LP, Dos Santos Mendonça J, da Luz TM, Matos SGDS, Rahman MS, Ragavendran C, Senthil-Nathan S, Guru A, Rakib MRJ, Mubarak NM, Rahman MM, Rocha TL, Islam ARMT, Malafaia G. Cellulose microcrystalline: A promising ecofriendly approach to control Culex quinquefasciatus larvae. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 901:165952. [PMID: 37536599 DOI: 10.1016/j.scitotenv.2023.165952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/29/2023] [Accepted: 07/30/2023] [Indexed: 08/05/2023]
Abstract
The growing use of synthetic chemical compounds/substances in vector control of mosquitoes, associated with their adverse effects on the environment and non-target organisms, has demanded the development of eco-friendly alternatives. In this context, this study aimed to evaluate the larvicidal action of different cellulose microcrystalline (CMs) concentrations and investigate their toxicity mechanisms in Culex quinquefasciatus fourth instar larvae as a model species. Probit analysis revealed that the median lethal concentrations (LC50) for 24 h and 36 h exposure were 100 and 58.29 mg/L, respectively. We also showed that such concentrations induced a redox imbalance in the larvae, marked by an increase in the production of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS), as well as a reduction in the activity of superoxide dismutase (SOD) and catalase (CAT). Furthermore, different alterations in the external morphology of the larvae were associated with the ingestion of CMs. On the other hand, exposure of adult zebrafish (Danio rerio) to LC5024h and LC5036h for seven days did not induce any behavioral changes or alterations mutagenic, genotoxic, biochemical, or in the production of cytokines IFN-γ and IL-10. Thus, taken together, our study demonstrates for the first time that the use of CMs can constitute a promising strategy in the control of C. quinquefasciatus larvae, combining insecticidal efficiency with an "eco-friendly" approach in the fight against an important mosquito vector of several human diseases.
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Affiliation(s)
- Sindoval Silva de Souza
- Post-Graduation Program in Biotechnology and Biodiversity, Federal University of Goiás, Goiânia, GO, Brazil; Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute - Urutaí Campus. Rodovia Geraldo Silva Nascimento, 2,5 km, Zona Rural, Urutaí, GO, Brazil
| | - Alex Rodrigues Gomes
- Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute - Urutaí Campus. Rodovia Geraldo Silva Nascimento, 2,5 km, Zona Rural, Urutaí, GO, Brazil; Post-Graduation Program in Ecology, Conservation, and Biodiversity, Federal University of Uberlândia, Uberlândia, MG, Brazil
| | - Abraão Tiago Batista Guimarães
- Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute - Urutaí Campus. Rodovia Geraldo Silva Nascimento, 2,5 km, Zona Rural, Urutaí, GO, Brazil
| | - Aline Sueli de Lima Rodrigues
- Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute - Urutaí Campus. Rodovia Geraldo Silva Nascimento, 2,5 km, Zona Rural, Urutaí, GO, Brazil; Post-Graduation Program in Conservation of Cerrado Natural Resources, Goiano Federal Institute, Urutaí, GO, Brazil
| | - Letícia Paiva de Matos
- Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute - Urutaí Campus. Rodovia Geraldo Silva Nascimento, 2,5 km, Zona Rural, Urutaí, GO, Brazil
| | - Juliana Dos Santos Mendonça
- Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute - Urutaí Campus. Rodovia Geraldo Silva Nascimento, 2,5 km, Zona Rural, Urutaí, GO, Brazil
| | - Thiarlen Marinho da Luz
- Post-Graduation Program in Biotechnology and Biodiversity, Federal University of Goiás, Goiânia, GO, Brazil; Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute - Urutaí Campus. Rodovia Geraldo Silva Nascimento, 2,5 km, Zona Rural, Urutaí, GO, Brazil; Post-Graduation Program in Ecology, Conservation, and Biodiversity, Federal University of Uberlândia, Uberlândia, MG, Brazil
| | - Stênio Gonçalves da Silva Matos
- Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute - Urutaí Campus. Rodovia Geraldo Silva Nascimento, 2,5 km, Zona Rural, Urutaí, GO, Brazil
| | - M Safiur Rahman
- Department of Environmental Science and Disaster Management, Noakhali Science and Technology University, Noakhali 3814, Bangladesh
| | - Chinnasamy Ragavendran
- Saveetha Dental College and Hospitals (SIMATS), Saveetha University Chennai, Tamil Nadu, India
| | - Sengottayan Senthil-Nathan
- Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Centre for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tirunelveli, Tamil Nadu 627 412, India
| | - Ajay Guru
- Department of Cariology, Saveetha Dental College and Hospitals, SIMATS, Chennai 600 077, Tamil Nadu, India
| | | | - Nabisab Mujawar Mubarak
- Petroleum and Chemical Engineering, Faculty of Engineering, Universiti Teknologi Brunei, Bandar Seri Begawan BE1410, Brunei Darussalam; Department of Biosciences, Saveetha School of Engineering, Saveetha institute of Medical and Technical Sciences, Chennai, India
| | | | - Thiago Lopes Rocha
- Laboratory of Environmental Biotechnology and Ecotoxicology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Goiás, Brazil
| | | | - Guilherme Malafaia
- Post-Graduation Program in Biotechnology and Biodiversity, Federal University of Goiás, Goiânia, GO, Brazil; Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute - Urutaí Campus. Rodovia Geraldo Silva Nascimento, 2,5 km, Zona Rural, Urutaí, GO, Brazil; Post-Graduation Program in Ecology, Conservation, and Biodiversity, Federal University of Uberlândia, Uberlândia, MG, Brazil; Post-Graduation Program in Conservation of Cerrado Natural Resources, Goiano Federal Institute, Urutaí, GO, Brazil.
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Mathivanan D, Kamaraj C, Suseem SR, Gandhi PR, Malafaia G. Seaweed Sargassum wightii mediated preparation of TiO 2 nanoparticles, larvicidal activity against malaria and filariasis vectors, and its effect on non-target organisms. ENVIRONMENTAL RESEARCH 2023; 225:115569. [PMID: 36848976 DOI: 10.1016/j.envres.2023.115569] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/20/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
Malaria and Lymphatic filariasis are considered significant public health concerns in several countries. As a researcher, controlling those mosquitos using safe and eco-friendly insecticides is essential. Thus, we aimed to explore the potential use of seaweed Sargassum wightii for the biosynthesis of TiO2 NPs and evaluate its efficiency in controlling disease-transmitting mosquito larvae (using Anopheles subpictus and Culex quinquefasciatus larvae as model systems (in vivo)) as well as its potential effect on non-target organisms (using Poecilia reticulata fish as an experimental model). XRD, FT-IR, SEM-EDAX, and TEM carried out the characterization of TiO2 NPs. It evaluated the larvicidal activity against the fourth instar larvae of A. subpictus and C. quinquefasciatus. The larvicidal mortality was observed after 24 h of exposure to S. wightii extract and TiO2 NPs. S. wightii synthesized TiO2 NPs show excellent activity against A. subpictus and C. quinquefasciatus (LC50 = 4.37 and 4.68; LC90 = 8.33 and 8.97; χ2 = 5.741 and 4.531) mg/L respectively. The GC-MS results indicate the presence of some important long-chain phytoconstituents like linoleic acid, palmitic acid, oleic acid methyl ester, and stearic acid, among others. Furthermore, when testing the possible toxicity of biosynthesized NPs in a non-target organism, no adverse effects were observed in Poecilia reticulata fish exposed for 24 h, considering the evaluated biomarkers. Thus, overall, our study results reveal that biosynthesized TiO2 NPs are an effective and exciting eco-friendly approach to controlling the A. subpictus and C. quinquefasciatus.
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Affiliation(s)
- D Mathivanan
- Department of Chemistry, School of Advanced Sciences, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Chinnaperumal Kamaraj
- Interdisciplinary Institute of Indian System of Medicine (IIISM), Directorate of Research and Virtual Education, SRM Institute of Science and Technology (SRMIST), Kattankulathur, 603203, Tamil Nadu, India.
| | - S R Suseem
- Department of Chemistry, School of Advanced Sciences, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Pachiyappan Rajiv Gandhi
- Division of Nano-biotechnology, Department of Zoology, Auxilium College (Autonomous), Gandhi Nagar, 632 006, Vellore District, Tamil Nadu, India
| | - Guilherme Malafaia
- Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute, Urutaí, GO, Brazil; Post-Graduation Program in Conservation of Cerrado Natural Resources, Goiano Federal Institute, Urutaí, GO, Brazil; Post-Graduation Program in Ecology, Conservation, and Biodiversity, Federal University of Uberlândia, Uberlândia, MG, Brazil; Post-Graduation Program in Biotechnology and Biodiversity, Federal University of Goiás, Goiânia, GO, Brazil.
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Reis LAM, Silva EVPD, Dias DD, Freitas MNO, Caldeira RD, Araújo PADS, Silva FSD, Rosa Junior JW, Brandão RCF, Nascimento BLSD, Martins LC, Neto JPN. Vector Competence of Culex quinquefasciatus from Brazil for West Nile Virus. Trop Med Infect Dis 2023; 8:tropicalmed8040217. [PMID: 37104343 PMCID: PMC10144584 DOI: 10.3390/tropicalmed8040217] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/08/2023] [Accepted: 03/15/2023] [Indexed: 04/08/2023] Open
Abstract
West Nile virus is characterized as a neurotropic pathogen, which can cause West Nile fever and is transmitted by mosquitoes of the genus Culex. In 2018, the Instituto Evandro Chagas performed the first isolation of a WNV strain in Brazil from a horse brain sample. The present study aimed to evaluate the susceptibility of orally infected Cx. quinquefasciatus from the Amazon region of Brazil to become infected and transmit the WNV strain isolated in 2018. Oral infection was performed with blood meal artificially infected with WNV, followed by analysis of infection, dissemination, and transmission rates, as well as viral titers of body, head, and saliva samples. At the 21st dpi, the infection rate was 100%, the dissemination rate was 80%, and the transmission rate was 77%. These results indicate that Cx. quinquefasciatus is susceptible to oral infection by the Brazilian strain of WNV and may act as a possible vector of the virus since it was detected in saliva from the 21st dpi.
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Affiliation(s)
- Lúcia Aline Moura Reis
- Graduate Program in Parasitary Biology in the Amazon Region, Center of Biological and Health Sciences, State University of Pará, Belém 66095-663, Brazil
| | - Eliana Vieira Pinto da Silva
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
| | - Daniel Damous Dias
- Graduate Program in Parasitary Biology in the Amazon Region, Center of Biological and Health Sciences, State University of Pará, Belém 66095-663, Brazil
| | - Maria Nazaré Oliveira Freitas
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
| | - Rossela Damasceno Caldeira
- Graduate Program in Biology of Infectious and Parasitary Agents, Biological Sciences Institute, Federal University of Pará, Belém 66077-830, Brazil
| | - Pedro Arthur da Silva Araújo
- Graduate Program in Biology of Infectious and Parasitary Agents, Biological Sciences Institute, Federal University of Pará, Belém 66077-830, Brazil
| | - Fábio Silva da Silva
- Graduate Program in Parasitary Biology in the Amazon Region, Center of Biological and Health Sciences, State University of Pará, Belém 66095-663, Brazil
| | - José Wilson Rosa Junior
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
| | | | - Bruna Laís Sena do Nascimento
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
| | - Lívia Caricio Martins
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
| | - Joaquim Pinto Nunes Neto
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
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Romero-Vega LM, Piche-Ovares M, Soto-Garita C, Barantes Murillo DF, Chaverri LG, Alfaro-Alarcón A, Corrales-Aguilar E, Troyo A. Seasonal changes in the diversity, host preferences and infectivity of mosquitoes in two arbovirus-endemic regions of Costa Rica. Parasit Vectors 2023; 16:34. [PMID: 36703148 PMCID: PMC9881273 DOI: 10.1186/s13071-022-05579-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 11/04/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Mosquitoes are vectors of various arboviruses belonging to the genera Alphavirus and Flavivirus, and Costa Rica is endemic to several of them. The aim of this study was to describe and analyze the community structure of such vectors in Costa Rica. METHODS Sampling was performed in two different coastal locations of Costa Rica with evidence of arboviral activity during rainy and dry seasons. Encephalitis vector surveillance traps, CDC female gravid traps and ovitraps were used. Detection of several arboviruses by Pan-Alpha and Pan-Flavi PCR was attempted. Blood meals were also identified. The Normalized Difference Vegetation Index (NDVI) was estimated for each area during the rainy and dry seasons. The Chao2 values for abundance and Shannon index for species diversity were also estimated. RESULTS A total of 1802 adult mosquitoes belonging to 55 species were captured, among which Culex quinquefasciatus was the most caught species. The differences in NDVI were higher between seasons and between regions, yielding lower Chao-Sørensen similarity index values. Venezuelan equine encephalitis virus, West Nile virus and Madariaga virus were not detected at all, and dengue virus and Zika virus were detected in two separate Cx. quinquefasciatus specimens. The primary blood-meal sources were chickens (60%) and humans (27.5%). Both sampled areas were found to have different seasonal dynamics and population turnover, as reflected in the Chao2 species richness estimation values and Shannon diversity index. CONCLUSION Seasonal patterns in mosquito community dynamics in coastal areas of Costa Rica have strong differences despite a geographical proximity. The NDVI influences mosquito diversity at the regional scale more than at the local scale. However, year-long continuous sampling is required to better understand local dynamics.
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Affiliation(s)
- Luis M. Romero-Vega
- Universidad de Costa Rica, San José, Costa Rica
- Universidad Nacional, Heredia, Costa Rica
| | - Marta Piche-Ovares
- Universidad de Costa Rica, San José, Costa Rica
- Universidad Nacional, Heredia, Costa Rica
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Abstract
In nature, viral coinfection is as widespread as viral infection alone. Viral coinfections often cause altered viral pathogenicity, disrupted host defense, and mixed-up clinical symptoms, all of which result in more difficult diagnosis and treatment of a disease. There are three major virus-virus interactions in coinfection cases: viral interference, viral synergy, and viral noninterference. We analyzed virus-virus interactions in both aspects of viruses and hosts and elucidated their possible mechanisms. Finally, we summarized the protocol of viral coinfection studies and key points in the process of virus separation and purification.
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10
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Mendonça-Gomes JM, Charlie-Silva I, Guimarães ATB, Estrela FN, Calmon MF, Miceli RN, Sanches PRS, Bittar C, Rahal P, Cilli EM, Ahmed MAI, Vogel CFA, Malafaia G. Shedding light on toxicity of SARS-CoV-2 peptides in aquatic biota: A study involving neotropical mosquito larvae (Diptera: Culicidae). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 289:117818. [PMID: 34333265 PMCID: PMC8291650 DOI: 10.1016/j.envpol.2021.117818] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/21/2021] [Accepted: 07/19/2021] [Indexed: 05/19/2023]
Abstract
Knowledge about how the COVID-19 pandemic can affect aquatic wildlife is still extremely limited, and no effect of SARS-CoV-2 or its structural constituents on invertebrate models has been reported so far. Thus, we investigated the presence of the 2019-new coronavirus in different urban wastewater samples and, later, evaluated the behavioral and biochemical effects of the exposure of Culex quinquefasciatus larvae to two SARS-CoV-2 spike protein peptides (PSPD-2002 and PSPD-2003) synthesized in our laboratory. Initially, our results show the contamination of wastewater by the new coronavirus, via RT-qPCR on the viral N1 gene. On the other hand, our study shows that short-term exposure (48 h) to a low concentration (40 μg/L) of the synthesized peptides induced changes in the locomotor and the olfactory-driven behavior of the C. quinquefascitus larvae, which were associated with increased production of ROS and AChE activity (cholinesterase effect). To our knowledge, this is the first study that reports the indirect effects of the COVID-19 pandemic on the larval phase of a freshwater invertebrate species. The results raise concerns at the ecological level where the observed biological effects may lead to drastic consequences.
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Affiliation(s)
| | - Ives Charlie-Silva
- Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo; São Paulo, SP, Brazil
| | | | - Fernanda Neves Estrela
- Programa de Pós-Graduação Em Conservação de Recursos Naturais do Cerrado, Instituto Federal Goiano; Urutaí, GO, Brazil
| | - Marilia Freitas Calmon
- Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho"; São José do Rio Preto, SP, Brazil
| | - Rafael Nava Miceli
- SeMAE - Serviço Municipal Autonômo de Água e Esgoto, São José do Rio Preto; São Paulo, SP, Brazil
| | - Paulo R S Sanches
- Instituto de Química, Universidade Estadual Paulista; Araraquara, SP, Brazil
| | - Cíntia Bittar
- Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho"; São José do Rio Preto, SP, Brazil
| | - Paula Rahal
- Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho"; São José do Rio Preto, SP, Brazil
| | - Eduardo M Cilli
- Instituto de Química, Universidade Estadual Paulista; Araraquara, SP, Brazil
| | | | - Christoph F A Vogel
- Department of Environmental Toxicology and Center for Health and the Environment, University of California, Davis, CA, 95616, USA
| | - Guilherme Malafaia
- Programa de Pós-Graduação Em Conservação de Recursos Naturais do Cerrado, Instituto Federal Goiano; Urutaí, GO, Brazil; Programa de Pós-Graduação Em Biotecnologia e Biodiversidade, Universidade Federal de Goiás, Goiânia, GO, Brazil; Programa de Pós-Graduação Em Ecologia e Conservação de Recursos Naturais, Universidade Federal de Uberlância, Uberlândia, MG, Brazil.
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11
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Kantor AM, Lin J, Wang A, Thompson DC, Franz AWE. Infection Pattern of Mayaro Virus in Aedes aegypti (Diptera: Culicidae) and Transmission Potential of the Virus in Mixed Infections With Chikungunya Virus. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:832-843. [PMID: 30668762 PMCID: PMC6467640 DOI: 10.1093/jme/tjy241] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Indexed: 06/09/2023]
Abstract
Mayaro virus (MAYV; Togaviridae; Alphavirus) has drawn increasing attention as an arthropod-borne virus with potential to cause outbreaks among the human populations of the Western Hemisphere. In the tropical regions of Central and South America, the virus exists in sylvatic cycles between mosquitoes and primate reservoirs such as marmosets. Although forest-dwelling mosquitoes are regarded as important vectors for MAYV, it has been shown previously that the virus can infect and potentially be transmitted by the mosquitoes, Aedes aegypti and Aedes albopictus (Diptera: Culicidae). Here, we compare the infection and transmission efficiencies of two MAYV strains, IQT 4235 from Iquitos, Peru ('IQT') and the type strain of MAYV from Trinidad, TRVL 4675 ('TRVL') in two laboratory-adapted Ae. aegypti strains, Higgs White Eye and Orlando. The TRVL strain was less efficiently transmitted by both mosquito strains than MAYV IQT. Based on the full-length nucleotide sequences of the two viral genomes, we show that the TRVL prototype strain of MAYV is phylogenetically ancestral and more distantly related to the IQT strain. The TRVL strain efficiently infected wild-type Ae. albopictus from Missouri and readily disseminated in those. Considering scenarios in which natural MAYV transmission cycles may overlap with those of chikungunya virus (CHIKV; Togaviridae; Alphavirus), we assessed the effects of mixed infections of the two viruses in mosquitoes based on coinfection or superinfection. Although coinfection had no measurable effect on the transmission potential of either virus, we observed superinfection exclusion for CHIKV in MAYV-infected mosquitoes but not for MAYV in CHIKV-infected mosquitoes.
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Affiliation(s)
- Asher M Kantor
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO
| | - Jingyi Lin
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO
| | - Allen Wang
- Department of Biological Sciences, University of Missouri, Columbia, MO
| | - Dana C Thompson
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO
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12
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Öhlund P, Lundén H, Blomström AL. Insect-specific virus evolution and potential effects on vector competence. Virus Genes 2019; 55:127-137. [PMID: 30632016 PMCID: PMC6458977 DOI: 10.1007/s11262-018-01629-9] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 12/21/2018] [Indexed: 01/08/2023]
Abstract
The advancement in high-throughput sequencing technology and bioinformatics tools has spurred a new age of viral discovery. Arthropods is the largest group of animals and has shown to be a major reservoir of different viruses, including a group known as insect-specific viruses (ISVs). The majority of known ISVs have been isolated from mosquitoes and shown to belong to viral families associated with animal arbovirus pathogens, such as Flaviviridae, Togaviridae and Phenuiviridae. These insect-specific viruses have a strict tropism and are unable to replicate in vertebrate cells, these properties are interesting for many reasons. One is that these viruses could potentially be utilised as biocontrol agents using a similar strategy as for Wolbachia. Mosquitoes infected with the viral agent could have inferior vectorial capacity of arboviruses resulting in a decrease of circulating arboviruses of public health importance. Moreover, insect-specific viruses are thought to be ancestral to arboviruses and could be used to study the evolution of the switch from single-host to dual-host. In this review, we discuss new discoveries and hypothesis in the field of arboviruses and insect-specific viruses.
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Affiliation(s)
- Pontus Öhlund
- Section of Virology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Box 7028, 750 07, Uppsala, Sweden
| | - Hanna Lundén
- Section of Virology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Box 7028, 750 07, Uppsala, Sweden
| | - Anne-Lie Blomström
- Section of Virology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Box 7028, 750 07, Uppsala, Sweden.
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13
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Colmant AMG, Hall-Mendelin S, Ritchie SA, Bielefeldt-Ohmann H, Harrison JJ, Newton ND, O’Brien CA, Cazier C, Johansen CA, Hobson-Peters J, Hall RA, van den Hurk AF. The recently identified flavivirus Bamaga virus is transmitted horizontally by Culex mosquitoes and interferes with West Nile virus replication in vitro and transmission in vivo. PLoS Negl Trop Dis 2018; 12:e0006886. [PMID: 30356234 PMCID: PMC6200184 DOI: 10.1371/journal.pntd.0006886] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 09/29/2018] [Indexed: 11/19/2022] Open
Abstract
Arthropod-borne flaviviruses such as yellow fever (YFV), Zika and dengue viruses continue to cause significant human disease globally. These viruses are transmitted by mosquitoes when a female imbibes an infected blood-meal from a viremic vertebrate host and expectorates the virus into a subsequent host. Bamaga virus (BgV) is a flavivirus recently discovered in Culex sitiens subgroup mosquitoes collected from Cape York Peninsula, Australia. This virus phylogenetically clusters with the YFV group, but is potentially restricted in most vertebrates. However, high levels of replication in an opossum cell line (OK) indicate a potential association with marsupials. To ascertain whether BgV could be horizontally transmitted by mosquitoes, the vector competence of two members of the Cx. sitiens subgroup, Cx. annulirostris and Cx. sitiens, for BgV was investigated. Eleven to thirteen days after imbibing an infectious blood-meal, infection rates were 11.3% and 18.8% for Cx. annulirostris and Cx. sitiens, respectively. Cx. annulirostris transmitted the virus at low levels (5.6% had BgV-positive saliva overall); Cx. sitiens did not transmit the virus. When mosquitoes were injected intrathoracially with BgV, the infection and transmission rates were 100% and 82%, respectively, for both species. These results provided evidence for the first time that BgV can be transmitted horizontally by Cx. annulirostris, the primary vector of pathogenic zoonotic flaviviruses in Australia. We also assessed whether BgV could interfere with replication in vitro, and infection and transmission in vivo of super-infecting pathogenic Culex-associated flaviviruses. BgV significantly reduced growth of Murray Valley encephalitis and West Nile (WNV) viruses in vitro. While prior infection with BgV by injection did not inhibit WNV super-infection of Cx. annulirostris, significantly fewer BgV-infected mosquitoes could transmit WNV than mock-injected mosquitoes. Overall, these data contribute to our understanding of flavivirus ecology, modes of transmission by Australian mosquitoes and mechanisms for super-infection interference. Mosquito-borne flaviviruses include medically significant members such as the dengue viruses, yellow fever virus and Zika virus. These viruses regularly cause outbreaks globally, notably in tropical regions. The ability of mosquitoes to transmit these viruses to vertebrate hosts plays a major role in determining the scale of these outbreaks. It is essential to assess the risk of emergence of flaviviruses in a given region by investigating the vector competence of local mosquitoes for these viruses. Bamaga virus was recently discovered in Australia in Culex mosquitoes and shown to be related to yellow fever virus. In this article, we investigated the potential for Bamaga virus to emerge as an arthropod-borne viral pathogen by assessing the vector competence of Cx. annulirostris and Cx. sitiens mosquitoes for this virus. We showed that Bamaga virus could be detected in the saliva of Cx. annulirostris after an infectious blood-meal, demonstrating that the virus could be horizontally transmitted. In addition, we showed that Bamaga virus could interfere with the replication in vitro and transmission in vivo of the pathogenic flavivirus West Nile virus. These data provide further insight on how interactions between viruses in their vector can influence the efficiency of pathogen transmission.
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Affiliation(s)
- Agathe M. G. Colmant
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Sonja Hall-Mendelin
- Public Health Virology, Forensic and Scientific Services, Department of Health, Queensland Government, Coopers Plains, QLD, Australia
| | - Scott A. Ritchie
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns, QLD, Australia
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Helle Bielefeldt-Ohmann
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
- School of Veterinary Science, The University of Queensland, Gatton Campus, QLD, Gatton Australia
| | - Jessica J. Harrison
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Natalee D. Newton
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Caitlin A. O’Brien
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Chris Cazier
- Technical Services, Biosciences Division, Faculty of Health, Queensland University of Technology, Gardens Point Campus, Brisbane, Qld, Australia
| | - Cheryl A. Johansen
- PathWest Laboratory Medicine WA, Nedlands, Western Australia, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Jody Hobson-Peters
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Roy A. Hall
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
- * E-mail: (RAH); (AFVDH)
| | - Andrew F. van den Hurk
- Public Health Virology, Forensic and Scientific Services, Department of Health, Queensland Government, Coopers Plains, QLD, Australia
- * E-mail: (RAH); (AFVDH)
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14
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Fujita R, Kato F, Kobayashi D, Murota K, Takasaki T, Tajima S, Lim CK, Saijo M, Isawa H, Sawabe K. Persistent viruses in mosquito cultured cell line suppress multiplication of flaviviruses. Heliyon 2018; 4:e00736. [PMID: 30167494 PMCID: PMC6107885 DOI: 10.1016/j.heliyon.2018.e00736] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/25/2018] [Accepted: 08/08/2018] [Indexed: 11/16/2022] Open
Abstract
In the growth kinetics analysis of flaviviruses in Aedes albopictus C6/36 cell lines obtained from the Japanese Collection of Research Bioresources (JCRB) Cell Bank and the European Collection of Authenticated Cell Culture (ECACC), these two cells line showed different viral susceptibility for Zika virus (ZIKV), Dengue virus (DENV), and Japanese encephalitis virus (JEV). Next-generation sequencing (NGS) analysis revealed that the C6/36 JCRB strain was persistently infected with two viruses without showing any cytopathic effects. The complete sequence analysis demonstrated that the one virus was Menghai rhabdovirus (MERV), which has been found from Aedes albopictus mosquito. The other virus was a novel virus, designated as Shinobi tetravirus (SHTV). Interestingly, the viral susceptibility of these two strains was almost even for Sindbis virus and Getah virus. We cloned SHTV and MERV from JCRB C6/36 cell line and then re-infected them into another C6/36 cell line, resulting in the reproduction of persistent infection with each virus. ZIKV growth was suppressed in SHTV and/or MERV re-infected C6/36 cells also. To our knowledge, this is the first demonstration that persistent infection with rhabdovirus and/or permutotetravirus suppressed flavivirus replication in mosquito cells.
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Affiliation(s)
- Ryosuke Fujita
- Department of Medical Entomology, National Institute of Infectious Diseases, Tokyo, Japan
- Isotope Imaging Laboratory, Creative Research Institution, Hokkaido University, Sapporo, Japan
- Department of Research Promotion, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Fumihiro Kato
- Department of Research Promotion, Japan Agency for Medical Research and Development, Tokyo, Japan
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Daisuke Kobayashi
- Department of Medical Entomology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Katsunori Murota
- Department of Medical Entomology, National Institute of Infectious Diseases, Tokyo, Japan
- Department of Research Promotion, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Tomohiko Takasaki
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Shigeru Tajima
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Chang-Kweng Lim
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Masayuki Saijo
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Haruhiko Isawa
- Department of Medical Entomology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kyoko Sawabe
- Department of Medical Entomology, National Institute of Infectious Diseases, Tokyo, Japan
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan
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15
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Abstract
Coinfections involving viruses are being recognized to influence the disease pattern that occurs relative to that with single infection. Classically, we usually think of a clinical syndrome as the consequence of infection by a single virus that is isolated from clinical specimens. However, this biased laboratory approach omits detection of additional agents that could be contributing to the clinical outcome, including novel agents not usually considered pathogens. The presence of an additional agent may also interfere with the targeted isolation of a known virus. Viral interference, a phenomenon where one virus competitively suppresses replication of other coinfecting viruses, is the most common outcome of viral coinfections. In addition, coinfections can modulate virus virulence and cell death, thereby altering disease severity and epidemiology. Immunity to primary virus infection can also modulate immune responses to subsequent secondary infections. In this review, various virological mechanisms that determine viral persistence/exclusion during coinfections are discussed, and insights into the isolation/detection of multiple viruses are provided. We also discuss features of heterologous infections that impact the pattern of immune responsiveness that develops.
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16
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Amuzu HE, Tsyganov K, Koh C, Herbert RI, Powell DR, McGraw EA. Wolbachia enhances insect-specific flavivirus infection in Aedes aegypti mosquitoes. Ecol Evol 2018; 8:5441-5454. [PMID: 29938064 PMCID: PMC6010864 DOI: 10.1002/ece3.4066] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 01/02/2023] Open
Abstract
Mosquitoes transmit a diverse group of human flaviviruses including West Nile, dengue, yellow fever, and Zika viruses. Mosquitoes are also naturally infected with insect-specific flaviviruses (ISFs), a subgroup of the family not capable of infecting vertebrates. Although ISFs are not medically important, they are capable of altering the mosquito's susceptibility to flaviviruses and may alter host fitness. Wolbachia is an endosymbiotic bacterium of insects that when present in mosquitoes limits the replication of co-infecting pathogens, including flaviviruses. Artificially created Wolbachia-infected Aedes aegypti mosquitoes are being released into the wild in a series of trials around the globe with the hope of interrupting dengue and Zika virus transmission from mosquitoes to humans. Our work investigated the effect of Wolbachia on ISF infection in wild-caught Ae. aegypti mosquitoes from field release zones. All field mosquitoes were screened for the presence of ISFs using general degenerate flavivirus primers and their PCR amplicons sequenced. ISFs were found to be common and widely distributed in Ae. aegypti populations. Field mosquitoes consistently had higher ISF infection rates and viral loads compared to laboratory colony material indicating that environmental conditions may modulate ISF infection in Ae. aegypti. Surprisingly, higher ISF infection rates and loads were found in Wolbachia-infected mosquitoes compared to the Wolbachia-free mosquitoes. Our findings demonstrate that the symbiont is capable of manipulating the mosquito virome and that Wolbachia-mediated viral inhibition is not universal for flaviviruses. This may have implications for the Wolbachia-based DENV control strategy if ISFs confer fitness effects or alter mosquito susceptibility to other flaviviruses.
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Affiliation(s)
- Hilaria E. Amuzu
- School of Biological SciencesMonash UniversityClaytonVic.Australia
| | - Kirill Tsyganov
- Monash Bioinformatics PlatformMonash UniversityClaytonVic.Australia
| | - Cassandra Koh
- School of Biological SciencesMonash UniversityClaytonVic.Australia
| | | | - David R. Powell
- Monash Bioinformatics PlatformMonash UniversityClaytonVic.Australia
| | - Elizabeth A. McGraw
- School of Biological SciencesMonash UniversityClaytonVic.Australia
- Department of EntomologyPennsylvania State UniversityUniversity ParkPennsylvania
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17
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Muturi EJ, Buckner E, Bara J. Superinfection interference between dengue-2 and dengue-4 viruses in Aedes aegypti mosquitoes. Trop Med Int Health 2017; 22:399-406. [PMID: 28150899 DOI: 10.1111/tmi.12846] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Dengue virus consists of four antigenically distinct serotypes (DENV 1-4) that are transmitted to humans by Aedes aegypti and Aedes albopictus mosquitoes. In many dengue-endemic regions, co-circulation of two or more DENV serotypes is fairly common increasing the likelihood for exposure of the two vectors to multiple serotypes. We used a model system of DENV-2 and DENV-4 to investigate how prior exposure of Aedes aegypti to one DENV serotype affects its susceptibility to another serotype. METHODS Aedes aegypti mosquitoes were sequentially infected with DENV-2 and DENV-4 and the infection and dissemination rates for each virus determined. RESULTS We found that prior infection of Ae. aegypti mosquitoes with DENV-4 rendered them significantly less susceptible to secondary infection with DENV-2. Although the results were not statistically significant, mosquitoes infected with DENV-2 were also less susceptible to secondary infection with DENV-4. The midgut dissemination and population dissemination rates for DENV-2 were significantly higher than those of DENV-4 when either virus was administered 7 days after administration of either a non-infectious blood meal or a blood meal containing a heterologous dengue serotype. CONCLUSION These results demonstrate that superinfection interference between DENV serotypes is possible within Ae. aegypti mosquitoes, but its effect on DENV epidemiology may be dependent on the fitness of interacting serotypes.
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Affiliation(s)
- Ephantus J Muturi
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Eva Buckner
- Manatee County Mosquito Control District, Palmetto, FL, USA
| | - Jeffrey Bara
- Department of Biology, University of Louisville, Louisville, KY, USA
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18
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Sudeep AB, Bondre VP, George R, Ghodke YS, Aher RV, Gokhale MD. Bagaza virus inhibits Japanese encephalitis & West Nile virus replication in Culex tritaeniorhynchus & Cx. quinquefasciatus mosquitoes. Indian J Med Res 2016; 142 Suppl:S44-51. [PMID: 26905241 PMCID: PMC4795346 DOI: 10.4103/0971-5916.176618] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND & OBJECTIVES Studies have shown that certain flaviviruses influence susceptibility of mosquitoes by inhibiting/enhancing replication of important flaviviruses. Hence, a study was designed to determine whether Bagaza virus (BAGV), a flavivirus isolated from Culex tritaeniorhynchus mosquitoes in India, alters susceptibility of Cx. tritaeniorhynchus and Cx. quinquefasciatus mosquitoes to Japanese encephalitis (JEV) and West Nile viruses (WNV). METHODS JEV and WNV infection in Cx. tritaeniorhynchus and Cx. quinquefasciatus mosquitoes in the presence of BAGV was carried out by intrathoracic (IT) inoculation and oral feeding methods. Mosquitoes were infected with BAGV and WNV/JEV either simultaneously or in a phased manner, in which mosquitoes were infected with BAGV by IT inoculation followed by super-infection with JEV/WNV after eight days post-infection (PI). JEV and WNV yield on 7 [th] and 14 [th] day PI after super-infection was determined by 50 per cent tissue culture infective dose (TCID 50 ) method. RESULTS In Cx. tritaeniorhynchus mosquitoes, prior infection with BAGV significantly reduced JEV and WNV replication while in Cx. quinquefasciatus, BAGV influence was only seen with WNV. Reduction in virus titre was observed in IT inoculated and oral fed mosquitoes irrespective of the infection mode. JEV replication was also found reduced in Cx. tritaeniorhynchus mosquitoes persistently infected with BAGV at passage four. INTERPRETATION & CONCLUSIONS BAGV infection in Cx. tritaeniorhynchus and Cx. quinquefasciatus mosquitoes altered their susceptibility to JEV and WNV producing low virus yield. However, the role of BAGV in inhibiting JEV/WNV replication in field mosquitoes needs further investigations.
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Affiliation(s)
- A B Sudeep
- National Institute of Virology, Microbial Containment Complex (ICMR), Pune, India
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19
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Smith DR. Waiting in the wings: The potential of mosquito transmitted flaviviruses to emerge. Crit Rev Microbiol 2016; 43:405-422. [PMID: 27800692 DOI: 10.1080/1040841x.2016.1230974] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The sudden dramatic emergence of the mosquito transmitted flavivirus Zika virus has bought to the world's attention a relatively obscure virus that was previously only known to specialist researchers. The genus Flavivirus of the family Flaviviridae contains a number of well-known mosquito transmitted human pathogenic viruses including the dengue, yellow fever, Japanese encephalitis and West Nile viruses. However, the genus also contains a number of lesser known human pathogenic viruses transmitted by mosquitoes including Wesselsbron virus, Ilheus virus, St. Louis encephalitis virus and Usutu virus. This review summarizes our knowledge of these lesser known mosquito transmitted flaviviruses and highlights their potential to emerge.
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Affiliation(s)
- Duncan R Smith
- a Institute of Molecular Biosciences and Center for Emerging and Neglected Infectious Diseases, Mahidol University , Thailand
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20
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Differential Infectivities among Different Japanese Encephalitis Virus Genotypes in Culex quinquefasciatus Mosquitoes. PLoS Negl Trop Dis 2016; 10:e0005038. [PMID: 27706157 PMCID: PMC5051684 DOI: 10.1371/journal.pntd.0005038] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 09/13/2016] [Indexed: 12/29/2022] Open
Abstract
During the last 20 years, the epidemiology of Japanese encephalitis virus (JEV) has changed significantly in its endemic regions due to the gradual displacement of the previously dominant genotype III (GIII) with clade b of GI (GI-b). Whilst there is only limited genetic difference distinguishing the two GI clades (GI-a and GI-b), GI-b has shown a significantly wider and more rapid dispersal pattern in several regions in Asia than the GI-a clade, which remains restricted in its geographic distribution since its emergence. Although previously published molecular epidemiological evidence has shown distinct phylodynamic patterns, characterization of the two GI clades has only been limited to in vitro studies. In this study, Culex quinquefasciatus, a known competent JEV mosquito vector species, was orally challenged with three JEV strains each representing GI-a, GI-b, and GIII, respectively. Infection and dissemination were determined based on the detection of infectious viruses in homogenized mosquitoes. Detection of JEV RNA in mosquito saliva at 14 days post infection indicated that Cx. quinquefasciatus can be a competent vector species for both GI and GIII strains. Significantly higher infection rates in mosquitoes exposed to the GI-b and GIII strains than the GI-a strain suggest infectivity in arthropod vectors may lead to the selective advantage of previously and currently dominant genotypes. It could thus play a role in enzootic transmission cycles for the maintenance of JEV if this virus were ever to be introduced into North America. Japanese encephalitis virus (JEV) is a zoonotic flavivirus, which is primarily transmitted by Culex species mosquitoes and a leading cause of pediatric encephalitis in Asia. JEV is also an important public health threat to countries outside the endemic region because collections of Cx. quinquefasciatus from around the world have demonstrated competence for the transmission of JEV and are capable of establishing enzootic transmission cycles between viremic avian and swine species. In the last two decades, the dominantly circulating genotype of JEV in endemic regions has experienced a significant shift (genotype III to Genotype I). It is unclear if the newly dominant circulating G1-b genotype can still be vectored by Cx. quinquefasciatus. In this study, Cx. quinquefasciatus collected from North America was demonstrated to be competent for the transmission of the newly dominant genotype. Different infectivities observed between the endemic strains and non-endemic strain provides the mechanistic knowledge of the selection and emergence of endemic genotypes after continuous viral evolution.
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Viral Interference and Persistence in Mosquito-Borne Flaviviruses. J Immunol Res 2015; 2015:873404. [PMID: 26583158 PMCID: PMC4637105 DOI: 10.1155/2015/873404] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/18/2015] [Accepted: 08/19/2015] [Indexed: 12/30/2022] Open
Abstract
Mosquito-borne flaviviruses are important pathogens for humans, and the detection of two or more flaviviruses cocirculating in the same geographic area has often been reported. However, the epidemiological impact remains to be determined. Mosquito-borne flaviviruses are primarily transmitted through Aedes and Culex mosquitoes; these viruses establish a life-long or persistent infection without apparent pathological effects. This establishment requires a balance between virus replication and the antiviral host response. Viral interference is a phenomenon whereby one virus inhibits the replication of other viruses, and this condition is frequently associated with persistent infections. Viral interference and persistent infection are determined by several factors, such as defective interfering particles, competition for cellular factors required for translation/replication, and the host antiviral response. The interaction between two flaviviruses typically results in viral interference, indicating that these viruses share common features during the replicative cycle in the vector. The potential mechanisms involved in these processes are reviewed here.
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Nasar F, Erasmus JH, Haddow AD, Tesh RB, Weaver SC. Eilat virus induces both homologous and heterologous interference. Virology 2015; 484:51-58. [PMID: 26068885 PMCID: PMC4567418 DOI: 10.1016/j.virol.2015.05.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 05/10/2015] [Accepted: 05/11/2015] [Indexed: 01/02/2023]
Abstract
Most alphaviruses are mosquito-borne and exhibit a broad host range, infecting many different vertebrates including birds, rodents, equids, and humans. Occasionally, alphaviruses can spill over into the human population and cause disease characterized by debilitating arthralgia or fatal encephalitis. Recently, a unique alphavirus, Eilat virus (EILV), was described that readily infects mosquito but not vertebrate cell lines. Here, we investigated the ability of EILV to induce superinfection exclusion. Prior infection of C7/10 (Aedes albopictus) cells with EILV induced homologous and heterologous interference, reducing the virus titers of heterologous superinfecting viruses (SINV, VEEV, EEEV, WEEV, and CHIKV) by ~10-10,000 fold and delaying replication kinetics by 12-48h. Similar to in vitro infection, prior in vivo EILV infection of Aedes aegypti mosquitoes delayed dissemination of chikungunya virus for 3 days. This is the first evidence of heterologous interference induced by a mosquito-specific alphavirus in vitro and in vivo.
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Affiliation(s)
- Farooq Nasar
- Institute for Human Infections and Immunity, Center for Tropical Diseases, and Department of Pathology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA; Virology Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702, USA(1)
| | - Jesse H Erasmus
- Institute for Human Infections and Immunity, Center for Tropical Diseases, and Department of Pathology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA
| | - Andrew D Haddow
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702, USA(1)
| | - Robert B Tesh
- Institute for Human Infections and Immunity, Center for Tropical Diseases, and Department of Pathology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA
| | - Scott C Weaver
- Institute for Human Infections and Immunity, Center for Tropical Diseases, and Department of Pathology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA.
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Datta S, Gopalakrishnan R, Chatterjee S, Veer V. Phylogenetic Characterization of a Novel Insect-Specific Flavivirus Detected in a Culex Pool, Collected from Assam, India. Intervirology 2015; 58:149-54. [DOI: 10.1159/000381901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 03/24/2015] [Indexed: 11/19/2022] Open
Abstract
Objective: We report the phylogenetic characterization of a unique flavivirus sequence detected in a wild Culex tritaeniorhynchus mosquito pool, collected from the northeast Indian state of Assam. Methods: DNA and RNA were extracted from field-collected mosquito pools. Extracts were subjected to PCR and reverse transcriptase PCR amplification using universal and type-specific primers for direct detection of flavivirus-specific viral nucleic acids. An amplified flavivirus nonstructural protein 5 (NS5) genetic region was sequenced and BLAST searched, and phylogenetic analyses performed with reference sequences retrieved from GenBank. Results: Phylogenetic analyses revealed the sequence to be related to insect-specific flaviviruses (ISFs) of the genus Flavivirus, family Flaviviridae. Despite being related to the Palm Creek virus (PCV; an ISF very recently reported from Northern Australia), the present sequence (provisionally named Assam virus) was found to be highly divergent from PCV and other ISF sequences available in GenBank. The partial NS5 sequence analysis demonstrated low nucleotide sequence identity (66-77%) with known ISFs reported from other parts of the globe. Conclusion: Findings of this study suggest the presence of a candidate novel ISF - the first to be reported from India.
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Muturi EJ, Bara J. Sindbis virus interferes with dengue 4 virus replication and its potential transmission by Aedes albopictus. Parasit Vectors 2015; 8:65. [PMID: 25633862 PMCID: PMC4316403 DOI: 10.1186/s13071-015-0667-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 01/16/2015] [Indexed: 02/01/2023] Open
Abstract
Background Mosquitoes transmit a number of arboviruses associated with disease outbreaks in humans and other animals. The majority of medically important arboviruses belong to three families: Togaviridae, Flaviviridae and Bunyaviridae. Several members of these families have overlapping distributions and share common vectors, increasing the potential for arboviral coinfections. This study examined how two model viruses: Sindbis virus (SINV, Togaviridae: Alphavirus) and dengue-4 virus (DENV-4, Flaviviridae: Flavivirus) may interact in C6/36 Aedes albopictus cells and in the mosquito vector Ae. albopictus. Methods C6/36 cells were coinfected, superinfected, or singly infected with SINV and DENV-4 and the two viruses quantified at different time points. Four to seven day old adult females of Ae. albopictus were also fed blood containing one or both viruses and viral infection and dissemination rates determined. Results Sindbis virus suppressed replication of DENV-4 in C6/36 Ae. albopictus cells with greater inhibition occurring when the two arboviruses were inoculated simultaneously compared to sequentially. In addition, Ae. albopictus simultaneously exposed to both arboviruses had significantly lower DENV-4 infection and population dissemination rates compared to those exposed to DENV-4 alone. Conclusion These results suggest that certain Alphaviruses may interfere with DENV-4 transmission by suppressing its replication and increasing vector refractoriness. The findings provide important insights into the potential contribution of mixed arboviral infections to DENV transmission dynamics.
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Maharaj PD, Bolling BG, Anishchenko M, Reisen WK, Brault AC. Genetic determinants of differential oral infection phenotypes of West Nile and St. Louis encephalitis viruses in Culex spp. mosquitoes. Am J Trop Med Hyg 2014; 91:1066-72. [PMID: 25157120 DOI: 10.4269/ajtmh.14-0289] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
St. Louis encephalitis virus (SLEV) has shown greater susceptibility to oral infectivity than West Nile virus (WNV) in Culex mosquitoes. To identify the viral genetic elements that modulate these disparate phenotypes, structural chimeras (WNV-pre-membrane [prM] and envelope [E] proteins [prME]/SLEV.IC (infectious clone) and SLEV-prME/WNV.IC) were constructed in which two of the structural proteins, the prM and E, were interchanged between viruses. Oral dose-response assessment with the chimeric/parental WNV and SLEV was performed to characterize the infection phenotypes in Culex mosquitoes by artificial blood meals. The median infectious dose required to infect 50% of Cx. quinquefasciatus with WNV was indistinguishable from that of the SLEV-prME/WNV.IC chimeric virus. Similarly, SLEV and WNV-prME/SLEV.IC virus exhibited an indistinguishable oral dose-response relationship in Cx. quinquefasciatus. Infection rates for WNV.IC and SLEV-prME/WNV.IC were significantly lower than SLEV.IC and WNV-prME/SLEV.IC infection rates. These results indicated that WNV and SLEV oral infectivities are not mediated by genetic differences within the prM and E proteins.
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Affiliation(s)
- Payal D Maharaj
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California
| | - Bethany G Bolling
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California
| | - Michael Anishchenko
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California
| | - William K Reisen
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California
| | - Aaron C Brault
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California
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Kenney JL, Solberg OD, Langevin SA, Brault AC. Characterization of a novel insect-specific flavivirus from Brazil: potential for inhibition of infection of arthropod cells with medically important flaviviruses. J Gen Virol 2014; 95:2796-2808. [PMID: 25146007 DOI: 10.1099/vir.0.068031-0] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the past decade, there has been an upsurge in the number of newly described insect-specific flaviviruses isolated pan-globally. We recently described the isolation of a novel flavivirus (tentatively designated 'Nhumirim virus'; NHUV) that represents an example of a unique subset of apparently insect-specific viruses that phylogenetically affiliate with dual-host mosquito-borne flaviviruses despite appearing to be limited to replication in mosquito cells. We characterized the in vitro growth potential and 3' untranslated region (UTR) sequence homology with alternative flaviviruses, and evaluated the virus's capacity to suppress replication of representative Culex spp.-vectored pathogenic flaviviruses in mosquito cells. Only mosquito cell lines were found to support NHUV replication, further reinforcing the insect-specific phenotype of this virus. Analysis of the sequence and predicted RNA secondary structures of the 3' UTR indicated NHUV to be most similar to viruses within the yellow fever serogroup and Japanese encephalitis serogroup, and viruses in the tick-borne flavivirus clade. NHUV was found to share the fewest conserved sequence elements when compared with traditional insect-specific flaviviruses. This suggests that, despite apparently being insect specific, this virus probably diverged from an ancestral mosquito-borne flavivirus. Co-infection experiments indicated that prior or concurrent infection of mosquito cells with NHUV resulted in a significant reduction in virus production of West Nile virus (WNV), St Louis encephalitis virus (SLEV) and Japanese encephalitis virus. The inhibitory effect was most effective against WNV and SLEV with over a 10(6)-fold and 10(4)-fold reduction in peak titres, respectively.
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Affiliation(s)
- Joan L Kenney
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
| | | | | | - Aaron C Brault
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
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A positively selected mutation in the WNV 2K peptide confers resistance to superinfection exclusion in vivo. Virology 2014; 464-465:228-232. [PMID: 25104615 DOI: 10.1016/j.virol.2014.07.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 06/27/2014] [Accepted: 07/08/2014] [Indexed: 11/23/2022]
Abstract
Molecular epidemiologic studies of North American (NA) West Nile virus (WNV; Flaviviridae, Flavivirus) have documented the displacement of the introduced NY99 genotype with WN02. In addition, these studies have shown that particular substitutions are under positive selection. One occurs in the C-terminus of the NS4A coding sequence and results in a valine to methionine substitution at position nine of the 2K peptide. 2K-V9M confers the ability to overcome superinfection exclusion in vitro. We hypothesized that WNV strains bearing 2K-V9M have higher fitness than wildtype in Culex quinquefasciatus mosquitoes. Although infection rates and viral titers were not significantly different, virus dissemination rates were significantly higher with WNV 2K-V9M. As a super-infecting virus, WNV 2K-V9M was more successful than wildtype, however, in a mixed infection, 2K-V9M was not. These data support observations that 2K-V9M confers a context-specific selective advantage in mosquitoes and provides an in vivo mechanism for its positive selection.
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Mores CN, Christofferson RC, Davidson SA. The role of the mosquito in a dengue human infection model. J Infect Dis 2014; 209 Suppl 2:S71-8. [PMID: 24872400 DOI: 10.1093/infdis/jiu110] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recent efforts to combat the growing global threat of dengue disease, including deployment of phase IIb vaccine trials, has continued to be hindered by uncertainty surrounding equitable immune responses of serotypes, relative viral fitness of vaccine vs naturally occurring strains, and the importance of altered immune environments due to natural delivery routes. Human infection models can significantly improve our understanding of the importance of certain phenotypic characteristics of viral strains, and inform strain selection and trial design. With human models, we can further assess the importance of the natural delivery route of DENV and/or the accompanying mosquito salivary milieu. Accordingly, we discuss the use of mosquitoes in such a human infection model with DENV, identify important considerations, and make preliminary recommendations for deployment of such a mosquito improved DENV human infection model (miDHIM).
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Affiliation(s)
- Christopher N Mores
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Rebecca C Christofferson
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Silas A Davidson
- Department of Entomology, Walter Reed Army Institute of Research, Silver Spring, Maryland
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Huber K, Jansen S, Leggewie M, Badusche M, Schmidt-Chanasit J, Becker N, Tannich E, Becker SC. Aedes japonicus japonicus (Diptera: Culicidae) from Germany have vector competence for Japan encephalitis virus but are refractory to infection with West Nile virus. Parasitol Res 2014; 113:3195-9. [PMID: 24948103 DOI: 10.1007/s00436-014-3983-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/06/2014] [Indexed: 11/30/2022]
Abstract
The interplay between arthropod-borne (arbo) viruses and their vectors is usually complex and often exert unique relationships. Aedes japonicus japonicus (Hulecoeteomyia japonica or Ochlerotatus japonicus japonicus), an invasive mosquito species with laboratory proven vector competence for a number of emerging viruses has been newly introduced to Germany and is currently expanding its range throughout the country. On the other hand, West Nile virus (WNV), an emerging arbovirus originating from Africa, is already circulating in several European countries and might soon be introduced to Germany. Because newly introduced and rapidly expanding vector species pose a potential risk for public health in Germany, we assessed the vectorial capacity of German Ae. j. japonicus populations for WNV and Japanese encephalitis virus (JEV). The results indicate that German Ae. j. japonicus are susceptible for JEV but are refractory to infection with WNV. Of 67 Ae. j. japonicus females challenged by feeding of WNV-containing blood, none had measurable amounts of WNV-RNA (0% infection rate) on day 14 post-infection. In contrast, all females challenged with JEV were positive for JEV-RNA (100% infection rate) on day 14 post-infection. The reason for WNV resistance remains to be determined but is independent from co-infection with other flaviviruses or the presence of endosymbiotic Wolbachia, since we found no evidence for other flavivirus infections within 1,033 tested A. j. japonicus females from the sampling region, nor detectable Wolbachia infection within 30 randomly selected individuals.
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Affiliation(s)
- Katrin Huber
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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Abstract
West Nile Virus was introduced into the Western Hemisphere during the late summer of 1999 and has been causing significant and sometimes severe human diseases since that time. This article briefly touches upon the biology of the virus and provides a comprehensive review regarding recent discoveries about virus transmission, virus acquisition, and human infection and disease.
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Turell MJ. Members of the Culex pipiens complex as vectors of viruses. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2012; 28:123-126. [PMID: 23401952 DOI: 10.2987/8756-971x-28.4.123] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Members of the Culex pipiens complex have been implicated as vectors of a number of arboviruses including St. Louis encephalitis, West Nile, Sindbis, and Rift Valley fever viruses. For some viruses, such as West Nile virus, laboratory studies have indicated that various members of this complex have a similar ability to become infected with and transmit virus, thus providing evidence for the similarity among the various members of this complex. On the other hand, although strains of Cx. pipiens from various parts of the world have all been relatively efficient vectors of Rift Valley fever virus, Cx. quinquefasciatus from Africa, Australia, and North America have been nearly refractory to this virus, thus indicating that the various members of this complex do not necessarily respond similarly to a particular arbovirus. Based on the similar response to some viruses and differing response to others, Cx. pipiens and Cx. quinquefasciatus appear to be closely related, but distinct species.
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Affiliation(s)
- Michael J Turell
- Department of Vector Assessment, Virology Division, USAMRIID, 1425 Porter Street, Fort Detrick, Maryland 21702-5011, USA
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Szemiel AM, Failloux AB, Elliott RM. Role of Bunyamwera Orthobunyavirus NSs protein in infection of mosquito cells. PLoS Negl Trop Dis 2012; 6:e1823. [PMID: 23029584 PMCID: PMC3459826 DOI: 10.1371/journal.pntd.0001823] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 08/06/2012] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Bunyamwera orthobunyavirus is both the prototype and study model of the Bunyaviridae family. The viral NSs protein seems to contribute to the different outcomes of infection in mammalian and mosquito cell lines. However, only limited information is available on the growth of Bunyamwera virus in cultured mosquito cells other than the Aedes albopictus C6/36 line. METHODOLOGY AND PRINCIPAL FINDINGS To determine potential functions of the NSs protein in mosquito cells, replication of wild-type virus and a recombinant NSs deletion mutant was compared in Ae. albopictus C6/36, C7-10 and U4.4 cells, and in Ae. aegypti Ae cells by monitoring N protein production and virus yields at various times post infection. Both viruses established persistent infections, with the exception of NSs deletion mutant in U4.4 cells. The NSs protein was nonessential for growth in C6/36 and C7-10 cells, but was important for productive replication in U4.4 and Ae cells. Fluorescence microscopy studies using recombinant viruses expressing green fluorescent protein allowed observation of three stages of infection, early, acute and late, during which infected cells underwent morphological changes. In the absence of NSs, these changes were less pronounced. An RNAi response efficiently reduced virus replication in U4.4 cells transfected with virus specific dsRNA, but not in C6/36 or C7/10 cells. Lastly, Ae. aegypti mosquitoes were exposed to blood-meal containing either wild-type or NSs deletion virus, and at various times post-feeding, infection and disseminated infection rates were measured. Compared to wild-type virus, infection rates by the mutant virus were lower and more variable. If the NSs deletion virus was able to establish infection, it was detected in salivary glands at 6 days post-infection, 3 days later than wild-type virus. CONCLUSIONS/SIGNIFICANCE Bunyamwera virus NSs is required for efficient replication in certain mosquito cell lines and in Ae. aegypti mosquitoes.
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Affiliation(s)
- Agnieszka M. Szemiel
- Biomedical Sciences Research Complex, School of Biology, University of St. Andrews, North Haugh, St. Andrews, Scotland, United Kingdom
| | | | - Richard M. Elliott
- Biomedical Sciences Research Complex, School of Biology, University of St. Andrews, North Haugh, St. Andrews, Scotland, United Kingdom
- * E-mail:
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Machado DC, Mondini A, Santana VDS, Yonamine PTK, Chiaravalloti Neto F, Zanotto PMDA, Nogueira ML. First Identification of Culex flavivirus (Flaviviridae) in Brazil. Intervirology 2012; 55:475-83. [DOI: 10.1159/000337166] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 01/31/2012] [Indexed: 11/19/2022] Open
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Vázquez A, Sánchez-Seco MP, Palacios G, Molero F, Reyes N, Ruiz S, Aranda C, Marqués E, Escosa R, Moreno J, Figuerola J, Tenorio A. Novel flaviviruses detected in different species of mosquitoes in Spain. Vector Borne Zoonotic Dis 2011; 12:223-9. [PMID: 22022811 DOI: 10.1089/vbz.2011.0687] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We report the characterization of three novel flaviviruses isolated in Spain. Marisma Mosquito virus, a novel mosquito borne virus, was isolated from Ochlerotatus caspius mosquitoes; Spanish Ochlerotatus flavivirus and Spanish Culex flavivirus, two novel insect flaviviruses, were isolated from Oc. caspius and Culex pipiens, respectively. During this investigation, we designed a sensitive RT-nested polymerase chain reaction method that amplifies a 1019bp fragment of the flavivirus NS5 gene and could be directly used in clinical or environmental samples for flavivirus characterization and surveillance. Analysis of the sequence generated from that amplicon contains enough phylogenetic information for proper taxonomic studies. Moreover, the use of this tool allowed the detection of additional flavivirus DNA forms in Culex, Culiseta, and Ochlerotatus mosquitoes.
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Affiliation(s)
- Ana Vázquez
- Laboratory of Arboviruses and Imported Viral Diseases, National Center for Microbiology, Instituto de Salud Carlos III-ISCIII, Madrid, Spain.
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Langevin SA, Bowen RA, Ramey WN, Sanders TA, Maharaj PD, Fang Y, Cornelius J, Barker CM, Reisen WK, Beasley DWC, Barrett ADT, Kinney RM, Huang CYH, Brault AC. Envelope and pre-membrane protein structural amino acid mutations mediate diminished avian growth and virulence of a Mexican West Nile virus isolate. J Gen Virol 2011; 92:2810-2820. [PMID: 21865445 DOI: 10.1099/vir.0.035535-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The hallmark attribute of North American West Nile virus (WNV) strains has been high pathogenicity in certain bird species. Surprisingly, this avian virulent WNV phenotype has not been observed during its geographical expansion into the Caribbean, Central America and South America. One WNV variant (TM171-03-pp1) isolated in Mexico has demonstrated an attenuated phenotype in two widely distributed North American bird species, American crows (AMCRs) and house sparrows (HOSPs). In order to identify genetic determinants associated with attenuated avian replication of the TM171-03-pp1 variant, chimeric viruses between the NY99 and Mexican strains were generated, and their replicative capacity was assessed in cell culture and in AMCR, HOSP and house finch avian hosts. The results demonstrated that mutations in both the pre-membrane (prM-I141T) and envelope (E-S156P) genes mediated the attenuation phenotype of the WNV TM171-03-pp1 variant in a chicken macrophage cell line and in all three avian species assayed. Inclusion of the prM-I141T and E-S156P TM171-03-pp1 mutations in the NY99 backbone was necessary to achieve the avian attenuation level of the Mexican virus. Furthermore, reciprocal incorporation of both prM-T141I and E-P156S substitutions into the Mexican virus genome was necessary to generate a virus that exhibited avian virulence equivalent to the NY99 virus. These structural changes may indicate the presence of new evolutionary pressures exerted on WNV populations circulating in Latin America or may signify a genetic bottleneck that has constrained their epiornitic potential in alternative geographical locations.
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Affiliation(s)
- Stanley A Langevin
- Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - Richard A Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Wanichaya N Ramey
- Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - Todd A Sanders
- Colorado Division of Wildlife, Fort Collins, CO 80526, USA
| | - Payal D Maharaj
- Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - Ying Fang
- Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - Jennine Cornelius
- Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - Christopher M Barker
- Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - William K Reisen
- Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - David W C Beasley
- Departments of Pathology and Microbiology and Immunology, Center for Emerging Infectious Diseases and Biodefense, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Alan D T Barrett
- Departments of Pathology and Microbiology and Immunology, Center for Emerging Infectious Diseases and Biodefense, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Richard M Kinney
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
| | - Claire Y-H Huang
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
| | - Aaron C Brault
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA.,Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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Diaz-Badillo A, Bolling BG, Perez-Ramirez G, Moore CG, Martinez-Munoz JP, Padilla-Viveros AA, Camacho-Nuez M, Diaz-Perez A, Beaty BJ, Munoz MDL. The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City. Parasit Vectors 2011; 4:70. [PMID: 21554725 PMCID: PMC3117809 DOI: 10.1186/1756-3305-4-70] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 05/09/2011] [Indexed: 01/06/2023] Open
Abstract
Background Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids. Results Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio) of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected. Conclusions Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p. quinquefasciatus were also collected and identified. The presence and abundance of these WNV competent vectors is a cause for concern. Understanding the distribution of these vectors can help improve viral surveillance activities and mosquito control efforts in Mexico City.
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Affiliation(s)
- Alvaro Diaz-Badillo
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Madero, México DF, México
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Kent RJ, Crabtree MB, Miller BR. Transmission of West Nile virus by Culex quinquefasciatus say infected with Culex Flavivirus Izabal. PLoS Negl Trop Dis 2010; 4:e671. [PMID: 20454569 PMCID: PMC2864301 DOI: 10.1371/journal.pntd.0000671] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 03/18/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The natural history and potential impact of mosquito-specific flaviviruses on the transmission efficiency of West Nile virus (WNV) is unknown. The objective of this study was to determine whether or not prior infection with Culex flavivirus (CxFV) Izabal altered the vector competence of Cx. quinquefasciatus Say for transmission of a co-circulating strain of West Nile virus (WNV) from Guatemala. METHODS AND FINDINGS CxFV-negative Culex quinquefasciatus and those infected with CxFV Izabal by intrathoracic inoculation were administered WNV-infectious blood meals. Infection, dissemination, and transmission of WNV were measured by plaque titration on Vero cells of individual mosquito bodies, legs, or saliva, respectively, two weeks following WNV exposure. Additional groups of Cx. quinquefasciatus were intrathoracically inoculated with WNV alone or WNV+CxFV Izabal simultaneously, and saliva collected nine days post inoculation. Growth of WNV in Aedes albopictus C6/36 cells or Cx. quinquefasciatus was not inhibited by prior infection with CxFV Izabal. There was no significant difference in the vector competence of Cx. quinquefasciatus for WNV between mosquitoes uninfected or infected with CxFV Izabal across multiple WNV blood meal titers and two colonies of Cx. quinquefasciatus (p>0.05). However, significantly more Cx. quinquefasciatus from Honduras that were co-inoculated simultaneously with both viruses transmitted WNV than those inoculated with WNV alone (p = 0.0014). Co-inoculated mosquitoes that transmitted WNV also contained CxFV in their saliva, whereas mosquitoes inoculated with CxFV alone did not contain virus in their saliva. CONCLUSIONS In the sequential infection experiments, prior infection with CxFV Izabal had no significant impact on WNV replication, infection, dissemination, or transmission by Cx. quinquefasciatus, however WNV transmission was enhanced in the Honduras colony when mosquitoes were inoculated simultaneously with both viruses.
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Affiliation(s)
- Rebekah J Kent
- Division of Vector-Borne Infectious Diseases, Arbovirus Diseases Branch, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
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Diversification of West Nile virus in a subtropical region. Virol J 2009; 6:106. [PMID: 19607722 PMCID: PMC2720385 DOI: 10.1186/1743-422x-6-106] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Accepted: 07/16/2009] [Indexed: 11/24/2022] Open
Abstract
Background West Nile virus (WNV) has spread across North, Central, and South America since its introduction in 1999. At the start of this spread, Florida was considered a potentially important area with regards to transmission due to its geographic, climatological, and demographic conditions. Curiously, the anticipated high levels of transmission or disease outbreaks have not been observed. As other studies have predicted that the lack of intense WNV transmission is not due to vector incompetence, we sought to evaluate the role of viral strain diversity in WNV transmission in Florida. Therefore, a phylogentic analysis was carried out on several isolates collected from three distinct locations in Florida. Results Contrasting with a positive control collected in Indian River County, Florida during 2003 that contains the original NY99 genotype with valanine at amino acid 159 of the envelope region, all of the isolates collected in 2005 contain the WN02 genotype composed of a substation with alanine at that position indicating the window of introduction of the WN02 genotype occurred between 2003 and 2005. From the eight isolates collected in Duval, Indian River, and Manatee Counties; there is also a silent nucleotide substitution that differentiates the isolates collected on the Atlantic side of the state compared to the isolate collected on the Gulf side, which groups closer to isolates from other locations near the Gulf. Conclusion As a whole, the Florida isolates contained numerous variable nucleotide and amino acid sites from the reference sequences, as well as each other; indicating greater nucleotide diversity within the Florida 2005 isolates than within other regions. Finally, a series of three amino acid substitutions surrounding a set of histidines located in the envelope coding region that hypothesized to play a role in conformational changes was found in the isolate collected in Indian River County, perhaps changing the antigenicity of the homodimer. Taken together, these findings expand our understanding of the temporal and spatial compartmentalization of West Nile virus subtypes within North America.
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