1
|
Lwande OW, Näslund J, Sjödin A, Lantto R, Luande VN, Bucht G, Ahlm C, Agwanda B, Obanda V, Evander M. Novel strains of Culex flavivirus and Hubei chryso-like virus 1 from the Anopheles mosquito in western Kenya. Virus Res 2024; 339:199266. [PMID: 37944758 PMCID: PMC10682293 DOI: 10.1016/j.virusres.2023.199266] [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] [Received: 06/19/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/12/2023]
Abstract
Surveillance of mosquito vectors is critical for early detection, prevention and control of vector borne diseases. In this study we used advanced molecular tools, such as DNA barcoding in combination with novel sequencing technologies to discover new and already known viruses in genetically identified mosquito species. Mosquitoes were captured using BG sentinel traps in Western Kenya during May and July 2019, and homogenized individually before pooled into groups of ten mosquitoes. The pools and individual samples were then used for molecular analysis and to infect cell cultures. Of a total of fifty-four (54) 10-pools, thirteen (13) showed cytopathic effect (CPE) on VeroB4 cells, eighteen (18) showed CPE on C6/36 cells. Eight (8) 10-pools out of the 31 CPE positive pools showed CPE on both VeroB4 and C6/36 cells. When using reverse transcriptase polymerase chain reaction (RT-PCR), Sanger sequencing and Twist Comprehensive Viral Research Panel (CVRP) (Twist Biosciences), all pools were found negative by RT-PCR when using genus specific primers targeting alphaviruses, orthobunyaviruses and virus specific primers towards o'nyong-nyong virus, chikungunya virus and Sindbis virus (previously reported to circulate in the region). Interestingly, five pools were RT-PCR positive for flavivirus. Two of the RT-PCR positive pools showed CPE on both VeroB4 and C6/36 cells, two pools showed CPE on C6/36 cells alone and one pool on VeroB4 cells only. Fifty individual mosquito homogenates from the five RT-PCR positive 10-pools were analyzed further for flavivirus RNA. Of these, 19 out of the 50 individual mosquito homogenates indicated the presence of flavivirus RNA. Barcoding of the flavivirus positive mosquitoes revealed the mosquito species as Aedes aegypti (1), Mansonia uniformis (6), Anopheles spp (3), Culex pipiens (5), Culex spp (1), Coquilletidia metallica (2) and Culex quinquefasciatus (1). Of the 19 flavivirus positive individual mosquitoes, five (5) virus positive homogenates were sequenced. Genome sequences of two viruses were completed. One was identified as the single-stranded RNA Culex flavivirus and the other as the double-stranded RNA Hubei chryso-like virus 1. Both viruses were found in the same Anopheles spp. homogenate extracted from a sample that showed CPE on both VeroB4 and C6/36 cells. The detection of both viruses in a single mosquito homogenate indicated coinfection. Phylogenetic analyses suggested that the Culex flavivirus sequence detected was closely related to a Culex flavivirus isolated from Uganda in 2008. All four Hubei chryso-like virus 1 segments clusters closely to Hubei chryso-like virus 1 strains isolated in Australia, China and USA. Two novel strains of insect-specific viruses in Anopheles mosquitoes were detected and characterized.
Collapse
Affiliation(s)
- Olivia Wesula Lwande
- Department of Clinical Microbiology, Umeå University, Umeå 901-85, Sweden; Umeå Centre for Microbial Research, Umeå University, Umeå 901-87, Sweden.
| | - Jonas Näslund
- Swedish Defence Research Agency, CBRN, Defence and Security, Umeå 901 82, Sweden
| | - Andreas Sjödin
- Swedish Defence Research Agency, CBRN, Defence and Security, Umeå 901 82, Sweden
| | - Rebecca Lantto
- Department of Clinical Microbiology, Umeå University, Umeå 901-85, Sweden
| | | | - Göran Bucht
- Department of Clinical Microbiology, Umeå University, Umeå 901-85, Sweden
| | - Clas Ahlm
- Department of Clinical Microbiology, Umeå University, Umeå 901-85, Sweden; Umeå Centre for Microbial Research, Umeå University, Umeå 901-87, Sweden
| | - Bernard Agwanda
- Mammalogy Section, National Museums of Kenya, Nairobi 40658-00100, Kenya
| | - Vincent Obanda
- Department of Research Permitting and Compliance Wildlife Research and Training Institute, Naivasha 842-20117, Kenya
| | - Magnus Evander
- Department of Clinical Microbiology, Umeå University, Umeå 901-85, Sweden; Umeå Centre for Microbial Research, Umeå University, Umeå 901-87, Sweden
| |
Collapse
|
2
|
Leal É, Ribeiro ESD'A, Monteiro FJC, Marques JP, Dos Santos Mendes D, Morais VS, Araújo ELL, Pandey RP, Chang CM, Deng X, Delwart E, da Costa AC, Lima K. Aedes aegypti Totivirus identified in mosquitoes in the Brazilian Amazon region. Virus Genes 2023; 59:167-172. [PMID: 36394716 DOI: 10.1007/s11262-022-01955-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/31/2022] [Indexed: 11/19/2022]
Abstract
The totiviridae family contains viruses with double-stranded RNA genomes of 4.6-7.0 kpb, which encode a capsid protein (CP) and RNA-dependent RNA polymerase (RdRp), and they are approximately 40 nm in diameter with icosahedral symmetry. Totiviruses were first isolated from mosquitoes collected in Shaanxi Province (China). Here, we report a new Aedes aegypti Totivirus (AaTV) identified in mosquitoes from the Amazon rainforest. Mosquitoes (Diptera: Culicidae) were collected from a forest reserve belonging to the Amazon forest in the city of Macapá, Amapá state, Northern Brazil. A viral sequence with a 5748 nucleotide length that was nearly identical to Aedes aegypti Totivirus (AaTV), here named Aedes aegypti Totivirus BR59AP, was detected. A detailed molecular analysis was performed and shows that AaTV-BR59AP is highly related to the AaTV strain from the Caribbean region. We emphasize the importance of the characterization of new viruses in mosquitoes to deepen our understanding of viral diversity in insects and their potential role in disease.
Collapse
Affiliation(s)
- Élcio Leal
- Laboratório de Diversidade Viral, Instituto de Ciências Biológicas, Universidade Federal Do Pará, Belem, Pará, 66075-000, Brazil
| | | | - Fred Julio Costa Monteiro
- Public Health Laboratory of Amapa-LACEN/AP, Health Surveillance Superintendence of Amapa, Macapa, 68905-230, Brazil
| | - Julia Pantoja Marques
- Public Health Laboratory of Amapa-LACEN/AP, Health Surveillance Superintendence of Amapa, Macapa, 68905-230, Brazil
| | - Diuliana Dos Santos Mendes
- Public Health Laboratory of Amapa-LACEN/AP, Health Surveillance Superintendence of Amapa, Macapa, 68905-230, Brazil
| | - Vanessa S Morais
- Faculdade de Medicina, Instituto de Medicina Tropical, Universidade de São Paulo, São Paulo, 05403-000, Brazil
| | - Emerson Luiz Lima Araújo
- General Coordination of Public Health Laboratories of the Strategic Articulation, Department of the Health Surveillance, Secretariat of the Ministry of Health (CGLAB/DAEVS/SVS-MS), Brasília, 70719-040, Brazil
| | - Ramendra Pati Pandey
- Centre for Drug Design Discovery and Development (C4D), SRM University, Delhi-NCR, Rajiv Gandhi Education City, Sonepat, Haryana, 131029, India
| | - Chung-Ming Chang
- Master & Ph.D. Program in Biotechnology Industry, Chang Gung University, No.259, Wenhua 1St Rd., Guishan Dist, Taoyuan, 33302, Taiwan, ROC
| | - Xutao Deng
- Vitalant Research Institute, 270 Masonic Avenue, San Francisco, CA, 94118-4417, USA.,Department Laboratory Medicine, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Eric Delwart
- Vitalant Research Institute, 270 Masonic Avenue, San Francisco, CA, 94118-4417, USA.,Department Laboratory Medicine, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Antonio Charlys da Costa
- Faculdade de Medicina, Instituto de Medicina Tropical, Universidade de São Paulo, São Paulo, 05403-000, Brazil
| | - Kledoaldo Lima
- Hospital das Clínicas, Federal University of Pernambuco, Recife, PE, 50670-901, Brazil. .,European Virus Bioinformatics Center, Leutragraben 1, 07743, Jena, Germany. .,Faculdade Pernambucana de Saúde, Recife, PE, 51150-000, Brazil.
| |
Collapse
|
3
|
Harrison JJ, Hobson-Peters J, Bielefeldt-Ohmann H, Hall RA. Chimeric Vaccines Based on Novel Insect-Specific Flaviviruses. Vaccines (Basel) 2021; 9:1230. [PMID: 34835160 PMCID: PMC8623431 DOI: 10.3390/vaccines9111230] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 12/30/2022] Open
Abstract
Vector-borne flaviviruses are responsible for nearly half a billion human infections worldwide each year, resulting in millions of cases of debilitating and severe diseases and approximately 115,000 deaths. While approved vaccines are available for some of these viruses, the ongoing efficacy, safety and supply of these vaccines are still a significant problem. New technologies that address these issues and ideally allow for the safe and economical manufacture of vaccines in resource-poor countries where flavivirus vaccines are in most demand are urgently required. Preferably a new vaccine platform would be broadly applicable to all flavivirus diseases and provide new candidate vaccines for those diseases not yet covered, as well as the flexibility to rapidly pivot to respond to newly emerged flavivirus diseases. Here, we review studies conducted on novel chimeric vaccines derived from insect-specific flaviviruses that provide a potentially safe and simple system to produce highly effective vaccines against a broad spectrum of flavivirus diseases.
Collapse
Affiliation(s)
- Jessica J. Harrison
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia; (J.H.-P.); (H.B.-O.); (R.A.H.)
| | - Jody Hobson-Peters
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia; (J.H.-P.); (H.B.-O.); (R.A.H.)
| | - Helle Bielefeldt-Ohmann
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia; (J.H.-P.); (H.B.-O.); (R.A.H.)
- School of Veterinary Science, University of Queensland, Gatton, QLD 4343, Australia
| | - Roy A. Hall
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia; (J.H.-P.); (H.B.-O.); (R.A.H.)
| |
Collapse
|
4
|
Daidoji T, Morales Vargas RE, Hagiwara K, Arai Y, Watanabe Y, Nishioka K, Murakoshi F, Garan K, Sadakane H, Nakaya T. Development of genus-specific universal primers for the detection of flaviviruses. Virol J 2021; 18:187. [PMID: 34526049 PMCID: PMC8442469 DOI: 10.1186/s12985-021-01646-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/23/2021] [Indexed: 12/03/2022] Open
Abstract
Background Flaviviruses are representative arboviruses carried by arthropods and/or vertebrates; these viruses can pose a public health concern in many countries. By contrast, it is known that a novel virus group called insect-specific flaviviruses (ISFs) also infects arthropods, although no such virus has yet been isolated from vertebrates. The characteristics of ISFs, which affect replication of human-pathogenic flaviviruses within co-infected mosquito cells or mosquitoes without affecting the mosquitoes themselves, mean that we should pay attention to both ISFs and human-pathogenic flaviviruses, despite the fact that ISFs appear not to be directly hazardous to human health. To assess the risk of diseases caused by flaviviruses, and to better understand their ecology, it is necessary to know the extent to which flaviviruses are harbored by arthropods. Methods We developed a novel universal primer for use in a PCR-based system to detect a broad range of flaviviruses. We then evaluated its performance. The utility of the novel primer pair was evaluated in a PCR assay using artificially synthesized oligonucleotides derived from a template viral genome sequence. The utility of the primer pair was also examined by reverse transcription PCR (RT-PCR) using cDNA templates prepared from virus-infected cells or crude supernatants prepared from virus-containing mosquito homogenates. Results The novel primer pair amplified the flavivirus NS5 sequence (artificially synthesized) in all samples tested (six species of flavivirus that can cause infectious diseases in humans, and flaviviruses harbored by insects). In addition, the novel primer pair detected viral genomes in cDNA templates prepared from mosquito cells infected with live flavivirus under different infectious conditions. Finally, the viral genome was detected with high sensitivity in crude supernatants prepared from pooled mosquito homogenates. Conclusion This PCR system based on a novel primer pair makes it possible to detect arthropod-borne flaviviruses worldwide (the primer pair even detected viruses belonging to different genetic subgroups). As such, an assay based on this primer pair may help to improve public health and safety, as well as increase our understanding of flavivirus ecology. Supplementary Information The online version contains supplementary material available at 10.1186/s12985-021-01646-5.
Collapse
Affiliation(s)
- Tomo Daidoji
- Department of Infectious Diseases, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan.
| | | | - Katsuro Hagiwara
- Veterinary Virology, School of Veterinary Medicine , Rakuno Gakuen University, Hokkaido, 069-8501, Japan
| | - Yasuha Arai
- Department of Infectious Diseases, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Yohei Watanabe
- Department of Infectious Diseases, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Keisuke Nishioka
- Department of Infectious Diseases, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Fumi Murakoshi
- Department of Infectious Diseases, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Kotaro Garan
- Department of Infectious Diseases, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Hiroki Sadakane
- Department of Infectious Diseases, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Takaaki Nakaya
- Department of Infectious Diseases, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| |
Collapse
|
5
|
Laureti M, Paradkar PN, Fazakerley JK, Rodriguez-Andres J. Superinfection Exclusion in Mosquitoes and Its Potential as an Arbovirus Control Strategy. Viruses 2020; 12:v12111259. [PMID: 33167513 PMCID: PMC7694488 DOI: 10.3390/v12111259] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 12/19/2022] Open
Abstract
The continuing emergence of arbovirus disease outbreaks around the world, despite the use of vector control strategies, warrants the development of new strategies to reduce arbovirus transmission. Superinfection exclusion, a phenomenon whereby a primary virus infection prevents the replication of a second closely related virus, has potential to control arbovirus disease emergence and outbreaks. This phenomenon has been observed for many years in plants, insects and mammalian cells. In this review, we discuss the significance of identifying novel vector control strategies, summarize studies exploring arbovirus superinfection exclusion and consider the potential for this phenomenon to be the basis for novel arbovirus control strategies.
Collapse
Affiliation(s)
- Mathilde Laureti
- Peter Doherty Institute for Infection and Immunity and Faculty of Veterinary and Agricultural Sciences, University of Melbourne, VIC 3000 Melbourne, Australia;
- CSIRO Health & Biosecurity, Australian Centre for Diseases Preparedness, VIC 3220 Geelong, Australia;
- Correspondence: (M.L.); (J.R.-A.)
| | - Prasad N. Paradkar
- CSIRO Health & Biosecurity, Australian Centre for Diseases Preparedness, VIC 3220 Geelong, Australia;
| | - John K. Fazakerley
- Peter Doherty Institute for Infection and Immunity and Faculty of Veterinary and Agricultural Sciences, University of Melbourne, VIC 3000 Melbourne, Australia;
| | - Julio Rodriguez-Andres
- Peter Doherty Institute for Infection and Immunity and Faculty of Veterinary and Agricultural Sciences, University of Melbourne, VIC 3000 Melbourne, Australia;
- Correspondence: (M.L.); (J.R.-A.)
| |
Collapse
|
6
|
Kubacki J, Flacio E, Qi W, Guidi V, Tonolla M, Fraefel C. Viral Metagenomic Analysis of Aedes albopictus Mosquitos from Southern Switzerland. Viruses 2020; 12:v12090929. [PMID: 32846980 PMCID: PMC7552062 DOI: 10.3390/v12090929] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 02/07/2023] Open
Abstract
A metagenomic study was performed on 498 female and 40 male Aedes albopictus mosquitos collected in August and September 2019 in Ticino, a region in southern Switzerland, to address the question regarding the risk of the local transmission of zoonotic viruses. A total of 13 viruses from seven different virus families and several unclassified viral taxa were identified. Reads of insect-specific flaviviruses were present in all pools, and a complete genome of aedes flavivirus was assembled and phylogenetically analysed. The most abundant virus was Wenzhou sobemo-like virus, assembled from 1.3 × 105 to 3.6 × 106 reads in each pool. In a pool of male mosquitos, a complete genome of aedes Iflavi-like virus was detected and phylogenetically analysed. Most importantly, genomes of human pathogenic viruses were not found. This is the first study to determine the virome of Ae. albopictus from Switzerland and forms a baseline for future longitudinal investigations concerning the potential role of Ae. albopictus as a vector of clinically relevant viruses.
Collapse
Affiliation(s)
- Jakub Kubacki
- Institute of Virology, University of Zürich, CH-8057 Zürich, Switzerland
- Correspondence: (J.K.); (C.F.)
| | - Eleonora Flacio
- Laboratory of Applied Microbiology, Department for Environment Constructions and Design, University of Applied Sciences and Arts of Southern Switzerland, CH-6500 Manno, Switzerland; (E.F.); (V.G.); (M.T.)
| | - Weihong Qi
- Functional Genomics Center Zurich, CH-8057 Zürich, Switzerland;
| | - Valeria Guidi
- Laboratory of Applied Microbiology, Department for Environment Constructions and Design, University of Applied Sciences and Arts of Southern Switzerland, CH-6500 Manno, Switzerland; (E.F.); (V.G.); (M.T.)
| | - Mauro Tonolla
- Laboratory of Applied Microbiology, Department for Environment Constructions and Design, University of Applied Sciences and Arts of Southern Switzerland, CH-6500 Manno, Switzerland; (E.F.); (V.G.); (M.T.)
| | - Cornel Fraefel
- Institute of Virology, University of Zürich, CH-8057 Zürich, Switzerland
- Correspondence: (J.K.); (C.F.)
| |
Collapse
|
7
|
Gomulski LM, Manni M, Carraretto D, Nolan T, Lawson D, Ribeiro JM, Malacrida AR, Gasperi G. Transcriptional variation of sensory-related genes in natural populations of Aedes albopictus. BMC Genomics 2020; 21:547. [PMID: 32767966 PMCID: PMC7430840 DOI: 10.1186/s12864-020-06956-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/27/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The Asian tiger mosquito, Aedes albopictus, is a highly dangerous invasive vector of numerous medically important arboviruses including dengue, chikungunya and Zika. In four decades it has spread from tropical Southeast Asia to many parts of the world in both tropical and temperate climes. The rapid invasion process of this mosquito is supported by its high ecological and genetic plasticity across different life history traits. Our aim was to investigate whether wild populations, both native and adventive, also display transcriptional genetic variability for functions that may impact their biology, behaviour and ability to transmit arboviruses, such as sensory perception. RESULTS Antennal transcriptome data were derived from mosquitoes from a native population from Ban Rai, Thailand and from three adventive Mediterranean populations: Athens, Greece and Arco and Trento from Italy. Clear inter-population differential transcriptional activity was observed in different gene categories related to sound perception, olfaction and viral infection. The greatest differences were detected between the native Thai and the Mediterranean populations. The two Italian populations were the most similar. Nearly one million quality filtered SNP loci were identified. CONCLUSION The ability to express this great inter-population transcriptional variability highlights, at the functional level, the remarkable genetic flexibility of this mosquito species. We can hypothesize that the differential expression of genes, including those involved in sensory perception, in different populations may enable Ae. albopictus to exploit different environments and hosts, thus contributing to its status as a global vector of arboviruses of public health importance. The large number of SNP loci present in these transcripts represents a useful addition to the arsenal of high-resolution molecular markers and a resource that can be used to detect selective pressure and adaptive changes that may have occurred during the colonization process.
Collapse
Affiliation(s)
- Ludvik M Gomulski
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Mosè Manni
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
- Department of Genetic Medicine and Development, University of Geneva Medical School, and Swiss Institute of Bioinformatics, Geneva, Switzerland
| | - Davide Carraretto
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Tony Nolan
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Daniel Lawson
- Department of Life Sciences, Imperial College London, London, UK
| | - José M Ribeiro
- NIAID, Laboratory of Malaria and Vector Research, NIH, Rockville, MD, 20852, USA
| | - Anna R Malacrida
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Giuliano Gasperi
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy.
| |
Collapse
|
8
|
Abílio AP, Silva M, Kampango A, Narciso I, Gudo ES, das Neves LCB, Sidat M, Fafetine JM, de Almeida APG, Parreira R. A survey of RNA viruses in mosquitoes from Mozambique reveals novel genetic lineages of flaviviruses and phenuiviruses, as well as frequent flavivirus-like viral DNA forms in Mansonia. BMC Microbiol 2020; 20:225. [PMID: 32723369 PMCID: PMC7385898 DOI: 10.1186/s12866-020-01905-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/14/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Mosquito-borne diseases involving arboviruses represent expanding threats to sub-Saharan Africa imposing as considerable burden to human and veterinary public health. In Mozambique over one hundred species of potential arbovirus mosquito vectors have been identified, although their precise role in maintaining such viruses in circulation in the country remains to be elucidated. The aim of this study was to screen for the presence of flaviviruses, alphaviruses and bunyaviruses in mosquitoes from different regions of Mozambique. RESULTS Our survey analyzed 14,519 mosquitoes, and the results obtained revealed genetically distinct insect-specific flaviviruses, detected in multiple species of mosquitoes from different genera. In addition, smaller flavivirus-like NS5 sequences, frequently detected in Mansonia seemed to correspond to defective viral sequences, present as viral DNA forms. Furthermore, three lineages of putative members of the Phenuiviridae family were also detected, two of which apparently corresponding to novel viral genetic lineages. CONCLUSION This study reports for the first-time novel insect-specific flaviviruses and novel phenuiviruses, as well as frequent flavivirus-like viral DNA forms in several widely known vector species. This unique work represents recent investigation of virus screening conducted in mosquitoes from Mozambique and an important contribution to inform the establishment of a vector control program for arbovirus in the country and in the region.
Collapse
Affiliation(s)
- Ana Paula Abílio
- Instituto Nacional de Saúde (INS)-Ministry of Health (MISAU), Vila de Marracuene, Estrada Nacional N°1, Parcela N°3943, P.O. Box: 264, Maputo, Mozambique.
- Faculty of Medicine, Eduardo Mondlane University (UEM), Maputo, Mozambique.
| | - Manuel Silva
- Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical (IHMT)/Universidade Nova de Lisboa (NOVA), and Global Health and Tropical Medicine (GHTM) Research Centre, Lisbon, Portugal
| | - Ayubo Kampango
- Instituto Nacional de Saúde (INS)-Ministry of Health (MISAU), Vila de Marracuene, Estrada Nacional N°1, Parcela N°3943, P.O. Box: 264, Maputo, Mozambique
| | - Inácio Narciso
- Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical (IHMT)/Universidade Nova de Lisboa (NOVA), and Global Health and Tropical Medicine (GHTM) Research Centre, Lisbon, Portugal
| | - Eduardo Samo Gudo
- Instituto Nacional de Saúde (INS)-Ministry of Health (MISAU), Vila de Marracuene, Estrada Nacional N°1, Parcela N°3943, P.O. Box: 264, Maputo, Mozambique
| | | | - Mohsin Sidat
- Faculty of Medicine, Eduardo Mondlane University (UEM), Maputo, Mozambique
| | | | - António Paulo Gouveia de Almeida
- Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical (IHMT)/Universidade Nova de Lisboa (NOVA), and Global Health and Tropical Medicine (GHTM) Research Centre, Lisbon, Portugal
| | - Ricardo Parreira
- Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical (IHMT)/Universidade Nova de Lisboa (NOVA), and Global Health and Tropical Medicine (GHTM) Research Centre, Lisbon, Portugal
| |
Collapse
|
9
|
Martin E, Tang W, Briggs C, Hopson H, Juarez JG, Garcia-Luna SM, de Valdez MW, Badillo-Vargas IE, Borucki MK, Frank M, Hamer GL. Cell fusing agent virus (Flavivirus) infection in Aedes aegypti in Texas: seasonality, comparison by trap type, and individual viral loads. Arch Virol 2020; 165:1769-1776. [PMID: 32440701 PMCID: PMC7351801 DOI: 10.1007/s00705-020-04652-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 04/10/2020] [Indexed: 11/05/2022]
Abstract
South Texas has experienced local transmission of Zika virus and of other mosquito-borne viruses such as chikungunya virus and dengue virus in the last decades. Using a mosquito surveillance program in the Lower Rio Grande Valley (LRGV) and San Antonio, TX, from 2016 to 2018, we detected the presence of an insect-specific virus, cell fusing agent virus (CFAV), in the Aedes aegypti mosquito population. We tested 6,326 females and 1,249 males from the LRGV and 659 females from San Antonio for CFAV by RT-PCR using specific primers. Infection rates varied from 0 to 261 per 1,000 mosquitoes in the LRGV and 115 to 208 per 1,000 in San Antonio depending on the month of collection. Infection rates per 1,000 individuals appeared higher in females collected from BG Sentinel 2 traps compared to Autocidal Gravid Ovitraps, but the ratio of the percentage of infected pools did not differ by trap type. The natural viral load in individual males ranged from 1.25 x 102 to 5.50 x 106 RNA copies and in unfed females from 5.42 x 103 to 8.70 x 106 RNA copies. Gravid females were found to harbor fewer viral particles than males and unfed females.
Collapse
Affiliation(s)
- Estelle Martin
- Department of Entomology, Texas A&M University, College Station, TX, USA. .,Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA.
| | - Wendy Tang
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Cierra Briggs
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Helena Hopson
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Jose G Juarez
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | | | - Megan Wise de Valdez
- Department of Science and Mathematics, Texas A&M University-San Antonio, San Antonio, TX, USA
| | | | | | - Matthias Frank
- Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Gabriel L Hamer
- Department of Entomology, Texas A&M University, College Station, TX, USA.
| |
Collapse
|
10
|
Akıner MM, Öztürk M, Başer AB, Günay F, Hacıoğlu S, Brinkmann A, Emanet N, Alten B, Özkul A, Nitsche A, Linton YM, Ergünay K. Arboviral screening of invasive Aedes species in northeastern Turkey: West Nile virus circulation and detection of insect-only viruses. PLoS Negl Trop Dis 2019; 13:e0007334. [PMID: 31059502 PMCID: PMC6522068 DOI: 10.1371/journal.pntd.0007334] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 05/16/2019] [Accepted: 03/26/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The recent reports of Aedes aegypti and Ae. albopictus populations in Turkey, in parallel with the territorial expansion identified in several surrounding countries, have raised concerns about the establishment and re-establishment of these invasive Aedes mosquitoes in Turkey. This cross-sectional study was performed to detect Aedes aegypti and Ae. albopictus in regions of recent incursions, and screen for viral pathogens known to be transmitted elsewhere by these species. METHODOLOGY Mosquitoes were collected at several locations in Artvin, Rize and Trabzon provinces of the Black Sea region during 2016-2017, identified morphologically, pooled and analyzed via generic or specific nucleic acid amplification assays. Viruses in positive pools were identified by product sequencing, cell culture inoculation and next generation sequencing (NGS) in selected specimens. PRINCIPAL FINDINGS The study group comprised 791 specimens. Aedes albopictus was the most abundant species in all locations (89.6%), followed by Ae. aegypti (7.8%) and Culex pipiens (2.5%). Mosquitoes were screened for viruses in 65 pools where fifteen (23.1%) were reactive. The infecting strains was identified as West Nile virus (WNV) in 5 pools (7.7%) with Ae. albopictus or Cx. pipiens mosquitoes. The obtained WNV sequences phylogenetically grouped with local and global lineage 1 clade 1a viruses. In 4 (6.2%) and 6 (9.2%) pools, respectively, cell fusing agent virus (CFAV) and Aedes flavivirus (AEFV) sequences were characterized. NGS provided a near-complete AEFV genome in a pool of Ae. albopictus. The strain is provisionally called "AEFV-Turkey", and functional analysis of the genome revealed several conserved motifs and regions associated with virus replication. Merida-like virus Turkey (MERDLVT), a recently-described novel rhabdovirus, was also co-detected in a Cx. pipiens pool also positive for WNV. CONCLUSIONS/SIGNIFICANCE Invasive Aedes mosquitoes are established in certain locations of northeastern Turkey. Herein we conclusively show the role of these species in WNV circulation in the region. Biosurveillance is imperative to monitor the spread of these species further into Asia Minor and to detect possible introduction of pathogens.
Collapse
Affiliation(s)
- Mustafa M. Akıner
- Recep Tayyip Erdogan University, Faculty of Arts and Sciences, Department of Biology, Rize, TURKEY
| | - Murat Öztürk
- Recep Tayyip Erdogan University, Faculty of Arts and Sciences, Department of Biology, Rize, TURKEY
| | - Aykut Buğra Başer
- Recep Tayyip Erdogan University, Faculty of Arts and Sciences, Department of Biology, Rize, TURKEY
| | - Filiz Günay
- Hacettepe University; Faculty of Sciences, Department of Biology, Division of Ecology, Ankara, TURKEY
| | - Sabri Hacıoğlu
- Ankara University; Faculty of Veterinary Medicine, Department of Virology, Ankara, TURKEY
| | - Annika Brinkmann
- Robert Koch Institute; Center for Biological Threats and Special Pathogens 1 (ZBS-1), Berlin, GERMANY
| | - Nergis Emanet
- Hacettepe University; Faculty of Medicine, Department of Medical Microbiology, Virology Unit, Ankara, TURKEY
| | - Bülent Alten
- Hacettepe University; Faculty of Sciences, Department of Biology, Division of Ecology, Ankara, TURKEY
| | - Aykut Özkul
- Ankara University; Faculty of Veterinary Medicine, Department of Virology, Ankara, TURKEY
| | - Andreas Nitsche
- Robert Koch Institute; Center for Biological Threats and Special Pathogens 1 (ZBS-1), Berlin, GERMANY
| | - Yvonne-Marie Linton
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, United States of America
- Walter Reed Biosystematics Unit, Smithsonian Institution Museum Support Center, Suitland, United States of America
| | - Koray Ergünay
- Hacettepe University; Faculty of Medicine, Department of Medical Microbiology, Virology Unit, Ankara, TURKEY
- * E-mail:
| |
Collapse
|
11
|
Fang Y, Zhang Y, Zhou ZB, Shi WQ, Xia S, Li YY, Wu JT, Liu Q, Lin GY. Co-circulation of Aedes flavivirus, Culex flavivirus, and Quang Binh virus in Shanghai, China. Infect Dis Poverty 2018; 7:75. [PMID: 30021614 PMCID: PMC6052644 DOI: 10.1186/s40249-018-0457-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/26/2018] [Indexed: 11/22/2022] Open
Abstract
Background With increases in global travel and trade, the spread of arboviruses is undoubtedly alarming. Pathogen detection in field-caught mosquitoes can provide the earliest possible warning of transmission. Insect-specific flavivirus (ISFV) has been first detected in 1991 and documented worldwide in the latest ten years. Although infection with ISFVs is apparently limited to insects, an increase in the infection rate of mosquito-borne flaviviruses may be able to induce cytopathic effects in vertebrate cells during co-infection with other human pathogens. However, little is known whether ISFVs persist in most regions of China. Methods During the mosquito activity season in 2016, a surveillance program was carried out to detect ISFVs in mosquitoes in metropolitan Shanghai, China. The presence of ISFVs was randomly tested in different species of mosquitoes using RT-PCR-based and hemi-nested PCR assays, following by the sequencing of PCR products. Sequences from positive pooled samples were compared with those deposited in GenBank. Thereafter, sequences of representative insect flaviviruses were used for further phylogenetic and molecular evolutionary analyses. Results Our investigations showed: (1) the presence of Aedes flavivirus (AEFV) in 11/161 pooled samples (nine pools in Songjiang District, one pool in Huangpu District, and one pool in Qingpu District) of Aedes albopictus, (2) the presence of Quang Binh virus (QBV) in 10/195 pooled samples (all in Chongming District) of Culex tritaeniorhynchus; and (3) the presence of Culex flavivirus (CxFV) in 9/228 pooled samples (six pools in Pudong New Area, two pools in Huangpu District, and one pool in Chongming District) of Cx. pipiens. Furthermore, phylogenetic analyses of the gene sequences of envelope proteins indicated that Shanghai CxFV strains belonged to the Asia/USA genotype. The overall maximum likelihood estimation values (and 95% confidence interval) for CxFV, QBV, and AEFV in mosquitoes collected in Shanghai in 2016 were 1.34 (0.66–2.45), 1.65 (0.87–2.85), and 1.51 (0.77–2.70) per 1000, respectively. Conclusions This study reveals the presence and the geographical distribution of ISFVs, and determines the genetic variation and the infection rate of ISFVs in Shanghai, China. At least, three insect flaviviruses including ISFVs, AEFV, CxFV, and QBV, co-circulate in this area. To our knowledge, this is the first report of AEFV in China. Electronic supplementary material The online version of this article (10.1186/s40249-018-0457-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Yuan Fang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Yi Zhang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.
| | - Zheng-Bin Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Wen-Qi Shi
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Shang Xia
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Yuan-Yuan Li
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Jia-Tong Wu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Qin Liu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Guang-Yi Lin
- Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China
| |
Collapse
|
12
|
Calisher CH, Higgs S. The Discovery of Arthropod-Specific Viruses in Hematophagous Arthropods: An Open Door to Understanding the Mechanisms of Arbovirus and Arthropod Evolution? ANNUAL REVIEW OF ENTOMOLOGY 2018; 63:87-103. [PMID: 29324047 DOI: 10.1146/annurev-ento-020117-043033] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The discovery of an odd virus from hematophagous arthropods 40 years ago by Stollar and Thomas described cell fusing agent virus in cells derived from Aedes aegypti mosquitoes. Then came the report of Kamiti River virus from Ae. macintoshi in 1999, followed by worldwide reports of the discovery of other viruses of mosquitoes, ticks, and midges that replicate only in arthropods and not in vertebrates or in vertebrate cells. These viruses (now totaling at least 64 published) have genomes analogous to viruses in various families that include arboviruses and nonarboviruses. It is likely that some of these viruses have been insufficiently studied and may yet be shown to infect vertebrates. However, there is no doubt that the vast majority are restricted to arthropods alone and that they represent a recently recognized clade. Their biology, modes of transmission, worldwide distribution (some have been detected in wild-caught mosquitoes in both Asia and the United States, for example), molecular characteristics of their genomes, and potential for becoming vertebrate pathogens, or at least serving as virus reservoirs, are fascinating and may provide evidence useful in understanding virus evolution. Because metagenomics studies of arthropods have shown that arthropod genomes are the sources of arthropod virus genomes, further studies may also provide insights into the evolution of arthropods. More recently, others have published excellent papers that briefly review discoveries of arthropod viruses and that characterize certain genomic peculiarities, but, to now, there have been no reviews that encompass all these facets. We therefore anticipate that this review is published at a time and in a manner that is helpful for both virologists and entomologists to make more sense and understanding of this recently recognized and obviously important virus group. This review focuses specifically on arthropod viruses in hematophagous arthropods.
Collapse
Affiliation(s)
- Charles H Calisher
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523-1690;
| | - Stephen Higgs
- Kansas State University, Manhattan, Kansas 66506-7600;
| |
Collapse
|
13
|
Roundy CM, Azar SR, Rossi SL, Weaver SC, Vasilakis N. Insect-Specific Viruses: A Historical Overview and Recent Developments. Adv Virus Res 2016; 98:119-146. [PMID: 28433051 DOI: 10.1016/bs.aivir.2016.10.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Arthropod-borne viruses (arboviruses) have in recent years become a tremendous global health concern resulting in substantial human morbidity and mortality. With the widespread utilization of molecular technologies such as next-generation sequencing and the advancement of bioinformatics tools, a new age of viral discovery has commenced. Many of the novel agents being discovered in recent years have been isolated from mosquitoes and exhibit a highly restricted host range. Strikingly, these insect-specific viruses have been found to be members of viral families traditionally associated with human arboviral pathogens, including but not limited to the families Flaviviridae, Togaviridae, Reoviridae, and Bunyaviridae. These agents therefore present novel opportunities in the fields of viral evolution and viral/vector interaction and have tremendous potential as agents for biocontrol of vectors and or viruses of medical importance.
Collapse
Affiliation(s)
- Christopher M Roundy
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX, United States; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States
| | - Sasha R Azar
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX, United States; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States
| | - Shannan L Rossi
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States; Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, United States
| | - Scott C Weaver
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX, United States; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States; Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, United States; University of Texas Medical Branch, Galveston, TX, United States; Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX, United States; University of Texas Medical Branch, Galveston, TX, United States
| | - Nikos Vasilakis
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States; Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, United States; University of Texas Medical Branch, Galveston, TX, United States.
| |
Collapse
|
14
|
Discovery of Novel Viruses in Mosquitoes from the Zambezi Valley of Mozambique. PLoS One 2016; 11:e0162751. [PMID: 27682810 PMCID: PMC5040392 DOI: 10.1371/journal.pone.0162751] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 08/26/2016] [Indexed: 11/19/2022] Open
Abstract
Mosquitoes carry a wide variety of viruses that can cause vector-borne infectious diseases and affect both human and veterinary public health. Although Mozambique can be considered a hot spot for emerging infectious diseases due to factors such as a rich vector population and a close vector/human/wildlife interface, the viral flora in mosquitoes have not previously been investigated. In this study, viral metagenomics was employed to analyze the viral communities in Culex and Mansonia mosquitoes in the Zambezia province of Mozambique. Among the 1.7 and 2.6 million sequences produced from the Culex and Mansonia samples, respectively, 3269 and 983 reads were classified as viral sequences. Viruses belonging to the Flaviviridae, Rhabdoviridae and Iflaviridae families were detected, and different unclassified single- and double-stranded RNA viruses were also identified. A near complete genome of a flavivirus, tentatively named Cuacua virus, was obtained from the Mansonia mosquitoes. Phylogenetic analysis of this flavivirus, using the NS5 amino acid sequence, showed that it grouped with 'insect-specific' viruses and was most closely related to Nakiwogo virus previously identified in Uganda. Both mosquito genera had viral sequences related to Rhabdoviruses, and these were most closely related to Culex tritaeniorhynchus rhabdovirus (CTRV). The results from this study suggest that several viruses specific for insects belonging to, for example, the Flaviviridae and Rhabdoviridae families, as well as a number of unclassified RNA viruses, are present in mosquitoes in Mozambique.
Collapse
|
15
|
Insect-specific flaviviruses in Aedes mosquitoes in Greece. Arch Virol 2016; 161:2183-8. [PMID: 27198866 DOI: 10.1007/s00705-016-2877-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 04/26/2016] [Indexed: 10/21/2022]
Abstract
Mosquitoes of the genus Aedes are known vectors of pathogenic flaviviruses, and insect-specific flaviviruses (ISFs) have been detected in members of this genus in numerous parts of the world. In order to gain insight into whether Aedes mosquitoes in Greece are infected by flaviviruses, 1173 Aedes spp. mosquitoes collected in 2010 and 2012 were grouped in 53 pools and tested by RT nested PCR using flavivirus generic primers. Eight pools (15.09 %) were found to be PCR positive: five pools (5/53, 9.4 %) contained RNA sequences related to Ochlerotatus caspius flavivirus (OCFV), an ISF previously detected in the Iberian peninsula, two pools (2/53, 3.8 %) contained sequences related to a mosquito flavivirus detected in Aedes vexans (AeveV) in Italy and the Czech Republic, and one pool contained a DNA sequence that was too short to identify accurately. The highest OCFV prevalence (12.9 %) was observed in August 2010 in the regional unit of Thessaloniki. Similar sequences were later obtained from two Culex spp. pools collected in 2013 in the same regions. A genetic difference of 0.2-1.4 % was seen among the Greek OCFV strains, which differed by 2.2-4.1 % from the Iberian strains and by 6.2-11.1 % from the Finnish Hanko virus. The genetic distances among strains varied depending on the genome region (genes for E, NS3 and NS5 proteins), with NS3 being the most variable. The present study shows no evidence of infection of Aedes mosquitoes with known pathogenic flaviviruses, but it expands the geographic distribution of OCFV in the eastern Mediterranean area. Any implication of ISFs for public health (either directly or through interactions with other flaviviruses in the mosquitoes) remains to be elucidated.
Collapse
|
16
|
Fernandes LN, Paula MBD, Araújo AB, Gonçalves EFB, Romano CM, Natal D, Malafronte RDS, Marrelli MT, Levi JE. Detection of Culex flavivirus and Aedes flavivirus nucleotide sequences in mosquitoes from parks in the city of São Paulo, Brazil. Acta Trop 2016; 157:73-83. [PMID: 26829359 DOI: 10.1016/j.actatropica.2016.01.026] [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] [Received: 11/27/2015] [Revised: 01/22/2016] [Accepted: 01/24/2016] [Indexed: 11/28/2022]
Abstract
The dengue viruses are widespread in Brazil and are a major public health concern. Other flaviviruses also cause diseases in humans, although on a smaller scale. The city of São Paulo is in a highly urbanized area with few green spaces apart from its parks, which are used for recreation and where potential vertebrate hosts and mosquito vectors of pathogenic Flavivirus species can be found. Although this scenario can contribute to the transmission of Flavivirus to humans, little is known about the circulation of members of this genus in these areas. In light of this, the present study sought to identify Flavivirus infection in mosquitoes (Diptera: Culicidae) collected in parks in the city of São Paulo. Seven parks in different sectors of the city were selected. Monthly mosquito collections were carried out in each park from March 2011 to February 2012 using aspiration and traps (Shannon and CD C-CO2). Nucleic acids were extracted from the mosquitoes collected and used for reverse-transcriptase and real-time polymerase chain reactions with genus-specific primers targeting a 200-nucleotide region in the Flavivirus NS5 gene. Positive samples were sequenced, and phylogenetic analyses were performed. Culex and Aedes were the most frequent genera of Culicidae collected. Culex flavivirus (CxFV)-related and Aedes flavivirus (AEFV)- related nucleotide sequences were detected in 17 pools of Culex and two pools of Aedes mosquitoes, respectively, among the 818 pools of non-engorged females analyzed. To the best of our knowledge, this is the first report of CxFV and AEFV in the city of São Paulo and Latin America, respectively. Both viruses are insect- specific flaviviruses, a group known to replicate only in mosquito cells and induce a cytopathic effect in some situations. Hence, our data suggests that CxFV and AEFV are present in Culex and Aedes mosquitoes, respectively, in parks in the city of São Paulo. Even though Flavivirus species of medical importance were not detected, surveillance is recommended in the study areas because of the presence of vertebrates and mosquitoes that could act as amplifying hosts and vectors of flaviviruses, providing the required conditions for circulation of these viruses.
Collapse
|
17
|
Comparative study on the effectiveness of different mosquito traps in arbovirus surveillance with a focus on WNV detection. Acta Trop 2016; 153:93-100. [PMID: 26466982 DOI: 10.1016/j.actatropica.2015.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 09/29/2015] [Accepted: 10/05/2015] [Indexed: 11/21/2022]
Abstract
The selection of the ideal trap for arbovirus surveillance is an issue of primary importance to increase the sensitivity of virus detection and the cost-effectiveness of the entomological surveillance. During the summer 2011, the effectiveness of five types of mosquito traps (CDC gravid trap, CO2(-)baited trap, BG-Sentinel™ and two experimental prototypes) to attract females potentially infected with West Nile virus were assessed. The study was carried out in three natural wetland sites located in the Emilia-Romagna Region (Northern Italy), using a Latin square scheme. Single night collections of adult females were performed and determination of species and physiological state (gravid, nulliparous or parous) was made upon return to the laboratory. The species most frequently collected in the gravid trap was Culex pipiens sl. L., being gravid females the large majority of the individuals. Species diversity was much higher in CO2(-)baited traps, which may therefore enable a more comprehensive description of the vector species composition and their role in arboviruses circulation. Our findings indicate that gravid traps can be a valid tool and should be integrated in the West Nile virus surveillance system in the Emilia-Romagna region, mainly based on collections made with CO2-baited traps.
Collapse
|
18
|
Medlock JM, Hansford KM, Versteirt V, Cull B, Kampen H, Fontenille D, Hendrickx G, Zeller H, Van Bortel W, Schaffner F. An entomological review of invasive mosquitoes in Europe. BULLETIN OF ENTOMOLOGICAL RESEARCH 2015; 105:637-63. [PMID: 25804287 DOI: 10.1017/s0007485315000103] [Citation(s) in RCA: 170] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Among the invasive mosquitoes registered all over the world, Aedes species are particularly frequent and important. As several of them are potential vectors of disease, they present significant health concerns for 21st century Europe. Five species have established in mainland Europe, with two (Aedes albopictus and Aedes japonicus) becoming widespread and two (Ae. albopictus and Aedes aegypti) implicated in disease transmission to humans in Europe. The routes of importation and spread are often enigmatic, the ability to adapt to local environments and climates are rapid, and the biting nuisance and vector potential are both an ecomonic and public health concern. Europeans are used to cases of dengue and chikungunya in travellers returning from the tropics, but the threat to health and tourism in mainland Europe is substantive. Coupled to that are the emerging issues in the European overseas territorities and this paper is the first to consider the impacts in the remoter outposts of Europe. If entomologists and public health authorities are to address the spread of these mosquitoes and mitigate their health risks they must first be prepared to share information to better understand their biology and ecology, and share data on their distribution and control successes. This paper focusses in greater detail on the entomological and ecological aspects of these mosquitoes to assist with the risk assessment process, bringing together a large amount of information gathered through the ECDC VBORNET project.
Collapse
Affiliation(s)
- J M Medlock
- Medical Entomology Group,MRA/BS,Emergency Response Department,Public Health England,Porton Down,Salisbury,UK
| | - K M Hansford
- Medical Entomology Group,MRA/BS,Emergency Response Department,Public Health England,Porton Down,Salisbury,UK
| | - V Versteirt
- Avia-GIS,Risschotlei 33,2980 Zoersel,Belgium
| | - B Cull
- Medical Entomology Group,MRA/BS,Emergency Response Department,Public Health England,Porton Down,Salisbury,UK
| | - H Kampen
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health,Südufer 10,17493 Greifswald - Insel Riems,Germany
| | - D Fontenille
- Centre National d'Expertise sur les Vecteurs (CNEV), Institut de recherche pour le développement (IRD), UMR MIVEGEC,BP 64501,34394 Montpellier,France
| | - G Hendrickx
- Avia-GIS,Risschotlei 33,2980 Zoersel,Belgium
| | - H Zeller
- Emerging and Vector-borne Diseases, European Centre for Disease Prevention and Control,Tomtebodavägen 11A,17183 Stockholm,Sweden
| | - W Van Bortel
- Emerging and Vector-borne Diseases, European Centre for Disease Prevention and Control,Tomtebodavägen 11A,17183 Stockholm,Sweden
| | - F Schaffner
- Avia-GIS,Risschotlei 33,2980 Zoersel,Belgium
| |
Collapse
|
19
|
Vasilakis N, Tesh RB. Insect-specific viruses and their potential impact on arbovirus transmission. Curr Opin Virol 2015; 15:69-74. [PMID: 26322695 DOI: 10.1016/j.coviro.2015.08.007] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 08/10/2015] [Accepted: 08/12/2015] [Indexed: 11/15/2022]
Abstract
Arthropod-borne viruses (arboviruses) are the causative agents of significant morbidity and mortality among humans and animals globally. In the past few years, the widespread adoption of next generation sequencing and metagenomics has led to a new era of virus discovery, where many novel viruses have been documented, exhibiting a restricted host-range in mosquitoes. They represent a wide-range of insect-specific viruses within the families of Bunyaviridae, Flaviviridae, Mesoniviridae, Reoviridae, Rhabdoviridae, Togaviridae, and the newly recognized taxon of Negeviruses. Collectively, their discovery has opened new vistas about the extent of viral diversity and evolution, their influence on vector competence and ability of their insect hosts to transmit human pathogens (e.g. arboviruses), and their potential development as biological control agents or novel vaccine platforms.
Collapse
Affiliation(s)
- Nikos Vasilakis
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Institute for Human Infectious and Immunity, The University of Texas Medical Branch, Galveston, TX 77555-0609, United States.
| | - Robert B Tesh
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Institute for Human Infectious and Immunity, The University of Texas Medical Branch, Galveston, TX 77555-0609, United States.
| |
Collapse
|
20
|
Calzolari M, Zé-Zé L, Vázquez A, Sánchez Seco MP, Amaro F, Dottori M. Insect-specific flaviviruses, a worldwide widespread group of viruses only detected in insects. INFECTION GENETICS AND EVOLUTION 2015; 40:381-388. [PMID: 26235844 DOI: 10.1016/j.meegid.2015.07.032] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 01/06/2023]
Abstract
Several flaviviruses are important pathogens for humans and animals (Dengue viruses, Japanese encephalitis virus, Yellow-fever virus, Tick-borne encephalitis virus, West Nile virus). In recent years, numerous novel and related flaviviruses without known pathogenic capacity have been isolated worldwide in the natural mosquito population. However, phylogenetic studies have shown that genomic sequences of these viruses diverge from other flaviviruses. Moreover, these viruses seem to be exclusive of insects (they do not seem to grow on vertebrate cell lines), and were already defined as mosquito-only flaviviruses or insect-specific flaviviruses. At least eleven of these viruses were isolated worldwide, and sequences ascribable to other eleven putative viruses were detected in several mosquito species. A large part of the cycle of these viruses is not well known, and their persistence in the environment is poorly understood. These viruses are detected in a wide variety of distinct mosquito species and also in sandflies and chironomids worldwide; a single virus, or the genetic material ascribable to a virus, was detected in several mosquito species in different countries, often in different continents. Furthermore, some of these viruses are carried by invasive mosquitoes, and do not seem to have a depressive action on their fitness. The global distribution and the continuous detection of new viruses in this group point out the likely underestimation of their number, and raise interesting issues about their possible interactions with the pathogenic flaviviruses, and their influence on the bionomics of arthropod hosts. Some enigmatic features, as their integration in the mosquito genome, the recognition of their genetic material in DNA forms in field-collected mosquitoes, or the detection of the same virus in both mosquitoes and sandflies, indicate that the cycle of these viruses has unknown characteristics that could be of use to reach a deeper understanding of the cycle of related pathogenic flaviviruses.
Collapse
Affiliation(s)
- Mattia Calzolari
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Bianchi 9, 25124 Brescia, Italy.
| | - Líbia Zé-Zé
- Centre for Vectors and Infectious Diseases Research, National Institute of Health, Avenida da Liberdade 5, 2965-575 Águas de Moura, Portugal; University of Lisbon, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, Lisbon, Portugal.
| | - Ana Vázquez
- Laboratory of Arbovirus and Imported Viral Diseases, National Center of Microbiology, Institute of Health "Carlos III", Ctra Pozuelo-Majadahonda km 2, 28220 Madrid, Spain.
| | - Mari Paz Sánchez Seco
- Laboratory of Arbovirus and Imported Viral Diseases, National Center of Microbiology, Institute of Health "Carlos III", Ctra Pozuelo-Majadahonda km 2, 28220 Madrid, Spain.
| | - Fátima Amaro
- Centre for Vectors and Infectious Diseases Research, National Institute of Health, Avenida da Liberdade 5, 2965-575 Águas de Moura, Portugal.
| | - Michele Dottori
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Bianchi 9, 25124 Brescia, Italy.
| |
Collapse
|
21
|
Blitvich BJ, Firth AE. Insect-specific flaviviruses: a systematic review of their discovery, host range, mode of transmission, superinfection exclusion potential and genomic organization. Viruses 2015; 7:1927-59. [PMID: 25866904 PMCID: PMC4411683 DOI: 10.3390/v7041927] [Citation(s) in RCA: 226] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 03/30/2015] [Accepted: 04/08/2015] [Indexed: 12/11/2022] Open
Abstract
There has been a dramatic increase in the number of insect-specific flaviviruses (ISFs) discovered in the last decade. Historically, these viruses have generated limited interest due to their inability to infect vertebrate cells. This viewpoint has changed in recent years because some ISFs have been shown to enhance or suppress the replication of medically important flaviviruses in co-infected mosquito cells. Additionally, comparative studies between ISFs and medically important flaviviruses can provide a unique perspective as to why some flaviviruses possess the ability to infect and cause devastating disease in humans while others do not. ISFs have been isolated exclusively from mosquitoes in nature but the detection of ISF-like sequences in sandflies and chironomids indicates that they may also infect other dipterans. ISFs can be divided into two distinct phylogenetic groups. The first group currently consists of approximately 12 viruses and includes cell fusing agent virus, Kamiti River virus and Culex flavivirus. These viruses are phylogenetically distinct from all other known flaviviruses. The second group, which is apparently not monophyletic, currently consists of nine viruses and includes Chaoyang virus, Nounané virus and Lammi virus. These viruses phylogenetically affiliate with mosquito/vertebrate flaviviruses despite their apparent insect-restricted phenotype. This article provides a review of the discovery, host range, mode of transmission, superinfection exclusion ability and genomic organization of ISFs. This article also attempts to clarify the ISF nomenclature because some of these viruses have been assigned more than one name due to their simultaneous discoveries by independent research groups.
Collapse
Affiliation(s)
- Bradley J Blitvich
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
| | - Andrew E Firth
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, UK.
| |
Collapse
|
22
|
Grisenti M, Vázquez A, Herrero L, Cuevas L, Perez-Pastrana E, Arnoldi D, Rosà R, Capelli G, Tenorio A, Sánchez-Seco MP, Rizzoli A. Wide detection of Aedes flavivirus in north-eastern Italy – a European hotspot of emerging mosquito-borne diseases. J Gen Virol 2015; 96:420-430. [DOI: 10.1099/vir.0.069625-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Michela Grisenti
- Department of Veterinary Sciences, University of Torino, largo Paolo Braccini 2, 10095 Grugliasco, Torino, Italy
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38010 San Michele all’Adige, Trento, Italy
| | - Ana Vázquez
- Laboratory of Arboviruses and Viral Imported Diseases, Institute of Health ‘Carlos III’, Ctra Pozuelo-Majadahonda, Km 2, 28220 Majadahonda, Madrid, Spain
| | - Laura Herrero
- Laboratory of Arboviruses and Viral Imported Diseases, Institute of Health ‘Carlos III’, Ctra Pozuelo-Majadahonda, Km 2, 28220 Majadahonda, Madrid, Spain
| | - Laureano Cuevas
- Electron Microscopy Department, National Center of Microbiology, Institute of Health ‘Carlos III’, Ctra Pozuelo-Majadahonda, Km 2, 28220 Majadahonda, Madrid, Spain
| | - Esperanza Perez-Pastrana
- Electron Microscopy Department, National Center of Microbiology, Institute of Health ‘Carlos III’, Ctra Pozuelo-Majadahonda, Km 2, 28220 Majadahonda, Madrid, Spain
| | - Daniele Arnoldi
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38010 San Michele all’Adige, Trento, Italy
| | - Roberto Rosà
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38010 San Michele all’Adige, Trento, Italy
| | - Gioia Capelli
- Laboratory of Parasitology, Istituto Zooprofilattico Sperimentale delle Venezie, viale dell’Università 10, 35020 Legnaro, Padova, Italy
| | - Antonio Tenorio
- Laboratory of Arboviruses and Viral Imported Diseases, Institute of Health ‘Carlos III’, Ctra Pozuelo-Majadahonda, Km 2, 28220 Majadahonda, Madrid, Spain
| | - Maria Paz Sánchez-Seco
- Laboratory of Arboviruses and Viral Imported Diseases, Institute of Health ‘Carlos III’, Ctra Pozuelo-Majadahonda, Km 2, 28220 Majadahonda, Madrid, Spain
| | - Annapaola Rizzoli
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38010 San Michele all’Adige, Trento, Italy
| |
Collapse
|
23
|
Bolling BG, Vasilakis N, Guzman H, Widen SG, Wood TG, Popov VL, Thangamani S, Tesh RB. Insect-specific viruses detected in laboratory mosquito colonies and their potential implications for experiments evaluating arbovirus vector competence. Am J Trop Med Hyg 2014; 92:422-8. [PMID: 25510714 DOI: 10.4269/ajtmh.14-0330] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Recently, there has been a dramatic increase in the detection and characterization of insect-specific viruses in field-collected mosquitoes. Evidence suggests that these viruses are ubiquitous in nature and that many are maintained by vertical transmission in mosquito populations. Some studies suggest that the presence of insect-specific viruses may inhibit replication of a super-infecting arbovirus, thus altering vector competence of the mosquito host. Accordingly, we screened our laboratory mosquito colonies for insect-specific viruses. Pools of colony mosquitoes were homogenized and inoculated into cultures of Aedes albopictus (C6/36) cells. The infected cells were examined by electron microscopy and deep sequencing was performed on RNA extracts. Electron micrograph images indicated the presence of three different viruses in three of our laboratory mosquito colonies. Potential implications of these findings for vector competence studies are discussed.
Collapse
Affiliation(s)
- Bethany G Bolling
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas
| | - Nikos Vasilakis
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas
| | - Hilda Guzman
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas
| | - Steven G Widen
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas
| | - Thomas G Wood
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas
| | - Vsevolod L Popov
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas
| | | | - Robert B Tesh
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas
| |
Collapse
|
24
|
Mulatti P, Ferguson HM, Bonfanti L, Montarsi F, Capelli G, Marangon S. Determinants of the population growth of the West Nile virus mosquito vector Culex pipiens in a repeatedly affected area in Italy. Parasit Vectors 2014; 7:26. [PMID: 24428887 PMCID: PMC3896690 DOI: 10.1186/1756-3305-7-26] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 01/08/2014] [Indexed: 12/03/2022] Open
Abstract
Background The recent spread of West Nile Virus in temperate countries has raised concern. Predicting the likelihood of transmission is crucial to ascertain the threat to Public and Veterinary Health. However, accurate models of West Nile Virus (WNV) expansion in Europe may be hampered by limited understanding of the population dynamics of their primary mosquito vectors and their response to environmental changes. Methods We used data collected in north-eastern Italy (2009–2011) to analyze the determinants of the population growth rate of the primary WNV vector Culex pipiens. A series of alternative growth models were fitted to longitudinal data on mosquito abundance to evaluate the strength of evidence for regulation by intrinsic density-dependent and/or extrinsic environmental factors. Model-averaging algorithms were then used to estimate the relative importance of intrinsic and extrinsic variables in describing the variations of per-capita growth rates. Results Results indicate a much greater contribution of density-dependence in regulating vector population growth rates than of any environmental factor on its own. Analysis of an average model of Cx. pipiens growth revealed that the most significant predictors of their population dynamics was the length of daylight, estimated population size and temperature conditions in the 15 day period prior to sampling. Other extrinsic variables (including measures of precipitation, number of rainy days, and humidity) had only a minor influence on Cx. pipiens growth rates. Conclusions These results indicate the need to incorporate density dependence in combination with key environmental factors for robust prediction of Cx. pipiens population expansion and WNV transmission risk. We hypothesize that detailed analysis of the determinants of mosquito vector growth rate as conducted here can help identify when and where an increase in vector population size and associated WNV transmission risk should be expected.
Collapse
Affiliation(s)
| | - Heather M Ferguson
- University of Glasgow, Institute of Biodiversity, Animal Health and Comparative Medicine, Glasgow G12 8QQ Scotland (UK.
| | | | | | | | | |
Collapse
|
25
|
Chong MK, Chua AJS, Tan TTT, Tan SH, Ng ML. Microscopy techniques in flavivirus research. Micron 2013; 59:33-43. [PMID: 24530363 DOI: 10.1016/j.micron.2013.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 12/11/2013] [Accepted: 12/11/2013] [Indexed: 11/29/2022]
Abstract
The Flavivirus genus is composed of many medically important viruses that cause high morbidity and mortality, which include Dengue and West Nile viruses. Various molecular and biochemical techniques have been developed in the endeavour to study flaviviruses. However, microscopy techniques still have irreplaceable roles in the identification of novel virus pathogens and characterization of morphological changes in virus-infected cells. Fluorescence microscopy contributes greatly in understanding the fundamental viral protein localizations and virus-host protein interactions during infection. Electron microscopy remains the gold standard for visualizing ultra-structural features of virus particles and infected cells. New imaging techniques and combinatory applications are continuously being developed to push the limit of resolution and extract more quantitative data. Currently, correlative live cell imaging and high resolution three-dimensional imaging have already been achieved through the tandem use of optical and electron microscopy in analyzing biological specimens. Microscopy techniques are also used to measure protein binding affinities and determine the mobility pattern of proteins in cells. This chapter will consolidate on the applications of various well-established microscopy techniques in flavivirus research, and discuss how recently developed microscopy techniques can potentially help advance our understanding in these membrane viruses.
Collapse
Affiliation(s)
- Mun Keat Chong
- Flavivirology Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 5 Science Drive 2, MD4 Level 3, Singapore 117545, Singapore
| | - Anthony Jin Shun Chua
- Flavivirology Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 5 Science Drive 2, MD4 Level 3, Singapore 117545, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Centre for Life Sciences (CeLS), 28 Medical Drive, #05-01, Singapore 117456, Singapore
| | - Terence Tze Tong Tan
- Flavivirology Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 5 Science Drive 2, MD4 Level 3, Singapore 117545, Singapore
| | - Suat Hoon Tan
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 12 Medical Drive, MD5, Singapore 117597, Singapore
| | - Mah Lee Ng
- Flavivirology Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 5 Science Drive 2, MD4 Level 3, Singapore 117545, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Centre for Life Sciences (CeLS), 28 Medical Drive, #05-01, Singapore 117456, Singapore; Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 12 Medical Drive, MD5, Singapore 117597, Singapore.
| |
Collapse
|
26
|
Lack of identification of Flaviviruses in oral and cloacal swabs from long- and short-distance migratory birds in Trentino-Alto Adige (North-eastern Italy). Virol J 2013; 10:306. [PMID: 24119320 PMCID: PMC3852823 DOI: 10.1186/1743-422x-10-306] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 10/03/2013] [Indexed: 11/10/2022] Open
Abstract
Background West Nile virus (WNV) and Usutu virus (USUV), both belonging to the genus Flavivirus, are emerging in Italy as important human and animal pathogens. Migratory birds are involved in the spread of Flaviviruses over long distances, particularly from Africa to Europe. Once introduced, these viruses can be further be dispersed by short-distance migratory and resident bird species. Thus far, there is still a considerable knowledge gap on the role played by different bird species in the ecology and transmission mechanisms of these viruses. The Region of Trentino-Alto Adige (north-eastern Italy) is located on the migratory route of many of the short- and long-distance migratory birds that cross the Alps, connecting northern Europe and western Asia with southern Europe and Africa. Until now, only a silent circulation of WNV and USUV within the territory of the Province of Trento has been confirmed by serological screening, whilst no cases of infected humans or animals have so far been reported. However, continuous spillover events of both viruses have been reported in neighbouring Regions. The aim of this study was to monitor the circulation of WNV and USUV in Trentino-Alto Adige, in order to detect if active virus shedding occurs in migratory birds captured during their seasonal movements and to evaluate the role that different bird species could play in the spreading of these viruses. Methods We carried out a biomolecular survey on oral and cloacal swabs collected from migratory birds during seasonal migrations. Birds belonging to 18 transaharian and 21 intrapaleartic species were examined during spring (n = 176) and autumn (n = 146), and were tested using a generic nested-PCR. Results All samples tested negative for Flaviviruses. The possible causes of unapparent shedding, along with ecological and epidemiological implications are discussed. Conclusions The lack of detection of active virus shedding in these bird species does not exclude the circulation of these viruses within the Trentino-Alto Adige region, as reported in previous studies. The possible ecological implications are discussed.
Collapse
|
27
|
Replication of West Nile virus, Rabensburg lineage in mammalian cells is restricted by temperature. Parasit Vectors 2012; 5:293. [PMID: 23241081 PMCID: PMC3534007 DOI: 10.1186/1756-3305-5-293] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 12/11/2012] [Indexed: 11/10/2022] Open
Abstract
Background The genus Flavivirus currently consists of approximately 80 single-strand positive-sense RNA viruses. These replicate in a range of hosts including myriad vertebrate, insect, and tick species. As a consequence of this broad host range, the majority of flaviviruses can be propagated in most vertebrate and insect cell cultures. This ability to infect arthropods and vertebrates usually is essential for maintenance of these viruses in nature. But recently, there has been the discovery of a number of flaviviruses that infect mosquitoes but not vertebrates. It remains largely unknown why certain flaviviruses infect vertebrates and mosquitoes while others infect mosquitoes or vertebrates exclusively. Methods Here, we initiated in vitro host range studies of Rabensburg virus (RABV), an intermediate between the mosquito-specific and horizontally transmitted flaviviruses, to provide information on the factor(s) that underlie the varying host range of flaviviruses. RABV is an intermediate between the mosquito-specific and horizontally transmitted flaviviruses because it does not infect mammalian or avian cell cultures, house sparrows, or chickens, but it does share genetic characteristics with the Japanese Encephalitis serogroup of flaviviruses. Results In vitro growth kinetic assays revealed the complete abrogation of RABV growth on Vero and E6 cells incubated at temperatures 35°C and higher, but surprisingly RABV infected, replicated efficiently, and displayed overt cytopathic effects (CPE) on Vero and E6 cell cultures incubated below 35°C. In contrast, RABV was fully viable, replicated efficiently, and displayed overt CPE on C6/36 cells incubated at 28°C or 37°C, thus implicating temperature as an important factor limiting the host range of RABV. Conclusions These data are critical for further study to more fully identify the determinants that mediate the evolution of biological transmission among flaviviruses. It also will be useful for studies that look to provide a comprehensive molecular definition of flavivirus-host cell interactions. And it will provide a cadre of information to design wet lab experiments to investigate the genetic changes that facilitate host switching, which may lead to new vertebrate pathogens or transmission pathways.
Collapse
|