title: Insect-specific flaviviruses, a worldwide widespread group of viruses only detected in insects.
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.
authors.affiliation: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Bianchi 9, 25124 Brescia, Italy. Electronic address: mattia.calzolari@izsler.it.
authors.forename: Mattia
authors.initials: M
authors.lastname: Calzolari
authors.affiliation: 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. Electronic address: libia.zeze@insa.min-saude.pt.
authors.forename: Líbia
authors.initials: L
authors.lastname: Zé-Zé
authors.affiliation: Laboratory of Arbovirus and Imported Viral Diseases, National Center of Microbiology, Institute of Health "Carlos III", Ctra Pozuelo-Majadahonda km 2, 28220 Madrid, Spain. Electronic address: a.vazquez@isciii.es.
authors.forename: Ana
authors.initials: A
authors.lastname: Vázquez
authors.affiliation: Laboratory of Arbovirus and Imported Viral Diseases, National Center of Microbiology, Institute of Health "Carlos III", Ctra Pozuelo-Majadahonda km 2, 28220 Madrid, Spain. Electronic address: paz.sanchez@isciii.es.
authors.forename: Mari Paz
authors.initials: MP
authors.lastname: Sánchez Seco
authors.affiliation: Centre for Vectors and Infectious Diseases Research, National Institute of Health, Avenida da Liberdade 5, 2965-575 Águas de Moura, Portugal. Electronic address: fatima.amaro@insa.min-saude.pt.
authors.forename: Fátima
authors.initials: F
authors.lastname: Amaro
authors.affiliation: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Bianchi 9, 25124 Brescia, Italy. Electronic address: michele.dottori@izsler.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Dottori
mesh_terms: D000818:Animals; D009033:Culicidae / Q000821:virology; D005416:Flavivirus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D018177:Flavivirus Infections / Q000453:epidemiology* / Q000635:transmission*; D006801:Humans; D007303:Insect Vectors / Q000821:virology*; D007313:Insecta / Q000821:virology*; D010802:Phylogeny; D011576:Psychodidae / Q000821:virology; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D017361:Viral Nonstructural Proteins
keywords: Aedes flavivirus; Cell fusing agent virus; Culex flavivirus; Insect-specific flavivirus; Kamiti River virus; Mosquito; Mosquito-only flavivirus; Ochlerotatus caspius flavivirus; Quang Binh virus; Sandfly