A Review of Knowledge Gaps and Tools for Orbivirus Research

Abstract

Although recognized as causing emerging and re-emerging disease outbreaks worldwide since the late 1800 s, there has been growing interest in the United States and Europe in recent years in orbiviruses, their insect vectors, and the diseases they cause in domestic livestock and wildlife. This is due, in part, to the emergence of bluetongue (BT) in northern Europe in 2006-2007 resulting in a devastating outbreak, as well as severe BT outbreaks in sheep and epizootic hemorrhagic disease (EHD) outbreaks in deer and cattle in the United States. Of notable concern is the isolation of as many as 10 new BT virus (BTV) serotypes in the United States since 1999 and their associated unknowns, such as route of introduction, virulence to mammals, and indigenous competent vectors. This review, based on a gap analysis workshop composed of international experts on orbiviruses conducted in 2013, gives a global perspective of current basic virological understanding of orbiviruses, with particular attention to BTV and the closely related epizootic hemorrhagic disease virus (EHDV), and identifies a multitude of basic virology research gaps, critical for predicting and preventing outbreaks.

Genomes of viral isolates derived from different mosquitos species

“…Orbiviruses within a single species group show greater than 91% identity with respect to the T2 protein sequence (Attoui H et al, 2012). Orbiviruses are transmitted primarily by arthropod vectors such as culicoid midges, phlebotomine sandflies, mosquitoes or ticks, and can infect a wide variety of vertebrate hosts including humans (Drolet et al, 2015). Using ICTV taxonomic criteria, the two novel orbiviruses described here (Big Cypress and Ninarumi) qualify as new species.…”

Molecular and Serological Survey of Selected Viruses in Free-Ranging Wild Ruminants in Iran

“…Clinical and serological surveys in European wild ungulates have shown BTV infection does not cause clinical disease but they can act as reservoirs of the virus for other ruminant hosts [41]. BTV circulation between wild and domestic populations relies upon arthropod vectors such as Culicoides midges [45, 46] with disease circulating in both populations. [47].…”

Letea Virus: Comparative Genomics and Phylogenetic Analysis of a Novel Reassortant Orbivirus Discovered in Grass Snakes (Natrix natrix)

“…The most studied orbiviruses are the Culicoides-borne Bluetongue virus (BTV, type species), African horse sickness virus (AHSV) and Epizootic hemorrhagic disease virus (EHDV), all known as important pathogens of livestock and wildlife [3]. Some orbiviruses such as Tribeč virus, Kemerovo, Lebombo and Orungo viruses have been detected in human infections and are considered human pathogens [4].…”