A Global Genomic Characterization of Nairoviruses Identifies Nine Discrete Genogroups with Distinctive Structural Characteristics and Host-Vector Associations

Abstract

Nairoviruses are primarily tick-borne bunyaviruses, some of which are known to cause mild-to-severe febrile illness in humans or livestock. We describe the genome sequences of 11 poorly characterized nairoviruses that have ecological associations with either birds (Farallon, Punta Salinas, Sapphire II, Zirqa, Avalon, Clo Mor, Taggert, and Abu Hammad viruses), rodents (Qalyub and Bandia viruses), or camels (Dera Ghazi Khan virus). Global phylogenetic analyses of proteins encoded in the L, M, and S RNA segments of these and 20 other available nairovirus genomes identified nine well-supported genogroups (Nairobi sheep disease, Thiafora, Sakhalin, Keterah, Qalyub, Kasokero, Dera Ghazi Khan, Hughes, and Tamdy). Genogroup-specific structural variations were evident, particularly in the M segment encoding a polyprotein from which virion envelope glycoproteins (Gn and Gc) are generated by proteolytic processing. Structural variations include the extension, abbreviation, or absence sequences encoding an O-glycosylated mucin-like protein in the N-terminal domain, distinctive patterns of conserved cysteine residues in the GP38-like domain, insertion of sequences encoding a double-membrane-spanning protein (NSm) between the Gn and Gc domains, and the presence of an alternative long open reading frame encoding a viroporin-like transmembrane protein (Gx). We also observed strong genogroup-specific associations with categories of hosts and tick vectors.

Structure and Characterization of Crimean-Congo Hemorrhagic Fever Virus GP38

“…at the Cterminus of GP38, suggesting release of GP38 from Gn similar to that observed for CCHFV (17). The presence of a furin-like cleavage site (RSKR in CCHFV) between the MLD and GP38…”

Tick-Borne Viruses and Biological Processes at the Tick-Host-Virus Interface

“…The most notable changes have occurred in families Bunyaviridae and Rhabdoviridae . The Bunyaviridae has been revised and elevated to the order Bunyavirales comprising 9 families and 13 genera (Briese et al, 2016; Junglen, 2016; Walker et al, 2016b). TBVs are included in three families— Nairoviridae, Phenuiviridae , and Peribunyaviridae .…”

“…TBVs are included in three families— Nairoviridae, Phenuiviridae , and Peribunyaviridae . Except for the most medically important member, Crimean-Congo haemorrhagic fever virus (CCHFV), the genus Orthonairovirus of the Nairoviridae comprises 11 other species, 9 of which are TBVs (Table 1) (Kuhn et al, 2016a,b; Walker et al, 2015, 2016b). The most recent emerging human disease causing significant mortality (up to 30% of cases) is caused by Severe fever with thrombocytopenia syndrome virus (SFTSV), a new member of the Phlebovirus genus ( Phenuiviridae ) first reported in China (Xu et al, 2011; Yu et al, 2011; Zhang et al, 2011).…”

A Review of Zoonotic Pathogens of Dromedary Camels

“…Mortality rates for these viruses along with other hemorrhagic fevers are high because of difficulties in disease diagnosis (World Health Organization 2016). Alkhurma hemorrhagic fever, CCHF, and Dera Ghazi Khan are mosquito-and tick-borne diseases where camels act as reservoirs and amplifiers (Carletti 2010;Walker et al 2016). Thus, vector surveillance and management around camels in addition to the aforementioned sanitation practices could be highly beneficial to control the spread of these diseases.…”

“…Other viruses that were found in camels include Alkhurma hemorrhagic fever (AHF) virus n = 1, Crimean-Congo hemorrhagic fever (CCHF) virus n = 4, rotavirus n = 2, camel contagious ecthyma n = 2, torque teno virus n = 1, and Dera Ghazi Khan virus n = 1 ( Moallin and Zessin 1988;Khan et al 1997;Al-Moslih et al 2007;Bazargani et al 2010;Carletti 2010;Ghosh et al 2011;Horton et al 2014;Jere et al 2014;Champour et al 2016;Walker et al 2016).…”