RNA viromes of Dermacentor nuttalli ticks reveal a novel uukuvirus in Qinghai Province,China

Ticks are a major parasite on the Qinghai-Tibet Plateau,western China,and represent an economic burden to agriculture and animal husbandry.Despite research on tick-borne pathogens that threaten humans and animals,the viromes of dominant tick species in this area remain unknown.In this study,we collected Dermacentor nuttalli ticks near Qinghai Lake and identified 13 viruses belonging to at least six families through metagenomic sequencing.Four viruses were of high abundance in pools,including Xınjiang tick-associated virus 1(XJTAV1),and three novel viruses:Qinghai Lake virus 1,Qinghai Lake virus 2(QHLV1,and QHLV2,unclassified),and Qinghai Lake virus 3(QHLV3,genus Uukuvirus of family Phenuiviridae in order Bunyavirales),which lacks the M segment.The minimum infection rates of the four viruses in the tick groups were 8.2%,49.5%,6.2%,and 24.7%,respectively,suggesting the prevalence of these viruses in D.nuttalli ticks.A putative M segment of QHLV3 was identified from the next-generation sequencing data and further characterized for its signal peptide cleavage site,N-glycosylation,and transmembrane region.Furthermore,we probed the L,M,and S segments of other viruses from sequencing data of other tick pools by using the putative M segment sequence of QHLV3.By revealing the viromes of D.nuttalli ticks,this study enhances our understanding of tick-borne viral communities in highland regions.The putative M segment identified in a novel uukuvirus suggests that previously identified uukuviruses without M segments should have had the same genome organization as typical bunyaviruses.These findings will facilitate virus discovery and our understanding of the phylogeny of tick-borne uukuviruses.

Highly pathogenic avian influenza H5N1 Clade 2.3.2.1c virus in migratory birds,2014–2015

A novel Clade 2.3.2.1c H5N1 reassortant virus caused several outbreaks in wild birds in some regions of China from late 2014 to 2015.Based on the genetic and phylogenetic analyses,the viruses possess a stable gene constellation with a Clade 2.3.2.1c HA,a H9N2-derived PB2 gene and the other six genes of Asian H5N1-origin.The Clade 2.3.2.1c H5N1 reassortants displayed a high genetic relationship to a human H5N1 strain(A/Alberta/01/2014).Further analysis showed that similar viruses have been circulating in wild birds in China,Russia,Dubai(Western Asia),Bulgaria and Romania(Europe),as well as domestic poultry in some regions of Africa.The affected areas include the Central Asian,East Asian-Australasian,West Asian-East African,and Black Sea/Mediterranean flyways.These results show that the novel Clade 2.3.2.1c reassortant viruses are circulating worldwide and may have gained a selective advantage in migratory birds,thus posing a serious threat to wild birds and potentially humans.