Nairobi Sheep Disease Virus RNA in Ixodid Ticks, China, 2013

摘要: To the Editor: Nairobi sheep disease virus (NSDV; genus Nairovirus, family Bunyaviridae) causes acute hemorrhagic gastroenteritis in and goats (1,2). First identified Nairobi, Kenya, 1910, it is considered endemic East Africa (1,3). Ganjam virus, a variant of NSDV, found India Sri Lanka (2). NSDV has limited effect on animals bred areas to which but can cause large losses during introduction new livestock or transport through these (4). In humans, infection febrile illness, headache, nausea, vomiting (5). Ticks are main transmission vectors many other viral pathogens therefore pose major threat public health (6,7). Here, we describe newly discovered named (China), by metagenomic analysis ticks collected from northeast region People’s Republic China (Liaoning, Jilin, Heilongjiang provinces) May–July, 2013, divided into 9 groups according tick species sampling sites. Four were morphologically identified: Haemaphysalis longicornis (84.8%); Dermacentor silvarum (7.2%); D. nuttalli (5.5%); Ixodes persulcatus (2.5%) (Technical Appendix Table 1). Of 6,427 collected, 3,410 (average 379 ticks/group, range 163–512); each group was homogenized SM buffer (50 mmol/L Tris, 10 MgSO4, 0.1 mol/L NaCl, pH 7.5). Viral RNA extraction, Solexa sequencing, described online Technical Appendix. Among sequences annotated mammalian viruses, 65 contigs target small (n = 15), medium 27), 23) segments genome Tables 2–4). To confirm results, 376-nt fragment gene segment amplified reverse transcription PCR (RT-PCR) using primers P1 (5′-AGCAAAGAGCACATTGACTGGGC-3′) P2 (5′-CTGTCACACCTGCCTTCCAA-3′). Ticks 3 H. positive for NSDV: 1 Jian, Jilin Province (125°34′E, 40°52′N); 2 cattle Jinxing, (130°38′E, 42°25′N); 5 Dandong, Liaoning (124°23′E, 40°07′N). negative. The obtained shared 92% identity with intermedia India. The full-length sequence then RT-PCR based conserved nairoviruses 5). complete small, medium, (China) (GenBank accession nos. {"type":"entrez-nucleotide-range","attrs":{"text":"KM464724-KM464726","start_term":"KM464724","end_term":"KM464726","start_term_id":"728892682","end_term_id":"728892686"}}KM464724-KM464726) contained 1,590, 5,077, 12,081 nt, respectively; that is, they similar NSDVs. Sequence comparisons showed 75.1%–89.6% NSDVs at nucleotide level 81.3%–96.7% deduced amino acid 6). Compared member within Nairovirus (Dugbe, Kupe, Hazara, Crimean Congo fever viruses), low identities (37.5%–68.6%) observed both levels Phylogenetic grouped together South Asia (Figure). Figure Phylogenetic nairoviruses. phylogenetic trees generated MEGA5.2 software (http://www.megasoftware.net). coding regions nucleocapsid protein (A), ... The remaining samples NSDV-positive used determine frequency analyze P2. We assayed 104 pools 15 ticks/pool, 8–40), 13 416 Jian 91 1,095 Jinxing Province; 12.5% (13/104) tested positive, 38.5% (5/13) 8.8% (8/91) Jinxing. higher prevalence may result more pools. Attempts isolate cell lines (Vero BHK-21) suckling mice unsuccessful; thus, its pathogenicity could not be determined. In Africa, primarily transmitted R. appendiculatus (5). (India Lanka), been isolated (H. intermedia, wellingtoni, haemaphysaloides), mosquitoes, humans; vector (5,8,9). had previously reported Asia. identified, genetically divergent novel strain, likely vector. Asia, our results indicate risk occurrence regions, where widely distributed (10). More extensive investigation clarifty natural circulation among should conducted surveillance improved prevent outbreaks Asia. Technical Appendix: Tick collection, extraction processing, data resulting identification ixodid ticks, China, 2013. Click here view.(107K, pdf)