Bacterial Microbiota in Unfed Ticks ( Dermacentor nuttalli ) From Xinjiang Detected Through 16S rDNA Amplicon Sequencing and Culturomics

Ticks are a major arthropod vector of zoonotic diseases affecting both humans and domestic animals worldwide. Thus, studying tick microbiota would aid in understanding of the potential threats posed by ticks. Approximately 8,000 unfed ticks, identified as Dermacentor nuttalli , were collected from the sylvosteppe in the western Tianshan mountains. To investigate their potential pathogens, we divided the ticks into 36 groups of 200–300 individuals each for examination with culturomics and 16S rDNA amplicon sequencing. A total of 237 bacterial genera were identified with the two methods. Culturomics identified 46 bacterial species from 23 genera, predominantly Pseudomonas , Pantoea , and Bacillus , whereas 16S rDNA sequencing identified 461 OTUs from 233 genera, predominantly Pseudomonas (53.8%), Coxiella (17.2%), and Pantoea (6.4%). Coxiella , Rickettsia , and ten other genera were discovered only by sequencing, because optimal cultivating conditions were not used for their isolation, whereas Arthrobacter and three other genera were discovered only through culturomics. Several of the identified bacteria, such as line-related sepsis-causing Delftia acidovorans and the pneumonia agent Acinetobacter pittii , can cause human diseases. Thus, both sequencing and culturomics methods are crucial for comprehensive understanding of the microbiota of D. nuttalli

Mapping of B-cell epitopes on the N- terminal and C-terminal segment of nucleocapsid protein from Crimean-Congo hemorrhagic fever virus.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne pathogen that causes severe disease in humans. CCHFV is widely distributed in more than 30 countries and distinct regions, which means that it poses a serious threat to human health. The nucleocapsid protein (NP) encoded by the CCHFV S gene is the primary detectable antigen in infected cells, which makes it an important viral antigen and a clinical diagnostic target. In this study, the modified biosynthetic peptide (BSP) method was used to identify the fine epitopes on the N- and C- terminals of NP from the CCHFV YL04057 strain using rabbit antiserum against CCHFV-NP. Nine epitopes were identified: E1a (178NLILNRGG185), E1b (184GGDENP189), E2 (352PLKWGKK358), E3 (363FADDS367), E4 (399NPDDAA404), E5a (447DIVASEHL454), E5b (452EHLLHQSL459), E6 (464SPFQNAY470) and E7 (475NATSANII482). Western blotting analysis showed that each epitope interacted with the positive serum of sheep that had been naturally infected with CCHFV. Amino acid sequence alignment between each epitope and their homologous proteins showed that they were almost 100% conserved among 12 CCHFV sequences from different lineages, except for epitopes E1a, E1b and E2. Three-dimensional structural modeling analysis showed that all identified epitopes were located on the surface of the NP "head" domain. This study identified fine epitopes on the N- and C- terminals of NP, which will increase the understanding of the structure and function of NP, and it could lay the foundation for the design and development of a CCHFV multi-epitope peptide vaccine and detection antigen

Fine mapping epitope on Glycoprotein-Gn from Severe Fever with Thrombocytopenia Syndrome Virus.

Severe Fever with Thrombocytopenia Syndrome Virus (SFTSV) was recently identified as a tick-borne pathogen that threat to human health. Since 2010, many countries including China, South Korea, and Japan have reported Human SFTS caused by SFTSV infection. The glycoprotein encoded by the SFTSV M gene is the major antigenic component on the viral surface, and responsible for the viral entry, which makes it an important viral antigen and a clinical diagnostic target. The present study aimed to map linear B cell epitopes (BCEs) on the N-terminal glycoprotein (Gn) from SFTSV strain WCH/97/HN/China/2011 using the modified biosynthetic peptide method. Five fine epitopes (E1, 196FSQSEFPD203; E2, 232GHSHKII238; E3, 256VCYKEGTGPC265; E4, 285FCKVAG290, and E5, 316SYGGM320) were identified using the rabbit antisera. Western blot analysis showed that all the five epitopes interacted with the positive serum of sheep that had been naturally infected with SFTSV. Three-dimensional structural modeling analysis showed that all identified BCEs were located on the surface of the SFTSV-Gn and contained flexible loops. The sequence alignment revealed high conservation of the identified BCEs among 13 SFTSV strains from different lineage. These mapped epitopes will escalate the understanding of the epitope distribution and pathogenic mechanism of SFTSV, and could provide a basis for the development of a SFTSV multi-epitope detection antigen

Fine epitope mapping of glycoprotein Gn in Guertu virus.

Guertu virus (GTV) is a tick-borne phleboviruses (TBPVs) which belongs to the genus Banyangvirus in the family of Phenuiviridae. In vitro and in vivo studies of GTV demonstrated that it was able to infect animal and human cell lines and could cause pathological lesions in mice. Glycoproteins (GP, including Gn and Gc) on the surface of Guertu virus (GTV) could bind to receptors on host cells and induce protective immunity in the host, but knowledge is now lacking on the information of B cell epitopes (BCEs) present on GTV-GP protein. The aim of this study was to identify all BCEs on Gn of the GTV DXM strain using rabbit pAbs against GTV-Gn. Seven fine BCEs and two antigenic peptides (APs) from nine reactive 16mer-peptides were identified, which are EGn1 (2PIICEGLTHS11), EGn2 (135CSQDSGT141), EGn3 (165IP EDVF170), EGn4 (169VFQEL K174), EGn5 (187IDGILFN193), EGn6 (223QTKWIQ228), EGn7 (237CHKDGIGPC245), AP-8 (299GVRVRPKCYGFSRMMA314) and AP-9 (355CASH FCSSAESGKKNT370), of which six of mapped BCEs were recognized by the IgG-positive sheep serum obtained from sheep GTV-infected naturally. Multiple sequence alignments (MSA) based on each mapped BCE motif identified that the most of identified BCEs and APs are highly conserved among 10 SFTSV strains from different countries and lineages that share relatively close evolutionary relationships with GTV. The fine epitope mapping of the GTV-Gn would provide basic data with which to explore the GTV-Gn antigen structure and pathogenic mechanisms, and it could lay the foundation for the design and development of a GTV multi-epitope peptide vaccine and detection antigen

First case of laboratory-confirmed severe fever with thrombocytopenia syndrome disease revealed the risk of SFTSV infection in Xinjiang, China

ABSTRACTThe Xinjiang Uygur Autonomous Region locating in Northwest of China was not considered the epidemic area of severe fever with thrombocytopenia syndrome (SFTS). Here we report the first laboratory-confirmed SFTS case that a female patient had tick bite in Xinjiang and illness onset after returning to Hainan Province. Laboratory tests identified SFTS virus (SFTSV) infection, and the virus was isolated from the patient’s serum sample. Furthermore, SFTSV prevalence among tick groups was identified, and IgM response to SFTSV from febrile patients was identified. The findings suggested that there have been risks of SFTSV infection due to exposure to ticks in Xinjiang

Discovery of Tick-Borne Karshi Virus Implies Misinterpretation of the Tick-Borne Encephalitis Virus Seroprevalence in Northwest China

Despite few human cases of tick-borne encephalitis virus (TBEV), high rates of TBEV seroprevalence were reported among humans and animals in Xinjiang Uygur Autonomous Region in Northwestern China. In this study, the Karshi virus (KSIV) was identified and isolated from Hyalomma asiaticum ticks in Xinjiang. It belongs to the genus Flavivirus of the family Flaviviridae and is closely related to TBEV. KSIV infects cell lines from humans, other mammals and ticks, and causes encephalitis in suckling mice. High minimum infection rates (4.96%) with KSIV were detected among tick groups. KSIV infections have occurred in sheep and marmots, resulting in antibody-positive rates of 2.43 and 2.56%, respectively. We further found that, of the KSIV antibody-positive serum samples from animals, 13.9% had TBEV exposure showing cross-reaction to KSIV, and 11.1% had KSIV infection resulting in cross-reaction to TBEV; 8.3% were likely to have co-exposure to both viruses (or may be infected with one of them and present cross-reactivity with the other). The results revealed a substantial KSIV prevalence among ticks in Xinjiang, indicating exposure of animals to KSIV and TBEV. The findings implied misinterpretation of the high rates of TBEV seroprevalence among humans and animals in previous studies. There is a need to develop detection methods to distinguish KSIV from TBEV and to perform an in-depth investigation of KSIV and TBEV prevalence and incidence in Northwestern China, which would enhance our preparation to provide medical treatment of emerging diseases caused by tick-borne viral pathogens such as KSIV

The first laboratory-confirmed SFTS case from the Xinjiang Uygur Autonomous Region importing to Hainan International Tourism Island

Severe fever with thrombocytopenia syndrome (SFTS) is an acute infectious disease caused by a tick-borne phlebovirus, which was reported to be continuously epidemic in Japan, Korea and in 23 provinces of China since 2010. Most laboratory-confirmed SFTS cases in China have been recorded in 18 Eastern and Central provinces. A few suspected cases with SFTS-like symptoms were reported to the Chinese Disease Prevention and Control Information System from provinces including Guangxi, Guangdong, Gansu and Xinjiang Uygur Autonomous Region (XJUAR), however diagnosis was not confrimed due to lack of molecular biological and virological evidence. Here we reported the first laboratory-confirmed SFTS case in 2017. A resident of Hainan International Tourism Island (HNITI) was bitten by ticks when traveling in XJUAR and had illness onset after returning to HNITI. RT-PCR detected SFTSV RNA in the patient’s serum samples. Antibodies against SFTSV were detected from the patient and the neutralization from serum samples was evaluated. And the samples of person who had close contact to the patient were also investigated. Moreover, a new SFTSV strain was isolated from the serum sample collected from the patient during acute phase of disease. The viral properties and phylogeny were further characterized. In addition, SFTSV was detected positive in ticks collected from XJUAR in 2017, which suggested that SFTSV was more widely distributed than we recognized. Therefore, this study identified the first SFTS case from XJUAR where confirmed cases have never been reported and demonstrated the substantial risk from SFTSV infection via tick bite there. It is also the first importing SFTS case in HNITI, which showed the significant role of human transport in disease spread and indicated that the recently authorized international tourism island may face more challenges for controlling other importing cases from different areas and countries

Taxonomy of the order Bunyavirales : update 2019

In February 2019, following the annual taxon ratification vote, the order Bunyavirales was amended by creation of two new families, four new subfamilies, 11 new genera and 77 new species, merging of two species, and deletion of one species. This article presents the updated taxonomy of the order Bunyavirales now accepted by the International Committee on Taxonomy of Viruses (ICTV).Peer reviewe

Taxonomy of the order Bunyavirales : update 2019

In February 2019, following the annual taxon ratification vote, the order Bunyavirales was amended by creation of two new families, four new subfamilies, 11 new genera and 77 new species, merging of two species, and deletion of one species. This article presents the updated taxonomy of the order Bunyavirales now accepted by the International Committee on Taxonomy of Viruses (ICTV).This work was supported in part through Battelle Memorial Institute’s prime contract with the US National Institute of Allergy and Infectious Diseases (NIAID) under Contract no. HHSN272200700016I (J. H. K.). This work was also funded in part by Grant 109520 by the UK Department of Health, Public Health England (R. H.). W. M. S. is supported by Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil (17/13981-0). This work was supported by the Intergovernmental Special Program of State Key Research and Development Plan from the Ministry of Science and Technology of China (2016YFE0113500) and European Union’s Horizon 2020 EVAg project (no. 653316).http://link.springer.com/journal/7052020-07-01hj2019Medical Virolog