Serological investigation of brucella infection using a dipstick assay among individuals with unexplained fever in farming-pastoral areas of Xinjiang, China.

OBJECTIVE: To evaluate the brucellosis detection of the dipstick assay coated with LPS antigen from Brucella melitensis vaccine strain M5 compared with Rose Bengal test (RB) and serum agglutination test (SAT), and investigate the brucella infection with the dipstick assay among people with unexplained fever in farming-pastoral areas of Xinjiang, China. METHODS: The dipstick assay was repeated to verify 130 positive and 200 negative serum samples, which had been confirmed by RB and SAT, for sensitivity and specificity analysis. Subsequently, 313 sera from people with unexplained fever in farming-pastoral areas including 6 counties in 3 regions where brucellosis is endemic and 200 sera from nonendemic city area (Urumqi City) in Xinjiang were detected with the dipstick assay for population infection rate survey. RESULTS: Sensitivity and specificity was 100% and 97% respectively with dipstick assay compared with RB and SAT. The average positive rate of sera from people with unexplained fever from farming-pastoral areas in Xinjiang was 18.5% (58/313) and the highest was 22.5% (9/40). CONCLUSIONS: The proportion of brucellosis infection among individuals with fever of unknown origin is relatively high in agricultural and pastoral areas of Xinjiang. The dipstick assay has a series of advantages such as low cost and fast speed, which make it suitable for the primary screening of high-risk populations.

Molecular evidence of Tula virus in Microtus obscurus in the region of Yili, Xinjiang, China.

BACKGROUND: Hantaviruses are important zoonotic pathogens, and they pose a profound risk to public health. So far, there has been no evidence showing that Tula virus (TULV), one species of hantavirus, is endemic in China. In this study, we captured rodents and found that the Tula virus had infected voles in Yili region, Xinjiang, China. METHODS: Rodents were captured by flooding their burrows in mountain pasture areas in Narati, Xinyuan County, Xinjiang, China. Hantavirus L gene fragments were amplified by nest RT-PCR using genus-specific primers. Positive samples were further identified by sequencing of RT-PCR products of S gene fragment for species identification. To identify the species of captured small mammals, the rodents' cytochrome b (Cytb) was amplified by PCR and sequenced. Phylogenetic analysis was used to show the clustering and evolution relationship of the viral nucleic acids. RESULTS: Here, 31 out of 198 voles captured (16%) were infected with TULV. Host sequencing analysis showed these voles were Microtus obscurus (M. obscurs). Alignment and phylogenetic analysis of the exon region (1191 bp) of the hantavirus S gene confirmed that all of the detected amplicons were TULV, which was similar to one strain of TULV identified in Kazakhstan. CONCLUSION: This is the first identification of Tula virus in China, and we found that M. obscurus acts as a natural reservoir for carrying the virus. Although the infection rate in the local human population remains unknown, the high prevalence of TULV in the small mammals in the region constitutes a risk that this putative pathogen may spread to the local population.

Seoul virus in the Brown Rat ( Rattus norvegicus ) from Ürümqi, Xinjiang, Northwest of China.

Hantavirus infections among human populations are linked to the geographic distribution of the host rodents that carry the viruses. To determine the presence and distribution of hantaviruses in the northern region of Xinjiang Uygur Autonomous Region (XUAR), northwestern China, 844 rodents were captured from five locations in four dissimilar habitats during 2010-14 and examined for Hantavirus infection. Hantavirus nucleic acids were firstly detected in the brown rat ( Rattus norvegicus ) from Ürümqi, China, indicating that the Hantavirus was transmitted into Ürümqi in XUAR and circulated by the brown rat. Our results suggest that the brown rat may act as a natural reservoir for the virus in XUAR.