Genetic diversity of Borrelia burgdorferi sensu lato isolates from Northeastern China.

Thirty-two strains of Borrelia burgdorferi sensu lato were isolated from Ixodes persulcatus ticks collected from northeastern China from May to June in 2004 and 2005. Restriction fragment length polymorphism (RFLP) analysis and sequence analysis of 5S-23S rRNA intergenic spacer revealed that 29 (90.6%) belonged to Borrelia garinii, demonstrating B, C, and a unique pattern. The remaining three isolates (9.4%) were Borrelia afzelii with pattern D. The phylogenetic analysis based on 5S-23S rRNA intergenic spacer showed that B. garinii and B. afzelii genospecies clustered into two separate lineages. B. garinii strains were classified into three different branches: All the strains with RFLP pattern C were in the same branch, strain VH10 with a unique RFLP pattern clustered with strains VH9 and MDH2 with pattern B, and the rest of the strains with pattern B constitute another branch. These findings demonstrate the genetic diversity of B. burgdorferi sensu lato isolates from northeastern China.

Genetic diversity of Borrelia burgdorferi sensu lato isolates from Northeastern China.

Thirty-two strains of Borrelia burgdorferi sensu lato were isolated from Ixodes persulcatus ticks collected from northeastern China from May to June in 2004 and 2005. Restriction fragment length polymorphism (RFLP) analysis and sequence analysis of 5S-23S rRNA intergenic spacer revealed that 29 (90.6%) belonged to Borrelia garinii, demonstrating B, C, and a unique pattern. The remaining three isolates (9.4%) were Borrelia afzelii with pattern D. The phylogenetic analysis based on 5S-23S rRNA intergenic spacer showed that B. garinii and B. afzelii genospecies clustered into two separate lineages. B. garinii strains were classified into three different branches: All the strains with RFLP pattern C were in the same branch, strain VH10 with a unique RFLP pattern clustered with strains VH9 and MDH2 with pattern B, and the rest of the strains with pattern B constitute another branch. These findings demonstrate the genetic diversity of B. burgdorferi sensu lato isolates from northeastern China.

Isolation and genetic characterization of hantaviruses carried by Microtus voles in China.

To gain more insights into hantavirus distribution in China, Microtus fortis were caught in Jilin province and M. maximowiczii in the Inner Mongolia Autonomous Region. Hantavirus specific RNA was detected by RT-PCR in 3 out of 26 M. fortis and 5 out of 64 M. maximowiczii. Two hantaviruses (Fusong-Mf-682 and Yakeshi-Mm-59) were isolated successfully in cell culture and their S and M segment nucleotide sequences were determined. Phylogenetic analysis of the S and M segment sequences revealed that the Mf-originated strains from Fusong were closely related to Vladivostok hantavirus (VLAV) with 99% nucleotide identity, but differed from the Yakeshi-Mm strains, with an amino acid divergence of more than 8.8% for the N protein and 11.8% for the GnGc proteins. Yakeshi-Mm strains were closely related to the Khabarovsk hantavirus (KHAV) isolated earlier from M. fortis in Khabarovsk, with an amino acid sequence identity of more than 98.4% for the S segment and 95.6% for the M segment. On phylogenetic trees, Yakeshi-Mm strains clustered together with KHAV and Topografov virus (TOPV) carried by Lemmus sibiricus. The results suggest that the hantavirus carried by M. fortis in China belongs to VLAV type and should be considered as a distinct hantavirus species. They also suggest that M. fortis is the natural host of VLAV (including Fusong-Mf strains), whereas M. maximowiczii is the natural host of KHAV including Yakeshi-Mm strains. Thus, in addition to Hantaan, Seoul, Dabieshan and Puumala-like Hokkaido viruses, at least two other hantaviruses, namely KHAV and VLAV, are circulating in China.

Study on the epidemiological characteristics of hemorrhagic fever with renal syndrome in Inner Mongolia / 中华流行病学杂志

<p><b>OBJECTIVE</b>In order to better understand the epidemiological features of Hantviruses in Inner Mongolia.</p><p><b>METHODS</b>Epidemiological surveillance data during the period of the past 52 years were analyzed. An epidemiological survey was carried out in the main epidemic areas in 2005.</p><p><b>RESULTS</b>A total of 8310 hemorrhagic fever with renal syndrome (HFRS) cases were reported in Inner Mongolia from 1955 to 2006, and distributed in 61 counties. HFRS cases were mainly distributed in the east part of Inner Mongolia before 1990. However, HFRS cases had occurred in the middle and western parts since 1990. Hulunbeier prefecture, from the eastern part of Inner Mongolia, had been the most severe area being hit by HERS since the first outbreak in 1955, with 7369 cases reported over the past 52 years, and accounted for 88.68% of the total cases in the whole autonomous region. Although no HFRS cases had been reported before 1999 in Bayannaoer which located in the western part of Inner Mongolia, a total of 95 cases were reported in 2005. Hantavirus antigens had been detected in 11 species of rodents so far,including Apodemus agrarius, Rattus norvegicus, Mus Musculus, Cricetulus barabensis, meriones meridianus, Microtus maximowiczii , Clethrionomys rutilus, Apodemus peninsulae, Phodopus roborvskii, Dipus sagitta and Allactaga sibirica.</p><p><b>CONCLUSION</b>Results suggested that the epidemics might remain at a relatively high level in the years to come in Inner Mongolia. Furthermore, there might be other types of Hantaviruses in addition to the already identified Seoul viral type in this area.</p>