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We analyzed 10 isolates of Francisella tularensis subspecies holarctica from China and assigned them to known clades by using canonical single-nucleotide polymorphisms. We found 4 diverse subtypes, including 3 from the most basal lineage, biovar japonica. This result indicates unprecedented levels of diversity from a single region and suggests new models for emergence. [ABSTRACT FROM AUTHOR]

Background: Tularemia was reported in China over 50 years ago, however, many epidemical characteristics remain unclear. In the present study, the prevalence of Francisella tularensis in ticks was investigated during an epidemiological surveillance in China and then we measured their genetic diversity by conducting multiple-locus variable- number tandem repeat analysis (MLVA). Results: 1670 ticks from 2 endemic areas (Inner Mongolia Autonomous Region and Heilongjiang Province) and 2 non-endemic areas (Jilin and Fujian Provinces) were collected and tested for evidence of tularemia by nested PCR. The prevalence of Francisella tularensis in ticks averaged 1.98%. The positive rates were significantly different among tick species, with Dermacentor silvarum and Ixodes persulatus responsible for all positive numbers. All F. tularensis that were detected in ticks belonged to F. tularensis subsp. holarctica and MLVA disclosed genetic diversity. One subtype was identified in 17 of 33 positive tick samples in three different study areas. Another subtype belonging to F. tularensis subsp. holarctica genotype was described for the first time in the current study. Conclusion: The study showed two tick species, D. silvarum and I. persulatus harboring the pathogen of tularemia in natural environment, indicating these two tick species might have a role in tularemia existence in China. MLVA results disclosed the genetic diversity F. tularensis and identified one genotype as the most prevalent among the investigated ticks in China. [ABSTRACT FROM AUTHOR]

A total of 420 rodents in China were examined for Francisella tularensis by polymerase chain reaction. The infection rates were 4.76% in total, and 11.65%, 10.00%, 6.56%, 1.77%, and 0% in Jilin, Xinjiang, Heilongjiang, Inner Mongolia, and Zhejiang, respectively. Sequence analysis showed that all the detected agents belonged to F. tularensis subsp. holarctica. [ABSTRACT FROM AUTHOR]