Investigation and source-tracing of an anthrax outbreak in Gansu Province, China

PLoS One. 2018 Aug 30;13(8):e0203267. doi: 10.1371/journal.pone.0203267. eCollection 2018.

Abstract

Anthrax is an endemic disease in China. Cases are reported every year, especially in the northwestern areas. In August 2016, an outbreak of 21 cutaneous anthrax cases was reported in Min County, Gansu Province, China. In this study, the general characteristics of the anthrax outbreak are described. Two molecular typing methods, canonical single-nucleotide polymorphism (canSNP) and multiple-locus variable-number tandem repeat analysis with 15 markers (MLVA15), were used to investigate the possible source of transmission and to identify the genetic relationship among the strains/samples isolated in this outbreak as well as previous isolates. In this outbreak, all patients were infected through contact with diseased livestock or contaminated animal products. Livestock had been introduced into the local area shortly before the outbreak from Gannan Prefecture (in Gansu Province), Sichuan and Qinghai Provinces. In the molecular typing analysis, there were two canSNP subgroups found in Gansu, A.Br.001/002 and A.Br.Ames, and five MLVA15 genotypes were observed. The strains collected from the anthrax outbreak in Min County in 2016 belonged to the A.Br.001/002 canSNP subgroup and the MLVA15-28 and MLVA15-30 genotype. Strains previously isolated from Sichuan, Inner Mongolia and Maqu County (in Gannan Prefecture, Gansu Province) were clustered with these outbreak-related strains/samples according to the MLVA15-30 genotype. The MLVA15-28 genotype was found in strains isolated from Gansu and Xinjiang in previous studies. Combining the epidemiological investigation and molecular typing results, we conclude that the patients in this outbreak were infected by a local pathogen present in the adjoining area of Gansu, Sichuan and Qinghai Provinces.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Animals
  • Anthrax / epidemiology*
  • Anthrax / genetics
  • Bacillus anthracis / genetics
  • Child
  • China / epidemiology
  • Disease Outbreaks
  • Female
  • Humans
  • Livestock
  • Male
  • Middle Aged
  • Minisatellite Repeats
  • Molecular Epidemiology
  • Molecular Typing
  • Polymorphism, Single Nucleotide
  • Young Adult

Grants and funding

This work was supported by National Science and Technology Mega-Projects of China (2012ZX1004208 and 2012ZX10004215, www.most.gov.cn) and National Priority Development Project on Key Science Instrument (2012YQ09019706, www.caiq.org.cn/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.