Changed epidemiology of anthrax and molecular characteristics of B.
anthracis in Inner Mongolia Autonomous Region, China
Abstract
Anthrax is a natural foci disease in Inner Mongolia, which poses a
severe threat to public health. In this study, the incidence number,
rate, and constituent ratio were used to describe the epidemiological
characteristics of anthrax in the region from 1956ā2018. The molecular
correlation and genetic characteristics of the strains were investigated
using canonical single-nucleotide polymorphisms (CanSNP), multiple-locus
variable-number tandem repeat analysis (MLVA-15), and whole genome
sequencing (WGS). The epidemiological characteristics of anthrax in
Inner Mongolia have altered significantly. The incidence was decreased
annually, the regional distribution of anthrax gradually transferred
from central and western regions to the eastern. Moreover, the
occupation distribution was evolved from multiple early occupations to
predominated by farmers and herdsmen. This indicates that reformulate
the control and prevention strategies is essential. Both A. Br. Ames and
A. Br. 001/002 subgroups were the predominant CanSNP genotypes of
Bacillus anthracis in Inner Mongolia. A total of 36 strains constituted
six shared MLVA-15 genotypes, suggesting an epidemiological link between
the strains of each shared genotype. The six shared genotypes ((GT1, 9,
11, and 15) and (GT8 and 12)) consisting of 2ā7 strains confirmed the
occurrence of multiple point outbreaks and cross-regional transmission
caused by multiple common sources of infection. Phylogenetic analysis
based on the core genome showed that strains from this study formed an
independent clade (Cā
¢), suggesting a common origin. Moreover, B.
anthracis showed a high genetic similarity with strain from Japan and
South Korea, the strains from this study may be originated from Japan.