Seroprevalence of human brucellosis and molecular characteristics of Brucella strains in Inner Mongolia Autonomous region of China, from 2012 to 2016

Abstract

In the present study, a total of 1102304 serum samples were collected to detected human brucellosis between the years 2012 and 2016 in Inner Mongolia. Overall, an average of 3.79% anti-Brucella positive in Inner Mongolia was presented but the range of positive rates were among 0.90 to 7.07% in 12 regions. Seroprevalence of human brucellosis increased gradually from 2012 to 2016. However, the incidence rate of human brucellosis showed a declining trend. One hundred and seven Brucella strains were isolated and identified as B. melitensis species, and B. melitensis biovar 3 was the predominant biovar. MLVA-11 genotypes 116 was predominant and had crucial epidemiology to the human population. All 107 strains tested were sorted into 75 MLVA-16 genotypes, with 54 single genotypes representing unique isolates. This result revealed that these Brucellosis cases had epidemiologically unrelated and sporadic characteristics. The remaining 21 shared genotypes among two to four strains, confirming the occurrence of crossinfection and multiple outbreaks. Extensive genotype-events were observed between strains from this study and Kazakhstan, Mongolia, and Turkey, these countries were key members of the grassland silk road. Long-time trade in small ruminants (sheep) in these countries has possibly promoted the spread of Brucella spp. in these regions.

Epidemiologically characteristics of human brucellosis and antimicrobial susceptibility pattern of Brucella melitensis in Hinggan League of the Inner Mongolia Autonomous Region, China

“…3 caused the majority of human brucellosis cases in northern and southern China [31][32][33]. However, 89% (48/54) of strains in this study carried MLVA-11 genotype 116; strains with this genotype have a vital epidemiological significance to the humans infected brucellosis [34]. A total of 54 strains were grouped into 12 shared genotypes, these genotypes represented 29 strains, and the genetic similarity coefficient among the strains was higher than 80%.…”

Spatiotemporal expansion of human brucellosis in Shaanxi Province, Northwestern China and model for risk prediction

“…Brucellosis is a bacterial zoonosis caused by genus Brucella, including B. abortus, B. canis, B. suis, B. ceti, B. pinnipedialis and B. inopinata ( Dadar, Shahali & Whatmore, 2019 ). Compared with the individual-to-individual transmission, the environment-to-individual transmission is more common ( Li et al, 2017 ), which means that most people are infected by contacting with Brucella in the environment, such as contaminated forage, water, grass, liquids, products, raw milk and the uterine fluids from infected animals ( Li et al, 2017 ; Nematollahi et al, 2017 ; Chen et al, 2013 ; Liu et al, 2020 ). Thus, shepherds, breeders, abattoirs workers, veterinarians and laboratory personnel who potentially contact the bacteria are at high risks ( Chen et al, 2016 ).…”

ONE Health Approach to Address Zoonotic Brucellosis: A Spatiotemporal Associations Study Between Animals and Humans

“…In China, 90% of brucellosis occurs in six northern agricultural provinces including Inner Mongolia, Shanxi, Heilongjiang, Hebei, Jilin, and Shaanxi. The Inner Mongolia Autonomous Region has the highest incidence rate of human and animal brucellosis throughout China ( 29 ). Human cases have been observed in those regions where animal farming is prevalent, particularly in areas with many poor rural farms and pastures in northwest China ( 30 ).…”

“…In the last 12 years, brucellosis has re-emerged in most regions of China, showing an annual accumulation in animal and human infections during this period ( 29 ). This is also evident in our meta-analysis which shows a general increasing trend in the prevalence, particularly for the recent past years.…”