Abstract

In China, brucellosis is an endemic disease and the main sources of brucellosis in animals and humans are infected sheep, cattle and swine. Brucella melitensis (biovars 1 and 3) is the predominant species, associated with sporadic cases and outbreak in humans. Isolates of B. abortus, primarily biovars 1 and 3, and B. suis biovars 1 and 3 are also associated with sporadic human brucellosis. In this study, the genetic profiles of B. melitensis and B. abortus isolates from humans and animals were analyzed and compared by multi-locus variable-number tandem-repeat analysis (MLVA). Among the B. melitensis isolates, the majority (74/82) belonged to MLVA8 genotype 42, clustering in the ‘East Mediterranean’ group. Two B. melitensis biovar 1 genotype 47 isolates, belonging to the ‘Americas’ group, were recovered; both were from the Himalayan blue sheep (Pseudois nayaur, a wild animal). The majority of B. abortus isolates (51/70) were biovar 3, genotype 36. Ten B. suis biovar 1 field isolates, including seven outbreak isolates recovered from a cattle farm in Inner Mongolia, were genetically indistinguishable from the vaccine strain S2, based on MLVA cluster analysis. MLVA analysis provided important information for epidemiological trace-back. To the best of our knowledge, this is the first report to associate Brucella cross-infection with the vaccine strain S2 based on molecular comparison of recovered isolates to the vaccine strain. MLVA typing could be an essential assay to improve brucellosis surveillance and control programs.

Highlights

  • Brucellosis, recognized as a zoonotic disease of global importance, is caused by bacteria of the genus Brucella, which currently encompasses ten recognized species [1,2,3]

  • B. melitensis has been the predominant species associated with human outbreaks and sporadic cases in China; B. abortus and B. suis are associated with sporadic epidemics [5]

  • We present the results of an investigation employing the Brucella multi-locus variable-number tandemrepeat analysis (MLVA) assay to address the identification of the S2 vaccine strain in animals in China

Read more

Summary

Introduction

Brucellosis, recognized as a zoonotic disease of global importance, is caused by bacteria of the genus Brucella, which currently encompasses ten recognized species [1,2,3]. Since 2008, 21 sentinel surveillance sites for animal and human brucellosis were established in 19 provinces nationwide. During this 5 years period, a number of animal and human isolates have been collected. MLVA genotyping of Chinese human B. melitensis isolates and B. suis biovar 3 isolates have been reported previously by our team [7]. None of these studies included animal isolates.

Objectives
Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call