Exploring the Diversity of Field Strains of Brucella abortus Biovar 3 Isolated in West Africa

Abstract

Brucellosis is one of the most widespread bacterial zoonotic diseases in the world, affecting both humans and domestic and wild animals. Identification and biotyping of field strains of Brucella are of key importance for a better knowledge of the epidemiology of brucellosis, for identifying appropriate antigens, for managing disease outbreaks and for setting up efficient preventive and control programmes. Such data are required both at national and regional level to assess potential threats for public health. Highly discriminative genotyping methods such as the multiple locus variable number of tandem repeats analysis (MLVA) allow the comparison and assessment of genetic relatedness between field strains of Brucella within the same geographical area. In this study, MLVA biotyping data retrieved from the literature using a systematic review were compared using a clustering analysis and the Hunter-Gaston diversity index (HGDI). Thus, the analysis of the 42 MLVA genotyping results found in the literature on West Africa [i.e., from Ivory Coast (1), Niger (1), Nigeria (34), The Gambia (3), and Togo (3)] did not allow a complete assessment of the actual diversity among field strains of Brucella. However, it provided some preliminary indications on the co-existence of 25 distinct genotypes of Brucella abortus biovar 3 in this region with 19 genotypes from Nigeria, three from Togo and one from Ivory Coast, The Gambia, and Niger. The strong and urgent need for more sustainable molecular data on prevailing strains of Brucella in this sub-region of Africa and also on all susceptible species including humans is therefore highlighted. This remains a necessary stage to allow a comprehensive understanding of the relatedness between field strains of Brucella and the epidemiology of brucellosis within West Africa countries.

Brucella melitensis , a latent “travel bacterium,” continual spread and expansion from Northern to Southern China and its relationship to worldwide lineages

“…B. melitensis is responsible for the vast majority of brucellosis in humans and animals in China [13], but the genetic relatedness of B. melitensis within China and its relationship to strains in other world areas is unknown. Investigation of species and genotype distributions, genetic relatedness, and molecular epidemiology of the main circulating strains is essential for understanding the epidemiology of human brucellosis, managing disease outbreaks and for establishing efficient prevention and control programmes [14].…”

Detection of Brucella abortus in Cows Suffering From Some Reproductive Disorders

“…Bovine brucellosis can be diagnosed using a variety of serological tests, which complicates the diagnosis for several reasons. However, there is a restriction to the tests, when the organism is intracellular, the disease enters a chronic stage, and the antibody titers may decrease [21,22]. The goal of the current investigation was to use PCR to identify Brucella spp.…”

Molecular Epidemiology Characteristics of Brucella abortus Strains in China and Their Relationships with World Lineages

“…HGDI analysis of B. abortus bv. 3 from West Africa showed that the highest diversity indices were observed with markers composing panel 2 with three to nine alleles, especially at bruce16, which is known as one of the most variable loci [37]. Betsy J et al reported that, historically, approximately 85% of B. abortus infections in the U.S. were caused by biovar 1, which would result in an HGDI≈0.2 [38].…”