Brucellosis Reemergence after a Decade of Quiescence in Palestine,
2015-2017: a Seroprevalence and Molecular Characterization Study
Abstract
Brucellosis is an endemic disease in many developing countries and
ranked by the World Health Organization among the top seven “neglected
zoonoses”. Although a Palestinian brucellosis control program was
launched in 1998, the disease reemerged after 2012. Interestingly, a
similar reemerging pattern was reported in the neighboring Israeli
regions. The aim of this work was to characterize the reemerging strains
and delineate their genetic relatedness. During 2015-2017, blood samples
from 1324 suspected patients were analyzed using two serological tests.
Seropositive samples were cultured, and their DNAs were analyzed by
different genetic markers to determine the involved Brucella species and
rule out any possible involvement of the Rev.1 vaccine strain. The rpoB
gene was sequenced from 9 isolates to screen for rifampicin-resistance
mutations. Multi Locus VNTR Analysis (MLVA-16) was used for genotyping
the isolates. The molecular analysis showed that all isolates were B.
melitensis strains unrelated to the Rev.1 vaccine. The rpoB gene
sequences showed four single nucleotide variations (SNVs) not associated
with rifampicin resistance. MLVA-16 analysis clustered the isolates into
22 unique genotypes that belong to the East Mediterranean lineage.
Altogether, our findings show that the reemergence of brucellosis was
due to B. melitensis strains of local origin, the Palestinian and
Israeli control programs’ weaknesses could be a major factor behind the
reemergence of the disease. However, other socioeconomic and
environmental factors must be investigated. Moreover, strengthening
brucellosis control programs and enhancing cooperation between all
stakeholders is essential to ensure long-term program outcomes to fight
brucellosis.