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.