Seroprevalence of Brucellosis and Isolation of Brucella from Small Ruminants That Had History of Recent Bbortion in Selected Kebeles of Amibara District, Afar region, Ethiopia
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Date
2016-06
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Addis Ababauniversity
Abstract
Brucellosis is one of the most frequent contagious neglected bacterial diseases with a serious
veterinary and public health importance through out the world. A cross-sectional study was
conducted from October 2015 to April 2016, to determine the seroprevalence of brucellosis
and isolate Brucella from small ruminants (sheep and goats) that had history of recent
abortion in selected kebeles of Amibara District, Afar Region. Ethiopia. Blood samples were
collected from a total of 226 small ruminants that had recent history of abortion for
serological test. Subsequently, 65 specimens (28milk, 28 vaginal swabs, 2 fatal abomasal
contents and 7 fetal membranes) were investigated from seropositive animals for Brucella
species isolation. All serum samples collected were screened serologically using the modified
Rose Bengal Plate Test (mRBPT) and sera positive with mRBPT were confirmed with
Complement Fixation Test (CFT). An overall seroprevalence among small ruminants
estimated at 7.52% (17/226; 95% CI: 7.41–1.36) were positive by combined mRBPT and CFT
analysis, while 12.4% (28/226; 95% CI: 1.22–16.44) were found positive by mRBPT alone.
Reproductive characteristics such as the stage of abortion (χ2=11.26; P < 0.001) and history
of retained fetal membrane (χ2=16.53; P<0.05) were significantly associated with increased
seropositivity result. A multivariable logistic regression analysis revealed that age
(OR=14.57, 95% CI: 1.72–123.6), parity status (OR=8.08, 95% CI: 1.11–58.57) and stage of
abortion (OR=8.94, 95% CI: 1.86–42.90) were significantly associated with Brucella
infection in clinically aborted small ruminants (P < 0.05). Brucella was isolated from 9
(13.8%) samples out of the 65 bacteriological samples cultured on Brucella Selective Agar.
Among the overall isolates, 3(10.7%) and 6 (21.4%) were from milk and vaginal swabs,
respectively. In this study all the isolates were obtained from seropositive goats milk and
vaginal swab. The isolates were B. melitensis based on biochemical test result, though further
test is required to biovariant level. In conclusion, the present serological test revealed that
brucellosis is moderatly prevalent among aborted small ruminants in the study area. The
isolation of B. melitensis from an aborted goats milk and vaginal swabs was not substantially
reported in Ethiopia until now, this report may be considered one of the indicative studies.
Therefore, further extensive molecular studies of the isolates and appropriate control
strategies are required to reduce its economic impact and risk of zoonotic infection in the
area.
Key words: Abortion, Afar Region, B. melitensis, Brucellosis, isolation, seroprevalence, small
ruminants
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Keywords
Abortion, Afar Region, B melitensis, Brucellosis, isolation, seroprevalence, smallruminants