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Beneficial approaches for controlling brucellosis

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Presented by Steven Olsen at a Workshop: An Integrated Approach to Controlling Brucellosis in Africa, Addis Ababa, 29-31 January 2013

Presented by Steven Olsen at a Workshop: An Integrated Approach to Controlling Brucellosis in Africa, Addis Ababa, 29-31 January 2013


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  • 1. Beneficial Approaches forBeneficial Approaches forControlling BrucellosisControlling BrucellosisDr. Steven OlsenNational Animal Disease CenterAmes, IA 50010Workshop: An Integrated Approach toControlling Brucellosis in Africa, Addis Ababa,29-31 January 2013
  • 2. Human BrucellosisHuman Brucellosis
  • 3. Components of a ControlComponents of a ControlProgramProgramSurveillanceVaccinationQuarantine/Removal of Infected/RiskReductionSanitationTrained Personnel, Records,Movement ControlRegionalization
  • 4. SurveillanceSurveillanceSerologic testingSales and abbatoirs (first point testing)Change of ownershipInterstate movementPeriodic Herd testingi.e. Milk testingTrained epidemiologist determinesinfected versus false positives
  • 5. Lipopolysaccharide structureLipopolysaccharide structureof virulent and vaccine strainsof virulent and vaccine strainsLipid ABrucella abortus strain 19Brucella abortus field strainsBrucella abortus strain RB51Sugars O-side chainKDOLipid A KDO Sugars O-side chainLipid A SugarsKDOThe O-side chain is the immunodominant antigenof Brucella for antibody responses
  • 6. VaccinationVaccinationApproved for use by species basedon Brucella infectionMay need to be regulated due tozoonotic and abortigenic potentialCould be used as a regulatorymethod to limit livestock movement
  • 7. Thoughts on BrucellosisThoughts on BrucellosisVaccinesVaccinesVaccination alone will not eradicate brucellosisVaccines are very good at reducingtransmission and clinical disease; very poor atpreventing seroconversion after exposureLong-term protection related to cell-mediatedimmunityAntibodies relatively unimportant for efficacyMany vaccine strains can be pathogenic inhumans or pregnant animals
  • 8. BrucellosisVaccines AvailableBrucellosisVaccines AvailableB. melitensis: strain Rev1(small ruminants)B. suis: noneB. abortus strains 19 or RB51,45/20 (cattle)B. canis noneB. ovis none
  • 9. Quarantine/Removal/Risk ReductionQuarantine/Removal/Risk ReductionQuarantine is a way to isolateinfection or prevent introductionRemoval of infected animals is usedin many countries but may be costprohibitiveRisk Reduction – evaluate husbandrypractices to identify ways to preventtransmission of brucellosis
  • 10. SanitationSanitationSegregate animals at parturitionRemove and burn afterbirth/abortedfetuses to prevent fomitetransmissionSanitize fluids/materials which may beroute of transmission (i.e. milk)
  • 11. Trained Personnel/Records/AnimalTrained Personnel/Records/AnimalMovementMovement Use personnel with knowledge ofprocedures and program Maintain records (vaccination, testing, etc)to allow assessment at later times Infrastructure/Teamwork/Communication Brucellosis is usually spread by animalmovement Animal Identification Essential Control of Testing
  • 12. Containment of Infection: Control orContainment of Infection: Control orEradication ProgramsEradication Programs Identify herd of origin and exposedherds/flock Herd/flock or area plan Quarantine and/or depopulation Permanent marking of infected animals Sanitation: Cleaning and disinfection Herd testing until disease eliminated Vaccination as applicable Epidemiologic Investigations and followup to detection of infection
  • 13. Control of Human BrucellosisControl of Human BrucellosisAddressing in domestic livestockmost economical approach- in 1 study benefit:cost ratio of 3.2 forvaccination (Roth et al 2004)Pasturization of milk productsPrecautions taken to prevent directtransmission
  • 14. SummarySummaryBrucellosis control programs requirea coordinated, committed regulatoryframeworkBenefits include: reduced humandisease, greater economic returnsfor livestock owner, possibleimproved trade opportunities
  • 15. Comparison of Strains RB51 andComparison of Strains RB51 and19 Vaccines in Cattle19 Vaccines in CattleStrain 19 Strain RB51Serology on StandardBrucellosis TestsPositive;Prolonged high titers withbooster vaccinationNegative, even onbooster vaccinationClearance in vivo Approx. 12 weeksPathogenicity Moderate to High LowEfficacy Good Similar to Strain 19Zoonotic Characteristics Significant HumanPathogenReduced Pathogenicityas compared to strain 19Use in Pregnant Cattle Low Dose may causesignificant abortions andhigh titersOccasional abortions