Overview of Small Animal
Brucellosis Control Strategies
Dr. Steven OlsenDr. Steven Olsen
National Animal Disease CenterNational Animal Disease Center
Ames, IA 50010Ames, IA 50010
Workshop: An Integrated Approach to Controlling Brucellosis
in Africa, Addis Ababa, 29-31 January 2013

Control of Human BrucellosisControl of Human Brucellosis
Addressing in domestic livestock mostAddressing in domestic livestock most
economical approacheconomical approach
- in 1 study benefit:cost ratio of 3.2 for- in 1 study benefit:cost ratio of 3.2 for
vaccination (Roth et al 2004)vaccination (Roth et al 2004)
Pasturization of milk productsPasturization of milk products

Basic PrinciplesBasic Principles
Increase Herd ImmunityIncrease Herd Immunity
Identify/Characterize InfectionIdentify/Characterize Infection
Reduce Infection/Prevent Spread orReduce Infection/Prevent Spread or
TransmissionTransmission
Reduce RiskReduce Risk
Improve Available Tools/TechniquesImprove Available Tools/Techniques

BrucellaBrucella spp.:Hostspp.:Host
RelationshipsRelationships
Brucella melitensisBrucella melitensis: sheep (breed: sheep (breed
differences)differences) goats (moregoats (more
susceptible)susceptible)
Brucella abortusBrucella abortus goatsgoats

Small Ruminant BrucellosisSmall Ruminant Brucellosis
VaccinesVaccines
B. melitensisB. melitensis:: Strain Rev1 (0.5-2 x10Strain Rev1 (0.5-2 x1099
CFU SQ or conjunctival)CFU SQ or conjunctival)
B. suisB. suis strain 2 (China)strain 2 (China)
B. abortusB. abortus nonenone

Protective Immunity againstProtective Immunity against
Brucella: Primarily Cell-mediatedBrucella: Primarily Cell-mediated
Humoral Immunity Cell-mediated Immunity **
antibodies
cytotoxicity
macrophage activation
intracellular pathogens
neoplasia
hypersensitivity
viruses
bacteria
parasites
Acquired Immunity

Thoughts on BrucellosisThoughts on Brucellosis
VaccinesVaccines
Vaccination alone will not eradicate brucellosisVaccination alone will not eradicate brucellosis
Vaccines are very good at reducing transmissionVaccines are very good at reducing transmission
and clinical disease; very poor at preventingand clinical disease; very poor at preventing
seroconversion after exposureseroconversion after exposure
Long-term protection related to cell-mediatedLong-term protection related to cell-mediated
immunityimmunity
Antibodies relatively unimportant for efficacyAntibodies relatively unimportant for efficacy
Many vaccine strains can be pathogenic in humansMany vaccine strains can be pathogenic in humans
or pregnant animalsor pregnant animals

Factors Affecting Effectiveness of aFactors Affecting Effectiveness of a
Vaccination ProgramVaccination Program
Efficacy of Vaccine in Targeted SpeciesEfficacy of Vaccine in Targeted Species
Delivery MethodDelivery Method
Percentage of population vaccinatedPercentage of population vaccinated
Duration of ImmunityDuration of Immunity
CostCost

Lipopolysaccharide structureLipopolysaccharide structure
of virulent and vaccine strainsof virulent and vaccine strains
Lipid A
Brucella abortus strain 19
Brucella abortus field strains
Brucella abortus strain RB51
Sugars O-side chainKDO
Lipid A KDO Sugars O-side chain
Lipid A SugarsKDO
The O-side chain is the immunodominant antigen
of Brucella for antibody responses

Tools that May Be UsefulTools that May Be Useful
Break country down into smaller areasBreak country down into smaller areas
Reward Herds/Areas for controllingReward Herds/Areas for controlling
diseasedisease
Concentrate Resources in Areas ofConcentrate Resources in Areas of
Greatest Infection or HumanGreatest Infection or Human
TransmissionTransmission
Risk ManagementRisk Management
Public EducationPublic Education