Differential Diagnosis of
Brucellosis Serologic Reactions
Steven G. Hennager
Bacterial and Hemoparasitic Serology Team
National Veterinary Services Laboratories
Workshop: An Integrated Approach to Controlling Brucellosis in Africa, Addis
Ababa, 29-31 January 2013
Safeguarding Animal Health

Dominant Brucella Antigens
Species
• Brucella melitensis
• Brucella abortus
• Brucella suis
• Brucella canis
• Brucella ovis
Primary Antigen
• M and A
• A and M
• A and M
• Rough
• Rough

Blue colonies = Smooth Brucella sp.
Crystal colonies = Rough Brucella sp.

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Immune response to Brucella infection
• Cell mediated response
• Humoral or antibody production

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Serologic Assays
 Antibody detection
 Serum
 Milk
 Rapid
 Inexpensive
 Sensitivity and Specificity
 Assays can be impacted by
 Vaccination
 Environmental conditions
Brucella card
test

Brucellosis Diagnostic Tests

Brucellosis Diagnostic Tests

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Brucellosis Diagnostic Tests

Brucellosis Diagnostic Tests

Brucellosis Diagnostic Tests

Brucellosis Diagnostic Tests

Other Brucella Diagnostic Tests
• Polymerase Chain Reaction (PCR)
• Culture Identification
• Western Blot

Amount of Isotype (ng)
Test IgM IgG1 IgG2 IgA
Tube 20 ----- 125 650
Card ----- 600 7500 -----
Riv ----- 1550 2750 -----
CF 6500 290 ----- -----
ELISA 155 190 220 700

Brief History
 19th century – Bruce isolated organism
from human spleens
 Linked organism to raw goat’s milk
 Genus named after him
 19th century – Bang discovered
organism that caused abortions in
cattle
 Named organism Bacillus abortus
 20th century – Evans recognized the
relationship between Bruce’s organism
and Bang’s organism
 Advocated pasteurization of milk
 Re-named organism Brucella abortus
Sir David
Bruce
L.F. Bernhard
Bang
Alice C. Evans

Acknowledge Superior Laboratory
Support
• De Anne Wall, Diane Davis, Barb
Kesl, Molly Fritz
– Serology Laboratory Technicians
Questions?