1. ‫بسم ا الرحمن الرحيم‬
GENUS: BRUCELLA
Prof. Khalifa Sifaw Ghenghesh

2. 
Aerobic, Gram-negative bacilli
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Appear as cocci, coccobacilli and short
bacilli
Non-motile, non-capsulate
Optimum temp. >> 37oC
Facultative intracellular parasites
Essentially pathogens of goats, Cattle,
sheep and pigs
 Causative
agents of Brucellosis
(typical zoonosis) worldwide
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Also known as Malta, Mediterranean
or undulant fever

3.  Important
species

B. melitensis >> goats & sheep
 B. abortus
>> cattle
 B. suis
>> pigs
 Important:
All 3 species can
infect man and domestic animals

4. Brucella species
gram-negative bacilli

5. Brucella abortus

6. PATHOGENESIS
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Incubation period: 10-30 days
Symptoms may be delayed for months
Enter the body through:
 Skin abrasions, mucous membranes of the
alimentary or respiratory tracts and
sometimes the conjunctivae>> reach the
blood through regional lymphatics.
Symptoms may vary without the fluctuating
temperature to act as guide.
Bacteria localize in various parts of the
reticulo-endothelial system resulting in
complications in any part of the body.
Symptoms include: malaise, low-grade fever,
lassitude, insomnia, irritability and swelling
around the joints.

7. LABORATORY DIAGNOSIS
1. Blood Culture
 Specimen

Blood (10 ml volumes)
 Inoculate
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Blood culture tubes or bottles
(glucose-serum broth)
Incubate in 10% CO2
Cultures should be retained for at
least 6-8 weeks before being
discarded as negative

8. Brucella melitensis colonies

9. 2. Serological Tests
 Standard
agglutination test
 Mercaptoethanol test
 Complement fixation test
 Coobs’ test
3. Brucellin Skin Test

10. TREATMENT AND CONTROL

Combination of streptomycin and
tetracycline or rifampicin and
doxycycline
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Vaccination of young cattle (6-8
months)
Pasteurization of milk or milk
products
Eradication by compulsory testing
animals and slaughtering positive
reactors.
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