GENUS: BRUCELLA Prof. Khalifa Sifaw Ghenghesh بسم الله الرحمن الرحيم

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

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

Brucella species gram-negative bacilli

Brucella abortus

PATHOGENESIS   Incubation period: 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.

LABORATORY DIAGNOSIS 1. Blood Culture   Specimen Blood (10 ml volumes)   Inoculate Blood culture tubes or bottles (glucose-serum broth) Incubate in 10% CO 2 Cultures should be retained for at least 6-8 weeks before being discarded as negative

Brucella melitensis colonies

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

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