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ZOONOSIS. A disease primarily of animals which can be transmitted to humans as a result of direct or indirect contact with the infected animal population. ZOONOSIS. Brucellosis Plague Listeriosis Anthrax Tularemia Erysipeloid. Brucellosis (Malta fever).
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ZOONOSIS A disease primarily of animals which can be transmitted to humans as a result of direct or indirect contact with the infected animal population
ZOONOSIS • Brucellosis • Plague • Listeriosis • Anthrax • Tularemia • Erysipeloid
Brucellosis (Malta fever) • Dr. David Bruce attended to an epidemic among the British troops in Malta (1887) • Isolated an organism from spleens of 4 fatal cases • Fulfilled the Koch’s postulate • Linked the disease to goat’s milk on the island
Brucellasp. Primarily affects people who work with animals or animal products (slaughterhouse workers, veterinarians, farmers, dairy workers) Four different species of Brucella are known to infect humans 100-200 cases seen per year
Morphology & physiology • Fastidious & aerobic • Facultative intracellular • Gram negative non motile cocobacilli
Species Animal reservoir • B. abortus Cattle • B. suis Swine Goats and sheep • B. melitensis • B. canis Dogs Brucella reservoir
Brucellosis in animals • Transmitted by contact with infected tissue or milk (oral, aerosol or abrasion) • Predilection for erythritol rich organs (breast, uterus, epididymis, ect.) • Abortions, mastitis and sterility
Brucellosis in humans • Skin abrasion, conjunctivae, inhalation or ingestion • Engulfed by neutrophils and monocytes (resistant to killing) • Localize regional lymph nodes • Infect phagocytic cells in the RE system and form granulomas
Symptoms • Aches, chills, fever (undulating) • Drenching sweating • Fatigue, myalgia, muscle weakness • Relapse common
Pathogenesis • 5’guanosine and adenine inhibit the degranulation of peroxidase-positive granules • Host damage due to hypersensitivity
Diagnosis • Symptoms and history • Blood culture on enriched media (slow: 4-6 weeks) • Organisms grow very slowly (6 weeks) • Serology (titer >640) • Skin test with brucellergin - delayed-type
Treatment • Prolonged use (several months) of rifampin with tetracycline or streptomycin