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brucellosis

brucellosis

introduction

  • aka Bang's disease, Crimean fever, Gibraltar fever, Malta fever, Maltese fever, Mediterranean fever, rock fever, or undulant fever
  • a highly contagious zoonosis caused by ingestion of unsterilized milk or meat from infected animals or close contact with their secretions
  • most commonly from ingesting infected unpasteurised milk or soft cheese from goats, or in abbatoir workers
  • Australia is at present free of cattle brucelosis, although it occurred in the past. Brucellosis of sheep or goats has never been reported. Brucellosis of pigs does occur. Feral pigs are the typical source of human infections in Australia.
  • transmission from human to human, through sexual contact or from mother to child, is rare but possible
  • The incubation period is highly variable. It is most commonly 1–2 months but ranges from 5 days to 60 days.
  • caused by Brucella spp. which are small, Gram-negative, non-motile, non-spore-forming, rod shaped (coccobacilli) clinically important bacteria that act as intracellular parasites causing chronic disease and usually persist for life.
  • Brucella species survive well in aerosols and resist drying.
  • Brucella abortus is the principal cause of brucellosis in cattle
  • Brucella melitensis is the main cause in goats and sheep, although B. ovis also is a cause in sheep
  • B. suis is the main cause in pigs
  • B. canis infects dogs
  • in 1954, B. suis became the first agent weaponized by the United States at its Pine Bluff Arsenal in Arkansas.

clinical features in humans

initial septicaemic phase "Malta fever"

  • undulant fevers
  • sweating, characteristicly smelling like wet hay
  • migratory arthralgia and myalgia
  • leukopenia
  • anaemia
  • some elevation AST, ALT

later focal spread

  • untreated cases may develop seeding, particularly to bone and joints
  • spondylodiscitis of lumbar spine
  • sacroiliitis
  • orchitis
  • granulomatous hepatitis
  • anaemia, leukopenia, thrombocytopenia
  • meningitis
  • uveitis
  • optic neuritis
  • endocarditis

chronicity

  • untreated cases tend to progress to a chronic life long illness

Dx

  • serology is preferred as blood cultures can take 2 months to grow in special broth
  • Pedro Pons sign on lumbar spine Xray (preferential erosion of antero-superior corner of lumbar vertebrae) is suspicious of brucellic spondylitis

Rx

  • The gold standard treatment for adults is daily intramuscular injections of streptomycin 1 g for 14 days and oral doxycycline 100 mg twice daily for 45 days (concurrently).
    • gentamicin 5 mg/kg by intramuscular injection once daily for seven days is an acceptable substitute when streptomycin is not available or difficult to obtain.
  • triple therapy of doxycycline, with rifampin and cotrimoxazole, has been used successfully to treat neurobrucellosis.
brucellosis.txt · Last modified: 2018/11/03 03:41 (external edit)