Brucellosis

• What is the significance of the lipopolysaccharide layer in Brucella?

  It has endotoxic activity
• How long can Brucella survive at 4 degrees Celsius?

  6 weeks
• What is the first species of Brucella isolated and by whom?

  Brucella melitensis by David Bruce
• What are the pathogenic species of Brucella that affect humans?

  Brucella melitensis, Brucella abortus, Brucella suis, and Brucella canis
• What are the historical names associated with Brucellosis?

  • Mediterranean fever
  • Maltese fever
  • Crimean fever
  • Undulent fever
  • Bang's disease
• What is the classification of Brucella as per the CDC?

  It is classified as a category B biological weapon
• What is the significance of the O chain in Brucella's lipopolysaccharide layer?


  It plays a significant role in virulence
• How long can Brucella survive in fresh cheese?

  15 to 100 days
• What happens to Brucella at 60 degrees Celsius for 10 minutes?

  It is killed
• What does pasteurization do to milk in relation to Brucella?

  It renders milk safe
• What are the characteristics of Brucella as a pathogen?

  • Gram-negative aerobic cocco bacilli
  • Intracellular organism
  • Non-spore forming, non-capsulate
  • Pathogenic species associated with specific animal hosts
• What is the epidemiology of Brucellosis?

  • Frequently encountered zoonotic disease worldwide
  • Common laboratory-acquired infection
  • Common in Mediterranean countries
• What is the pathogenic bacterium associated with brucellosis in humans?

  Brucella
• How many biovars does Brucella melitensis have?

  3 biovars
• What is the microaerophilic requirement for Brucella abortus?

  1. 10% CO2
• How many biovars does Brucella abortus have?

  7 biovars
• What is the microaerophilic requirement for Brucella suis?

  1. 10% CO2
• How many biovars does Brucella canis have?

  5 biovars
• What are the characteristics of Brucella pathogens?

  • No defined endotoxin
  • Lipopolysaccharide layer has endotoxic activity
  • O chain plays a significant role in virulence
  • Antigenic features recognized by the immune system
  • Survives for 6 weeks at 4°C, 30 days in ice cream, and 15 to 100 days in fresh cheese
  • Killed at 60°C for 10 minutes
  • Pasteurization renders milk safe
• What is the significance of the O chain in Brucella's virulence?


  It plays a significant role in virulence
• How long can Brucella survive in dead abortuses?

  Viable for prolonged periods
• What is the classification of brucellosis in terms of zoonotic disease?

  It is frequently encountered worldwide
• What category is Brucella classified as by the CDC?

  Category B biological weapon
• Who are commonly affected by brucellosis?

  Farmers, veterinarians, doctors, and laboratory workers
• What are the animal hosts for different Brucella species?

  • B. mellitensis: Sheep, goats, camels, buffalo
  • B. abortus: Bison, camels
  • B. suis: Pigs, reindeer, rodents
  • B. canis: Dogs
• What is the leading cause of human brucellosis transmission?

  Contaminated sheep and goat milk
• How can brucellosis be transmitted through direct contact?

  Through skin bruises or lacerations with infected animals or their secretions
• Is human-to-human transmission of brucellosis common?

  No, it is rare
• What is a major virulence factor of Brucella?


  The lipopolysaccharide structure on the cell membrane
• What are the pathogenesis mechanisms of Brucella?

  • Survives intracellularly in macrophages
  • Blocks macrophage apoptosis
  • Inhibits production of Tumor necrosis factor alpha
  • Suppresses T helper 1 mediated immune response
  • Activates adenine guanine monophosphate pathways
  • Detoxifies reactive oxygen intermediates
• What is the incubation period for brucellosis?

  1. 4 weeks
• What are the common symptoms of brucellosis?

  • Arthralgia
  • Fever and fatigue
  • Sweating and malodorous perspiration
  • Myalgia
  • Lack of appetite
  • Chills or back pain
• What are the clinical findings associated with brucellosis?

  • Fever
  • Hepatomegaly
  • Splenomegaly
  • Lymphadenopathy
  • Scrotal swelling
  • Peripheral arthritis
• What are the complications of brucellosis?

  • Osteoarticular involvement: sacroilitis, spondylodiskitis, peripheral arthritis
  • Neurologic involvement: acute meningitis, meningoencephalitis, brain abscess
  • Genitourinary tract: epididymorchitis
  • Cardiovascular: endocarditis, pancarditis
  • Ocular, respiratory, cutaneous, and hematologic manifestations
  • Affects pregnancy: sterility and first trimester abortions
• What are the key diagnostic methods for brucellosis?

  • History of occupational exposure and consumption of unpasteurized milk
  • Blood and bone marrow isolation
  • Bone marrow is most sensitive in chronic infections
  • Samples incubated in broths
  • Blood cultures kept for 6-8 weeks before declaring negative
• What is the reference technique for serology in brucellosis?

  Serum agglutination test (SAT)
• How long after symptom onset can the SAT test become positive?

  1. 10 days
• What are the treatment recommendations for brucellosis?

  • Monotherapy is not recommended
  • Doxycycline + Streptomycin for uncomplicated disease
  • Ceftriaxone + doxycycline or rifampicin for neurobrucellosis
  • Sulfamethoxazole-trimethoprim + rifampicin in children
• What are the prevention strategies for brucellosis?

  • Eradication from domestic animals
  • Vaccination of sheep, cattle, and goats with live attenuated vaccines
  • Compulsory testing of animals and slaughtering positive reactors