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Brucellosis

Brucellosis

21 March 2017

Causative agent

Brucellosis is an infectious disease caused by the bacteria of the genus Brucella. These bacteria primarily infect animals, such as cattle, dogs, pigs, sheep and goats. 

Clinical features

The symptoms of brucellosis are nonspecific. They include fever, sweat, headache, pain in muscles, joint, and/or back, fatigue, loss of appetite, and physical weakness. Severe infections may affect the brain, heart, skin, other organs or body systems. The disease may progress to a chronic one and persist for years.

Mode of transmission

Brucellosis can be transmitted to humans from infected animals or contaminated animal products through the following ways:

  • Consume contaminated products, including unpasteurised dairy products, raw or undercooked meat or internal organs.
  • Contact through breaks in the skin or mucous membrane with infected animal tissues, blood, urine, vaginal discharges, aborted foetuses, and placentas.
  • Inhale contaminated aerosols.

Direct human-to-human spread is rare.

High risk groups

People who are occupationally exposed to infected animals or their tissues, such as slaughterhouse workers, meat-packing workers, veterinarians and laboratory workers, are relatively at high risk of contracting brucellosis. In Hong Kong, brucellosis is a notifiable occupational disease.

Incubation period

The incubation period is variable. Usually 5 - 60 days, but can be as long as several months.

Management

Brucellosis can be treated by antibiotics. 

Prevention

Vaccine is available for animals only. To prevent the infection, members of the public are urged to observe good personal and food hygiene. Adopt the 5 Keys to Food Safety in handling food, i.e. Choose (Choose safe raw materials); Clean (Keep hands and utensils clean); Separate (Separate raw and cooked food); Cook (Cook thoroughly); and Safe Temperature (Keep food at safe temperature) to prevent foodborne diseases:

  • Do not consume unpasteurised dairy products, raw or undercooked meat and internal organs.
  • Wash hands thoroughly with liquid soap and water after having contacts with animals or their secretions.
  • Cover wounds properly.
  • Wear appropriate protective gears, including gloves, goggles and gowns or aprons, when handling animal tissues or internal organs especially for those who are exposed occupationally.

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