Type of exposure	Definition
Occupational exposure to live poultry	refers to poultry related professional exposure (e.g. poultry breeding, trafficking, sale, and quarantine) in the two weeks prior to the onset of illness.
Visiting live bird market (LBM)	refers to the visit of a wholesale or retail market of live poultry or birds within the two weeks prior to the onset of symptoms.
Exposure to sick or dead poultry	refers to direct physical contact with, or in proximity to, sick or dead poultry or its production or faeces in the two weeks prior to onset.
Exposure to backyard poultry	refers to whether the case had been exposed to poultry raised in the backyard within two weeks prior to onset.
Any exposure to poultry	refers to direct contact, indirect contact or proximity to healthy, sick or dead poultry (including any kind of poultry or birds, e.g. chicken, ducks, goose, pet birds, pigeons, et al.) in LBMs, backyard, farm, or neighborhood, or consumption of improperly processed poultry products.
Human case contact	refers to a patient with a history of close contact with a confirmed or probable human H5N1 case (any time from the day before the onset of illness to death or during the period that case was hospitalized) in the two weeks before the onset of symptoms.