Brief history of exposure of the 12 confirmed case-patients
||Raised chickens in backyard. Chickens died unexpectedly 5 days before illness onset. Frequently played with chickens and had direct contact with carcasses.
||Raised chickens in backyard, but chickens did not die. Two months before onset, ducks in a nearby area died unexpectedly.
||Raised chickens in backyard. Three days before onset, chickens started to die. The last patient died on the date he became sick. He buried all carcasses.
||Raised 60 chickens in back yard. All chickens died unexpectedly 1 month before onset. She burned and buried carcasses without protection.
||Raised fighting cocks that died 4 days before onset. Reported direct contact with carcasses. Ate chicken with suspected H5N1 influenza.
||No poultry in family. Helped slaughter one ill chicken 2 days before onset.
||Mother slaughtered 2 ill chickens in house 4 days before onset. No direct contact with chickens. Mother got sick on same day and died without laboratory confirmation.
||Chickens in backyard died unexpectedly. Grandfather slaughtered ill chickens. No direct contact with chickens but played near slaughtering area.
||No poultry in family. Frequently played on ground near a chicken farm that reported unexpected poultry deaths.
||Helped raise chickens in backyard. Eight days before onset, chickens died unexpectedly and patient assisted with slaughtering.
||Factory worker living in province A during weekdays but in province B on weekends. Fighting cocks lived at a neighboring house. Province B reported outbreaks 2 months before onset. No contact with live or dead chickens.
||Raised 40–50 chickens in backyard. Chickens started to die 5 days before onset. Buried and slaughtered ill chickens every day until onset date.