Infective agents and chronic bronchitis.
D000328:Adult; D000937:Antigen-Antibody Reactions; D001991:Bronchitis / Q000097:blood*; D002908:Chronic Disease / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012621:Seasons; D014780:Viruses