Defense mechanisms against viruses in the upper respiratory tract.
D000818:Animals; D002645:Chickens; D004195:Disease Models, Animal; D009297:Nasal Mucosa / Q000503:physiopathology*; D009522:Newcastle disease virus / Q000472:pathogenicity; D009668:Nose Diseases / Q000150:complications; D012141:Respiratory Tract Infections / Q000503:physiopathology*; D014777:Virus Diseases; D014802:Vitamin A Deficiency / Q000150:complications