title: Outbreak of avian tuberculosis in 48-week-old commercial layer hen flock.
abstract: This report describes an outbreak of tuberculosis in a flock of 38,500 48-wk-old layer hens. Clinical characteristics of the process included a gradual drop in egg production and feed intake, as well as an increased mortality rate. Two well-defined clinical features were observed. On the one hand, a number of birds displayed good body condition and continued to lay but presented granulomatous nodular lesions, particularly in the infraorbital sinus, liver, and intestine. In contrast, other hens were emaciated and presented granulomatous lesions of various sizes throughout the internal organs. The lesions observed in the various organs of all the affected birds consisted of granulomas containing acid/alcohol-fast bacilli. The presence of Mycobacterium avium was confirmed through polymerase chain reaction techniques. This report describes the epidemiologic and histopathologic characteristics of the outbreak.
authors.affiliation: Department of Animal Pathology II, Veterinary Teaching Hospital (Service of Pathology), Veterinary School, Universidad Complutense de Madrid, 28040-Madrid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: González
authors.forename: Antonio
authors.initials: A
authors.lastname: Rodriguez-Bertos
authors.forename: Isabel
authors.initials: I
authors.lastname: Gimeno
authors.forename: Juana M
authors.initials: JM
authors.lastname: Flores
authors.forename: Manuel
authors.initials: M
authors.lastname: Pizarro
mesh_terms: D000818:Animals; D003937:Diagnosis, Differential; D004196:Disease Outbreaks / Q000662:veterinary*; D005260:Female; D007422:Intestines / Q000473:pathology; D008099:Liver / Q000473:pathology; D008297:Male; D009162:Mycobacterium avium / Q000302:isolation & purification; D010058:Oviposition; D011201:Poultry Diseases / Q000453:epidemiology* / Q000382:microbiology / Q000473:pathology; D012621:Seasons; D013154:Spleen / Q000382:microbiology / Q000473:pathology; D014379:Tuberculosis, Avian / Q000175:diagnosis / Q000453:epidemiology* / Q000473:pathology