title: Pathology of naturally occurring bovine tuberculosis in England and Wales.
abstract: The aim of this study was to obtain a contemporary data set of pathology in tuberculin reactor and in-contact cattle in England and Wales. Four hundred animals (200 reactors and 200 in-contacts) from 242 farms located in 14 counties in Western England and Wales were examined. The mean number of lymph nodes (LNs) with tuberculosis (TB)-like lesions per TB-confirmed animal was 1.7 in reactors and 1.5 in in-contact animals. Tuberculous lesions in both reactor and in-contact animals were most commonly observed in the LNs of the thorax, followed by the head and abdomen, particularly the mediastinal, retropharyngeal and tracheobronchial LNs. Twenty-five reactors had macroscopic lesions in the palatine tonsils. Among TB-confirmed cattle, 27% of reactors and 9% of in-contact animals had gross TB-like lesions in the lungs, particularly in the caudal lobes. Gross lesions that were not TB-confirmed were parasitic granulomas (45%), bacterial or mycotic club-forming pyogranulomas (27%) and bacterial abscesses (23%). Diagnostic sensitivity was maximised when bacteriology and histopathology were used concurrently. Stage IV granulomas, alone or in combination with other stages, constituted 63% of lesions, while 16% of lesions were stage I/II granulomas. Caseous necrosis and calcification were common features of the granulomas encountered in natural Mycobacterium bovis infections, even with pathology limited to a small number of sites. Granulomas often covered large areas of histological sections and typically contained only small numbers of acid fast bacilli.
authors.affiliation: Department of Pathology, Veterinary Laboratories Agency-Weybridge, Addlestone, Surrey, England, UK. ernesto.liebana@efsa.europa.eu
authors.forename: E
authors.initials: E
authors.lastname: Liebana
authors.forename: L
authors.initials: L
authors.lastname: Johnson
authors.forename: J
authors.initials: J
authors.lastname: Gough
authors.forename: P
authors.initials: P
authors.lastname: Durr
authors.forename: K
authors.initials: K
authors.lastname: Jahans
authors.forename: R
authors.initials: R
authors.lastname: Clifton-Hadley
authors.forename: Y
authors.initials: Y
authors.lastname: Spencer
authors.forename: R G
authors.initials: RG
authors.lastname: Hewinson
authors.forename: S H
authors.initials: SH
authors.lastname: Downs
mesh_terms: D000818:Animals; D002417:Cattle; D004739:England / Q000453:epidemiology; D005260:Female; D006099:Granuloma / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary*; D008168:Lung / Q000382:microbiology / Q000473:pathology; D008198:Lymph Nodes / Q000382:microbiology / Q000473:pathology; D008297:Male; D009163:Mycobacterium bovis / Q000302:isolation & purification / Q000472:pathogenicity*; D009928:Organ Specificity; D014066:Palatine Tonsil / Q000382:microbiology / Q000473:pathology; D014380:Tuberculosis, Bovine / Q000453:epidemiology / Q000473:pathology*; D014852:Wales / Q000453:epidemiology