Pathology of naturally occurring bovine tuberculosis in England and Wales.
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.
Liebana
E
E
Department of Pathology, Veterinary Laboratories Agency-Weybridge, Addlestone, Surrey, England, UK. ernesto.liebana@efsa.europa.eu
Johnson
L
L
Gough
J
J
Durr
P
P
Jahans
K
K
Clifton-Hadley
R
R
Spencer
Y
Y
Hewinson
R G
RG
Downs
S H
SH
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