R. Barthel et al., Pathologic findings and association of Mycobacterium bovis infection with the bovine NRAMP1 gene in cattle from herds with naturally occurring tuberculosis, AM J VET RE, 61(9), 2000, pp. 1140-1144
Objective-To determine necropsy and Mycobacterium bovis culture results in
cattle from herds with tuberculosis, the role of the bovine NRAMP1 gene rn
resistance and susceptibility to infection with M bovis, and the associatio
n between magnitude of the tuberculous lesions and various types of M bovis
Animals-61 cattle from herds with tuberculosis in Texas and Mexico.
Procedure-61 cattle were evaluated by necropsy; 59 had positive and 2 had n
egative caudal fold tuberculin intradermal lest (CFT) results. Thirty-three
cattle with positive CFT results were genotyped to evaluate polymorphism o
f the 3' untranslated region of the bovine NRAMP1 gene, using single-strand
ed conformational analysis, 9 were resistant to M bovis with no tuberculous
lesions and negative M bovis culture results, and 24 were susceptible with
tuberculous lesions and positive M bovis culture results. Isolates of M bo
vis were analyzed by restriction fragment length polymorphism (RFLP) on the
basis of IS6110 sequences and direct-repeat fingerprinting patterns.
Results-21 (35.6%; 21/59) cattle with positive CFT results had tuberculous
lesions or positive culture results; in addition, 1 of 2 cattle with negati
ve CFT results had tuberculous lesions and positive culture results. Tuberc
ulous lesions were most common in the thorax (35/63, 55.5%) and lymphoid ti
ssues of the head (10/63; 15.9%). Tuberculous lesions varied from 1 to 11/a
nimal; 8 of 21 (38.1%) had solitary lesions. Associations were not found be
tween resistance or susceptibility to infection with M bovis and polymorphi
sm in the NRAMP1 gene or between the magnitude of the lesions and various R
FLP types of M bovis isolates.
Conclusions and Clinical Relevance-The NRAMP1 gene does not determine resis
tance and susceptibility to infection with M bovis in cattle.