Further evaluation of an indirect enzyme-linked immunosorbent assay for the diagnosis of bovine tuberculosis.
The sensitivity and specificity of an ELISA for the detection of bovine IgG anti-Mycobacterium bovis antibodies were 73.6% and 94.1%, respectively, as determined in 53 bacteriologically confirmed tuberculous cattle and 101 healthy cattle from a tuberculosis-free area. In addition, the results of ELISA and tuberculin tests in 149 cattle were compared with those of subsequent necropsy studies. Both tests failed to detect 2 animals with tuberculous lesions and positive culture; 3/12 cattle with M. bovis isolation and no lesions, and 2/7 with atypical mycobacterial infection reacted to tuberculin, but none had antibodies; in 128 cattle with neither lesions nor mycobacterial isolation, 6 were tuberculin reactors and 7 others had antibodies. Negative results were obtained by ELISA in 21/22 paratuberculous cattle. Antibodies were not detected in 88.9% to 96.4% of 697 cattle from two tuberculin negative herds of an endemic area. In a herd with proved M. bovis infection, distribution of seropositive animals in tuberculin and non-tuberculin reactors was similar. Antibody responses to cutaneous tuberculin stimuli were observed in 4 experimentally infected cattle, but only in 2/10 healthy controls after repeated PPD stimuli. Nine controls which had either received a single tuberculin dose or none showed no increase in antibody levels. The low sensitivity of this ELISA limits its usefulness as a diagnostic tool for bovine tuberculosis eradication campaigns. However, it could be helpful in epidemiological surveillance if its efficiency to identify infected herds is demonstrated.
Ritacco
V
V
Commission of Scientific Research, Province of Buenos Aires, Argentina.
López
B
B
Barrera
L
L
Nader
A
A
Fliess
E
E
de Kantor
I N
IN
D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis*; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay; D007074:Immunoglobulin G / Q000032:analysis*; D008297:Male; D009163:Mycobacterium bovis / Q000276:immunology*; D011237:Predictive Value of Tests; D014374:Tuberculin Test / Q000662:veterinary; D014380:Tuberculosis, Bovine / Q000175:diagnosis*
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G