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.
Commission of Scientific Research, Province of Buenos Aires, Argentina.
V
V
Ritacco
B
B
López
L
L
Barrera
A
A
Nader
E
E
Fliess
I N
IN
de Kantor
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