Evaluation of an ELISA-PPD for the diagnosis of bovine tuberculosis in field trials in Brazil.
Bovine tuberculosis is a major health problem in Brazil. The intradermal tuberculin test is the standard test for its detection, but it can lack both sensitivity and specificity. The purpose of this study was to evaluate a bovine enzyme-linked immunosorbent assay- (ELISA - PPD) under field conditions in Brazil. A total of 1632 animals from 13 dairy farms were tested with the intradermal tuberculin test (ITT). Two hundred and seven cows gave a positive reaction, which represents 12.7 per cent of the cattle studied. The sensitivity and specificity rates to ITT were 87.7 per cent and 95.2 per cent, respectively. From the 1632 animals 15 per cent of each herd (220 in total) were selected to be tested by the ELISA. Differences between mean optical density (OD) of the control group, ITT -positive and ITT -negative groups were all significant (P<0.01). The sensitivity rates to ELISA - PPD were 86.7 per cent, while specificity was 90.6 per cent. The use of ELISA - PPD is suggested for situations where the investigation of the whole herd is more important than the individual testing of each cow. In addition, the ELISA - PPD can also be helpful when a collective diagnosis is desired to elucidate clinical suspicions of disease, or in the first steps of a control program, for identification of foci.
Lilenbaum
W
W
Department of Microbiology, Universidade Federal Fluminense, Rio de Janeiro, 24210-130, Brazil. mipwalt@vm.uff.br
Ribeiro
E R
ER
Souza
G N
GN
Moreira
E C
EC
Fonseca
L S
LS
Ferreira
M A
MA
Schettini
J
J
D000818:Animals; D001938:Brazil / Q000453:epidemiology; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary*; D005260:Female; D007428:Intradermal Tests / Q000662:veterinary; D012680:Sensitivity and Specificity; D014374:Tuberculin Test / Q000379:methods / Q000662:veterinary*; D014380:Tuberculosis, Bovine / Q000175:diagnosis* / Q000453:epidemiology