Identification of Mycobacterium bovis in bovine clinical samples by PCR species-specific primers.
Tuberculosis, caused by Mycobacterium bovis is emerging as the most important disease affecting cattle. Furthermore, it results in a major public health problem when transmitted to humans. Due to its difficult and non-specific diagnosis, M. bovis has been declared to be one of the etiologic agents causing significant economic loss in the cattle industry. Our group evaluated a more rapid and specific method, based on a new polymerase chain reaction species-specific primers, which amplifies a 470-base pair fragment of the M. bovis genome. A total of 275 milk-producing cows were studied by intradermal tuberculin test (ITT) which gave 184 positive and 91 negative cases. From them, 50 animals were taken from a cattle ranch free of tuberculosis. Three different samples were collected from each animal (blood, nasal mucus, and milk). Positive results were obtained from 26 animals by PCR (11.4%), 1 by bacteriological culturing (0.4%) and 1 by bacilloscopy (0.4%). This finding suggests, as in previous reports, that ITT, normally used for bovine tuberculosis detection, has the inconvenience of having a broad range of specificity and sensitivity, and the PCR technique is a more specific and sensitive test to detect infection associated with M. bovis. Therefore, we propose this PCR assay as a useful tool in the epidemiological characterization of infected animals in areas considered to be at high risk of transmission.
Romero
R E
RE
Department of Molecular Biology, Instituto de Inmunología, Hospital San Juan de Dios, Universidad Nacional de Colombia, Santafé de Bogotá.
Garzón
D L
DL
Mejía
G A
GA
Monroy
W
W
Patarroyo
M E
ME
Murillo
L A
LA
D000818:Animals; D002417:Cattle; D003105:Colombia / Q000453:epidemiology; D017931:DNA Primers; D005260:Female; D016679:Genome, Viral; D006801:Humans; D008892:Milk; D009163:Mycobacterium bovis / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods; D014380:Tuberculosis, Bovine / Q000175:diagnosis* / Q000453:epidemiology; D015047:Zoonoses
D017931:DNA Primers