Medline ® Abstract for Reference 20

SETTING: The epidemiology of zoonotic tuberculosis (ZTB) in humans in Mexico is poorly known.

OBJECTIVE: To identify isolates of Mycobacterium bovis in humans and cattle by polymerase chain reaction (PCR), and establish the clinical and epidemiological importance of ZTB in humans.

DESIGN: From 1995 to 2009, 124 isolates from patients with TB and 60 isolates from cattle were analysed. PCR identification was performed using the oxy R gene, and the clinical and epidemiological aspects of ZTB in humans were investigated.

RESULTS: PCR identified 93 M. bovis isolates: 35 (28%) from the 124 human isolates and 58 (97%) from the 60 cattle isolates. The sensitivity and specificity of the method were 100%. ZTB in the 35 patients presented as extra-pulmonary TB (EPTB) in 74%: 51% were children, 69% had malnutrition, 51% had consumed unpasteurised milk and 6% had contact with animals; 11% were relapses and 31% died.

CONCLUSIONS: PCR using the oxy R gene is highly sensitive, specific and rapid for the identification of M. bois. ZTB is a serious public health problem, and presented as EPTB in children with malnutrition and those who had consumed unpasteurised milk. ZTB provokes relapses and a high mortality rate.