Contact investigation for cases of pulmonary Mycobacterium bovis.

SETTING

A local tuberculosis control program in San Diego County, California.

OBJECTIVE

To determine the yield of contact investigations of pulmonary Mycobacterium bovis cases.

DESIGN

Retrospective review of medical records comparing tuberculin skin test (TST) conversion rates found in contact investigations of pulmonary M. bovis cases to conversion rates found in contact investigations of pulmonary M. tuberculosis cases.

RESULTS

For the years 1994-2001, we identified 77 contacts of pulmonary M. bovis cases and 469 contacts of M. tuberculosis cases that met the study criteria. TST conversion rates were not significantly different based on species of the source case (13% for M. bovis, 15% for M. tuberculosis, P = 0.20). This finding was also observed when the results were stratified by presence of a cavity on chest X-ray, history of cough at diagnosis and human immunodeficiency virus (HIV) status of the source case.

CONCLUSION

These results suggest that contact investigations for pulmonary M. bovis cases should be conducted in the same manner as those conducted for pulmonary M. tuberculosis cases.