Several risk factors are associated with the development of TB disease or progression from infection to disease. The most important of these factors is HIV disease. HIV status was unknown or the test was not offered in the great majority of the cases. Due to the small numbers of individuals diagnosed with both TB and HIV, significant variation in the numbers of cases identified can be expected to occur due to chance alone. The breakdown can be see in Table 2 .
Occupation is another variable used to detect trends.
Six health care workers were diagnosed with disease in 1998. Pulmonary cases are of particular concern since these individuals may actively transmit the disease to others. To break this cycle of transmission, appropriate and adequate therapy must be initiated and continued for the duration of the treatment period. Table 4 shows the impact of those guidelines on the prescribing practices of physicians before and after the new guidelines were adopted. Seven cases were reported at the time of death or were dead at the time of diagnosis.