Figure 1

Schematic view of decision trees. The top portion of the figure summarizes the sequence of events leading to possible tuberculosis infection after travel, and the use of post-travel screening (by skin testing or chest radiography) to detect latent infection or active disease. If two-step tuberculin skin testing is undertaken before travel, then post-travel testing is limited to travelers with negative baseline results, while those with positive baseline results may be referred for isoniazid treatment, as described in the text and in Table 1. Persons who return from travel with latent infection enter the Markov process illustrated in the lower portion of the figure, although those who receive isoniazid may be cured of latent infection and face no future risk of reactivation.