Extensively drug-resistant tuberculosis: an isolation order, public health powers, and a global crisis.

CENTURIES AFTER THE FORMAL CREATION OF QUARantine, the practice continues to evoke concern when implemented to halt the spread of dangerous microbes. Witness the controversy generated by US citizen Andrew Speaker, whom the US Centers for Disease Control and Prevention (CDC) detained and isolated because he was diagnosed with pulmonary disease caused by extensively drug-resistant tuberculosis (XDRTB). Speaker’s case made compelling news, but it also raised questions about the emergence of XDR-TB, the adequacy of public health powers in the United States, and the international dimensions of the XDR-TB threat.