World Health Organization (WHO) figures show that each year an estimated 9 million new cases of tuberculosis (TB) arise in the world. The growth of this disease remains particularly strong in Africa owing to a high proportion of HIV patients (nearly 13% compared with less than 1% in Asian countries for example). This region of the world is experiencing accelerating advance of a deadly combination of AIDS and TB, developed because the virus weakens the immune system of TB-infected individuals. Sensitivity to the standard test for TB infection is weakened in HIV-positive patients. New techniques based on in vitro determination of the rate of interferon-³ have recently been developed.