WHO disease staging system

WHO Disease Staging System for HIV Infection and Disease

In 1990, the World Health Organization (WHO) grouped these infections and conditions together by introducing a staging system for patients infected with HIV-1. An update took place in September 2005. Most of these conditions are opportunistic infections that are easily treatable in healthy people.

• Stage I: HIV infection is asymptomatic and not categorized as AIDS
• Stage II: includes minor mucocutaneous manifestations and recurrent upper respiratory tract infections
• Stage III: includes unexplained chronic diarrhea for longer than a month, severe bacterial infections and pulmonary tuberculosis
• Stage IV: includes toxoplasmosis of the brain, candidiasis of the esophagus, trachea, bronchi or lungs and Kaposi's sarcoma; these diseases are indicators of AIDS.