Contents

• Introduction
• The Definition of AIDS
• The Designation AIDS Is a Surveillance Tool
• Quantifying the Epidemic
• A Brief History of the Emergence of AIDS
• Initial Theories
• Retrovirus Hypothesis
• Seroprevalence Surveys
• HIV and Other Lentiviruses
• Course of HIV Infection
• Immunologic Profile of People with AIDS
• Mechanisms of CD4+ T Cell Depletion
• Koch's Postulates Fulfilled
• Evidence From Animal and Laboratory Models
• Geographic Considerations
• Evidence From Blood Donor-recipient Pairs
• Impact of HIV Infection on Mortality of Hemophiliacs
• Pediatric AIDS
• Single Source Outbreak of Pediatric AIDS
• Answering the Skeptics: The "Risk-AIDS" or "Behavioral" Hypothesis
• AIDS and Injection Drug Users
• Sex and the AIDS Epidemic
• Drug Use in the Pre-AIDS Era
• AZT and AIDS
• Disease Progression Despite Antibodies
• Risks Associated with Transfusion
• Exposure to Factor VIII
• Distribution of AIDS Cases
• AIDS in Africa
• Conclusion
• References

Introduction

The acquired immunodeficiency syndrome (AIDS) is characterized by the progressive loss of the CD4+ helper/inducer subset of T lymphocytes, leading to severe immunosuppression and constitutional disease, neurological complications, and opportunistic infections and neoplasms that rarely occur in persons with intact immune function. Although the precise mechanisms leading to the destruction of the immune system have not been fully delineated, abundant epidemiologic, virologic and immunologic data support the conclusion that infection with the human immunodeficiency virus (HIV) is the underlying cause of AIDS.

The evidence for HIV's primary role in the pathogenesis of AIDS is reviewed elsewhere (Ho et al., 1987; Fauci, 1988, 1993a; Greene, 1993; Levy, 1993; Weiss, 1993). In addition, many scientists (Blattner et al., 1988a,b; Ginsberg, 1988; Evans, 1989a,b, 1992; Weiss and Jaffe, 1990; Gallo, 1991; Goudsmit, 1992; Groopman, 1992; Kurth, 1990; Ascher et al., 1993a,b; Schechter et al., 1993a,b; Lowenstein, 1994; Nicoll and Brown, 1994; Harris, 1995) have responded to specific arguments from individuals who assert that AIDS is not caused by HIV. The present discussion reviews the AIDS epidemic and summarizes the evidence supporting HIV as the cause of AIDS.