AIDS and Other Manifestations of HIV Infection

Gary Wormser, Gary Wormser

• Publisher: Academic Press
• Year: 2004
• ISBN:
  9780080471969
• Edition: 4
• Topic: Technik & Maschinenbau
• Subtopic: Gesundheit & Sicherheit in der Industrie

Extensively revised and updated, the new edition of AIDS and Other Manifestations of HIV Infection is an essential reference resource providing a comprehensive overview of the biological properties of this etiologic viral agent, its clinicopathological manifestations, the epidemiology of its infection, and present and future therapeutic options.

• Expanded section on clinical manifestations includes new chapters on cardiovascular, renal and dermatologic manifestations of HIV infection
• Additional chapters on molecular diagnostic techniques, the role of host genetic variation in HIV infection and its manifestations, the discovery and development of new HIV medicines, analysis of HIV dynamics using mathematical models, toxicities of antiretroviral therapy, HIV drug susceptibility testing, practical therapeutics and the global impact of HIV and AIDS

Chapter 1 The Epidemiology of HIV and AIDS

Patricia L. Fleming [email protected]

Division of HIV/AIDS Prevention, National Center for HIV/STD/TB Prevention, CDC, 1600 Clifton Rd. NE, Atlanta GA 30333

The emergence and dissemination of a new infectious disease agent worldwide within the span of two decades at the end of the twentieth century has presented unprecedented medical, social, and political challenges. The human immunodeficiency virus (HIV) and the syndrome of opportunistic illnesses that characterize late-stage HIV disease, known as the acquired immunodeficiency syndrome (AIDS), have claimed over 20 million lives worldwide and the Joint United Nations Program on AIDS (UNAIDS) estimates that there were more than 40 million HIV-infected persons living worldwide in 2001 (1). In the United States (U.S.), the Centers for Disease Control and Prevention (CDC) estimates that there were 850,000–950,000 prevalent cases of HIV/AIDS in 2000 (2). More than 467,000 deaths of persons with AIDS have occurred since the epidemic was first recognized in 1981 (3–5). Despite recent successes in treating HIV that have increased survival and substantially decreased death rates (6,7), HIV remains a devastating illness, without cure, that mainly affects young adults. Its social and economic tolls threaten to destabilize some countries in the developing world and it continues to be a costly and controversial disease in the U.S.

Understanding the epidemiology of HIV provides an important foundation for clinicians in recognizing risk behaviors associated with clinical manifestations suggestive of HIV infection in their patients, and encouraging acceptance of HIV testing, adoption of risk-reduction strategies to prevent further transmission, and treatment to prevent opportunistic illnesses and delay disease progression.

At the start of the third decade of the HIV pandemic, and following the terrorism of September 11, 2001 and the subsequent bio-terrorism, the government and the public have a heightened awareness of the crucial role of public health preparedness in assuring well-being. Disease surveillance, prevention and control are in the headlines. Health care providers have a renewed appreciation of their responsibility to report cases of notifiable diseases to public health authorities. This chapter reviews the historical context of the epidemic, summarizes the global epidemic, presents HIV/AIDS surveillance data to characterize affected populations, describes trends in the incidence and prevalence of HIV and AIDS, describes clinical manifestations and the impact of treatment, and identifies emerging issues that challenge the ability to prevent and control HIV.

BACKGROUND AND CONTEXT

The HIV pandemic is arguably the most compelling public health crisis of the post-World War II generation. In the post-World War II era, infectious diseases were on the wane. Common bacterial infections were readily treated with available antibiotics; ubiquitous childhood diseases (e.g. polio, measles, mumps) were preventable with vaccination; even the scourge of smallpox was eradicated worldwide. The epidemiology and clinical management of chronic diseases such as heart disease and cancers and an emerging interest in environmental health were ascendant public health priorities.

In 1981, with the first reports of what came to be called AIDS, a new awareness of the threat of emerging infectious diseases arose. Within two years, the epidemiologic evidence suggested that a new infectious agent was responsible for cases of unusual opportunistic illnesses, indicative of severe immunosuppression. The pattern of AIDS case reports suggested that this disease agent was likely transmitted through sexual contact (homosexual and heterosexual), sharing of drug injecting paraphernalia, contamination of the blood supply, and perinatally from mother to child (8–13). By 1983, a new retrovirus was isolated from AIDS patients and identified as the causative agent (14,15). An antibody test was developed that enabled diagnosing HIV infection early in the disease course and permitted screening of the blood supply (16). By March of 1985, universal screening of the blood supply, coupled with voluntary donor deferral and heat-treatment of blood components, had virtually eliminated new HIV infections through transfusions or the receipt of blood products by hemophiliacs. During the first decade, the U.S. government and all state and territorial health departments began to conduct AIDS case surveillance to monitor the outcome of HIV infection and its impact on the population. Anonymous serologic surveys of the prevalence of HIV antibodies in some populations were implemented using blood routinely collected for other purposes in a large number of hospitals and clinics serving high-risk clients in diverse geographic settings, and in selected accessible populations such as military applicants and women giving birth. These surveys revealed that HIV was more widespread and more prevalent than AIDS case data suggested (17).

Many warning signs of the potential for the emergence or re-emergence of great pandemics caused by infectious agents were accumulating during the latter half of the twentieth century: increasing population pressures, migration and urbanization, political or social upheaval, and especially in western countries, the sexual revolution and drug-culture. Emerging from obscure African origins, HIV was introduced into susceptible populations in North America and western Europe and spread rapidly during the latter part of the 1970s and early 1980s. In the western countries, its spread was most rapid among homosexual men and drug-injectors. The epidemic had spread worldwide by the late 1980s. In Africa, the epidemic was termed “Pattern II”, i.e. heterosexually-acquired HIV predominated, as opposed to the homosexual and drug injecting associated epidemics in North America and Western Europe (i.e. “Pattern I”). In Asia, Latin America and the Caribbean, heterosexual and drug-use associated transmission led to rapid spread and recently, a drug-use associated epidemic has emerged in eastern European nations (18,19).

Despite the warning signs of fertile ground for an infectious disease epidemic, HIV continues to confound medical and public health practitioners worldwide. As yet, there is no cure, and no vaccine. The ability to mount effective prevention and control efforts is complicated by social taboos, fear and prejudice. In the U.S., because HIV is spread principally through sex and sharing of drug-injection paraphernalia, and disproportionately affects racial/ethnic minority populations and homosexual men, discussions of HIV prevention inevitably touch on sensitive cultural topics. There is not one standard or paradigm for providers or communities to adopt in communicating behavioral risk reduction messages or implementing programs to promote HIV prevention. Yet, HIV remains eminently preventable through behavior change.

The complexity of the virus itself, its mechanism of action, and its effects on the immune system have stimulated giant leaps forward in research in basic science, immunology, and virology. This knowledge has rapidly advanced HIV clinical management and influenced medical practice far beyond HIV. The epidemic has also changed how affected communities influence government. New coalitions of communities, government, academics, and private industry have mobilized funding, defined research priorities, stimulated a growing pipeline of d...