Hivaids Has Claimed Millions of Lives Worldwide

In recent years, all other forms of immunodeficiency have been overshadowed by an epidemic of severe immunodeficiency caused by the infectious agent called human immunodeficiency virus 1, or HIV-1. The disease that HIV-1 causes, acquired immunodeficiency syndrome (AIDS) was first reported in the United States in 1981 in Los Angeles, New York, and San Francisco. A group of patients displayed unusual infections, including the opportunistic fungal pathogen Pneumocystis carinii, which causes a pneumonia called PCP (P. carinii pneumonia) in persons with immunodeficiency. In addition to PCP, some patients had Kaposi's sarcoma, an extremely rare skin tumor, as well as other, rarely encoun tered opportunistic infections. More complete evaluation of the patients showed that they had in common a marked deficiency in cellular immune responses and a significant decrease in the subpopulation of T cells that carry the CD4 marker (T helper cells.) When epidemiologists examined the background of the first patients with this new syndrome, it was found that the majority of those afflicted were homosexual males. As the number of AIDS cases increased and the disease was recognized throughout the world, persons found to be at high risk for AIDS were homosexual males, promiscuous heterosexual individuals of either sex and their partners, intravenous drug users, persons who received blood or blood products prior to 1985, and infants born to HIV-infected mothers.

Since its discovery in 1981, AIDS has increased to epidemic proportions throughout the world. As of December 2000, the cumulative total number of persons in the United States reported to have AIDS was 688,200, and of these approximately 420,000 have died. Although reporting of AIDS cases is mandatory, many states do not require reporting of cases of HIV infection that have not yet progressed to AIDS. Therefore, there is no official count of the number of HIV-infected individuals; as many as 1 million Americans are estimated to be infected. Although the death rate from AIDS has decreased in recent years because of improved treatments, AIDS remains among the leading killers of persons in the 25-44-year-old age range in this country (Figure 19-6). The fact that the number of yearly AIDS deaths has leveled off is encouraging, but does not indicate an end to the epidemic in this country; there were an estimated 45,000 persons newly infected in 2000.

I 25

Unintentional injuries

Cancer Heart disease

I 25

84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99* Year

FIGURE 19-6

Unintentional injuries

Cancer Heart disease

84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99* Year

FIGURE 19-6

Death rates of the leading causes of death in persons aged 25-44 years in the United States for the years 1982-99 (* = preliminary data). The heavy line shows that the death rate per 100,000 persons caused by AIDS surpassed any other single cause of death in this age range during the period 1993 to 1995. The recent decrease in AIDS deaths in the United States is attributed to improvements in anti-HIV drug therapy, which prolongs the lives of patients. [National Vital Statistics Report.]

The magnitude of the AIDS epidemic in the United States is dwarfed by figures for other parts of the world. The global distribution of those afflicted with AIDS is shown in Figure 19-7. In sub-Saharan Africa an estimated 25.3 million persons were living with AIDS at the end of 2000, and in South and Southeast Asia there were another 5.8 million. There are an estimated 36.1 million persons worldwide with AIDS, including over 5 million children. In addition, there are over 8 million children who have been orphaned by the death of their parents from AIDS. Recent estimates from the World Health Organization indicate that there were 5.3 million new HIV infections in 2000, or an average of almost 15,000 persons infected each day during that year. This number includes a daily infection toll of 1700 children under 15 years of age.

The initial group of AIDS patients in the United States and Western Europe was predominantly white and male. Although this remains the group predominantly affected in these areas, more recently the distribution in the United States has shifted to include a larger proportion of women (20% in 2000 versus 6% in 1985) and an increasing proportion of minorities (39% black and Hispanic in 1996 versus

11% in 1985). Worldwide, the number of AIDS patients distributes more equally between males and females, and in sub-Saharan Africa, which has the highest incidence of AIDS, about 50% of those afflicted are females.

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