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Why does AIDS persist at such a high rate in Sub-Saharan Africa? Helen Epstein, in NY Times Magazine, June 13, 2004, suggests that the reason is infidelity. – In South Africa, Kenya and other countries, men have several on-going commitments. This contrasts to the US pattern of either “one night stands” or serial monogamy. This argument is highly charged emotionally. Can we evaluate it biologically? 00001-E-1– 27 June 2000 A global view of HIV infection 33 million adults living with HIV/AIDS as of end 1999 Adult prevalence rate 15.0% – 36.0% 5.0% – 15.0% 1.0% – 5.0% 0.5% – 1.0% 0.1% – 0.5% 0.0% – 0.1% not available 00001-E-2– 27 June 2000 Leading causes of disease burden globally, 1999 Rank % of total 1 Acute lower respiratory infections 6.7 2 HIV/AIDS 6.2 3 Perinatal conditions 6.2 4 Diarrhoeal diseases 5.0 5 Ischaemic heart disease 4.1 6 Unipolar major depression 4.1 7 Cerebrovascular disease 3.5 8 Malaria 3.1 12 Tuberculosis 2.3 00001-E-3– 27 June 2000 Source: The World Health Report 2000, WHO Leading causes of death globally, 1999 Rank % of total 1 Ischaemic heart disease 12.7 2 Cerebrovascular disease 9.9 3 Acute lower respiratory infections 7.1 4 HIV/AIDS 4.8 5 Chronic obstructive pulmonary disease 4.8 6 Perinatal conditions 4.2 7 Diarrhoeal diseases 4.0 8 Tuberculosis 3.0 11 Malaria 1.9 00001-E-4– 27 June 2000 Source: The World Health Report 2000, WHO Leading causes of disease burden in Africa, 1999 Rank % of total 1 HIV/AIDS 2 Malaria 9.9 3 Acute lower respiratory infections 8.5 4 Diarrhoeal diseases 6.5 5 Perinatal conditions 6.5 6 Measles 4.7 7 Maternal conditions 3.4 8 Tuberculosis 2.3 9 Congenital abnormalities 1.7 10 Road traffic accidents 1.7 00001-E-5– 27 June 2000 19.9 Source: The World Health Report 2000, WHO Leading causes of death in Africa, 1999 Rank % of total 1 HIV/AIDS 20.6 2 Acute lower respiratory infections 10.3 3 Malaria 9.1 4 Diarrhoeal diseases 7.3 5 Perinatal conditions 5.9 6 Measles 4.9 7 Tuberculosis 3.4 8 Cerebrovascular disease 3.2 9 Ischaemic heart disease 3.0 10 Maternal conditions 2.4 00001-E-6– 27 June 2000 Source: The World Health Report 2000, WHO Changes in life expectancy in selected African countries with high HIV prevalence, 1950 to 2000 65 60 Botswana Uganda South-Africa 55 Zambia 50 Zimbabwe 45 40 35 1950-55 1955-60 1960-65 1965-70 1970-75 1975-80 1980-85 1985-90 1990-95 1995-00 00001-E-7– 27 June 2000 Source: United Nations Population Division, 1998 Estimated adult HIV prevalence in Kenya, 1990-1999 16 HIV prevalence (%) 14 12 10 8 6 4 2 0 90 00001-E-8– 27 June 2000 91 92 93 94 95 96 Source: National AIDS and STD Control Programme, 1999 and UNAIDS 97 98 99 HIV prevalence among pregnant women in South Africa, 1990 to 1999 HIV prevalence (%) 25 22.8 22.4 98 99 20 17 14.2 15 10.4 10 7.6 5 4 1.7 2.1 91 92 0.7 0 90 00001-E-9– 27 June 2000 93 94 95 Source: Department of Health, South Africa 96 97 Median HIV prevalence among pregnant women in urban areas in Uganda, 1985 to 1998 35 HIV prevalence (%) 30 25 20 15 10 5 0 85 00001-E-10– 27 June 2000 86 87 88 89 90 91 92 93 Source: STD/AIDS Control Programme, Uganda 94 95 96 97 98 HIV prevalence in military personnel in Africa Nigeria: 11% among peacekeepers returning from Sierra Leone and Liberia vs 5% in adult population South Africa: 60-70% in military vs 20% in adult population 00001-E-11– 27 June 2000 Source: Nigeria AIDS bulletin No 15, May 20, 2000; The Mail & Guardian, Pretoria, March 31, 2000; UNAIDS/WHO 1999 estimate HIV prevalence rate and frequency of sexually transmitted infection (STI) episodes, Carletonville miners, South Africa, 1991-1998 HIV prevalence (%) 90 80 70 60 50 40 30 20 10 0 1 2-4 5-9 Number of STI episodes 00001-E-12– 27 June 2000 Source: Ballard R, 2000 (unpublished data). 10+ Individuals are more infectious to others when they have been newly infected Epstein argues that the concurrent partners strategy favors widespread transmission because a newly infected individual is likely to visit several partners during the highly infectious period. An individual with “one night stands” or serial monogamy may put fewer people at risk during this period even if the total partners per 6 months is similar. 00001-E-13– 27 June 2000 00001-E-14– 27 June 2000 Condom use Numerous studies have found that people in many locales have increased use of condoms with “casual” partners or prostitutes. Use of condoms with regular partners has increased less dramatically. What if there are several “regular partners?” 00001-E-15– 27 June 2000 Why does this behavior persist? Women without access to funds (especially younger women) rely on male partners for financial contributions In Kenya and South Africa, “sugar daddies” commonly help girls with school fees as well as luxuries. 00001-E-16– 27 June 2000 Uganda’s success Early devastating epidemic created public awareness Cultural openness about sexual matters Visible campaign– ABC: Abstain, Be Faithful, Use Condoms – Zero Grazing Participation of women’s activist groups 00001-E-17– 27 June 2000 The AIDS story as it is told in Uganda 00001-E-18– 27 June 2000 What do we know? What do we need to know? How can we shape this into a workable case study? Is there adequate room for complexity, for multiple approaches, for scientific investigation? Can we tie in questions that lead students to explore the mechanisms of drug action, vaccines or the immune response? 00001-E-19– 27 June 2000 Impact of HIV/AIDS on urban households, Côte d’Ivoire General population Families living with AIDS 30 000 Francs CFA 25 000 20 000 15 000 10 000 5 000 Monthly income per capita Monthly consumption per capita Savings/Disavings 0 – 5 000 00001-E-20– 27 June 2000 Source: Simulation-based on data from Bechu, Delcroix and Guillaume, 1997 Reduction in production in a household with an AIDS death, Zimbabwe Reduction in output Crops Maize 61% Cotton 47% Vegetables 49% Groundnuts 37% Cattle owned 29% 00001-E-21– 27 June 2000 Source: Stover & Bollinger, 1999 HIV prevalence rate among teenagers in Kisumu, Kenya, by age 35 33.3 29.4 HIV prevalence (%) 30 25 22 20 17.9 boys girls 15 10 8.6 8.3 3.6 5 0 0 0 15 00001-E-22– 27 June 2000 2.2 16 17 Age in years 18 Source: National AIDS Programme, Kenya, and Population Council, 1999 19 Age in years Projected population structure with and without the AIDS epidemic, Botswana, 2020 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 Projected population structure in 2020 Males 140 120 100 80 Females 60 40 20 0 20 40 60 80 Population (thousands) 00001-E-23– 27 June 2000 Source: US Census Bureau, World Population Profile 2000 100 120 140 Deficits due to AIDS HIV prevalence rate among 13 to 19-year-olds, Masaka, Uganda, 1989 to 1997 5 girls HIV prevalence (%) 4 boys 3 2 1 0 1989/90 00001-E-24– 27 June 2000 1990/91 1991/92 1992/93 1993/94 Source: Kamali et al. AIDS 2000, 14: 427-434 1994/95 1995/96 1996/97 HIV prevalence rate among pregnant 15-24 year-olds by educational status, Uganda 30 illiterate HIV prevalence (%) primary education 25 secondary education 20 15 10 5 0 1991-1994 00001-E-25– 27 June 2000 Source: Kilian A et al. AIDS 1999, 13: 391-398. 1995-1997 Estimated impact of AIDS on under-5 child mortality rates, selected African countries, 2010 250 Deaths per 1000 live births 200 Without AIDS With AIDS 150 100 50 0 Botswana 00001-E-26– 27 June 2000 Kenya Malawi Tanzania Source: US Census Bureau Zambia Zimbabwe Trends in HIV prevalence in selected populations in Kampala, Uganda; Dakar, Senegal; and Thailand; 1989 to 1999 30 Kampala, <20 year old ANC Thailand, 21 year old military conscripts 25 HIV prevalence (%) Dakar, all ages ANC 20 15 10 5 0 89 00001-E-27– 27 June 2000 90 91 92 93 94 95 96 Source: National STD/AIDS Control Programmes, Senegal and Uganda Armed Forces Research Institute of Medical Sciences, Thailand 97 98 99