Treasures of the Internet: AIDS

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Untitled Jul 20, 2008
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Untitled Global overview

Untitled Sub-Saharan Africa

Untitled Middle East and North Africa

Untitled Eastern Europe, Russia and Central Asia

Untitled Asia and the Pacific

Untitled Latin America and the Caribbean

Untitled More Developed Countries (MDCs)

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Read more about the Untitled AIDS epidemic in individual countries in Untitled Africa

Untitled Sub-Saharan Africa

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Sub-Saharan Africa has just over 10% of the world’s population, but is home to close to two-thirds of all people living with Untitled HIV —some 25 million (range: 23.1–27.9 million). In 2003 alone, an estimated 3 million people (range: 2.6–3.7 million) in the region became newly infected, while 2.2 million (range: 2.0–2.5 million) died of Untitled AIDS . Among young people 15–24 years of age, 6.9% of women (range: 6.3–8.3%) and 2.1% of men (range: 1.9–2.5%) were living with Untitled HIV by the end of 2003.

Many African countries are experiencing generalized epidemics. This means that Untitled HIV is spreading throughout the general population, rather than being confined to populations at higher risk, such as sex workers and their clients, men who have sex with men, and injecting drug users. In sub-Saharan Africa, as the total adult population is growing, the number of people living with Untitled HIV is increasing, with the result that adult prevalence has remained stable in recent years (see Fig. 2). However, this overall stabilization of prevalence in the sub-Saharan region conceals important regional variations.

Although prevalence is stable in most countries, it is still rising in a few countries, such as Madagascar and Swaziland, and is declining nationwide in Uganda and in smaller areas in several other countries. Stabilized infection levels in an epidemic often result from rising death rates from Untitled AIDS , which conceal a continuing high rate of new infections. Even when Untitled HIV prevalence falls, as in Uganda, the number of new infections can remain high.

Epidemic in sub-Saharan Africa, 1985‚2003

Figure 2

Within countries, there can be variations in prevalence by region. It has long been recognized that in most countries Untitled HIV infection levels are higher in urban than in rural areas. A review of national community-based studies shows that Untitled HIV prevalence in urban areas is about twice as high as in rural areas (see Fig. 3).

HIV prevalence among 15‚49-year-olds in urban and rural areas, selected sub-Saharan African countries, 2001‚2003

Figure 3

Women face greater risk

African women are being infected at an earlier age than men, and the gap in Untitled HIV prevalence between them continues to grow. At the beginning of the epidemic in sub-Saharan Africa, women living with Untitled HIV were vastly outnumbered by men. But today there are, on average, 13 infected women for every 10 infected men—up from 12 infected women for every 10 infected men in 2002. The difference between infection levels is more pronounced in urban areas, with 14 women for every 10 men, than in rural areas, where 12 women are infected for every 10 men (Stover, 2004).

The difference in infection levels between women and men is even more pronounced among young people aged 15–24. A review of Untitled HIV -infection levels among 15–24-year-olds compared the ratio of young women living with Untitled HIV to young men living with Untitled HIV (see Fig. 4). This ranges from 20 women for every 10 men in South Africa, to 45 women for every 10 men in Kenya and Mali.

HIV prevalence among 15‚24-year-olds in selected sub-Saharan African countries, 2001‚2003

Figure 4

In sub-Saharan Africa, heterosexual transmission is by far the predominant mode of Untitled HIV transmission. Unsafe injections in health-care settings are believed to be responsible for around 2.5% of all infections. Recently, it has been suggested that unsafe medical injections account for most Untitled HIV transmission in the region (Gisselquist et al., 2002). However, a recent thorough review of the evidence concluded that, while a serious issue, unsafe injections are not common enough to play a dominant role in Untitled HIV transmission in sub-Saharan Africa (Schmid et al., 2004).

The ‘unsafe injections’ theory does not take into account the possibility that people sick with Untitled HIV -related disease might receive more injections. Moreover, the pattern of injections in health-care settings does not match sub-Saharan Africa’s Untitled HIV -infection distribution pattern by age and sex. Although the safety of injections must be assured in all health-care settings, effective strategies addressing sexual transmission have the largest potential to turn the epidemic around in this region.

Diverse levels and trends

There is tremendous diversity across the subcontinent in the levels and trends of Untitled HIV infection (see Fig. 5). Southern Africa remains the worst-affected region in the world, with data from selected antenatal clinics in urban areas in 2002 showing Untitled HIV prevalence of over 25%, following a rapid increase from just 5% in 1990. Prevalence among pregnant women in urban areas was 13% in Eastern Africa in 2002, down from around 20% in the early 1990s. During this period, prevalence in West and Central Africa remained stable.

There is no single explanation for why the epidemic is so rampant in Southern Africa. A combination of factors, often working in concert, seems to be responsible. These factors include poverty and social instability that result in family disruption, high levels of other sexually transmitted infections, the low status of women, sexual violence, and ineffective leadership during critical periods in the spread of Untitled HIV . An important factor, too, is high mobility, which is largely linked to migratory labour systems.

Median HIV prevalence (%) in antenatal clinics in urban areas,

Figure 5

The epidemics in Southern Africa have grown rapidly. For example, in Swaziland, the average prevalence among pregnant women was 39% in 2002—up from 34% in 2000 and only 4% in 1992. Moreover, in a number of countries, the penetration of the virus into the general population has exceeded what was considered possible. In Botswana, weighted antenatal clinic prevalence has been sustained at 36% in 2001, 35% in 2002, and 37% in 2003. In South Africa, prevalence among pregnant women was 25% in 2001 and 26.5% in 2002.

In parts of East and Central Africa, there are signs of real decline in infections in some countries. This is most notable in Uganda, where national prevalence dropped to 4.1% (range: 2.8–6.6%) in 2003. In Kampala, prevalence was around 8% in 2002—down from 29% 10 years ago. But even Uganda cannot afford to relax: surveys suggest that today’s young people may be less knowledgeable about Untitled AIDS than their counterparts in the 1990s.

Mobility and the spread of Untitled HIV

Human mobility has always been a major driving force in epidemics of infectious disease. Two recent studies have examined its role in the spread of Untitled HIV .

One study on the relationship between mobility, sexual behaviour and Untitled HIV infection in an urban population interviewed a representative sample of 1913 men and women in YaoundÈ, Cameroon. The study measured mobility over a one-year period. It found Untitled HIV prevalence of 7.6% among men who had been away from home for periods longer than 31 days. Prevalence among those who had been away for less than 31 days in the year was 3.4%, while prevalence among those who had not been away from home in the previous 12 months was 1.4%. The association between men’s mobility and Untitled HIV was apparently related to risky sexual behaviour and remained significant after controlling for other important variables. There was no association between women’s mobility and Untitled HIV infection (LydiÈ et al., 2004).

Across Southern Africa, the phenomenon of men migrating to urban centres in search of work and leaving their partners and children at home in rural areas is widespread and has complex historical roots. Researchers interested in the role migration plays in spreading Untitled HIV in South Africa studied the pattern of infection in couples in Hlabisa, a rural district of KwaZulu-Natal, in which nearly two-thirds of adult men spent most nights away from home.

Seroprevalence of HIV-1 for Low-Risk Populations: Southern Africa

Seroprevalence of HIV-1 for Low-Risk Populations: Southern Africa

in Black and White or Map Data Table

Figure 6

The study confirmed that migration does play an important role in spreading Untitled HIV but revealed a more complex picture than had been expected, which challenged some basic assumptions. Looking at discordant couples (that is, couples in which just one partner is Untitled HIV -positive), the study found that, in nearly 30% of cases, the infected person was the female partner who stayed home in the rural area, while her migrant partner was Untitled HIV -negative. In other words, migration may create vulnerability to Untitled HIV exposure at both ends of the trail, and the virus may be spread in both directions (Lurie et al., 2003).

The association of mobility with Untitled HIV infection may also affect the findings of household surveys. Mobile men, who generally have higher levels of Untitled HIV infection, are less likely to be found at home for these surveys. This is especially important in countries with high levels of mobility or migration, and for surveys with a high proportion of absentees.

No other country in the region has so dramatically reversed the epidemic as Uganda, but Untitled HIV prevalence among pregnant women has declined in several other places. For example, in the Ethiopian capital, Addis Ababa, prevalence has fallen from a peak of 24% in 1995 to 11% in 2003. Prevalence has also dropped in several sites in Kenya, including in Nairobi, while prevalence in many other sites appears stable. However, not all countries in the region show stabilized levels. In Madagascar, there has been an alarming rise in prevalence among pregnant women; it increased by almost fourfold since 2001, to reach 1.1% in 2003.

In West Africa, the epidemic is diverse and changeable. National prevalence has remained relatively low in the Sahel countries, with prevalence around 1%. However, the overall figures can conceal very high infection levels among certain population groups. In Senegal, for example, national Untitled HIV prevalence is below 1% (range: 0.4–1.7%); yet, among sex workers in two cities, prevalence rose from 5% and 8% respectively in 1992, to 14% and 23% in 2002. Prevalence levels are highest in CÙte d’Ivoire at 7% (range: 4.9–10%), although Abidjan recorded its lowest level (6%) in a decade in 2002.

Seroprevalence of HIV-1 for Low-Risk Populations: West Africa

Seroprevalence of HIV-1 for Low-Risk Populations: West Africa

in Black and White or Map Data Table

Figure 7

Benin and Ghana show Untitled HIV prevalence in the 2–4% range, with little change over time. Nigeria, with a population of over 120 million, has the highest number of people living with Untitled HIV in West Africa. The national prevalence in 2003 was 5.4% (range: 3.6–8%). Untitled HIV prevalence among pregnant women ranges from 2.3% in the south-west region to 7% in the north-central region. Variation between states is even larger—from 1.2% in Osun to over 6% in Kaduna and to 12% in Cross River. Untitled HIV prevalence among pregnant women is over 1% in all states and is over 5% in 13 states.

African HIV-1 Seroprevalence for High-Risk Urban Populations