As HIV is predominantly a sexually transmitted disease, the largest number of people infected are those of reproductive age. Thus, the HIV epidemic not only reduces the total number of people, but the age and sex composition changes, with a population dominated by the elderly and the youth.
The reproductive age group is also the most productive. When a person is sick, the household not only has to manage without his or her labour contribution, but also with the loss of labour from those who have to care for the sick family member.
AIDS is characterized by recurrent periods of sickness, and consequently a recurrent loss of labour. This eventually erodes agricultural production and food security. Much of rural agricultural production is highly labour-dependent. In some agro-ecological zones, labour demands are concentrated in specific and critical periods of the year. In those areas sickness or funeral attendance may mean that the planting season is missed, and with it a full crop.
FAO estimates that in the 25 hardest-hit countries in Africa, AIDS has killed around 7 million agricultural workers since 1985; it could kill 16 million more before 2020. The most affected African countries could lose up to 26 percent of their agricultural labour force within two decades. As agriculture still represents a large proportion of the gross domestic product, this loss in labour could have severe impacts on national economies.
In many countries, AIDS is erasing decades of progress made in improving mortality conditions and extending life expectancies. The average life expectancy in sub-Saharan Africa is now 47 years, when it would have been 62 years without AIDS. In Botswana, for example, life expectancy at birth has dropped to a level not seen in this country since 1950.