In areas where the economy is based on subsistence or peasant farming, most of the work is done by young men and women. This is also the age group which is most affected by HIV/AIDS.

When people are ill, they become unable to work and so, unless other people can be found to do the work, the amount which the farm produces will fall. Land may have to be left unused because there are not enough people to do the necessary jobs such as weeding or applying fertilisers and pesticides. In addition to this, some crops may be left in the fields to waste because there aren't enough people to help with the harvesting.

This means that the amount of food available will fall. In areas such as Southern Africa where drought means that there are often shortages of food, HIV/AIDS makes the problems of food production and availability even worse.

One way of dealing with the impact of HIV/AIDS is to pay people to do the work which ill family members would usually do. This is usually not an option though because people cannot afford to pay workers.

One other alternative is to call on additional family labour. Children can take on the work which ill members of the family cannot do. This means that children may have to drop out of school and so education levels are lower in areas with high rates of HIV/AIDS.

Equally, many older people may be recalled to be part of the farm labour. In Africa older people do not 'retire' in a formal sense. Instead they gradually pass their tasks on the farm and in the household to the younger generation.

However, where the younger generation are unable to work because of illness, the older generation may need to continue to work for longer than they would normally have done. This often reduces the productivity of the farm as older people may be less efficient especially at heavier tasks.

Because of these problems of labour supply, it seems that in Africa rural productivity has been falling as a result of HIV/AIDS. Additional family labour cannot make up for the loss of experienced workers.

This is a serious problem in Africa where for many years, before HIV/AIDS became a problem, there has been a problem in producing enough food. HIV/AIDS is not the main cause of the food problem, but it makes it worse and makes it much more difficult to deal with.

Agricultural land in Kenya. Click on image for bigger version