A City Guide To Liling for death being diarrhoea, dysentery and lower respiratory tract infections. Major killers among the adult population included tuberculosis and malaria. One particular problem now facing many developing countries in Africa is HIV infection and AIDS. Botswana, Zimbabwe and Swaziland have HIV infection rates of per cent or higher UNAIDS There are over million AIDS orphans in the region and this number is expected to rise to more than million by the year UNAIDS Of note also is that the richest country in the world, the USA, fared rather badly on this index, at only th place in the rankings, with an equivalent of good health’ expectancy of years. A number of explanations for this apparent anomaly include the following, some of which are considered in more depth later in the chapter n Some social groups within the USA, such as Native Americans and the inner-city poor, have extremely poor health ? more characteristic of developing countries rather than rich industrialised ones. n HIV has contributed to a higher proportion of death and disability to young and middle-aged Americans than in most other industrialised countries. n The USA is one of the leading countries for cancers relating to tobacco use, especially lung cancer and chronic lung disease. A City Guide To Liling 2016.