Poverty, social attitudes, religion and politics all play their part.Take Latin America. In Chile and Venezuela, like many other parts of the world, HIV/Aids is a disease of poverty, politics and discrimination. In countries where religion remains a fundamental part of everyday life, Aids awareness seems relatively high.HIV/Aids is a disease of the barrios, or poor urban areas, of Santiago and Caracas. But while numbers are not high in comparison to Africa, they are significant enough for politicians and health workers to worry about whether they are getting the balance right between prevention, information and treatment. Here the issues are over the civic rights of people with Aids, and the availability of reasonably priced drugs.Chile has just 1 per cent of Latin America’s Aids cases.

“What Aids has done in Chile is bring out, forcefully, the right to health as a basic citizenship right,” says Thierry Lemaresquier, the UNDP resident representative in the country. “There has been discrimination in access to treatment.”Draft legislation addressing this has a good chance of being approved, and this is one positive outcome of the Aids epidemic. Fortunately, in the farthest-flung regions of the continent, HIV/Aids has not yet become a catastrophe.Here and in Venezuela health workers are grappling with HIV/Aids as a poverty issue, not solely one of health. People with Aids have to be empowered to achieve the benefits taken for granted elsewhere: both countries are negotiating with Brazil to try to import anti-Aids therapies at prices within reach of health workers and patients.In Venezuela, the resident representative Niky Fabiancic says infection by Aids is low.

In a country of around 24 million people, there have been 8,400 deaths in 17 years, although up to 400,000 people may be infected “The numbers are low. The challenge is to keep it that way,” says Mr Fabiancic.As in Chile, religion, social attitudes and sheer geographical isolation may have played a part in keeping down the number of infections. They must also be taken account in deciding on a strategy to combat the spread of the disease. NGOs have played a significant role in writing a new constitution which ensures rights of access to treatment for people with Aids.With UNDP prompting, the Ministry of Health has identified Aids as one of six priority areas with an increase in budget from $2m (£1.4m) to $50m (£35m) last year About half is spent on prevention, half on treatment. Drugs are free, but if supplies of generic drugs can begin to flow from Brazil, many more can be treated.Compare that with another country with a low incidence of Aids: China. China has the potential of becoming the world’s worst Aids meltdown.

China is the Earth’s most populous nation, with 1.2 billion inhabitants. The population is so big, yet HIV/Aids incidence is small: a fraction of 0.1 per cent – now. But in the future?The UNDP’s resident representative, German-born Kerstin Leitner, treats HIV/Aids as much as a human rights issue in China as a medical one. “In China, our biggest battle is to get Aids out of the context that this is just another disease that the health department ought to deal with,” she says.”The prevalence is tiny, but it’s there and spreading. The first case was in 1985 in a south-western province and in less than 20 years it is all over.