Dorothy H. Crawford is a Professor of Medical Microbiology and Assistant Principle for the Public Understanding of Medicine at the University of Edinburgh. Her most recent book, Deadly Companions: How Microbes Shaped Our History, takes us back in time to follow the interlinked history of microbes and man, impressing upon us how a world free of dangerous microbes is an illusion. In an excerpt this morning we looked at SARS. The excerpt below looks at the effect of poverty on disease.
It is glaringly obvious from a glance at the figures that poverty is the major cause of microbe-related deaths. On a worldwide scale microbes are still major killers, accounting for one in three of all deaths. But the huge discrepancy in the death rates between rich and poor nations reveals the stark reality. Whereas only 1–2 per cent of all deaths in the West are caused by microbes, this figure rises to over 50 per cent in the poorest nations of the world, and it is in these highly microbe-infected areas where over 95 per cent of the global deaths from infections occur. Most of the 17 million killed by microbes each year are children in developing countries where the link with poverty is clear. It is the poor who are malnourished, live in filthy, overcrowded urban slums and go without clean drinking water or sewage disposal, and therefore they are the ones who fall prey to the killer microbes: HIV, malaria, TB, respiratory infections and diarrhea diseases like cholera, typhoid and rotavirus; all eminently preventable and treatable given the resources.
The spread of HIV is an excellent example of how microbes exploit the poor, striking at the most disadvantaged in the community. The virus emerged in Central Africa and spread silently throughout the continent in the 1970s, given a head start by its long silent incubation period, and aided by despotic leaders, corrupt governments, civil wars, tribal conflicts, droughts and famines. Carried by undisciplined armies and terrorists, the virus infiltrated city slums, infected commercial sex workers, was picked up by migrant workers and passed on to their wives and families. While malnutrition accelerated the onset of AIDs, breakdown of health-care services in the political turmoil of Africa excluded any possibility of medical support for the millions in need.
Now we are living through the worst pandemic the world has ever known, with 40 million living with HIV, 25 million already dead and around 10,000 dying daily—the equivalent of over three 9/11disasters every twenty-four hours. A third of people living in sub-Saharan African cities are HIV-infected, and while highly active antiretroviral therapy (HAART) has converted this lethal disease into a manageable chronic infection in the West, presently only a tiny proportion of Africans living with HIV receive this treatment; for most there is no hope of obtaining the drugs vital for keeping them alive.
The dynamics of HIV in Africa reflects its mode of spread. As the virus is sexually transmitted gender inequalities mean that women are particularly vulnerable. In general they are poorer and less well educated than their male counterparts, and are often powerless to choose or restrict their sexual partners, or to insist on condom use. Indeed many are forced to exchange sex for essentials like food, shelter and schooling. Now one in four African women are HIV-infected by the age of twenty-two years (compared to one in fourteen men of the same age), and women account for 60 per cent of all those living with HIV.
Over 90 per cent of HIV-positive women in Africa are mothers, and the virus has created 15 million orphans worldwide, 12 million of them in sub-Saharan Africa. These children are bearing the burden of the HIV pandemic; they miss school to care for their sick mothers or to earn the family income; the virus has not only deprived them of their parents but their childhood and their education as well.