"Fresh air can seriously damage your health". A most unlikely Government Health warning but, for the patient with Acquired Immunodeficiency Disease Syndrome, AIDS, air-borne infection presents a constant threat of pneumonia and death. Nearly all will die of diseases caused by microbes that are everywhere in the environment, and harmless to the normal, healthy individual. It could almost be said that air, water and food carry death to anyone infected with the Human Immunodeficiency Virus, HIV - the causative agent of AIDS. The World Health Organisation estimates that, by the end of the decade, ten million people will have died from AIDS-related disease, and a further forty million will be infected by HIV. This is an epidemic of plague proportion, and the majority of its victims will be from the poorest countries of sub-Saharan Africa and South East Asia.
In an individual with AIDS the protective immune system has collapsed.
As a result, the individual becomes susceptible to infection by a variety of environmental microbes. These microbes present no problem to the healthy individual, but can be fatal to the AIDS patient. For instance, Pneumocystis carinii - a fungal like organism, is a major cause of pneumonia-related death in AIDS patients in the developed world. Few doctors would have encountered this infection in their normal practice before the start of the AIDS epidemic in the 1980s.
Indoor swimming presents a hazard of infection from Mycobacterium avium - an organism that is found in soil, water and fresh vegetables, and is distantly related to the causative agent of Tuberculosis. Before the AIDS epidemic established itself, only twenty-four cases of Mycobacterium avium infection had ever been reported in the medical literature. In 1985 it was considered to present no health risk, even to AIDS patients. By 1990, over twelve thousand clinical...