perfectly natural. undeniably inevitable.

"The emergence of AIDS, Ebola and any number of other rain-forest agents (viruses) appears to be a natural consequence of the ruin of the tropical biosphere.

The emerging viruses are surfacing from ecologically damaged parts of the earth. Many of them come from the tattered edges of tropical rain forest, or they come from tropical savanna that is being settled rapidly by people. The tropical rain forests are the deep reservoirs of life on the planet, containing most of the world's plant and animal species. The rain forests are also its largest reservoirs of viruses, since all living things carry viruses. When they come out of an ecosystem, they tend to spread in waves through the human population, like echoes from the dying biosphere.

In a sense, the earth is mounting an immune response against the human species. It is beginning to react to the human parasite, the flooding infection of people, the dead spots of concrete all over the planet, the cancerous rot outs in Europe, Japan, and the United States, thick with replicating primates, the colonies enlarging and spreading and threatening to shock the biosphere with mass extinctions. Perhaps the biosphere does not 'like' the idea of five million humans. Or it could also be said that the extreme amplification of the human race, which has occured in the past hundred years or so, has suddenly produced a very large quantity of meat, which is sitting everywhere in the biosphere and may not be able to defend itself against a life form that might want to consume it.

Nature has interesting ways of balancing itself. The rain forest has its own defences. The earth's immune system, so to speak, is seeing the presence of the human species and is starting to kick in. The earth is attempting to rid itself of an infection by the human parasite. Perhaps AIDS is the first step in a natural process of clearance.

I begin to wonder, with a sense of foreboding, if AIDS might not be the end but only the beginning. I suspect that AIDS is not an accident or an isolated occurence but a step in a natural process that does not look friendly to my species, and that AIDS might not be Nature's pre-eminent display of power. Whether the human race can actually maintain a population of five million or more without a crash with a hot virus remains an open question. Unanswered. The answer lies hidden in the labyrinth of tropical ecosystems. AIDS is the revenge of the rain forest. It is only the first act of the revenge."

taken from "The Hot Zone" by Richard Preston