Mary Pearl; Where Flu Comes From.(Interview)(Excerpt)

Byline: Anne Underwood

Protection of the environment often seems like a low-priority issue when stacked up against more immediate concerns. But a healthy environment is no mere luxury, says Mary Pearl, president of the Wildlife Trust. It is a prerequisite for human health. Pearl and her colleagues spearheaded the development of "conservation medicine"--a scientific exploration of the links between the health of humans, wildlife and eco-systems. Among the trust's current projects: a collaboration to monitor the spread of avian flu among wild birds and research uncovering the origin of SARS. Pearl spoke recently with newsweek's Anne Underwood. Excerpts:

UNDERWOOD: How did the whole idea of conservation medicine develop? PEARL: It's an approach that evolved from the recognition of a crisis--namely, unprecedented levels of disease, driven byhuman-induced environmental degradation. Since the mid-1970s, more than 30 new diseases have emerged, including AIDS, Ebola, Lyme disease and SARS. Most of these are believed to have moved from wildlife to human populations. Yet no one was getting a grip on the totality of the picture. Damaged ecosystems--characterized by toxins, degradation of habitat, removal of species and climate change--create conditions for pathogens to move in ways they wouldn't normally move.

How so?

The destruction of the Peruvian rain forest, for example, has led to an explosion of malaria-bearing mosquitoes that thrive in sunlit ponds created by logging operations. Even a 1 percent increase in deforestation leads to an 8 percent increase in mosquitoes, according to Jonathan Patz at the University of Wisconsin.

Does the wild-animal trade play a role in the spread of disease?

You never import just one species. You import the animal and all its parasites and pathogens. A few weeks ago the British government identified the deadly H5N1 strain of bird flu in an imported parrot that was being held in quarantine. But half the wildlife trade is illegal, so it's not even being monitored.