Because we pulled together a series of recent findings and showed an underlying trend: emerging diseases are affecting wildlife in the same dramatic way as they affect humans. People are citing us because they realize that many of the diseases they've been working on are part of this trend.

  Does it describe a new discovery or new methodology that's useful to others?

The paper covers a new conceptual link rather than a specific discovery. We examined the literature and, using definitions of emerging diseases in humans, identified a group of emerging diseases in wildlife. We then analyzed their underlying causes and showed that almost all were driven by changes to the environment made by humans. This was a surprising result with serious ramifications for conservation and public health.

The real background was a series of high profile wildlife die-offs that were attributed to infectious diseases: mycoplasmal conjunctivitis in house finches; morbillivirus infections in seals; canine distemper in African wild dogs and Serengeti Lions etc. Andrew Cunningham and myself had recently discovered the first definitively proven case of a disease causing extinction of a species (a Partula snail). In 1997 we teamed up with Alex Hyatt plus a group of Australian and United States workers and identified a fungal pathogen associated with amphibian declines in Australian and Central American amphibians. It was clear that the amphibian disease was an emerging disease, increasing in impact and geographic range just like A.I.D.S. or drug-resistant tubercleosis and we started to make the conceptual links between wildlife and humans.

Our paper was the first to bring together the evidence that wildlife populations are being significantly threatened by a group of so-called "emerging" diseases. We revealed close parallels in the underlying causes that drive disease emergence in humans and wildlife. Our first conclusion was that just like many of the devastating emerging diseases in human populations, some of these wildlife diseases were causing mass die-offs, i.e. declines and even extinctions were threatening biodiversity. For each wildlife disease, we analyzed the underlying factors driving emergence and found that these were almost all directly linked to human environmental changes. This has serious implications for public health because most emerging diseases of humans have animal origins. Therefore if our environmental changes are driving increased impact of wildlife diseases, it's likely that they're increasing the movement of animal pathogens into human populations. It also has conservation implications, because it suggests that, to get to the root cause of disease threats to wildlife, we have to tackle the environmental changes that drive them.