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Emerging Infectious Diseases

© Kenneth Friedman

Also, the human impact on global climate change affects habitats. Some scientists predict, for example, that we can expect to see shifts in bird, animal and plant populations as the world becomes warmer. Suppose that within these changes we see new-to-the-region birds migrating from South and Central America and they bring diseases previously unrelated to the new region. Not much different than the unwelcome West Nile virus that New York and neighboring states are worrying so much about. "Recent analyses of nucleic acid sequences have shown that avian influenza can be transmitted directly from birds to humans," Williams writes. Birds also bring with them organisms that get deposited in lakes and other water bodies and who knows what kind of unwanted soup creates.

Williams writes: "Weather patterns can cause changes in the prevalence of certain parasites that are deadly to some species of sheep. Researchers are finding new diseases even in sites considered pristine. A newly discovered fungal disease has recently been identified as the cause of amphibian mortality in the Central American and Australian rain forests, areas scientists thought were beyond the reach of human environmental change."

To confront the potential for emerging diseases, Williams says the report's authors say researchers have "begun to search for new animal diseases as part of a strategy to control emerging disease threats to humans, but far too little is known about potential threats at this point."

While scientists are worried about human diseases that may be linked to wildlife diseases, some scientists are worried about the effect that animal diseases can have biodiversity. In other words, animals may become extinct at the hands of hunters, but they also can become extinct from disease, and we don't know much about this phenomenon. What if, for example, pathogens are transported in the ballast of a ship, internationally transported waste, or someone's smuggled wildlife, and the effect is felt by delicate systems such as the Galápogos Islands, Madagascar, the Amazon and Australian rainforests, Antarctica or elsewhere.

Williams quotes Daszak: "Just how science can offset the effects of emerging infectious diseases in wildlife is yet unclear, but the scope of the problem is becoming increasingly obvious." Furthermore, "The problems involved have clear economic consequences." For example, they wrote in the report, "post-exposure treatment given to 655 people who had potential contact with a single rabid kitten in a New Hampshire pet store in 1994 cost $1.1 million. The costs of Lyme disease treatments of all kind in the U.S. may be as much as $500 million a year."