Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login

Site Notices
Posted: 10/31/2006 4:11:46 AM EST
Shape of things to come? Not my words, just found it interesting reading.

Infectious and sometimes deadly wildlife diseases are inching closer to Yellowstone National Park, and few of its most famous animals seem immune from the threat. The list reads like a who's who of troubling bugs and viruses: chronic wasting disease, West Nile, avian flu, whirling disease, hantavirus and brucellosis. Some are already in Yellowstone; others may be coming. If they take hold, they threaten elk, bison, deer and other mammals along with native trout and birds. Several factors are at work changing the dynamics of animal disease: more people and domestic animals living near the park, less room outside Yellowstone to find relief from disease outbreaks, and the emergence of several dangerous diseases that move quickly and infect previously unexposed animal populations. "What worked to its advantage for hundreds of years was (Yellowstone's) relative isolation, but that's just breaking down," said David Roberts, head of the ecology department at Montana State University. "You have all these organisms that are moving around much more than they used to." Park officials recently signed an agreement with MSU and the University of California at Davis to launch a program to track and study wildlife diseases in Yellowstone. The Yellowstone Wildlife Health Program, the first of its kind for a national park, will combine expertise from several disciplines to get a handle on existing and anticipated diseases in the park and how they might affect its prized wildlife populations.

"Health issues of wildlife are part and parcel of their ecology," said Glenn Plumb, chief of the natural resources branch at Yellowstone. "The challenge is when wildlife diseases start to upset the ecology of the critters ... or moves beyond that and becomes an issue that's damaging to the resources or setting it up for conflict." No one knows for sure whether a virulent strain of bird flu or chronic wasting disease will make it to Yellowstone, he said, but it behooves wildlife officials to be ready. "I don't know that it's inevitable, but I see the way (CWD) is moving around and I think we need to be prepared," Plumb said. The Yellowstone Park Foundation, a private nonprofit group that helps fund park projects, is hoping to raise $222,220 for the program by the end of the year so it can get under way next spring, said Michael Cary, the foundation's director. The five-year project is a chance to learn about diseases in Yellowstone and to get insight into how wildlife diseases operate elsewhere in the country. "Yellowstone offers what I characterize as America's largest Petri dish," Cary said. That natural laboratory has been no stranger to diseases. Brucellosis has been the most talked-about disease ever in the Yellowstone ecosystem, which harbors its last wild reservoir. The contagion, which can cause animals to abort fetuses, is believed to have been passed from domestic cattle in Yellowstone to wild bison sometime in the early 1900s.

Since then, the disease has spread - it's also in elk, especially those that frequent man-made feedgrounds in Wyoming - and has led to a polarizing conflict over how to manage wild bison and keep the disease from infecting cattle outside Yellowstone's boundaries. Margaret Wild, one of two wildlife veterinarians with the Park Service, said no one wants to see a similar situation with other diseases in Yellowstone. "What we've really got to be concerned about is preventing disease from getting into wildlife populations," Wild said. "Once we get them into wildlife populations, they are difficult to manage." Chronic wasting disease is of particular concern. It attacks the brains of infected deer and elk, causing them to become emaciated, act abnormally and eventually die. It's still unclear exactly how the disease spreads, but a recent study among deer indicated it could be passed through blood and saliva. The disease, similar to bovine spongiform encephalopathy in cattle, hasn't been found in Yellowstone. But two infected mule deer were shot last fall outside Thermopolis, Wyo., the closest documented cases to Yellowstone. "Is it moving or is increased surveillance just picking up what's already there? We just don't know," said Jeff Obrecht, a spokesman for the Wyoming Game and Fish Department. "Worst-case scenario, you assume it might be spreading, that doesn't mean you can mount any defense."

The disease has already shown up in elk and deer at Rocky Mountain National Park in Colorado and Wind Cave National Park in South Dakota. "There's nothing about Yellowstone that's immune to these kinds of problems," Roberts said. The arrival of high-pathogen bird flu in Yellowstone is still theoretical, too, but strains of the virus have shown an ability to move quickly across the globe. One of the biggest concerns in the park would be the nonmigratory trumpeter swans. Only 18 were counted in the park last year. Because of their low numbers and slow breeding, a deadly disease could be devastating. "If something happens, you can't replace them with other nonmigratory birds," Plumb said. Yellowstone has had its share of diseases in wildlife. But more people have moved closer to the park, along with their domesticated animals and pets, increasing the likelihood that wild animals might contract a new disease. "There are more people living in closer contact with more animals than any time in our planet's history," Plumb said.

Modern conveniences, especially ease and speed of travel, also have made the world more vulnerable to hitchhiking diseases. "Human behavior has changed so drastically in the last couple of decades and we're seeing the impact of that," said Jonna Mazet, a veterinarian with the wildlife health center at UC-Davis. When diseases arrive, they find unprepared animal populations that haven't co-evolved with the particular strains and are quickly susceptible. "If a native population lacks the antibodies to these particular pathogens, it's likely to spread more rapidly than otherwise," Roberts said. In places such as Yellowstone where there are dense pockets of wildlife, disease can spread especially quickly. "It's relatively easy for (diseases) to get established in some populations," Roberts said. Changing climate, too, could give diseases an edge. Shifts in weather and temperature could allow pathogens to get into places they haven't been before or stress wildlife to the point where they're more susceptible. "It could mean that diseases work in different ways," Plumb said. The new program will aim to keep watch on diseases and their health effects in Yellowstone and to limit the transmission between domestic and wild animals, in both directions.

Top Top