Wildlife Disease News Digest

Genetic Analysis Finds Greater Threat in Frog-Killing Fungus
University of California - Berkeley (Posted by sciencedaily.com)
06 Aug 2007
Photo courtesy of VT Vredenburg
Area: California USA

A deadly fungus that has decimated populations of mountain yellow-legged frogs in the Sierra Nevada can likely be spread by sexual reproduction, seriously complicating efforts to save the frogs from extinction, according to a new genetic analysis led by researchers at the University of California, Berkeley. The dramatic decline of the mountain yellow-legged frog over the past several decades has been attributed to the introduction of non-native predatory fish in some areas and to chytridiomycosis, a quickly spreading disease caused by this waterborne fungus, Batrachochytrium dendrobatidis. The study, to appear in next week's edition of the journal Proceedings of the National Academy of Sciences, suggests that the frog-killing fungus may end up playing the bigger role in the frog's demise because of the pathogen's ability to spread over long distances and possibly persist in the environment as a consequence of sexual reproduction, according to the researchers.

"This group of fungi, when it reproduces sexually, can create spores that can last for a decade," said John Taylor, UC Berkeley professor of plant and microbial biology and principal investigator of the study. "That could make this pathogen a harder problem to defeat. As a resistant spore, the fungus could be transported by animals, including humans or birds, or lay dormant in an infected area until a new host comes along." Biologists are still determining exactly how this fungus, first identified in 1998, kills the amphibians it infects, but most believe that the pathogen disrupts the frogs' ability to absorb water through its skin.

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Lyme Disease Cases Double in Two Years
Times Argus - timesargus.co
07 Aug 2007
M Huff
Area: Vermont USA

The number of reported cases of Lyme disease, an infection transmitted by the bite of deer ticks (properly called "black-legged ticks"), has doubled in Vermont in the past two years. Data from the Vermont Department of Health show that in 2005, 29 Vermonters contracted Lyme disease from Vermont ticks. In 2006, the number rose to 62. So far this year, 71 cases of Lyme disease in humans have been reported. The highest concentration of cases are in the southern part of the state – 25 in Bennington County and 13 in Windham County, six in Addison, Chittenden and Rutland counties, five in Windsor, two in Franklin, Lamoille, Orleans and Washington counties and one in Caledonia and Orange counties – and the tick season isn't over yet.

The only counties without reported cases of Lyme disease are Essex and Grand Isle. But that doesn't mean Lyme disease doesn't exist there, nor does it mean that the people with reported cases of Lyme disease got it in the counties where they live. The state tracks cases by county of residence. That means someone who lives in Franklin County could have been infected on a visit to Grand Isle County, even though Grand Isle has no reported cases.

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Veterinarians and Physicians: Working Together for One Medicine [Editorial]
American Medical News - amednews.com
13 Aug 2007
Area: United States

The AMA and the American Veterinary Medical Assn. are collaborating on the One Health Initiative as human and animal medicine join forces to fight existing and emerging zoonotic diseases.

About 60% of all human pathogens are zoonotic, transmissible between animals and people. Even more striking, approximately 75% of recently emerging infectious diseases affecting humans are of animal origin. These Centers for Disease Control and Prevention statistics underscore just how important a new partnership being forged between the worlds of human and animal medicine is to public health. The American Medical Association and American Veterinary Medical Assn. are taking the lead.

Last September, Roger Mahr, DVM, newly elected as AVMA president, announced his intent to launch an effort to unite human and veterinary medicine to improve animal and public health. Then in June, the AMA voted at its Annual Meeting to increase collaboration with the veterinary community to better recognize, monitor and treat zoonotic diseases, and more broadly collaborate in medical education and biomedical research. Just a month later, AMA President Ronald M. Davis, MD, offered his support to Dr. Mahr's project, dubbed the One Health Initiative. The One Health concept is not new. Dr. Mahr pointed out in a 2006 address that physician Sir William Osler, founder of the modern medical teaching concept, wrote in the 1800s that "veterinary medicine and human medicine complement each other and should be considered as one medicine."

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Anthrax Bacterium's Deadly Secrets Probed
Research Councils UK (Posted by sciencedaily.com)
06 Aug 2007
Area: United Kingdom

New insights into why the bug that causes anthrax behaves in the unusual way that it does have come to light thanks to a development under the UK e-Science Programme. Researchers at the North East Regional e-Science Centre have found that the proteins the anthrax bacterium secretes equip it to grow only in an animal host and not in the soil. This finding sheds light on why Bacillus anthracis does not grow in soil, even though in many ways it resembles a soil-growing bacterium. It has the ability to lie dormant in soil for, in some cases, hundreds of years and then to cause a rapid, often fatal, illness when ingested by a suitable animal host. Bioterrorists have exploited this ability to deadly effect.

Dr. Anil Wipat, Professor Colin Harwood, Tracy Craddock and colleagues at the North East Regional e-Science Centre in Newcastle revealed the new insights after developing a method for deducing and characterising the proteins a bacterium secretes simply from a knowledge of its genome sequence. Secreted proteins equip a bacterium to survive in its environment and so reveal much about its lifestyle. A soil-living bacterium, for example, secretes proteins that enable it to take up nutrients from the soil. A disease-causing bacterium may secrete proteins that subvert the host's immune system, enabling the bacterium to infect cells or survive in the bloodstream.

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Saving the Tasmanian Devil, with the Help of New Synchrotron
CSIRO Australia (Posted by sciencedaily.com)
03 Aug 2007
Area: Australia

Australia’s new $A200m synchrotron in Melbourne could contribute to the fight to save the Tasmanian devil from the outbreak of facial tumour disease currently decimating devil populations, according to Dr Jeff Church from CSIRO Textile and Fibre Technology in Geelong. Dr Church says he will use the synchotron to see if the disease causes any biochemical changes in the devils which could be detected in their hair before the disease becomes apparent. “If we find a consistent change, it could lead to the development of a test which will allow detection of the cancer before the tumours become evident,” he says. “This would make any quarantine strategy easier to establish, as well as much more efficient.”

The idea is based on Australian research showing disease-related changes in the composition of human hair. The suggestion is that similar changes could occur in Tasmanian devils’ hair when the facial tumour disease is triggered. “But, the theory needs to be fully tested,” Dr Church says. “It might work or it might not.” The synchrotron’s infra-red beamline combined with a microscope and spectrometer – which detects how different materials absorb and reflect the radiation – can be used to determine if the composition of hair differs between diseased animals and healthy ones.

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