Just a little FYI. The first confirmed case of CWD was not documented east of the Mississippi River until February of 2002 in three WILD whitetail deer. It was first recognized in Colorado in the early 80's but is suspected to have been around much longer than that. CWD prion protein can be detected in several parts of an infected animal. The best test result generally comes from the medulla at the level of the obex (brain tissue near the area where the spine connects to the skull), and retropharyngeal lymph node(throat area). It can also be found in the palatine tonsil, rectal anal associated lymphoid tissue and on occasion the retina of the eye. If any one is ever interested in learning how to sample their deer I will be glad to show you how it is done and where to send your samples to be tested. The rectal anal test is proving to be a way of surveying live captive animals that are believed to have been exposed. It is not as sensitive as the other test areas but improvements can grow in leap and bounds in the medical field and it will hopefully be a very valuable tool in the near future.
Now for the study I promised..................
Source: WY Fish and Game Dept.
Oct 15, 2008 Cheyenne WY - A long term study looking at the effects of CWD on elk populations suggests the always fatal disease may not cause precipitous declines in those populations
Researchers at the WYG&F Tom Thorne/Beth Williams Wildlife Research Center at Sybille have been looking at the long term effects of CWD on the elk population since 2002. "Though the study is not complete, there has been significant public interest in the study and what it might tell us about how CWD could affect overall elk populations, Especially those that are artificially concentrated on WY winter feed grounds," Said Eric Kezler, WGFD's Public Information Officer. "We know that CWD is always fatal to individual animals, but we also know animals may be infected for five years or more before they succumb to the disease, so they have a chance to reproduce multiple times. There has never been any research to look at how these factors might affect overall elk population trends in the presence of the disease. Our researchers did some preliminary estimates on the data we have so far to help give the public at least some initial ideas about what this study is telling us."
In, 2002 40 elk calves were captured in the National Elk Refuge and brought to Sybille for additional brucellosis research. Because of new federal regulations restricting research on brucellosis at the time, researchers instead decided to use the elk for a long term CWD research project.
CWD has existed at Sybille for almost 30 years and most, if not all, elk and deer housed here eventually contract CWD, either from the environment or other infected animals. CWD affects elk in the wild differently, and experts do not yet understand why some contract CWD before others, and why some do not at all. The study was designed to allow the elk to live at Sybille until they died; document each animals age, cause of death, and other data; and then develop models to help predict how elk population might rise or fall as a result.
"We assume that the CWD mortality rates observed at Sybille would represent the most extreme exposure to the CWD infectious prion, because the elk would be exposed continuously throughout their lives," said Terry Kreeger, Veterinary Services Supervisor for the WGFD. "Thus, this research would be used to design a model to predict the effects of CWD on wild elk populations representing a worst case scenario."
31 of the 40 original elk have died so far, all from CWD. But most of the elk had one or more calves (not all were allowed to be bred every year). Researchers have used this data to estimate any future changes in this elk population. " Accounting for calf production and recruitment and using simple life-table analysis, we estimate that there would have been a 47% increase in this population," said Kreeger. "That is 59 elk out of the original population of 40.
Kreeger warns that these data are preliminary and that it would be speculative at this point to extrapolate these data to any wild elk populations. Once all of the elk in the original study population has died, researchers will use data from wild elk to account for additional factors such as predation mortality, hunting mortality, production and recruitment to model what effects CWD would have in free ranging population using state or federal feed grounds, where elk are concentrated in winter.
According to WFGD assistant Wildlife Chief Scott Talbott: " Based on these preliminary data and our life table analysis, in the presence of CWD it appears the elk in this study would maintain a stable or increasing population."
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Topic: Re: CWD STUDY (Read 1288 times)
