CWD Found in VA

Antler333 said:

That being said, CWD can be conquered by surpressing or eliminating the agent prior to nervous system infection, hence this is a window to achieve a "CURE". Now when I said the antibiotics surpress the disease, I was NOT talking about secondary symptoms from complications, like pneumonia. I was talking surpression of the TSE agent specifcally. Review Prusiners work on Doxicycline and it affect on bad prion reproduction. Tetracycline derivitives SEEM to slow or stop PrP propagation. Why is that? If certain antibiotics are administed prior to classic disease characteristics, will it stop or slow the disease from reaching and multiplying in lymph and nervous tissue? My inquiring mind wants to know.



Are some animals immune? Although the Ft Collins pens have had 100% fatality from CWD, that is not the norm for the disease. IN the wild, Either its not very transmittable (a high treshold for infection) or there is some form of immunity. Elk MM and LL's are suggestive of different levels of susepceptability, correct? Possiblity due to immune system variation, correct? If the genotype can affect infection rates, is that due to immune system response? IF so, then perhaps an immunity CAN BE attained thru some sort of artifical process, not much different than a vaccine-created immunity.



Lastly, addressing the live animal test. Current tests on rectal lymph, throat lymph are late stage disease indicators,and are not at all suitable for "clean herd" testing. No one should be using these tests as signs of a clean wild or captive herd. They just are not accurate for early disease.

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Hi Antler333,

Thanks for this post, you made some great points. Prusiner did indeed do some interesting research on doxycycline although it wasn't specific to CWD and the research on tetracycline was also not done on CWD-specific prions (which does beg the question- why haven't we done this with CWD if it looked promising?). I would also like to know if antibiotics could slow or stop the disease progression- what an easy fix that would be and we could all move on to other things.



As for immunity, yes, there is some possibility that immunity could be attained through an artificial process. We actually tested a vaccine for CWD that had shown promise in mice, it didn't work as we had hoped in deer but people are still investigating that possibility. Also, it depends on what you mean by "not very transmissible", Rocky Mountain National Park reported an 11% infection rate in the elk that they collared last year which is a fairly high infection rate for such a slow-moving disease (though that population is admittedly overcrowded which is unquestionably a contributing factor).



The tests available right now are for late-stage disease but could be used in conjunction with the current post-mortem testing in order to remove positive (and possibly infective) animals from a herd so that the amount of infectious material that the animal would contribute to a given area could be limited. I do agree that the tests are not suitable for declaring a herd "clean", but they could be used as a non-lethal monitoring tool. They could also be used to detect and treat positive animals- if a treatment is ever found.

Rocky Mountain National Park reported an 11% infection rate in the elk that they collared last year which is a fairly high infection rate for such a slow-moving disease (though that population is admittedly overcrowded which is unquestionably a contributing factor).

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Truby, What is the prediction now for the Rocky Mountain Elk herd? Seems with the wolves and the CWD it will hardly stand a chance of surviving. According to the science, it should be down to less than 1/2 what it used to be by now. How is it doing? I wander how it got so overpopulated in the first place? CWD must have just popped up out of no-where! Otherwise with that infection rate and always being fatal, it should have wiped out the population by now.

TrubyUSDA said:

Hi Antler333,

Thanks for this post, you made some great points. Prusiner did indeed do some interesting research on doxycycline although it wasn't specific to CWD and the research on tetracycline was also not done on CWD-specific prions (which does beg the question- why haven't we done this with CWD if it looked promising?).

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Seems to me, this is basic homework which should have been done years ago. While it looks promising, the implications of this "antibiotic" effect are potentially huge. Whether its variant scrapie (as was tested), CWD or whatever, Why would an antibiotic cause bad Prion production to slow or cease. Prusiner had a weak argument for a chemical effect, but the 800# gorilla is that a tetracycline deritive (being a strong bacteria-stat, i.e it prevents bacteria from reproducing) is supressing a bacterialogical agent.

TrubyUSDA said:

Also, it depends on what you mean by "not very transmissible", Rocky Mountain National Park reported an 11% infection rate in the elk that they collared last year which is a fairly high infection rate for such a slow-moving disease (though that population is admittedly overcrowded which is unquestionably a contributing factor).

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the Rocky Mtn Natl elk herd is effectively an unfenced captive herd that is trapped between a high mtn divide and human civilization of the CO Front Range. They have habituated to humans quite well and are undoubtedly fed by local residents of Estes Park etc. NOw, Could an early exposure to weak CWD create an immunity (see my prior paragraph), or is it really always fatal. This perhaps could explain Sams query. Why is the herd still viable? perhaps it is developing a progressive immunity.



A more perplexing problem is the apparent infection rate on Muleys in the Front RAnge. Way high, approaching, what, a sampled 30%, yet the population is not collapsing. At least I dont think so. IS there a sampling bias? (the optimist?) Or perhaps the epicenter of the disease is Ft Collins and this rate is what can be expected 4o years from now in the sparsely infected areas of the country that allow the disease to progress. (the pessimist). A reasonable explaination for the continuing viability of a herd is that Muleys can be quite prolific. Having say three sets of twins before the disease wastes them away. That can explain a high infection rate AND an expanding herd.

TrubyUSDA said:

The tests available right now are for late-stage disease but could be used in conjunction with the current post-mortem testing in order to remove positive (and possibly infective) animals from a herd so that the amount of infectious material that the animal would contribute to a given area could be limited. I do agree that the tests are not suitable for declaring a herd "clean", but they could be used as a non-lethal monitoring tool. They could also be used to detect and treat positive animals- if a treatment is ever found.

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Hmmm, to that I agree,and offer that if a treatment is found; chances are the testing methods for this disease will be a whole lot better, and hence these are simply interim tests that will be replaced quickly (I hope).



TRUBY, Now to a new offshoot: Ohio State's Dr MA's recent publication of figuring out how to create misfolded bad prions that can cause a TSR-like disease. Have you read this? If so any comments?