Bat cull 'will not stop WNS spreading'

[peter febb]

"We developed a model taking into account the complexity of the bat life history, looking at the roosts and the areas where there are large contacts between the bats," said co-author Thomas Hallam from the Department of Ecology and Evolutionary Biology at the University of Tennessee.

"Given the dispersal aspect of the problem and the complexity of hibernating bat ecology, it was a case that these things together certainly meant that culling would not work in the case of bats."

link:http://www.bbc.co.uk/news/science-environment-11878001

[wyandottecaver]

thats cause they are using too much math and not the real world. I have a hibernacula of 30,000 bats with WNS ready to disperse in the spring. Culling will never get them all, so *some* will get away (say 3000) and each have X percent chance (say 10% to make the math easier) to spread WNS at their contact points. .10 X 3000 or .10 X 30,000 the answer seems obvious. You don't stop WNS with that 1 culling...but you DO reduce its vector load. You then cull the new sites you find and so forth.

So yes, in that manner you never stop WNS...But you might go from 100 new infected hibernacula to 10 or even 1 in a given year.

".....Writing in Conservation Biology, they add that a cull would not work because the source of the fungal pathogen is believed to occur in the environment...."

Be nice to know where they got that. Per John Lovaas the original researcher who did the lab studies on environmental transmission says the results were contaminated and that NO ONE can yet get GD to grow in soil.

[John Lovaas]

".....Writing in Conservation Biology, they add that a cull would not work because the source of the fungal pathogen is believed to occur in the environment...."

Be nice to know where they got that. Per John Lovaas the original researcher who did the lab studies on environmental transmission says the results were contaminated and that NO ONE can yet get GD to grow in soil.

I was thinking about that quote in the article- and they would be correct, if, by 'environment', they are talking about the surfaces where the bats roost. The WI-NY/VT bat transfers, and research from Fort Drum, suggest that the fungus(I'll say spores) persist on the surfaces where the bats roosted. There would likely be less competition with, degradation by, other viruses/bacteria/fungi/mites than what the cave soil environment would offer.

Would a mite eat a spore? I don't know. It would be a tiny morsel, even for a mite.

You are right about the environmental transmission- researchers are currently batting 0 for 2 in infecting bats via aerosol means. The work to inoculate cave soils with spores in the lab- and to get mycelial growth- is just starting.

I'm starting to think about just how few places in the 'environment' there are for bats to come in contact with Gd mycelia or spores. One fact David Blehert mentioned at the December WI NRB meeting was that Gd spores survive for 60-90 days at 80F. Which would be a cold summer in TAG ;-) I'm waiting for the audio transcript of the meeting to find out where that info came from.

But that got me thinking about how well the spores(or mycelial fragments) can survive as a bat goes into 'summer mode'- but I do not know how much time cave bats spend in caves in the summer. Enough for a bat to carry spores into another hibernaculum, I suppose. How many of those spores would survive on the bat through the summer- especially in a bat house?

As to culling. When would you do it? The minute you detect a bat carrying Gd? with WNS? The next hibernation season after it is detected?

I can live with the idea of ensuring that infected bats do not exit an infected hibernaculum during the winter (possibly travelling to an adjacent uninfected hibernaculum). I still can't live with the idea of culling an entire colony.

My emotional, unscientific corollary would be the explanation I was given by a WIDNR attorney as their defense for excluding bats from a cave- you would have a cave that is WNS-free. He would be technically correct. It would also be a bat-free cave.

If you cull an infected colony, you would have a cave that is free of infected bats- but there will still be a cave that is capable of infecting bats.

[wyandottecaver]

I'd be curious about that. The WI to VT situation used sites that not only contained the roost surfaces, but also the organic (poo/carcasses?) residue from WNS bats. Thus do we have any data that points to roost surfaces alone? I can believe they could...I just dont know if we have really discriminated out "rock" cave environments from "poo" cave environments....?

I guess my view of culling is that once a site has WNS, we know most if not all those bats are apparently going to die. Whether they die this year before emergence, or next year after a summer of spreading WNS they are still dead. Until some evidence of immunity at a level capable of sustaining the population is seen, is it better to let those "dead bats walking" disperse WNS (I would argue faster, farther, and to more sites) or kill em all (or as many as we practically can) and reduce the number of "typhoid marys" wandering the landscape?

That 1 site may indeed remain an infection source, at least for some period. But caves dont move. Even if you missed the transient bats you would still be dealing with fewer total bats thus fewer total dispersal agents.

[BrianC]

I find the idea of culling bats curious. I also know that this fungus will mutate over a fairly short time. If slowing the spread occurs, the mutation will happen before the spread has found its way where it can go. A mutated form will possibly affect the resistant bats with a completely new strain, lowering the resilient population. As with most pathological infections, the quicker it runs its course, the quicker its immunities are possible.


It might be better to carry infected bats everywhere quickly to get this over quicker?

[John Lovaas]

I also know that this fungus will mutate over a fairly short time.

How so?

[BrianC]

I also know that this fungus will mutate over a fairly short time.

How so?

RIP Repeat induced point mutation. If not this exact sexual reproductive mutation, another mutation will occur. It will happen, so trying to cull bats could have extreme control issues. I guess the main point considered would be that really nothing we can do will either slow, or stop WNS.

[John Lovaas]

RIP Repeat induced point mutation. If not this exact sexual reproductive mutation, another mutation will occur.

Yes. I was just reading about it. How does this apply to Geomyces destructans? Bread mold is still bread mold, even if some if it's genes are mutated- it still has all the physical characteristics of bread mold, but its genome is ever so slightly changed.

How do you know that mutations will occur in Gd, and how that will change the characteristics of Gd?

jl

[BrianC]

RIP Repeat induced point mutation. If not this exact sexual reproductive mutation, another mutation will occur.

Yes. I was just reading about it. How does this apply to Geomyces destructans? Bread mold is still bread mold, even if some if it's genes are mutated- it still has all the physical characteristics of bread mold, but its genome is ever so slightly changed.

How do you know that mutations will occur in Gd, and how that will change the characteristics of Gd?

jl

Whatever mutation occurs,The bats will, or will not respond similarly. If some bats are able to resist one type fungal bacterial infection, they might not find resistance in another. Bacteriological mutations are much more dramatic if indeed we find this is the issue, and Gd is just opportunistic.

[BrianC]

Remember, we know very little about this fungus. We must anticipate the possibilities.

[wyandottecaver]

john,

anything is possible if you just post it on cavechat. Physics, biology, the laws of man and god...none of those apply here....didn't you know that?

I think the fact that the U.S. strain is apparently IDENTICAL to the European strain that has likely been around for decades, gives us a pretty good indication of its mutation probabilities.

[Batgirl]

anything is possible if you just post it on cavechat.