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Iain
Moderator
United Kingdom
745 Posts |
 Posted - 06 Jul 2009 : 07:48:59
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I took the time over the weekend to read the article in the latest edition of 'Pest' magazine on the testing of rats' tails for resistance mutations. I found it a useful introduction to a very complex subject.
But I had one problem with it.
The suggestion was that a single rat's tail can give you the information you need on the resistance status of a population of rats.
I'm sorry, but it can't.
Not wishing to delve into the weird and wonderful world of statistical analysis, all I will say is that a single sample cannot give you the information you need to enable you to plan a strategy to deal with a possible resistant population.
You may be lucky and that one individual may have a mutated gene present - but that cannot tell you the likely extent of the problem. Is one in ten rats affected? One in five? One in a hundred? You simply have no way of telling from a single sample.
And what do you do if it comes back a negative?
I would suggest that the minimum sample size should be 10 tails. And unless you can negotiate a 'bulk discount', that will be a significant investment.
And what if you do find out that your sample was, for example, 'heterzygous for the L120Q gene' - what then?
Fortunately the boffins on the Rodenticide Resistance Action Group (RRAG) are putting together a 'crib sheet' on suggestions as to what to do if you happen to have one of the (8 and counting) mutant genes linked to anticoagulant resistance in the UK. That should be available within the next couple of months.
It is great that we have this technology available to us, but it will only be as good as interpretation of the results allows. And then, how you turn that interpretation into practical action.
There will be few easy answers with this problem, though one thing you can be certain of - it will be a growing one. |
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The Spotlight Kid
Moderator
1461 Posts |
Posted - 06 Jul 2009 : 08:05:19
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Come on Iain, talking about rat tails when I'm trying to eat my breakfast? |
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Tomo
Senior Member
United Kingdom
239 Posts |
Posted - 24 Jul 2009 : 08:56:43
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I think better control of who are allowed to use rodenticids would be of better use but we�ve been through this before.
If farms were only allowed to use competent fully trained pest control professional maybe resistance would be less of an issue.
Also using Romax CP would be or could be another step in the right direction?
Regard's Tomo |
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Jonathan Peck
Senior Member
United Kingdom
242 Posts |
Posted - 24 Jul 2009 : 11:28:24
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Wayne
Using coumatetralyl in any form will not give successful control of resistant rats and could increase the resistance problem.
Best wishes
Jonathan
Best wishes
Jonathan Peck
Killgerm Group |
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Iain
Moderator
United Kingdom
745 Posts |
Posted - 24 Jul 2009 : 13:14:19
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Jonathan,
There's 'resistant rats' and 'resistant rats' - it all depends which mutation you're talking about.
I do hope you're not suggesting that rats resistant to warfarin couldn't be controlled by a very palatable bait based on coumatetralyl?
I would not suggest that rats resistant to difenacoum or bromadialone could be controlled, of course, but I do feel you need to be a little more specific.
There are at least 8 mutations to the VKORC1 gene in the UK, each with different responses to anticoagulant rodenticides.
Regards,
Iain |
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Tomo
Senior Member
United Kingdom
239 Posts |
Posted - 24 Jul 2009 : 14:19:04
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Now there is something I did not realise I thought that if a rat problem seemed resistant to one active it was good practice to change to another.
So if resistant to difenacoum change to bromadiolone etc, therefore I thought coumatetralyl would be ideal to mop up resistant strains of either.
But as many things in life it now apears to be not that simple.
I did understand that rats resistant to chlorophacinone were also resistant to warfarin and vice-verca.
Have I got it right that coumatetralyl presents less risk (of secondary poisoning) to wildlife?
Regard's Tomo |
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Jonathan Peck
Senior Member
United Kingdom
242 Posts |
Posted - 24 Jul 2009 : 18:22:45
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Iain
The resistance problem in the UK is not because of resistance to warfarin, it is because of resistance to bromadialone and difenacoum. This is because very little warfarin is used in the UK for rat control compared to the second generation anti-coagulants.
As we both know, using coumatetralyl against difenacoum or bromalialone resistant rats is not the answer. This is the crux of the matter because resistance to these two second generation actives appears to be spreading and unless we are allowed to use brodifacoum and flocoumafen in and around buildings we will soon not be able to control rats in a number of areas in the UK.
That is why the Huddersfield Rodenticide Resistance project has been set up under the management of a steering committee led by Rob Smith with support from Alan Buckle, Adrian Meyer and John Charlton. The project is being funded by BASF, Bayer, Bell, BPCA, Killgerm, PelGar and Syngenta. The intention of the project is to establish good scientifically based evidence on the extent of resistance to second generation anti-coagulants in the UK. HSE are supporting the project by appointing a liaison scientist with the steering group so as to ensure that the protocols, etc., meet the HSE requirements. The DNA testing will be carried out at Huddersfield University.
This is separate from the tail testing service which Huddersfield University already operates. The project steering committee will decide which areas they want to survey and arrange for local nominated pest controllers to collect some ten tails per site. It is very important that the tails are collected and sent in a proper audited manner and so the steering committee will not be able to process just any tails sent in by pest controllers.
The project will start next month and run for some 12 - 15 months.
Best wishes
Jonathan |
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Iain
Moderator
United Kingdom
745 Posts |
Posted - 25 Jul 2009 : 09:52:28
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Jonathan,
I did wonder when this initiative was going to be announced. My congratulations to all those involved, as it will surely produce invaluable information.
I presume therefore that wherever the relevant mutations are found the recommendation will be made to cease the use of bromadialone and difenacoum and an application be made to the HSE for the limited, emergency use of either brodifacoum or flocoumafen around the infested buildings.
Once the ACP start to receive large numbers of such applications they will hopefully wake up to the fact that we have a problem in parts of the UK, so will perhaps see that there is more to be considered than simply the environmental case that they are aware of at present.
So perhaps you should have said:
"Using difenacoum, bromadiolone (and coumatetralyl) in any form will not give successful control of resistant rats and could increase the resistance problem."
Until then, pest controllers in day to day rat control, with a wage to earn, should indeed follow 'Tomo's' suggestion ..."that if a rat problem seemed resistant to one active it was good practice to change to another". Certainly coumatetralyl can be used in that situation, alongside difenacoum and bromadiolone.
Should a resistant mutation thenbe found in that population, appropriate measures should then be taken.
These would include stopping the use of anticoagulants out doors, trying gassing, trapping, shooting and habitat modification where appropriate and if these are not suitable, to apply for the emergency use of brodifacoum or flocoumafen, via one of the manufacturers concerned.
Regards,
Iain.
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andyb
Senior Member
United Kingdom
466 Posts |
Posted - 25 Jul 2009 : 14:59:14
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Is it me or do "Inside rodents" not find Brodiacoum or flocoumafen as attractive as the other second gen baits? We don't keep either any more due to the lack of up take in sewers etc, The new Romax CP Rat Coumatetralyl formulation is very palatable to rats as is the Ratimore tray, we are in a lucky situation where we don't have any known resistance in our area and can use Romax CP outside in boxes and rat hole baiting, Ratimore is used inside due to the plastic tray preventing surface contact with the rodenticide even so we rotate the active ingredients we use inside regularly, we have seriously taken the pasta type baits on board, we now get very little spillage and a much reduced amount of mollusc spoiled bait.
How substantial is the resistance problem in the UK, where are the hot spots, how quickly are the bait tolerant rats spreading, has the problem been caused by evolving rats or poor baiting techniques over the years?
ANDY B
www.abcomplete.co.uk |
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Rat Tail Testing
