Weil's disease

[Jim Gibbinson]

Like most anglers I frequently use lake/river water to wet my groundbait - and something I'm conscious of is the risk of Weil's disease (Leptospirosis). According to The Leptospirosis Information Centre website (http://www.leptospirosis.org) leptospirosis bacterium cannot survive in salt water. Does anyone have the medical knowledge to know how much salt would need to be added to lake/river water (gm or tsp salt per 100ml lake/river water) to render it safe? Failing that, does anyone know how much salt (gm or tsp) is in 100ml of average sea water (sea water is completely safe in leptospirosis terms)?

[Newt]

From

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[url="http://www.gracepublication.org/java/3(3)04.htm"]http://www.gracepublication.org/java/3(3)04.htm[/url]

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quote:

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Abstract: The survival time of Leptospira interrogans serovar hardjo in water, soil and cattle urine in Malaysia were evaluated. The survival time of serovar hardjo in the six types of water samples varied considerably. The longest survival time recorded was for 264 hours (11 days) in river water with between pH 6.7 and pH 7.3 placed in shaded area. The shortest survival time was recorded in seawater pH 6.5 to pH 6.8, with dissolved solid salt content between 3.78% and 3.85%. The leptospires were killed almost immediately after inoculation into seawater. The survival time of serovar hardjo in the three types of soil with three different water content, kept under either direct sun or shaded area were variable. The minimum survival time was 2 hours and maximum was 144 hours (6 days). Serovar hardjo survived in undiluted urine for only 2 hours under direct sun and 6 hours under shaded area. The survival time of serovar hardjo was longer in urine diluted with distilled water compared to undiluted urine. In diluted urine under direct sun, serovar hardjo can survive for up to 48 hours (2 days), under shaded area for up to 72 hours (3 days) and in refrigerator (4 C) for 984 hours (41 days). Under experimental conditions serovar hardjo survived in water, soil and urine remained infective up to 1 to 7 days post inoculation. ....

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edit note: the parens in the URL make the forum software choke so I had to put it in code tags but if you copy/paste into your browser you will get the full article

[Jim Gibbinson]

Newt, thank you for that. How much salt would I need to add to a given quantity of freshwater to mirror the salinity of seawater? "Solid salt content between 3.78% and 3.85%" means nothing to me - does it refer to volume or weight? Or does it apply to a measure of salt content as compared with freshwater (with freshwater "scoring" 0%)? Sorry if I'm being obtuse, but but maths has never been my strong point...

[Newt]

35gm salt per 1000ml water will give you 3.5% salt solution assuming all the solids did dissolve.

[Socksy Squirrel]

It refers to % weight to volume w/v.

So the salt water varies between 37.8 and 38.5 g of salt per litre or six ounces per imperial gallon.

 

[ 22. March 2005, 04:15 PM: Message edited by: Socksy Squirrel ]

[Newt]

As a thought - salt (as long as you avoid the 'table salt' with iodine and some other chemicals added) is attractive to preds and probably isn't bothersome to other species.

 

If you used lake water and the right amounts of salt to mix up your bait, it should provide safety from Weils and probably not have any bad effects on your fishing. I'd suggest kosher salt as being your best source.

[A Worm OOE]

Newt

I am glad you made that last post. I had visions of Jim dumping salt into the local lakes to make them safe.

[Guest PhilB]

The "Fly Dressers Guild" published a list of precautions to take for anglers. The gist is; Cover any cuts with waterproof dressings and if you do get a cut whilst fishing apply an antiseptic and cover it up with a dressing. Wash before eating, don't rub your nose and mouth whilst fishing. The disease is carried by rats and spread via their urine so don't leave unwanted food or bait by the water which would give them a ready food supply. (Perhaps you could wet your groundbait with urine )

[Jim Gibbinson]

Thanks again Newt, thanks too to Socksy Squirrel. The maths is now within my capabilities!

 

Just to reassure A Worm on One End, I don't plan to turn my pits and reservoirs into inland seas by dumping vast quantities of salt in them! My intention is to use a container to mix up, say, 200ml of water with the appropriate amount of salt (7gm by my calculations), and use that to dampen my groundbait mix.

 

I've caught large numbers of tench, carp and bream on baits that are naturally salty (cockles and peeled prawns), so I'm confident that salt isn't a deterrent - indeed, I get the impression that the aforementioned species quite like salt (some of the groundbait additives I've used successfully have also been naturally salty).

 

Thanks again those who have responded to my query. Weil's disease is probably a low risk in the large waters where I fish, but it's comforting to know that I can reduce the risk of infection to virtually zero by using water to which salt has been added to mix my groundbait.

[Newt]

Jim - please share your results. I'm interested in how well salt works as an attractant in a variety of baits.

 

I know the for me, soft plastic lures with heavy salt content have the preds holding on to the lure a little longer than otherwise (so better chance of hooking) and I've been playing with adding salt to a variety of carp and catfish baits.

 

As noted though - avoid the table (iodized) variety. Sea salt is good. Kosher is less expensive where I live and just as good I think.

 

Another suggestion would be to pre-dissolve the salt at home and bring it to the swim in containers. If you use distilled water and heat it you should easily be able to dissolve the 7gm of salt in a very small amount of water.