02-07-1977 Planning Packet - Laserfiche WebLink

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W^m . •- . .. . ■ .. *\ZnfomatioB LaafLtt No* 8 MINNESOTA DEPARTMENT OF NATURAL RESOURCES mVIRONHENT SECTION DIVISKRI or FISH AND WIlJ>liIIS f CONTROL OP SWIMMERS* ITCH AND liTiCHBS awimners* Itch L ■? ' .' Swiaiffl«r^ (schistosome dermatitis) is a temporal^ but annoying skin infection 1 t)|^ may be acqun'^d~By bathe^^^ lakes, usually in'June euid July* i^e causative J oreaHrs?ir ts u liny puraMte that lives part of its life in snails and matures in aquatic birds and maiasaJs,"'usually Waterfowl* Humans are not the normal host and the tinyT^eo"Swimming"~pairasiies (schistosome cercariae) die when they enter the human skin* The ^eseffev of this Toreign body in the skin causes severe itching at the site of pene tration somewhat siMl^ to a mosquito bits* A heavy infection may produce a rash sometimes confused with ivy poisoning* nny such skin condition should be seen by a physician Thestory of the organisms causing swimmers' itch is quite complicated adult stage is e tiny f]uke (trematode)^hnt lives in the blood vessels of aquatic bird) and mammals, often wild ducks* When the flukes are mature they mate and the females lay eggs in the smilTerT^intestinnl veins of the host animal. From here the eggs migrate r into the intestine from which they leave the animal in the droppings* These eggs hatch into tiny free-swimming animals (miracidia) which burrow into certain kinds of snails* Four species of snails h.ve been found to carry swimmers* itch in Minnesota* In the snail the organism further develops and multiplies, finally emerging in warm weather as minute fork-tailed free-swimming animals (cercariae) that are barely visible to the naked eye. Often many thousands of the cercariae are released from an infected snail each day for a period of a week or more. On release from the snail they swim and drift about seeking r. suitable bird or mammal host* Accidental penetration of skin of bathers •’t this time results in swimmers* itch. I a .1 Because the causative organisms are harbored by snails it is usually possible to control or alleviate swimmers* itch oubreaks by killing the snails along a beach area with copper sulphate (blue vitriol) at the rate of 3 pounds per liPOO square feet* Large cfysfalsof copper sulphate may be scattered over the shallow water area harboring snails or placed in a burlap bag and towed about the area to be treated until dissolved* For best resultc treatment should extend from the water*s edge outward to the drop-off or to the outer edge of heavy weed growth. However, treatment to a depth of 4 feet has often been satisfactory. Where possible, treated areas should be continuous for 500 to 500 feet along the shore or extend 100 feet on either side of the bathing area to reduce the possibility of drift of infective organisms from untreated areas. Application of copper sulphate should be made from the shoreline outward to repel any small fish that might be in the area and v.hich might be killed by the high concentrations used. oince th»* concentration of copper sulphate used is quite high, it is recommended that water in treated areas not be used for 4S hours after treatment* oome control of swimmers* itch may be accomplished by keeping beaches clean of masser of weeds and other debris that provide protection for snails* A permit is required for application of copper sulphate (or any other chemical) to public lakes and streams. Application for such a permit should be made to the section of T3chnical Services, Division of Game and Fish, Department of Natural Re sources, 39C' Centennial Building, dt* Paul, Minnesota, 531S5. m »1I1^> 1 '.i OFFICE PHONE • 4744167 January 7, TO WHOM IT RE: Swlmmc I treated Donald 0*R< swimners ll The above i Derma Cort Sincerely, MilCoh H. MHS:ckg \ \ \: