How it happens
The life cycle of the parasite causing whirling disease is complex,one. Once established in the skull of an adult fish, Myxobolus cerebralis, which is only about 10 microns, or .01 millimeters in size, is released into the water after the fish dies and decomposes. These microscopic parasites are then devoured by tubifex worms that live in the mud of freshwater streams and lakes.
The worms act as a second host for the parasite, which metamorphoses into these 300-micron monsters then known as triactinomyxon, or “TAMs,” the parasites remain in the mud-dwelling worms until they are excreted into the lower water column. Nearby trout redds are particularly vulnerable to the parasite, which can attach to the skins and shoot spores into the juvenile trout, penetrating their skin and beginning the cycle once again.
There is no treatment for whirling disease at this time. The best way is to inspect and just clean all your equipment with fresh water ie: hose it down well (especially remove mud and sediment) then allow for a minimum of 24 to dry (a bleach solution is not an answer). In my opinion banning felt is just a knee jerk attitude. There are too many other items like nets,, waders, laces, fly vests and all your other items even damp flies. The disease is transmitted through spores.
Equipment used for swimming, paddling, boating, water pumping, life jackets, or through infected fish (alive or dead) and fish parts are more likely to spread spores. It has been detected in all the western states and many northeastern watersheds.
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