About Whirling Disease
Whirling disease is caused by the Myxobolus cerebralis parasite effecting fish like salmon, trout and other similar species. The disease usually causes neurological damage to young fish causing the effected fish to "whirl" in a cork screw pattern. This makes feeding difficult, makes it easy for predators to eat the fish and thus their survival rates are greatly reduced. The diseases causes significant damage to the fishing industry, some estimates show that damage is in the 100s of millions dollars per year in lost revenue.
When infected fish dies millions of whirling disease spores get released into to the water, where it then infects other fish. Whirling disease is very resistant to damage it can withstand extreme temperatures, and can usually survive for at least 20 years in the water. Whirling disease is common in 22 states including New Jersey, New York, Ohio, just to name a few. It's also found in numerous European countries and New Zealand.
Fortunately the parasite doesn't effect humans, though care needs to be taken to prevent spread of the disease from one fishing area to another. Best way is to make sure all your fishing equipment is cleaned thoroughly after each fishing session.