Whirling disease, Myxobolus cerebalis, is spread by microscopic spores found on the bottom of ponds, lakes and rivers. It cannot be contracted by humans and fish carrying the spores are safe to eat. In the life cycle of the disease, the spores are eaten by tubifex worms and develop into Triactinomyons while inside the worms. The Triactinomyons are released from the tubifex worms into the water, where they cling to the bodies of trout and burrow into the fish's nervous system. Another metamorphosis within the fish results in a mature spore attacking the cartilage right behind the fish's head.
Black tails are additional evidence of a whirling-disease infection.
Young rainbow and cutthroat trout, birth to nine months, are particularly vulnerable to whirling disease, although brown trout are relatively resistant to it. Brown trout are native to Europe and evolved with whirling disease. New Mexico has several alternatives for dealing with whirling disease. Seven Springs hatchery is scheduled for renovation, Sloane said, so the infestation should be controlled through that work. Renovating Lisboa Springs to eliminate the need to raise fish in Pecos River water could eliminate the problem there.