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. Covering raceways also could reduce the spread of whirling disease by birds and mammals, but human anglers also can take many steps to reduce its spread. Moving live infected fish, or parts of dead infected fish, is probably the biggest source of contamination.