They are also looking at the life histories of the tubifex worms to more fully determine their role as a whirling disease host. Canada has a worm similar to tubifex tubifex but it does not operate as a host to the WD parasite. Scientists do not know why. Research in Patagonia, Argentina has not turned up any tubifex worms. Thus so far no host for the parasite has been found and no incidence of WD has been discovered there.
More research is needed, say the scientists.
Tubifex worms live in organically enriched habitats. They increase in density as water temperatures increase, up to a point, then they release fewer and fewer WD spores as water temperatures rise. The WD lifecycle is 200 days. Whirling disease spores can live in mud outside the worm host for over 20 years. The spore grappling hook, released by the worm, drifts in the water column for 10 days.