Prevalence and Speciation of Lungworms in Maine Moose

The moose is a large cervid ruminant found throughout the northern United States, Europe, and Canada. In recent years, moose populations have been declining within some regions of the northern United States. A study done in 2012 by the University of Maine Animal Health Laboratory suggested that a novel lungworm species of the genus Dictyocaulus may contribute to moose mortality in Maine. Lungworms weaken the immune system of the host and cause parasitic bronchitis. The current 2013 study analyzed 90 sets of moose lungs collected during the legal moose-hunting season. Of these, 28 showed lungworm infections. 10 infections were characterized as heavy with over 50 worms. These heavy infections all showed ”checkerboard” pathology on lung surfaces distal to bronchial tubules colonized by lungworms. Only 1 infection containing less than 50 worms showed this pattern. This suggests that a heavy lungworm burden causes significant lung pathology in Maine moose. Preliminary morphologic analyses showed that Maine moose are probably only infected by one genus of lungworm at a given time; most appeared consistent with Dictyocaulus morphology. Further exploration of the ITS2 gene sequences from lungworms of Maine moose sampled in 2013 was also consistent with previously reported Dictyocaulus ITS2 sequences.