Gastrointestinal nematodes of moose (Alces alces) in relation to supplementary feeding

Winter supplementary feeding of wildlife is controversial because it may promote parasite and disease transmission by host aggregation. We investigated the effect of winter supplemental feeding of Scandinavian moose (Alces alces) on gastrointestinal (GI) parasite infection in two counties of southern Norway by comparing fecal egg counts of moose using, and not using, feeding stations between January 2007 and March 2010. We identified three different GI nematodes based on egg morphology. All three were found in Hedmark county while in Telemark county we found only Trichuris sp. (prevalence 33%). Prevalence of Trichostrongylidae (65%) and Nematodirus sp. (26%) in Hedmark was not affected by feeding station use. However, the probability of infection varied significantly between years sampled (Trichostrongylidae) and age class (Nematodirus sp.). Fecal egg counts (FEC), a proxy for intensity of infection, of Trichostrongylidae were higher in the year when winter weather conditions were more challenging and prevalence was higher, and decreased with increasing body mass. Adult moose had higher FECs than did juvenile moose, and female juveniles had lower abundances than did male juveniles. Use of feeding stations did not affect probability of infection with any of the nematodes or intensity of infection with Trichostrongylidae. We discuss our findings in terms of parasite life histories and recommend that parasitologic surveillance be included in the monitoring of feeding programs.