Effect of Dermacentor albipictus (Acari:Ixodidae) on blood composition, weight gain and hair coat of moose, Alces alces.

The physiological effects of the winter tick, Dermacentor albipictus, on moose, Alces alces, were investigated. Blood composition, weight gain, food intake and change in the hair coat of moose calves, four infested with D. albipictus larvae, and eight uninfested, were monitored. Infested moose groomed extensively, apparently in response to feeding nymphal and adult ticks, and developed alopecia. Other clinical signs included: chronic weight loss, anemia, hypoalbuminemia, hypophosphatemia, and transient decreases in serum aspartate transaminase and calcium during the period of nymphal and adult female tick engorgement. Infested animals did not become anorexic. Two moose with severe hair loss had increases in gamma globulin shortly after the onset of female tick engorgement. Results suggest that alopecia is associated with tick resistance. Animals that groom and develop hair loss likely carry fewer ticks and therefore suffer less severely from blood loss.