SUSCEPTIBILITY OF BIGHORN SHEEP (OVIS-CANADENSIS) TO EXPERIMENTALLY-INDUCED FASCIOLOIDES MAGNA INFECTIONS

Three captive Rocky Mountain bighorn sheep (Ovis canadensis canadensis ), consisting of a female lamb, a yearling ram, and a 2 1/2-yr-old cas trated ram were inoculated orally with 50 (n = 1) or 100 (n = 2) metac ercariae of Fascioloides magna in November 1991. All three sheep died from fluke infection on postinoculation days 104, 140, and 197, respec tively. Numbers of F. magna recovered were 3 (3%), 18 (36%), and 21 (2 1%). All flukes were immature and were recovered from liver (n = 36), lungs (n = 2), or peritoneal spaces (n = 4). Two white-tailed deer (Od ocoileus virginianus), each were inoculated orally with 100 metacercar iae at the same time as the bighorn sheep. Eggs of F. magna were detec ted in the feces of the deer on postinoculation days 199 and 211, resp ectively. Both deer remained healthy for the year-long experiment. Thu s, bighorn sheep are susceptible to infection with F. magna and are li kely to die within approximately 6 months of exposure.