Susceptibility of mule deer (Odocoileus hemionus) and two species of North American molluscs to Elaphostrongylus cervi (Nematoda: Metastrongyloidea).

An experimental study was done to determine whether Elaphostrongylus cervi can be transmitted to common intermediate and definitive hosts indigenous to North America. First-stage larvae of E. cervi obtained from red deer (Cervus elaphus elaphus) in New Zealand developed to the infective third stage in snails (Triodopis multilineata) and slugs (Deroceros reticulatum). Two mule deer (Odocoileus hemionus) were inoculated orally with 102 or 406 third-stage larvae. One animal developed a patent infection on day 121 postinoculation (PI), and the other had numerous first-stage larvae in its lungs and colonic feces on 128 days PI when it was killed. A control red deer inoculated with 100 larvae began passing larvae on 119 days PI. Larval excretion was low and intermittent in the mule deer and during the first 4 wk of patency in the red deer. Both mule deer developed progressive neurological disease beginning on day 104 PI and had to be killed 4 or 7 wk later, respectively. The red deer remained clinically normal.