Parelaphostrongylus andersoni (Nematoda: Protostrongylidae) and P. odocoilei in two cervid definitive hosts.

Infectivity (as percentage of initial dose), location, orientation, and productivity (as maximum weekly larval output) of adult Parelaphostrongylus andersoni Prestwood, 1972 and P. odocoilei (Hobmaier and Hobmaier, 1934) were compared in white-tailed deer (Odocoileus virginianus) (WTD) and mule deer (Odocoileus hemionus) (MD). Fourteen WTD and 10 MD were exposed to third-stage larvae of P. andersoni or P. odocoilei. Infectivity was 20% and 31%, respectively, in 7 WTD and 4 MD exposed to P. andersoni and 45% in 6 MD exposed to P. odocoilei. No nematodes were recovered from 7 WTD exposed to P. odocoilei. Nematodes were usually found in pairs, although the sex ratio was 3 females: 2 males in all deer. Most adults (greater than 90%) were located in connective tissue within skeletal muscles of the host. Distribution among muscles varied with total number recovered and, perhaps, time after exposure. Productivity was 1,834 larvae/gram and 2,630 larvae/gram, respectively, in 8 WTD and 3 MD exposed to P. andersoni and 0.9 larvae/gram and 15,103 larvae/gram, respectively, in 7 WTD and 5 MD exposed to P. odocoilei. The data were similar for P. andersoni infections in the 2 deer species but markedly different for P. odocoilei in these hosts. These results represent the first experimental demonstration of infection of mule deer with P. andersoni, and illustrate its potential occurrence in these hosts in wild populations.