Mineral licks as a potential nidus for parasite transmission

Discrete landscape features can concentrate animals in time and space, leading to non-random interspecific encounters. These encounters have implications for predator-prey interactions, habitat selection, intraspecific competition, and transmission of parasites and other pathogens. The lifecycle of the parasitic nematode Parelaphostrongylus tenuis requires an intermediate host of a terrestrial gastropod. Natural hosts of P. tenuis are white-tailed deer, and an aberrant host of conservation concern is moose, which are susceptible to high levels of mortality as a naive host to the parasite. Intermediate hosts become infected when P. tenuis larvae are shed in deer feces, then consumed or enter the gastropod through the foot. Incidental (or perhaps intentional) ingestion of infected gastropod intermediate hosts by aberrant or dead-end hosts often results in mortality of that animal. We present photographic evidence depicting a potential mechanism for transmission from infected white-tailed deer to moose, heretofore not examined in the literature. We deployed remote cameras at mineral licks around Grand Portage Indian Reservation in northeastern Minnesota, USA. We observed white-tailed deer defecating at mineral lick sites and geophagous moose at the same sites. We hypothesize that mineral licks may act as a nidus for P. tenuis transmission between deer and moose in this system and call for further research into the potential role of mineral licks in parasite transmission.