Evidence for Multiple Transmission Routes for Pseudorabies in Wild Hogs

Pseudorabies is a herpes viral infection that constantly threatens the commercial pig industry as it decreases birthrates and increases piglet mortality. While transmission routes in domestic pigs are known, disease dynamics in the reservoir of wild hog populations is not well understood. We formulate a model, which is discrete in space and time, for pseudorabies in a wild hog population in Great Smoky Mountains National Park and consider four potential transmission routes: density-dependent direct transmission, increased transmission during mating season, transmission from mothers to piglets during nursing, and carriers becoming reinfected due to stress. We estimate parameters from available data using all combinations of transmission routes and analyze results in order to provide evidence for various transmission routes that may exist in the population. Results provide evidence that all transmission routes may exist in the population with the strongest evidence for carriers becoming reinfected due to stress. The use of a spatial–temporal discrete model connected to data about the habitat and involving disease spread is a novel feature of this work.