Evaluation of Virus-Free and Wild-Type Isolates of Using a Porcine Ear Model.

White-nose syndrome (WNS), responsible for the mass mortality of North American bats, lacks economically viable and practical models for infection, the causative agent of WNS. Not only are many susceptible North American insectivorous bats nearing extinction and, thus, scarce for experimental studies, but they are difficult to care for and maintain in captivity because of their specialized habitats and diets. In this study, we explored porcine ears as a potential substrate for studying infection development and the dynamics of growth in the laboratory. Porcine ear skin shares many tissue-level similarities with bat skin and is a readily available resource. We found the porcine ear model provided a substrate faithfully mimicking external colony morphology and internal histology similar to what is seen with infections in bat wing membranes. This model provided a major advance by distinguishing virulence attributes between a wild-type strain harboring a partitivirus common to all North American strains of the fungus and an isogenic virus-cured strain. ImageJ analysis showed that the cured strain was reduced significantly in ability to produce hyphal cover and showed less spore production on porcine skin. Taken together, these results strengthen our previous finding that the partitivirus infection has a role in WNS and provides a valuable model host tool in understanding virulence factors for therapeutic application. This work describes an important insight into the role of partitivirus in fungal biology and provides a model system for studying white-nose syndrome in bats, which has decimated North American populations.