Making the most of mortalities: Novel host-parasite records in a sandy inland mouse (Pseudomys hermannsburgensis)

Abstract

From 2020 to 2022, systematic investigation of wildlife mortalities on Dirk Hartog Island, Western Australia was initiated to inform wildlife disease risk analyses for translocation purposes. As part of this monitoring, in November 2020, a sandy inland mouse (Pseudomys hermannsburgensis) was found deceased with multiple comorbidities. Gross necropsy, histopathology and ancillary molecular testing identified several novel host-parasite associations. Sarcoptes scabiei was identified via molecular methods in association with consistent cutaneous pathology, representing the first known detection of this parasite in an Australian native rodent. A putative novel virus belonging to the subfamily Gammaherpesvirinae was also identified, representing the first known detection of a herpesvirus (Orthoherpesviridae) from this species, although it was not clearly associated with other disease processes. A heavy burden of the cestode Hymenolepis microstoma was also present in the gastrointestinal tract, representing a new host record for this species, whilst a pancreatic adenocarcinoma was also found. Beyond the novelty of these host records, these findings contribute to important health baselines of rodent populations on Dirk Hartog Island and highlight the value of investigating mortalities and implementing health surveillance as part of ecological monitoring and wildlife translocation projects.