Psychosocial impacts of a mouse plague and ongoing psychological stress.

In 2020-21, parts of eastern Australia experienced a severe mouse plague, estimated to have caused up to AUD$1 billion worth of damage. Yet, the mental health impacts of such a pest plague are not empirically known. The present study sought to quantify and model the psychosocial impacts of the 2021 mouse plague and measure ongoing psychological stress two years post-plague, to provide insights into social impacts and mental wellbeing during a significant biosecurity incursion. An online survey (N = 1,691) measured key psychosocial impact metrics included psychological traits, emotional states (depression, disgust, embarrassment), perceptions of social impacts (response costs, attitudes), support (social, government), and perceived threat of future plague. A partially mediated path model accounted for 74% of variability observed in perceived severity of impacts and ongoing psychological stress. Severity of impacts was predominantly influenced by perceived response costs, negative mood states (i.e. depression) and disgust elicited by the odour of mice. The most influential direct predictors of ongoing psychological stress were depressive symptoms at the time of the plague, and concerns that a future mouse plague would be dangerous or catastrophic to oneself. This study provides empirical insights into both acute social impacts during a significant pest incursion, as well as ongoing psychological stress. Social impacts are rarely measured or modelled; yet these factors are critically important in understanding the effect of severe pest incursions on communities whose livelihoods often depend on the agricultural sector.