In 2006 a deadly fungus, Pseudogymascus destructans (Pd), made its way to a cave in New York and has since infected 12 species of North American bat with White nose syndrome (WNS). One of the most affected species is the little brown bat (Myotis lucifugus). Little brown bat maternity colonies infected with WNS have experienced over 90% population loss, and there are colonies in western North America that haven’t been exposed to Pd yet and face the same devastating population losses in the near future. The steady advancement of the WNS disease front into naive colonies has necessitated increased pathogen surveillance and investigation into little brown bats disease progression and colony recovery. As part of a greater project focused on crafting a predictive model of colony recovery trajectories and non-invasive colony assessment tool, expression of cytokine biomarkers was measured and assessed on their ability to inform on individual disease severity and colony health. We assayed cytokine biomarker mRNA of the three pro-inflammatory cytokines known to be produced during Pd infection, IL-6, IL-17α, IL-1β, in minimally invasive little brown bat wing biopsies (n=81) and in non-invasive guano samples (n=638) from all female maternity colonies that have seen initial devastating population loss due to WNS and begun to recover, to varying degrees of success. Non-invasive guano collection could be a powerful tool for colony assessment and we investigated if cytokine biomarkers in guano could be indicative of individual or colony health. Expression of cytokine mRNA in wing biopsies was investigated as a pathologically relevant tissue experiencing direct fungal infection to assess its correlation to expression seen in guano and their ability to inform on host inflammatory status. All 81 wing biopsies had RNA successfully extracted and 631 of 638 guano samples had RNA successfully extracted. mRNA expression of cytokines in non-invasive guano samples was highly variable and nearly 200 samples had no target cytokine expression. mRNA expression in wing biopsies was also variable, however all biopsies had target cytokine expression. Wing cytokine expression had a limited ability to predict disease stage, IL-6 and IL-1 β expressions were significantly lower in mid WNS compared to individuals in the early stage of the disease (IL-6 p=0.030, IL-1 β p=0.042), while IL-6 was significantly higher at the post WNS timepoint compared to mid WNS (p=0.028). This result was not similar in the guano samples which had no significant differences between WNS disease stages. IL-17α expression in the wing had some significant differences when compared to colony growth rate, with higher expression from low to both medium and high growth rate (p=0.011, p=0.015). To evaluate the ability of cytokine mRNA expression to indicate inflammatory status we isolated dermal fibroblasts from wing biopsies and exposed them to inflammatory agent lipopolysaccharide and found no significant changes in cytokine mRNA expression between the control and inflamed conditions. These results have led us to believe that cytokine mRNA expression is not the best predictor of colony recovery. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Gerber et al. (Fri,) studied this question.