Skip to main content
U.S. flag

An official website of the United States government

Countcolors, an R package for quantification of the fluorescence emitted by Pseudogymnoascus destructans lesions on the wing membranes of hibernating bats

Author(s):

Sarah E. Hooper
Hannah Weller

Year:

2020

Publication type:

Scientific Journal (JRNL)

Primary Station(s):

Northern Research Station

Source:

Journal of Wildlife Diseases. 56(4). 10 p.

Description

Pseudogymnoascus destructans colonizes the wing membrane of hibernating bats with the potential to form dense fungal hyphae aggregates within cupping erosions. These fungal cupping erosions emit a characteristic fluorescent orange-yellow color when the wing membrane is transilluminated with 385 nm UV light. The purpose of this study was to create and validate the R package, countcolors, for quantifying the distinct orange–yellow ultraviolet (UV) fluorescence in batwing membrane lesions caused by P. destructans. Validation of countcolors was completed by first quantifying the percent area of 20, 2.5 cm2 images. These generated images were of two known pixel colors ranging from 0% to 100% of the pixels. The countcolors package accurately measured the known proportion of a given color in each image. Next, 40, 2.5 cm2 sections of UV transilluminated photographs of little brown bat (Myotis lucifugus) wings were given to a single evaluator. The area of fluorescence was both manually measured and calculated using image analysis software and quantified with countcolors. There was good agreement between the two methods (Pearson's correlation=0.915); however, the manual use of imaging software showed a consistent negative bias. Reproducibility of the analysis methods was tested by providing the same images to naive evaluators who previously never used the software; no significant difference (P=0.099) was found among evaluators. Using the R package countcolors takes less time than does manually measuring the fluorescence in image analysis software, and our results showed that countcolors can improve the accuracy when quantifying the area of P. destructans infection in bat wing-membranes.

Citation

Hooper, Sarah E.; Weller, Hannah; Amelon, Sybill K. 2020. Countcolors, an R package for quantification of the fluorescence emitted by Pseudogymnoascus destructans lesions on the wing membranes of hibernating bats. Journal of Wildlife Diseases. 56(4). 10 p. https://doi.org/10.7589/2019-09-231.​

Cited

Publication Notes

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
https://www.fs.usda.gov/treesearch/pubs/61104