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Updated: May 11, 2026
In Vivo Confocal Microscopy: A Standard Operating Procedure for the Detection of Demodex Mites at the Eyelid Margin
Published on: July 3, 2025
Five observations of a third morphologically distinct feline Demodex mite
Karen A Moriello1, Sandra Newbury, Howard Steinberg
1School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive West, Madison, WI 53706, USA. moriellk@svm.vetmed.wisc.edu
Background:
Feline demodicosis is caused by infestation with Demodex cati and/or Demodex gatoi. These two mites have distinctive morphological appearances.
Objectives:
To describe five observations of a morphologically distinct feline Demodex mite in 10 cats. All cats were in or adopted from an animal shelter.
Results:
A mite with blunted ends longer than D. gatoi but shorter than D. cati was observed in one or multiple cats from animal shelters. Mean mite size was 139 ± 4.5 μm (n = 41 mites). Similar features among the cases included a history of recent recovery or presence of concurrent illness at the time of diagnosis. Pruritus was variable. Hairs were easily epilated in large amounts, and mites were found on either skin scrapings or hair trichograms; mites were most commonly found on the proximal third of hairs examined via trichogram.
Clinical Importance:
Reports of this mite are uncommon but when present tend to be in cats with concurrent illnesses. Awareness of this mite morphology will hopefully provide other investigators with specimens for molecular testing to determine whether this is a third species or a variant of D. gatoi or D. cati.
