Case report of mite infestation of the external ear in Carollia perspicillata: Histological features of the ear.

Bats host a diverse assemblage of ectoparasites that occupy specific anatomical microhabitats, yet the histological effects of these associations remain poorly documented. Here, we report a case of mite infestation of the external ear in the Neotropical bats species Carollia perspicillata and Carollia brevicauda, with a detailed histological characterisation of the auricle and inner ear of C. perspicillata. Bats were captured during biodiversity monitoring programmes in Antioquia, Colombia, and mites were collected and identified morphologically. Histological and histochemical analyses of ear tissues were conducted using haematoxylin and eosin, periodic acid-Schiff, and Masson's trichrome staining. Mites were identified as Spelaeorhynchus praecursor (Spelaeorhynchidae), occurring exclusively on the external ear with infestation frequencies of 6.6% for C. perspicillata and 5.8% for C. brevicauda. Histological examination of the auricle revealed a thin keratinised stratified squamous epithelium, abundant sebaceous glands, well-developed striated skeletal muscle, elastic cartilage, and prominent white adipose tissue at the auricular base. Only minimal focal leukocytic infiltrates were observed, with no evidence of severe pathological alterations associated with mite attachment. The inner ear displayed preserved cochlear architecture, with eosinophilic fibrillar and granular material in the scala vestibuli and scala tympani, interpreted as perilymphatic content or processing artefacts. This study provides baseline histological data on ear tissues in C. perspicillata and documents a localised mite-host association with limited tissue response, contributing to the understanding of bat ectoparasitism and ear morphology in Neotropical chiropterans.