Coccidioidal structures obtained from a naturally infected Carollia perspicillata bat (upper images) and experimentally infected mice (lower images). A) Macroscopic aspect of Coccidioides posadasii culture recovered from homogenate of bat lungs. B) Microscopic view of C. posadasii culture from bat lungs showing hyaline hyphae with arthroconidia and disjunctor cells (lactophenol cotton blue staining). C) Mature spherule filled with endospores in lung tissue (10% KOH) of bat. D) Bursting spherule with endospores in mouse lung tissue (10% KOH). E) Histopathologic features of mouse lungs revealing parasitic coccidioidal forms by periodic acid-Schiff staining. F) Coccidioidal forms on mouse lungs shown by Grocott-Gomori methenamine-silver staining. Scale bars = 20 μm.