Morphological and Molecular Identification of Physaloptera praeputialis Infection and Description of Associated Gastric Lesions in the European Wildcat (Felis silvestris).

Physaloptera praeputialis is a common gastric spirurine of domestic and wild felids worldwide, but its pathological importance in European felids and the molecular characterisation of European isolates remain poorly documented. This study identifies P. praeputialis in European wildcats (Felis silvestris) from central Spain using morphological and molecular approaches and describes the associated gastric lesions. Thirty free-ranging wildcats were examined by necropsy, coproscopical analysis, and post-mortem inspection. Adult Physaloptera specimens were recovered from 11/30 (36.7%) wildcats, and they were identified morphologically and by 18S rRNA sequencing as P. praeputialis. Three infected wildcats presented well-demarcated intramural fibroplastic gastric nodules characterised by marked fibrosis, abundant collagen deposition, reactive fibroblasts, and eosinophil-rich inflammatory infiltrates surrounding intralesional adult female nematodes containing embryonated eggs. Molecular analysis of worms from the lesions confirmed their identity as P. praeputialis. Gross and histopathological features of these nodules were indistinguishable from those traditionally attributed to Cylicospirura spp. These findings provide the first direct evidence that P. praeputialis can induce fibroplastic gastric nodules in felids and should be considered in the differential diagnosis of lesions classically attributed to Cylicospirura spp. They also highlight the value of integrating morphological, molecular, and histopathological approaches in the diagnosis of gastric spirurine infections.