Diversity of Parasitic Fauna and Associated Gill Histopathology in Cyprinus Carpio From The Indus River, Pakistan

Abstract

The present study explores the diversity of parasitic infections and the associated histopathological changes in the gills of Cyprinus carpio (common carp) collected from the Indus River at Hund, Swabi, Pakistan. A total of sixteen fish specimens were obtained from two sampling sites and examined for parasitic infestation and gill tissue pathology using light microscopy and Hematoxylin and Eosin (H&E) staining. Multiple parasite taxa were recorded, including Bothriocephalus acheilognathi, Diplostomum spp., Lernaea cyprinacea, Piscicola geometra, Camallanus spp., Chaetogaster diastrophus, and Nais communis. Histopathological analysis revealed pronounced gill lesions, characterized by epithelial hyperplasia, lamellar fusion, edema, necrosis, and leukocytic infiltration, suggesting compromised respiratory efficiency associated with parasitic burden. The results highlight the relevance of parasitic infections as bioindicators of environmental stress and fish health. This study enhances current knowledge of host–parasite interactions and provides baseline information for monitoring aquatic ecosystem health and supporting sustainable fisheries management in the Indus River basin.