First report of Ichthyobodo necator, a flagellate protozoan parasite, in Schizothorax niger from the River Jhelum in the Kashmir Himalayas, India

Ichthyobodo necator was obtained from skin during a parasitological survey conducted for the detection of ectoparasites in Schizothorax fish species from the River Jhelum, Kashmir, India, over a period of six months. Out of 290 collected fish samples, only one fish was found to be infected with I. necator (flagellate protozoan parasite). The primary pathological changes observed in the skin tissue during this study were the destruction of the epidermis, formation of vacuoles in the epidermal cells, and significant hyperplasia of the goblet cells. Epidermal cells were observed to have lost their interlinking cell membranes, and the outer surface layers of the epidermis occasionally seemed to slough. In addition, scanning electron microscopy (SEM) was used to provide a detailed morphological examination and deeper exploration of the intricate relationship between parasite and host. The SEM images clearly reveal comma-shaped I. necator organisms attached to the host cell through an attachment disc. These observations are based on histopathological observations of a single individual. The findings presented here contribute not only to the knowledge of parasite diversity in the Kashmir Himalayas but also serve as a foundation for future research on the ecology, biology, and management of freshwater ecosystems. This is the first record of the flagellate protozoan fauna of the Schizothoracines from the Kashmir Valley, India.