Morphological and Histopathological Description of Myxobolus Adlardi N. SP. (Cnidaria: Myxosporea: Myxozoa) Infecting an Indian Major CARP, Labeo Rohita Hamilton, 1822 from A Cold Water Wetland in Punjab (India)

The present study was aimed to isolate myxozoan parasites infecting the freshwater fish Labeo rohita from Ranjit Sagar Wetland, Punjab from September, 2014 to August, 2015. Out of 50 fish specimens examined, 10 were found to be infected. The identification upto species level was done on the basis of morphological and morphometric attributes of the myxospores. Myxobolus adlardi n. sp. was characterized by the presence of ovoidal plasmodia of 0.2–0.9 mm in diameter in the gill filaments of Labeo rohita. Mature myxospores were pyriform and ellipsoidal in frontal view and lemon shaped in sutural view measuring 7.98×4.83 μm. Polar capsules were two, equal, bottle shaped measuring 3.50×1.76 μm in size. The prevalence of infection was found to be 20%. The intensity of infection or the mean abundance was determined by the gill plasmodial index (GPI) based on the number of countable plasmodia by stereozoom trinocular microscopy. Histopathological observations indicated the presence of intrafilamental-epithelial type, FE plasmodia in the gill filaments causing atrophy and destruption of the filaments.