In the present study, Henneguya bicaudi n. sp. infecting gills of Cirrhinus mrigala (Ham.) an Indian major carp from Harike Wetland in Punjab, India, has been described on the basis of myxospore morphology and partial amplification of the SSU rRNA gene. The pseudocysts of H. bicaudi n. sp. were located within the gill filament, whitish with round to irregular outer margin and 0.5-0.7 mm in diameter, 3-4 pseudocysts each containing about 50-100 myxospores were detected per gill. Mature myxospores were oblongate, 21.0 × 6.2 μm had a caudal appendage bifurcating into two thin thread-like branches starting posterior to middle of its length. The two equal polar capsules were 3.14 × 2.02 μm. The present species was compared morphologically with 21 species of the genus Henneguya infecting fresh water fishes in India and related geographical area. H. bicaudi n. sp. differed in having a peculiar oblongate shape and size of the myxospore, equal polar capsules, and also by the location of the point of bifurcation of the caudal appendage. 18S rDNA sequences of H. bicaudi n. sp. obtained revealed 96% homogeneity with H. pseudorhinogobi (Kageyama et al., Fish Sci 75:657-663, 2009) infecting gill filaments of Rhinogobius sp. (Rutter, PANS Philad 56-90, 1897) in Japan. The intensity of infection was determined by the gill pseudocyst index (GPI) based on the number of countable pseudocysts by stereo zoom trinocular microscopy per gill (on one side).

In the present study, a new species Myxobolus dermiscalis n. sp. infecting scales of Labeo rohita, an Indian major carp from Harike Wetland in Punjab, India has been described on the basis of spore morphology and amplification of a part of 18S rDNA gene. The pseudocysts of M. dermiscalis n. sp. are milky white with irregular outline, 0.5–3.6 mm in diameter embedded within the dermal scale in the form of a cavity. The spores 5.84–7.98 × 3.98–5.98 μm in size, having two equal polar capsules 3.98–5.98 × 1.85–3.85 μm in size. The most differentiating feature from closely related species, Myxobolus saugati (Kaur and Singh, 2011) is the presence of two parietal folds at the posterior – lateral margins of the shell valves. The present species is regarded as host, organ and tissue specific in nature. The partial sequence of SSU gene of M. dermiscalis n. sp. clustered with other Myxobolus species infecting cyprinids available in the GenBank. Blast search revealed 98% homogeneity with Myxobolus sp (KM401439) infecting scales of L. rohita in Myanmar (unpubl. data). The present myxobolid parasite has been recorded to cause serious, highly symptomatic disease of the scales, causing their loosening from the skin of L. rohita. It rendered the host fish unsightly giving it cloudy appearance with white patches and mucoid body surface. Scale pseudocyst Index (SPI) has been provided to record the intensity of infection.

A synopsis of 52 nominal species of the genus Kudo, 1933 reported to infect freshwater fishes in India is presented. These species infect various organs such as gills, fins, scales, skin, muscles, gall bladder, kidney etc. The diagnostic features of the genus include tear-shaped myxospores with smooth shell valves and single polar capsule. The members are histozoic in their nature of parasitism infecting fresh water fishes. The present manuscript is aimed to compile the list of reported species in India along with essential information on morphometrics of vegetative stage, host, organ preference and pathogenic effects if any. Maximum number of species are recorded from state of West Bengal (25) followed by 23 in Punjab (out of which 8 were already reported from other states of India), Andhra Pradesh (7), Orissa (3), Manipur (1) and Haryana (1). Majority of the species have been recorded to infect major and minor carps (43 species) and 9 species in cat fishes. Out of 43 species infecting Indian major carps, infected the epithelial lining of gill filament of and also the wall of the duodenum and pectoral fin of in Harike Wetland (Punjab). Organ distribution of the species belonging to the genus indicated that the plasmodia of 27 species were located in the gills, 14 species in the fins, 7 species in the gall bladder, 4 species in muscles and 3 species in kidney, 2 each in scale and skin on the head region and 1 species each in brain, eye, spleen, liver and wall of the duodenum. Recent studies conducted by the authors and also by few earlier studies in West Bengal have documented many species of to cause serious gill haemorrhagic disease and dermal lesions. Histological studies on the gills of cultured carps in Punjab infected with members of have indicated that these parasites cause 15-20 % damage to respiratory surface leading to localized loss of function.

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