Vol.:(0123456789) 1 3 Acta Parasitologica https://doi.org/10.2478/s11686-018-00014-8 ORIGINAL PAPER Molecular Genetic Studies on Myxobolus cylindricus and Henneguya mystasi (Myxosporea: Myxobolidae) Infecting Two Indian Fish Species, Channa gachua and Mystus vittatus, Respectively A. Chaudhary 1  · A. Gupta 2  · U. Goswami 1,3  · G. Cech 3  · K. Molnár 3  · H. S. Singh 1  · C. Székely 3 Received: 7 August 2018 / Accepted: 29 November 2018 © Witold Stefański Institute of Parasitology, Polish Academy of Sciences 2019 Abstract Introduction Myxozoan infections of Indian freshwater fishes are relatively well studied, but their validity is supported with molecular and phylogenetic data only for a few species. Objectives The primary objective was to present molecular data for two Myxozoan species, Myxobolus cylindricus and Henneguya gachua collected from Indian freshwater fishes, the dwarf snakehead Channa gachua and the striped dwarf catfish Mystus vittatus, respectively. Methods Various organs of 56 C. gachua and 48 M. vittatus were dissected. Myxozoan plasmodia with mature spores were collected from the gills under a dissecting microscope. Spores obtained from plasmodia from infected hosts were fixed in 80% ethanol in vials and sent for further morphological and molecular examinations to Hungary. The 18S rDNA gene of Myxobolus and Henneguya spp. was amplified using nested polymerase chain reaction (PCR). Phylogenetic analysis was performed using maximum likelihood (ML) and Bayesian inference (BI) methods. Results Morphological characteristics of M. cylindricus and H. mystasi spores corresponded to the original descriptions made by Sarkar, Mazumdar and Pramanik, 1985 and Haldar, Samal, and Mukhopadhyay, 1997, respectively. Phylogenetic analysis of the 18S rDNA gene revealed that the sequences of M. cylindricus differed from those of most Indian Myxobolus sp., known mostly from cyprinid fishes and formed a subgroup with Myxobolus neurophilus, a parasite of a perciform host, and with Henneguya chaudhuryi, a species belonging to a different genus but described from a closely related channid host. It was also closely related to another Henneguya species, H. lesteri, described from Sillago analis, a coastal fish. Henneguya mystasi had the closest similarity to Henneguya bicaudi, a species described from an Indian cyprinid fish and to Henneguya pellucida reported from a characid fish known from South America. Conclusion Molecular data received by us gives a solid basis for further identification of these myxozoans, the pathogenicity of which probably plays an economic role at culturing the hosts. Keywords Myxobolus · Henneguya · Morphology · Molecular study · 18S rDNA · Meerut · India Introduction The phylum Myxozoa comprises a diverse group of para- sites characterised by multicellular spores and polar cap- sules enclosing polar filaments [17]. Myxozoa are a group of parasites posing a major threat to the development of both farmed and wild fish species [36]. About 60 genera were established in the class of Myxosporea, where Myxobolus Bütschli, 1882 and Henneguya Thélohan, 1892 are the most species-rich genera [11–14, 36]. In Indian fishes, Kaur and Singh [31] reported 130 known Myxobolus species, while Kalavati and Nandi [27] reported 23 Henneguya species. Since then the number of described species has increased * C. Székely szekely.csaba@agrar.mta.hu 1 Department of Zoology, Chaudhary Charan Singh University, Meerut, Uttar Pradesh, India 2 Department of Zoology, D.N.P.G. College, Meerut, Uttar Pradesh, India 3 Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, PO Box 18, 1581 Budapest, Hungary