Molecular and phylogenetic characterization of a Cnidarian parasite (Cnidaria: Myxozoa) Thelohanellus bifurcata, infecting gills of Indian major carp, Labeo rohita

J Parasit Dis. 2024 Dec;48(4):767-774. doi: 10.1007/s12639-024-01706-x. Epub 2024 Jul 22.

Abstract

Gill haemorrhagic disease is a significant health issue in Indian major carps, including Labeo rohita. In this study, we investigate the molecular description of Thelohanellus bifurcata, the identified causative agent of gill haemorrhagic disease in these fishes. Remarkably, no-one published molecular description of T. bifurcata exists to date. Through molecular analysis, we examined the genetic characteristics of T. bifurcata and explored its potential relationship with other Thelohanellus species found in India, thus further investigating the possibility of a species complex. The present species shows maximum homogeneity of 99.33% with T. bifurcata (KJ476886) (unpublished), 97.32% with T. filli (KR340464) with a base pair difference of only 4 and 30 respectively. The prevalence of T. bifurcata infection in L. rohita was found to be 17%. The findings of this study shed light on the molecular characteristics of T. bifurcata and contribute to our understanding of its prevalence and evolutionary relationships within the Thelohanellus genus.

Keywords: Fresh water fish; Gill haemorrhagic disease; India; Phylogeny; Thelohanellus bifurcata.