Supplementary studies on Henneguya guanduensis (Cnidaria: Myxosporea) infecting gills and intestine of Hoplosternum littorale in Brazil: Ultrastructural and molecular data

Abstract

Henneguya guanduensis was originally described as a gill parasite of the Hoplosternum litoralle, a siluriform fish belonging to the Callichthyidae family. A study was undertaken with 58 specimens of H. litoralle taken from Batalha River in the state of São Paulo. The fish were collected and examined searching for lesions and/or myxosporean plasmodia. The prevalence of infection was 9.31% in the gills and 5.17% in the intestine. The mature spores had elongated bodies with polar capsules of inequal size and a caudal length greater than body length. Morphological characteristics identified the parasite as H. guanduensis. Molecular analysis of the SSU rDNA partials sequences resulted in a 1796 bp and 1712 bp for gills and intestine repectively, demonstrating significant genetic differences with previously described species of Henneguya and 99.7% similarity to each other when aligned. Phylogenetic analysis comparing the SSU rDNA sequence of H. guanduensis with closest species as indicated by BLASTn Max Score showed H. guanduensis as sister species of H. loretoensis in a subclade compose by species that parasites fishes from Amazon basin. This is the first report of the finding of Henneguya guanduensis spores in the intestine of Hoplosternum littorale.