An ultrastructural and histopathological study ofHenneguya pellucidan. sp. (Myxosporea: Myxobolidae) infectingPiaractus mesopotamicus(Characidae) cultivated in Brazil

Abstract

Summary :During a study of myxosporean parasites of cultivated freshwater fish, a new myxosporean species, Henneguya pellucida n. sp., was discovered. Of the 120 Piaractus mesopotamicus sampled, only 10 specimens (8.3 %) were infected. Yellow, round plasmodia measuring 0.5-3 mm were found in the serous membrane of the visceral cavity and in the tunica externa of the swim bladder. Sporogenesis was asynchronous, with the earliest developmental stages aligned prevailingly along the endoplasmic periphery and mature spores in the central zone. The mature spores were pear shaped (total length: 33.3 ± 1.5 µm, mean ± SD; width: 4.1 ± 0.4 µm; body length: 11.4 ± 0.3 µm; caudal process length: 24.1 ± 1.5 µm). The polar capsules were elongated (length: 4.0 ± 0.4 µm; width: 1.6 ± 0.2 µm). The development of the parasite in the swim bladder produced thickening of the tunica externa and a granulomatous reaction. There was no correlation between the prevalence of the parasite and the chemical and physical characteristics of the water. Infection was recorded only in juvenile specimens ranging in size from 9.5 to 20 cm. (longueur totale : 33,3 ± 1,5 µm, moyenne ± SD ; largeur : 4,1 ± 0,4 µm ; longueur du corps : 11,4 ± 0,3 µm ; longueur du processus caudal : 24 1 ± 1,5 µm Résumé

Myxosporidiosis in intensively-reared Piaractus mesopotamicus: Histopathological diagnosis by means of Ziehl-Neelsen staining

“…These structures were not measured because of lack of detailing, since these were young spores (Adriano et al 2005).…”

Extraction and recovery technique for myxozoan parasites from the Piaractus mesopotamicus kidney embedded in paraffin

“…and Myxobolus sp. (Myxobolidae) are among the most important parasites causing damage to farmed fishes in Brazil (MARTINS et al, 1997;1999a;1999b;MARTINS, 2004;ADRIANO et al, 2005;SCHALCH;MORAES, 2005). Identification at the genus level in histological sections may be obtained according to the technique proposed by Manrique et al (2012) using Ziehl-Neelsen stain or Giemsa in fresh mounts for microscope observation (MEYERS et al, 1977).…”

Molecular phylogeny and ultrastructure of Myxobolus cf. cuneus, a parasite of patinga hybrid and Henneguya pseudoplatystoma, a parasite of pintado hybrid

“…Of all myxosporean genera, the Myxobolus Bütschli, 1882 and Henneguya Thelohan, 1892 have the highest abundance of species found in fish (Eiras 2002;Eiras et al 2005Eiras et al , 2014Eiras and Adriano 2012;Adriano et al 2012). In Brazil, due to their economic importance in fisheries and aquaculture, fish of the Piaractus and Pseudoplatystoma Bleeker, 1862 genera have received significant attention from icthyoparasitologists, with a rapid increase in knowledge of the myxosporean fauna that infect these fish (Martins et al 1997;Adriano et al 2005aAdriano et al , 2005bAdriano et al , 2006Adriano et al , 2012Naldoni et al 2009Naldoni et al , 2011Naldoni et al , 2014Carriero et al 2013;Müler et al 2013).…”