Histology, ultrastructure and prevalence of Henneguya piaractus (Myxosporea) infecting the gills of Piaractus mesopotamicus (Characidae) cultivated in Brazil

Abstract

The histopathological and ultrastructural characteristics of Henneguya piaractus, a parasite of the gill lamellae of Piaractus mesopotamicus, are reported here. Histological analysis showed that the plasmodia were of the intralamellar type. The development of the plasmodia resulted in marked dilatation of the infected lamellae, with the neighbouring lamellae being displaced laterally. Discreet epithelial hyperplasia was observed, but there was no inflammatory reaction. Ultrastructural analysis showed that the plasmodium had a single thin wall that was in direct contact with the host cells. Pinocytic canals and points of phagocytosis were observed in the wall. The prevalence of the parasite varied according to host size, with the lowest prevalence occurring in hosts up to 10 cm long.

Histopathological and ultrastructural studies of Myxobolus turpisrotundus from allogynogenetic gibel carp Carassius auratus gibelio in China

“…In all infection sites, the plasmodia were with the same complex structure arrangement: cup-like cells with unknown derivation, a thin collagenous fibril layer, areolar connective tissue, basement membrane and host epithelial cell. This finding is in line with former reports (Adriano et al 2005, Zhang et al 2010. Manera (2016) indicated that fibroblast and collagen encapsulation of plasmodia may protect the parasite against external influences whereas Martyn et al (2002) mentioned that the complexity is probably selectively permeable for nourishing the parasite.…”

Spatial and seasonal variations on Henneguya exilis prevalence on cage intensive cultured channel catfish (Ictaluruspunctatus) in Tamaulipas, Mexico

“…In our study no correlation between prevalence and host size was observed. Adriano et al (2005) found similar results with Henneguya caudalongula in cultured fish and Gbankoto et al (2001) with other myxosporean species of wild fish. According with Griffin et al (2009), closed earthen ponds and multi-batch culture is a more favorable environment for dissemination of myxozoan parasites in the catfish industry.…”

“…In 2008, the aquaculture of channel catfish in Mexico reached 970 ton (CONAPESCA, 2008) with Tamaulipas as the first producer using controlled systems. Biotic factors can affect the prevalence of pathogens in these systems, as wild fish population around cages (Beveridge, 2002), size host (Adriano et al, 2005), fish species (Beecham et al, 2010) and abiotic factors as stress by management (Lio-Po & Lim, 2002) or low levels of dissolved oxygen (Francis-Floyd, 1993). Some reports show the effect of fish age (Saksida et al, 2007), stress (Hammell & Dohoo, 2005), fish mean weight (Heuch et al, 2009), type of ecosystems (Vagianou et al, 2006) and temperature (Johnson et al, 2004;Antonelli et al, 2010), on outbreaks and prevalence of pathogens in fish cultured in sea water cages, but there are few studies that have examined factors affecting pathogen prevalence in freshwater cages.…”

Supplementary studies on Henneguya doneci Schulman, 1962 (Myxozoa: Myxosporea) infecting the gill filaments of Carassius auratus gibelio (Bloch) in China: histologic, ultrastructural, and molecular data

“…(Vita et al 2003;Adriano et al 2005;Abdel-Ghaffar et al 2005;Azevedo et al 2008;Quraishy et al 2008). The desmosome-like junctions between two valvogenic cells in the present myxosporeans prove the generally accepted viewpoint that Myxozoa are multicellular animals (Siddall et al 1995).…”