Henneguya pseudoplatystoma n. sp. causing reduction in epithelial area of gills in the farmed pintado, a South American catfish: Histopathology and ultrastructure

Abstract

The present study is part of an ongoing investigation into the characteristics of Myxozoan parasites of Brazilian freshwater fish and was carried out using morphology, histopathology and electron microscopy analysis. A new Myxosporea species (Henneguya pseudoplatystoma) is described causing an important reduction in gill function in the farmed pintado (a hybrid fish from a cross between Pseudoplatystoma corruscans and Pseudoplatystoma fasciatum), which is a commercially important South American catfish. From a total of 98 pintado juveniles from fish farms in the states of São Paulo and Mato Grosso do Sul (Brazil), 36 samples (36.7%) exhibited infection of the gill filaments. Infection was intense, with several plasmodia occurring on a same gill filament. The plasmodia were white and measured up to 0.5mm in length; mature spores were ellipsoidal in the frontal view, measuring 33.2+/-1.9 microm in total length, 10.4+/-0.6 microm in body length, 3.4+/-0.4 microm in width and 22.7+/-1.7 microm in the caudal process. The polar capsules were elongated, measuring 3.3+/-0.4 microm in length and 1.0+/-0.1 microm in width and the polar filaments had six to seven turns. Histopathological analysis revealed the parasite in the connective tissue of the gill filaments and lamella. No inflammatory process was observed, but the development of the plasmodia reduced the area of functional epithelium. Ultrastructural analyses revealed a single plasmodial wall, which was in direct contact with the host cells and had numerous projections in direction of the host cells as well as extensive pinocytotic canals. A thick layer (2-6 microm) of fibrous material and numerous mitochondria were found in the ectoplasm. Generative cells and the earliest stage of sporogenesis were seen more internally. Advanced spore developmental stages and mature spores were found in the central portion of the plasmodia.

Henneguya cuniculator sp. nov., a parasite of spotted sorubim Pseudoplatystoma corruscans in the São Francisco Basin, Brazil

“…These carnivorous, migratory fish can reach up to 160 cm in length and 100 kg in weight (Froese & Pauly 2011), and due to the high quality of their meat, they play an important role in the fishing economy of the regions in which they are found (Campos 2005). P. corruscans is important for Bra zilian aquaculture, as fingerlings created by crossbreeding of this species with P. reticulatum Eigenmann & Eigenmann, 1889 are reared in fish farms across the country (Naldoni et al 2009). This hybrid fish is called 'pintado,' and its production in Brazilian fish farms ABSTRACT: Henneguya cuniculator sp.…”

“…Resale or republication not permitted without written consent of the publisher reached 2486 t in 2010 (MPA 2012). It is sold in the Brazilian market, and is also exported to several countries (Mar & Terra 2013).…”

“…Since then, 5 other species have been described: H. pseudoplatystoma Naldoni et al, 2009, was found infecting hybrid pintado taken from fish farms in the states of São Paulo and Mato Grosso do Sul, and H. eirasi Naldoni et al, 2011, H. multiplasmodialis Adriano et al, 2012, Henneguya m. Carriero et al, 2013, and Myxobolus flavus Carriero et al, 2013, were found infecting both P. corruscans and P. reticulatum taken from natural environments in the Brazilian Pantanal wetland (Naldoni et al 2009, Carriero et al 2013). …”

Parasitological assessment in the hybrid surubim (Pseudoplatystoma reticulatum x P. corruscans), with uncommon occurrence of Monogenea parasites

“…Naldoni et al (2009) described the myxozoan Henneguya pseudoplatystoma from the gills of the hybrid surubim farmed in the of Mato Grosso do Sul. Jerônimo et al (2013) evaluated the distribution of ectoparasites in the gill arches of this host under farming conditions.…”

Parasitofauna de cachara cultivado em tanque-rede no rio Paraguai

“…taxas de prevalência com importantes lesões tissulares, especialmente em animais mantidos em cativeiro, como descrito para Henneguya pseudoplatystoma em surubim híbrido (Naldoni et al, 2009), e para H. eirasi em pintado e cachara (Naldoni et al, 2011). No presente trabalho, também foram registradas altas taxas de prevalência desses parasitos, possivelmente em razão da facilidade na transmissão horizontal com o adensamento populacional.…”