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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetics, Physiology, and Health Research to Improve Catfish Production

Location: Warmwater Aquaculture Research Unit

Title: Morphological and molecular characterization of novel species of Henneguya found in the gills of farm-raised channel catfish, Ictalurus punctatus

Authors
item Rosser, Thomas -
item Griffin, Matt -
item Quiniou, Sylvie
item Khoo, Lester -
item Pote, Linda -

Submitted to: Southeast Society of Parasitologists
Publication Type: Abstract Only
Publication Acceptance Date: April 6, 2013
Publication Date: April 10, 2013
Citation: Rosser, T.G., Griffin, M., Quiniou, S., Khoo, L., Pote, L. 2013. Morphological and molecular characterization of novel species of Henneguya found in the gills of farm-raised channel catfish, Ictalurus punctatus. Southeast Society of Parasitologists. P.15.

Technical Abstract: Channel catfish Ictalurus punctatus is host to at least eight different species of myxozoan parasites in the genus Henneguya. Four of these species have been molecularly characterized; however, the life cycles of only two have been experimentally and molecularly confirmed. Some of these species can illicit severe pathology upon infection, such as H. ictaluri, the causative agent of proliferative gill disease in cultured channel and hybrid catfish. Recently, during a routine health screening of farm-raised channel catfish, several fish presented with deformed primary lamellae harboring nodular white cysts approximately 1.25 mm in diameter. These cysts contained numerous Henneguya myxospores, with a lanceolate shaped spore body 17.1 ± 1.0 µm (mean ± SD; range = 15.0-19.3 µm) in length and 4.8 ± 0.4 µm (3.7-5.6 µm) in width. Pyriform shaped polar capsules were 5.8 ± 0.3 µm in length (5.1-6.4 µm) and 1.7 ± 0.1 µm (1.4-1.9 µm) in width. The two caudal processes were 40.0 ± 5.1 µm in length (29.5-50.0 µm) with a total spore length of 57.2 ± 4.7 (46.8-66.8 µm). The contiguous 18S rRNA sequence generated from five excised cysts did not match any Henneguya spp. currently in GenBank. The greatest sequence homology (91% over XXXX bp) was to Henneguya pellis, a parasite associated with blister-like lesions on the skin of blue catfish, Ictalurus furcatus. Based on the unique morphology and 18S rRNA sequence of this isolate, we believe this isolate to be a previously undocumented species of the genus Henneguya.

Last Modified: 11/25/2014
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