DAO 120:91-107 (2016)  -  DOI: https://doi.org/10.3354/dao03016

Disease surveillance of Atlantic herring: molecular characterization of hepatic coccidiosis and a morphological report of a novel intestinal coccidian

Sarah E. Friend1, Jan Lovy1,*, Paul K. Hershberger2

1New Jersey Division of Fish and Wildlife, Office of Fish and Wildlife Health and Forensics, 605 Pequest Road, Oxford, New Jersey 07863, USA
2US Geological Survey, Western Fisheries Research Center, Marrowstone Marine Field Station, 616 Marrowstone Point Road, Nordland, Washington 98358, USA
*Corresponding author:

ABSTRACT: Surveillance for pathogens of Atlantic herring, including viral hemorrhagic septicemia virus (VHSV), Ichthyophonus hoferi, and hepatic and intestinal coccidians, was conducted from 2012 to 2016 in the NW Atlantic Ocean, New Jersey, USA. Neither VHSV nor I. hoferi was detected in any sample. Goussia clupearum was found in the livers of 40 to 78% of adult herring in varying parasite loads; however, associated pathological changes were negligible. Phylogenetic analysis based on small subunit 18S rRNA gene sequences placed G. clupearum most closely with other extraintestinal liver coccidia from the genus Calyptospora, though the G. clupearum isolates had a unique nucleotide insertion between 604 and 729 bp that did not occur in any other coccidian species. G. clupearum oocysts from Atlantic and Pacific herring were morphologically similar, though differences occurred in oocyst dimensions. Comparison of G. clupearum genetic sequences from Atlantic and Pacific herring revealed 4 nucleotide substitutions and 2 gaps in a 1749 bp region, indicating some divergence in the geographically separate populations. Pacific G. clupearum oocysts were not directly infective, suggesting that a heteroxenous life cycle is likely. Intestinal coccidiosis was described for the first time from juvenile and adult Atlantic herring. A novel intestinal coccidian species was detected based on morphological characteristics of exogenously sporulated oocysts. A unique feature in these oocysts was the presence of 3 long (15.1 ± 5.1 µm, mean ±SD) spiny projections on both ends of the oocyst. The novel morphology of this coccidian led us to tentatively name this parasite G. echinata n. sp.


KEY WORDS: Atlantic herring · Clupea harengus · Coccidiosis · Goussia clupearum · Goussia echinata


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Cite this article as: Friend SE, Lovy J, Hershberger PK (2016) Disease surveillance of Atlantic herring: molecular characterization of hepatic coccidiosis and a morphological report of a novel intestinal coccidian. Dis Aquat Org 120:91-107. https://doi.org/10.3354/dao03016

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