Skip to main content
U.S. flag

An official website of the United States government

Ichthyophonus sp. Infection in Opaleye (Girella nigricans)

February 21, 2020

Over a 3-year-period, 17 wild-caught opaleye (Girella nigricans) housed in a public display aquarium were found dead without premonitory signs. Grossly, 4 animals had pinpoint brown or black foci on coelomic adipose tissue. Histologically, liver, spleen, heart, and posterior kidney had mesomycetozoan granulomas in all cases; other organs were less commonly infected. Four opaleye had goiter; additional substantial lesions were not identified. Granulomas surrounded melanized debris, leukocytes, and mesomycetozoa represented by folded membranes (collapsed schizont walls), intact schizonts (50- to >200 µm in diameter with a multilaminate membrane), plasmodia (budding from schizonts or free in tissue), or rarely germinal tubes (budding from schizonts). Ichthyophonus was grown from fresh tissues in tissue explant broth cultures of the heart, liver, and/or spleen. Polymerase chain reaction using 18S ribosomal DNA primers amplified a 1730-bp region, and the DNA sequence was most similar to Ichthyophonus hoferi, which is often associated with freshwater aquaculture fish.

Publication Year 2020
Title Ichthyophonus sp. Infection in Opaleye (Girella nigricans)
DOI 10.1177/0300985819900015
Authors Elise E. B LaDouceur, Judy St. Leger, Alexandria Mena, Ashley MacKenzie, Jacob Gregg, Maureen K. Purcell, William N. Batts, Paul Hershberger
Publication Type Article
Publication Subtype Journal Article
Series Title Veterinary Pathology
Index ID 70209068
Record Source USGS Publications Warehouse
USGS Organization Western Fisheries Research Center