Diversity of Veronaea botryosa from different hosts and evaluation of laboratory challenge models for phaeohyphomycosis in Acipenser transmontanus

Esteban Soto, Christine Richey, Stephen R. Reichley, Brittany Stevens, Kirsten V. Kenelty, Janiee Lewis, Barbara Byrne, Nathan P. Wiederhold, Thomas B. Waltzek, Matthew F. Sheley, Alvin C. Camus, Matt J. Griffin

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Veronaea botryosa has been identified as a pathogen of cultured white sturgeon Acipenser transmontanus. In 2015, samples from 19 white sturgeon were received for diagnosis, of which 14 cultured positive for V. botryosa. Intraspecific variability among V. botryosa isolates from different clinically affected hosts and geographic regions was investigated using repetitive extragenic palindromic PCR fingerprinting (rep-PCR). The rep-PCR profiles of 16 V. botryosa isolates from a human, sea turtles, and cultured fish were distinct from those of other phaeoid fungi belonging to the genera Cladophialophora and Exophiala. To gain a better understanding of the pathogenesis of V. botryosa mycosis, 5 laboratory challenge methods were evaluated in white sturgeon fingerlings. Intramuscular (IM) and intracoelomic (IC) injection challenges produced cumulative mortalities of 13.3% (8/60) and 3.3% (2/60), respectively, and V. botryosa was recovered from 100% (10/10) of dead fingerlings. Affected fish exhibited abnormal orientation and/or failure to maintain neutral buoyancy, emaciation, coelomic distension, exophthalmos, cutaneous erythema, and ulcerated skin. After 6 wk, surviving fish were euthanized, and samples of liver were taken for mycological evaluation. Viable fungus was detected in 90% and 100% of fish surviving IM and IC challenge, respectively. No V. botryosa-associated mortality was detected in other groups challenged by immersion, immersion with abrasion, or orally. Both IM and IC challenge routes appear suitable for the induction of V. botryosa infection in white sturgeon and can serve as models for the study of disease pathogenesis associated with this emergent pathogen.

Original languageEnglish (US)
Pages (from-to)7-18
Number of pages12
JournalDiseases of Aquatic Organisms
Volume125
Issue number1
DOIs
StatePublished - 2017

Keywords

  • Fungus
  • Mycosis
  • Sturgeon
  • Veronaea

ASJC Scopus subject areas

  • General Medicine

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