Identification of Fusarium solani species complex from infected zebrafish (Danio rerio)

Although Fusarium sp. infections have been reported in aquatic invertebrates, studies of Fusarium spp. as fish pathogens remain very limited. In our study, a fungus was isolated from diseased zebrafish (Danio rerio). DNA sequence analysis of the fungus, based on a partial region of the translation elongation factor 1α gene (EF-1α), the internal transcribed spacer region and domains D1 and D2 of the large subunit of the ribosomal RNA gene (ITS plus LSU), and the RNA polymerase II subunit gene (RPB2), showed 99.9-100% homology to Fusarium solani species complex sequences. Multilocus sequence typing analysis based on 3-locus haplotypes (EF-1α, ITS plus LSU, and RPB2) suggests that the isolated strain was type 3+4-P. Challenge experiments showed that this organism could be pathogenic to zebrafish, but usually does not infect healthy subjects under normal circumstances.