Veterinary Fusarioses within the United States

Area of Science:

• Mycology
• Veterinary Medicine
• Molecular Phylogenetics

Background:

• Fusarium species are known fungal pathogens.
• Understanding the diversity of Fusarium strains in veterinary mycoses is crucial for diagnosis and treatment.
• Previous studies have not fully characterized the genetic diversity of Fusarium from veterinary sources.

Purpose of the Study:

• To assess the genetic diversity and evolutionary relationships of Fusarium strains isolated from veterinary sources.
• To identify the key Fusarium species complexes and individual species involved in veterinary mycoses.
• To determine the phylogenetic distribution of veterinary-relevant Fusarium strains.

Main Methods:

• Multilocus DNA sequence data from 67 Fusarium strains of veterinary origin.
• Phylogenetic analyses to determine species complexes and relationships.
• Sequence type (ST) analysis to assess genetic diversity within species complexes.

Main Results:

• The 67 strains represented 23 distinct Fusarium species across eight species complexes.
• The Fusarium solani species complex (FSSC) comprised the majority (70.1%) of veterinary isolates, including 8 phylospecies and 33 sequence types.
• Fusarium falciforme, F. keratoplasticum, and Fusarium sp. FSSC 12 were the most prevalent FSSC species, associated with equine keratitis and marine vertebrates/invertebrates, respectively.
• The Fusarium incarnatum-equiseti species complex (FIESC) was the second most important clade.
• Several sequence types showed widespread geographic distribution, including transoceanic presence.

Conclusions:

• Fusarium strains causing veterinary mycoses exhibit significant phylogenetic diversity.
• Accurate species-level identification of veterinary-associated Fusarium requires multilocus DNA sequence data.
• The FSSC and FIESC are key species complexes in veterinary Fusarium infections.