Fusarium incarnatum : a paradigm for One Health pathogen dynamics across humans, animals, and the environment

The Fusarium incarnatum-equiseti species complex (FIESC) is a harmful plant pathogen responsible for diseases, such as root rot, fruit rot, leaf blight, and wilt, in various crops. Recently, it has been increasingly associated with both superficial and invasive infections in humans and animals. Additionally, this pathogen produces mycotoxins, posing significant risks to public health. This study aims to characterize the molecular and morphological characteristics of FIESC isolates obtained from various sources, including human, veterinary, and plant samples. Molecular identification was performed using multilocus sequence typing (MLST), targeting the internal transcribed spacer (ITS) rDNA, the second-largest subunit of the RNA polymerase gene (RPB2), and translation elongation factor 1 alpha (TEF-1α). Based on MLST analysis, all FIESC isolates were found to belong to the Incarnatum clade and were classified into two species: F. irregulare and F. pernambucanum . Furthermore, these isolates demonstrated the ability to penetrate and colonize human nails, porcine skin, and muskmelon fruits. In this study, we report members of FIESC as a newly identified pathogens in Taiwan capable of cross-infection among humans, animals, and plants. These findings highlight the dual significance of Fusarium : it poses a serious threat to agriculture by compromising plant health and crop yields while also representing a public health risk due to its ability to infect humans and animals. IMPORTANCE The Fusarium incarnatum-equiseti species complex (FIESC) is a significant plant pathogen affecting a wide range of crops, leading to substantial agricultural losses worldwide. In this study, we report that Fusarium isolates belonging to F. pernambucanum and F . irregulare obtained from various sources, including respiratory specimens from human, cat, rabbit, and turtle, along with plant samples from muskmelon fruits, represent newly identified pathogens in Taiwan. Our findings suggest that these isolates possess the potential for cross-infection among plants, animals, and humans, underscoring their importance in both agricultural and medical contexts. Notably, the plant isolates PLMF1 and BDMF7 demonstrate the ability to transition from plant pathogens to zoonotic pathogens, highlighting a concerning adaptability.