20 pages, 4 figures, supplemental information https://doi.org/10.1016/j.isci.2022.104588.-- Data and code availability:
• All data have been deposited at NCBI GenBank: OL630144 and OL630145, NCBI SRA BioProject: PRJNA789574, at MorphoSource Project: 000405843, and at USAP-DC Project: p0010221, and are publicly available as of the date of publication. Biological materials have been deposited at the Zoological Museum of the University of Copenhagen. Additional accession numbers and DOIs are listed in the key resources.
• This paper does not report original code.
• Any additional information required to reanalyze the data reported in this paper is available from the lead contact upon requestClimate changes can promote disease outbreaks, but their nature and potential impacts in remote areas have received little attention. In a hot spot of biodiversity on the West Antarctic Peninsula, which faces among the fastest changing climates on Earth, we captured specimens of two notothenioid fish species affected by large skin tumors at an incidence never before observed in the Southern Ocean. Molecular and histopathological analyses revealed that X-cell parasitic alveolates, members of a genus we call Notoxcellia, are the etiological agent of these tumors. Parasite-specific molecular probes showed that xenomas remained within the skin but largely outgrew host cells in the dermis. We further observed that tumors induced neovascularization in underlying tissue and detrimentally affected host growth and condition. Although many knowledge gaps persist about X-cell disease, including its mode of transmission and life cycle, these findings reveal potentially active biotic threats to vulnerable Antarctic ecosystemsThis work was funded by the National Science Foundation grants OPP-1947040 (JHP and ArV), PLR-1444167 (HWD), and OPP-1543383 (JHP, TD, and HWD)With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)Peer reviewe
