RT Journal Article T1 Editorial: Intraspecies variability in apicomplexan parasites: epidemiology, traits and virulence A1 Arranz Solís, David A1 Mukhopadhyay, Debanjan AB Single cell eukaryotic obligate intracellular apicomplexan parasites are major cause of life-threatening infections in humans (Plasmodium spp., Toxoplasma gondii,Cryptosporidium spp.) and cause significant effect on cattle and poultry industries Neospora caninum and Eimeria spp.) that leads to massive global economic loss everyyear. The outcome of infection and pathogenesis by apicomplexan parasites are largely dependent on the host and the parasite strain genotypes (Mukhopadhyay et al., 2020). Inthe current ‘omics’ era, with large datasets and new technologies frequently developed, the challenge is to combine these datasets to better understand the biological mechanisms bywhich parasites infect hosts and cause diseases, emphasizing the identification of key proteins that could be targeted for therapeutic or immunoprophylactic interventions. Dueto the advent of the newer ‘game-changer’ methodologies, especially the CRISPR-Cas systems and the multi-omics driven approaches (whole genome sequencing,transcriptomics, proteomics, metabolomics, etc.), identification of newer strains and genotype-phenotype correlations became easier (Seeber and Steinfelder, 2016). In thissense, recent reports have highlighted that freshly obtained isolates have different phenotypic and genotypic traits compared to reference strains (Uzelac et al., 2024). Inaddition, new clinical signs and histopathological changes have also been described in different hosts or animal models (Sánchez-Sánchez et al., 2019). Finally, the distributionand epidemiology of each specific parasite is of relevance to understanding their importance in geographical areas that may be associated with outbreaks or cases withparticularly unexpected outcomes PB Frontiers Media YR 2024 FD 2024 LK https://hdl.handle.net/20.500.14352/110424 UL https://hdl.handle.net/20.500.14352/110424 LA eng NO Arranz-Solís, D., & Mukhopadhyay, D. (2024). Editorial: Intraspecies variability in apicomplexan parasites: epidemiology, traits and virulence. Frontiers in cellular and infection microbiology, 14, 1497043. https://doi.org/10.3389/fcimb.2024.1497043 NO Author contributionsDA-S: Writing – original draft, Writing – review & editing. DM: Writing – original draft, Writing – review & editing.FundingThe author(s) declare financial support was received for the research, authorship, and/or publication of this article. DA-S is funded by the César Nombela research grant (2023-T1/BIO-28962)from the Atracción de talento de la Comunidad de Madrid program. DM is funded by a Start Up research grant (SRG) from SERB, Govt. of India SRG/2022/001381.Conflict of interestThe authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision. NO Department of Science & Technology (India) DS Docta Complutense RD 6 abr 2025