Host genomic markers and candidate regions associated with Babesia bovis infection in cattle: A systematic review

Babesia bovis is one of the most pathogenic agents of bovine babesiosis and remains a major constraint to cattle production in tropical and subtropical regions. This systematic review synthesizes the available evidence on host genomic markers linked to B. bovis in cattle, with emphasis on genome-wide association studies, major histocompatibility complex variants, and host-response studies relevant to marker discovery. PubMed/MEDLINE, Scopus, and Web of Science Core Collection were searched using a predefined strategy, complemented by targeted searching and citation tracking. The searches identified 1090 records; after removal of 463 duplicates, 627 unique records were screened and 23 reports were retained for structured narrative synthesis. A meta-analysis was not performed because the evidence was heterogeneous in phenotype definition, population, design, and effect measure. Direct host-side genomic evidence remains scarce and is dominated by a small number of population-specific studies. The strongest genome-wide evidence comes from Hereford and Braford cattle, with top SNP signals on BTA1, 2, 5, 6, 12, 16, 17, 18, 24 and 26 and positional candidate genes including ATP8A1, LCP1, LRCH1, QSOX1, FGF2, DSC1, DSC3, FGFR2 and CEBPG. BoLA-DRB3*011:01 was associated with resistance to B. bovis infection in Crioulo Lageano cattle. Overall, host response appears polygenic, weakly heritable, and strongly influenced by immune regulation, breed background, host-vector interaction, and epidemiological context. No single marker is currently validated for routine selection across breeds; future progress will require larger reference populations, improved phenotyping, and independent validation.