Pathogens and Parasites of Feral and Managed Honey Bee, <i>Apis mellifera</i> , Colonies from Utah, USA

Abstract \Abstract Honey bee colonies in the United States continue to experience health challenges driven by parasites, pathogens, and environmental stressors. To establish a statewide baseline for honey bee health in Utah, we conducted a multi pathogen and parasite survey of 429 feral and managed Apis mellifera colonies collected from seventeen counties across three major ecological regions between 2008 and 2021. Colonies were screened for Varroa destructor , Nosema apis , N. ceranae , Lotmaria passim , Crithidia mellificae , and the bacterial symbionts Spiroplasma apis and S. melliferum . Overall pathogen and parasite occurrence in Utah was low: N. ceranae and L. passim were each detected in 7.3% of colonies, while V. destructor was found in 9.0% of colonies screened. No samples were positive for N. apis , Crithidia spp., or either Spiroplasma species. Pathogen prevalence did not differ significantly between feral and non-migratory managed colonies, but strikingly low Varroa levels were observed in A-lineage feral colonies, with only one of forty-four colonies (2.3%) testing positive. Pathogens and parasites were detected across all ecological regions, although prevalence varied geographically and among mitochondrial DNA lineages. These results provide the first comprehensive assessment of pathogens and parasites in Utah honey bees, establish a critical baseline for future monitoring, and highlight the need for targeted studies investigating the potential mite resistance or reduced exposure of Utah’s A-lineage feral populations.