Baseline Detection of Honey Bee Viruses and Nosema ceranae in Apis Species from Cambodia and Laos

Honey bees provide essential pollination services in natural and agricultural ecosystems, yet little is known about honey bee-associated pathogens in Cambodia and Laos. Here, we screened 53 colonies from 10 sites, including Apis cerana (n = 28), A. mellifera (n = 18), A. dorsata (n = 4), and A. florea (n = 3), for common honey bee viruses and the microsporidian Nosema ceranae using PCR and RT-PCR assays. Six viruses—acute bee paralysis virus, black queen cell virus, deformed wing virus type A, Israeli acute paralysis virus, Kashmir bee virus, and Lake Sinai virus—and N. ceranae were detected in A. cerana and A. mellifera, with overall low detection frequencies across sites. No targets were detected in A. dorsata or A. florea; however, the limited sample sizes for these species restrict interpretation of absence. Partial gene fragment sequences showed similarity to previously reported Asian isolates, indicating consistency with known regional viral diversity. These findings provide baseline detection data for honey bee-associated pathogens in Cambodia and Laos and support the need for expanded sampling across host species and seasons to better characterize pathogen occurrence in the region.