Interception of an Apis dorsata swarm with Tropilaelaps mercedesae and Kuzinia morsei mites on a cargo vessel inbound to the United States

In 2025, a swarm of giant honey bees, Apis dorsata dorsata , was detected on board a cargo vessel prior to arrival at the port of Elizabeth, New Jersey, USA. Apis dorsata is a quarantine species not native to the United States, and further inspection of the bees uncovered 28 mites that were identified as Tropilaelaps mercedesae by morphological and DNA barcoding analysis. Tropilaelaps mercedesae is an ectoparasite of honey bees that is not yet present in the USA. An additional mite species, Kuzinia morsei , was also observed. Molecular screening of common honey bee pathogens in 42 intercepted bees showed a 5% prevalence of trypanosomatid infections and a 2% prevalence of American foulbrood. Additionally, Black queen cell virus (BQCV) and Deformed wing virus B (DWV-B) were detected in 38% and 7% of the samples, respectively. To our knowledge, this is the first detection of T. mercedesae and K. morsei on a vessel bound for the USA, as well as the first interception of a whole swarm of A. dorsata dorsata . Phylogenetic analysis of the CO1 sequence data indicated that the intercepted bee swarm originated from a southern India lineage. Our findings indicate that exotic bee swarms can harbor parasitic mites and multiple bee pathogens, both critical to the apiculture industry. Additionally, our findings reveal that Tropilaelaps mites can survive extended periods associated with adult bees and in the absence of brood, suggesting greater potential for long-distance movement and introduction risk. This study provides new insights into Tropilaelaps dispersal and swarm-mediated pathogen movement, thereby improving our ability to predict establishment and outbreak risk crucial for countering invasive agricultural threats. The findings also emphasize that early detection, through coordinated port and shipboard surveillance, and strong interagency collaboration, is vital for reducing the risk of agricultural pest and pathogen introductions into the USA.