Molecular survey for the honey bee (Apis mellifera L.) trypanosome parasites Crithidia mellificae and Lotmaria passim.
Honey bee populations in the United States have been fluctuating in recent years. Although this has not been attributed to any one cause, recent studies have shown that multiple interactions among microorganisms may contribute to their decline. Several honey bee internal parasites have been overlooked as probable causes of decline; these include two different species of trypanosomes Crithidia mellificae and Lotmaria passim. Both parasites have been understudied in honey bee populations and could contribute to population disease dynamics. This study explored a molecular diagnostic survey for C. mellificae and L. passim using multiplex-PCR. Honey bee samples from both feral and managed populations were collected from eight states. This is the first national honey bee trypanosome survey in the United States. A total of 1,360 samples were surveyed during this study in which, 11% were positive for L. passim; while no cases of C. mellificae were detected using multiplex-PCR analysis. Infection rates of states positive for L. passim ranged from 17% (New York) to 0.70% (Utah). Only one state (Mississippi) was not positive for L. passim. The proportion of positive L. passim samples was significantly different between managed and feral honey bee colonies. Results revealed that the honey bee parasitic trypanosome L. passim has a widespread distribution in the United States and should be considered as a potential contributor to honey bee health decline.