| Because plague, a flea-borne disease caused by the bacterium Yersinia pestis, causes the death of >90 % of individuals in a black-tailed prairie dog (Cynomys ludovicianus) colony, it has been argued that another rodent that is resistant to plague is necessary to maintain and spread the disease. While northern grasshopper mice (Onychomys leucogaster ) share fleas with many rodents, including prairie dogs, it is not clear if prairie-dog fleas (Oropsylla hirsuta) can feed on, and therefore transmit, the pathogen to grasshopper mice. PCR assays and gel electrophoresis were used to identify the source of blood meals in three species of fleas combed from their three primary rodent hosts, and from grasshopper mice as a secondary host. Most (53-83%) fleas combed from their primary hosts contained only DNA of their primary hosts. Most (52-53%) fleas associated with prairie dogs and thirteen-lined ground squirrels (Spermophilus tridecemlinatus), but combed from grasshopper mice, contained grasshopper mouse DNA. These findings indicate that grasshopper mice are fed upon by fleas usually associated with prairie dogs and other rodents, underscoring their possible role in the transmission and persistence of plague in prairie dog colonies. |
