Plague Vector Studies Part I. The rate of transfer of fleas among Citellus, Rattus and Sylvilagus under field conditions in southern California1

The extent of transfer of fleas among Citellus, Rattus and Sylvilagus was studied. Electrical fences were used to confine the mammals in O.4-ha fields. Based on analysis of 92,694 fleas from 620 hosts, it is concluded that Xenopsylla cheopis, Diamanus montanus, and Hoplopsyllus anomalus will attack atypical hosts, in the same habitat as their usual hosts, at epizootiologically significant rates. An X. cheopis index of 1 occurred on ground squirrels (Citellus beecheyi), and of 0.9 on rabbits (Sylvilagus audubonii).