House Mice and Commensal Rats in Relation to the Dissemination of Rat Fleas

In the course of recent studies on murine typhus fever at Tampa, Florida, it was necessary to maintain a culture of oriental rat fleas, Xenopsylla cheopis. White mice, Mus musculus, were used as hosts to these ectoparasites, according to a technique modified from one in use at the Bureau of Entomology and Plant Quarantine at Orlando. The relationships between flea and mouse were observed over a two-year period.During the same time it was frequently desired to feed fleas on roof rats, Rattus rattus, and comparable observations were made. Laboratory personnel, responsible for these routine operations, reported a divergence of flea behavior with respect to the two species of host. Subsequent observations have repeatedly confirmed their findings. These later observations are here reported since they may have bearing, as a side light, on the epidemiology of murine typhus fever and other diseases of commensal rodents in which ectoparasites serve as vectors.