Pasteurella pestis detection in Fleas by fluorescent antibody staining

In an effort to develop a method for the rapid field identification of plague-infected fleas, the authors have studied the feasibility of direct fluorescent antibody staining of the midgut contents of fleas fed on mice infected with Pasteurella pestis. Fluorescent antibodies prepared from antisera derived from rabbits inoculated with the water-soluble P. pestis fraction 1b antigen, the somatic antigen of heat-killed P. pestis (Bryans strain), and live avirulent (strain A1122) or virulent (Yreka strain) plague vaccines were used used in this study.This direct staining method proved to be impracticable, but encouraging results were obtained by fluorescent antibody staining of broth cultures of macerates of infected fleas after 24-48 hours' incubation.The broth enrichment technique has not yet been evaluated in the field, but it is expected to be of value since it is relatively simple to perform and requires only material that can easily be transported to remote areas.