The District of Hamakua, Hawaii, is an endemic area for plague. During the course of plague investigations, we observed an instance of salmonellosis in a rat (Rattus norvegicus) trapped at Hamakua.
The rat was killed and its spleen, liver, and lymph nodes (inguinal, axillary, and ilial) were homogenized in normal saline solution; the homogenized tissues amounted to about 20 to 30% of the suspension obtained. Of this blended material, 1.0 ml was injected intraperitoneally into a guinea pig, which died 8 days later. At necropsy of the guinea pig, there was considerable hemorrhage throughout the subcutaneous tissue of the abdomen and an enlarged spleen with numerous, pinpoint necrotic foci. The liver appeared to be normal and the lungs were not consolidated. The axillary and inguinal lymph nodes were slightly enlarged.
A slide contact smear of the spleen, with Wayson's stain, contained numerous bipolar organisms, simulating Pasteurella pestis.