Tularemia in the Cat.

Abstract

The susceptibility of the cat to tularemia was considered by McCoy 1 in his original description of the disease which he later named tularemia. The infective material consisting of an emulsion of spleen of a guinea pig dead on the 5th day after inoculation, was injected into 3 young cats. The control guinea pig died. McCoy reported that the cats suffered no ill effects and when examined at necropsy on the 14th day, there was no reaction at the site of the inoculation, and no buboes had formed. He concluded it was safe to infer that cats are probably not susceptible to this infection.

In a later publication this problem was again considered by McCoy, 2 and he reported on the subcutaneous inoculation of 4 cats with large doses of an emulsion made from liver of a guinea pig dead of the disease. He stated that all cats remained well, while the control guinea pig died on the 7th day.

Cases of tularemia which have occurred in Minnesota 3 have incriminated the cat as a possible carrier of the disease, and indicate that cats sometimes acquire an active infection after eating an animal dead from tularemia.

A rabbit which was responsible for a human case of tularemia was fed to 3 cats of a household and appeared to be the cause of a serious illness lasting about a week in the 3 cats eating the carcass. A 4th cat which did not eat the infective material did not become sick.

A second human case appeared to obtain the infection of tularemia by the bite of a sick cat, the cat dying a few hours after inflicting the wound.

Because of these suggestive findings we have reinvestigated the susceptibility of the cat to tularemia by feeding infective material. A young cat was given a carcass of a guinea pig dead of tularemia, and the cat consumed the entire carcass in one day. Two days later the cat did not appear to be well, and when given a second guinea pig carcass on the 3rd day consumed only one-half of it, but finished eating the carcass on the 4th day. The following day it appeared to be well. On the 8th day the cat again consumed the entire carcass of a guinea pig dead of tularemia, and on the 13th day it consumed another infected carcass. Except for the short period following ingestion of the first pig the cat appeared to be perfectly well and would purr very vigorously upon being petted. It was chloroformed on the 18th day. Its blood gave a positive agglutination for Bact. tularense in a dilution of 1:80. At necropsy all organs were apparently normal.