CHAPTER XIV
TULARAEMIA
Definition and Synonyms
Definition.—This is a plague-like disease of various rodents, transmissible to man, caused by an organism Bacterium tularense, which is not closely allied to any other species. A number of human cases have been reported from Utah, where the disease is prevalent among the jack rabbits, and the transmission to man is through the bite of a horsefly, Chrysops discalis, which has previously sucked the blood of infected jack rabbits.
The site of the bite in man is usually marked by a punched-out ulcer, which is associated with swelling and suppuration of the glands draining the area. The general symptoms are sudden onset, with rigors, followed by an irregular fever of three or four weeks’ duration and by a prolonged convalescence. Several cases have been reported in the middle west due to handling infected rabbits. There have been a number of infections in laboratory workers where the local signs have been absent. In man death rarely results from the disease.
Synonyms.—Deer-fly fever (in man). Plague-like disease (in rodents).
History and Geographical Distribution
History.—In 1911 McCoy and Chapin discovered the B. tularense in a plague-like disease, first described by McCoy in the California ground squirrel. They described the organism, succeeded in cultivating it on special media, transmitted the infection to various rodents by feeding, nasal inoculation and injection of infected blood, and demonstrated the probable natural mode of transmission by the squirrel flea.
In recent publications, Francis, Lake and Mayne, and Wayson have recorded the transmission of the disease experimentally by the house fly (Musca domestica), the horsefly (Chrysops discalis), the stable fly (Stomoxys calcitrans), the rabbit louse, the mouse louse and the bedbug, and have shown that the freshly recovered organism can be grown on other than the special media previously recommended.
Geographical Distribution.—The first case of infection occurring in man was reported from Ohio by Wherry and Lamb in 1914. Since then a number of cases have been reported by Francis among rural residents of Utah and by Francis and Lake among laboratory workers handling animals infected with B. tularense.