Explore the recorded discovery and history of Francisella tularensis, with source links and stated limits.
PHAC describes F. tularensis as a Gram-negative, non-motile coccobacillus, non-sporing and aerobic, requiring cystine for growth, and distinguishes Jellison type A, which is highly virulent, from type B, which causes milder disease. Its infectious dose is extraordinarily low — PHAC gives 5 to 10 organisms by the respiratory route against 10⁶ to 10⁸ by ingestion. CDC states that people become infected through tick and deer fly bites, skin contact with infected animals, drinking contaminated water, and inhaling contaminated aerosols or agricultural and landscaping dust, and that naturally occurring infections have been reported from all states except Hawaii. Human-to-human transmission is rare.
LPSN records the basonym “Bacterium tularense” McCoy and Chapin 1912, and its etymology notes that tularensis pertains to Tulare County, California, where the disease was first described in rodents. The name therefore records where a rodent outbreak was investigated, not where the organism originated or where people were first infected.
LPSN records Francisella tularensis (McCoy and Chapin 1912) Dorofeev 1947, retained on the 1980 Approved Lists of Bacterial Names. Type strain ATCC 6223 / B 38. The genus honours Edward Francis.
These references do not identify a first person ever infected. The 1912 description came from a rodent disease investigation in Tulare County, California, so it dates a veterinary and laboratory milestone rather than a first human case or a geographic origin of the species.
Source check: 2026-09-20. Educational content; independent scientific review remains pending.