When found in nature, Francisella tularensis can survive for several weeks at low temperatures in animal carcasses, soil, and water.

Bacterium tularense was soon isolated by George Walter McCoy (1876–1952) of the US Plague Lab in San Francisco and reported in 1912.

In 1922, Edward Francis (1872–1957), a physician and medical researcher from Ohio, discovered that Bacterium tularense was the causative agent of tularemia, after studying several cases with symptoms of the disease.

It was characterized as a relatively nonvirulent Francisella; only two tularemia cases in North America have been attributed to the organism, and these were only in severely immunocompromised individuals.

[10] F. tularensis can survive for weeks outside a mammalian host[citation needed] and has been found in water,[8] grassland, and haystacks.

Aerosols containing the bacteria may be generated by disturbing carcasses due to brush cutting or lawn mowing; as a result, tularemia has been referred to as "lawnmower disease".

Inhalation of bacteria,[8] particularly biovar F. t. tularensis,[citation needed] leads to the potentially lethal pneumonic tularemia.

[citation needed] Entry into the macrophage occurs by phagocytosis and the bacterium is sequestered from the interior of the infected cell by a phagosome.

[12] A hemolysin activity, named NlyA, with immunological reactivity to Escherichia coli anti-HlyA antibody, was identified in biovar F. t.

[13] Acid phosphatase AcpA has been found in other bacteria to act as a hemolysin, whereas in Francisella, its role as a virulence factor is under vigorous debate.

This indicates F. tularensis has evolved to depend on the host organism for certain nutrients and other processes ordinarily taken care of by these disrupted genes.

[18] Infection by F. tularensis is diagnosed by clinicians based on symptoms and patient history, imaging, and laboratory studies.

If working with cultures of F. tularensis, in the lab, wear a gown, impermeable gloves, mask, and eye protection.