History of tularemia research: from the Astrakhan Pestis Ambulans to a ubiquitous independent nosological entity

Today, the legitimacy of tularemia as an independent nosological entity is beyond doubt, as both its causative agent and clinical manifestations are well studied. However, this diagnosis is just over 100 years old. In the late 19th century, practicing physicians began to acknowledge the existence, within the well-known disease of plague, of a more or less distinct form of it (as S.P. Botkin referred to as “plague of mild strength,” pestis ambulans, pestis nostras, peste frustre, etc.), characterized by a relatively mild course and, at the very least, low contagiousness or even a complete absence of human-to-human transmission. The causative agent of this disease was isolated only in 1911 by American researchers G.W. McCoy and C.W. Chapin (the article on this discovery was published in 1912) from California ground squirrels (gophers) during an investigation of a “plague-like disease” in these rodents near Tulare Lake. The microorganism was named Bacterium tularense after the place of its identification. The association of this pathogen with human diseases involving intoxication syndrome and lymphadenopathy was established in 1921 by American physician and researcher E. Francis, who coined the name “tularemia.” In other words, the discovery of tularemia followed the reverse path: not from clinical observation to etiology, but from the pathogen to the clinical features of the disease. In Japan, tularemia was first described in 1924–1925 by H. Ohara under the name Yatobyo (yato meaning wild rabbits and byo meaning disease); by 1925, its identity as tularemia had been confirmed. The diagnosis was first introduced and later widely accepted in the Soviet Union in 1926. Subsequently, cases of tularemia have been reported in nearly all countries (except South America), and in 1947 the pathogen was justifiably renamed to Francisella tularensis.