Tularemia was initially described in 1911 as a plague-like illness in rodents by McCoy and Chapin in California, USA. In 1912, the organism F. tularensis (called Bacterium tularense at the time) was cultured for the first time from squirrels in the region. Two years later, researchers Wherry and Lamb in Ohio described the first F. tularensis infection in humans [3,18].
In 1919, Dr. Edward Francis proposed “tularemia” to describe several clinical conditions caused by F. tularensis. He also deduced that wild rabbits were the source of infection. Tularemia is also known as rabbit fever for this reason.
Simultaneously, other researchers were hard at work trying to understand tularemia. In 1923, Parker et al. made a significant discovery that ticks were the primary vectors of the disease. However, it took almost two decades later to isolate and name the causative agent.
Dr. Francis also accidentally discovered that F. tularensis was highly infectious when he and his entire team contracted the disease. In honor of his dedicated work on Tularemia, the bacteria was named Franciscella Tularensis in 1947 after his death [3,5,18].
By 1960, around 85% of all cases of tularemia in the south-central US were found to be associated with tick exposure. Rabbits were the main contributors to the spread of tularemia to humans . Eventually, it was discovered that tularemia could be spread through other vectors, including deer flies, which is why the disease is also known as deer fly fever.
Tularemia as a Biological Weapon
Since the pathogen is infectious and can be aerosolized, many nations began exploring its potential as a biological weapon . Japan started early research on using F. tularensis as a biological weapon in 1932 and performed experiments on prisoners of war. China also developed bioweapons using F. tularensis and other species. For instance, during the Second World War, over 10,000 people were subjected to bioweapon experiments involving F. tularensis and other contagious organisms .
By the mid-twentieth century, the United States and the Soviet Union (including Russia) also began research using F. tularensis. They used genetic engineering techniques to create new strains of bacteria that are antibiotic-resistant and vaccine-subverting. These new versions were stockpiled to be used as biological weapons .
According to a former Soviet Union biological weapons scientist, most tularemia outbreaks in Eastern Europe during the Second World War resulted from bio-attacks. Modified strains of F. tularensis were used intentionally to cause infectious disease outbreaks. The Soviet Union continued to conduct research on biological weapons even in the 1990s .
In the 1950s and 1960s, the US conducted voluntary human experiments using F. tularensis on inmates in penitentiaries and non-combatant soldiers . However, the country later prohibited further attempts to develop such toxins. And after the Biological Weapons Convention of 1972 banned the development, production, and stockpiling of bacteriological and toxic weapons, all US stockpiles were destroyed .