Causes

Tularemia doesn't occur naturally in humans and isn't known to pass from person to person. However, tularemia occurs worldwide, especially in rural areas, because many mammals, birds and insects are infected with F. tularensis. The organism can live for weeks in soil, water and dead animals.

Unlike some infectious diseases that spread from animals to people in just one way, tularemia has several modes of transmission. How you get the disease usually determines the type and severity of symptoms. In general, you can get tularemia through:

• Insect bites. Although a number of insects carry tularemia, ticks and deer flies are most likely to transmit the disease to humans. Tick bites cause a large percentage of cases of ulceroglandular tularemia.
• Exposure to sick or dead animals. Ulceroglandular tularemia can also result from handling or being bitten by an infected animal, most often a rabbit or hare. Bacteria enter the skin through small cuts and abrasions or a bite, and an ulcer forms at the wound site. The ocular form of tularemia can occur when you rub your eyes after touching an infected animal.
• Airborne bacteria. Bacteria in the soil can become airborne during gardening, construction or other activities that disturb the earth. Inhaling the bacteria can lead to pneumonic tularemia. Laboratory workers who work with tularemia also are at risk of airborne infection.
• Contaminated food or water. Although uncommon, it's possible to get tularemia from eating undercooked meat of an infected animal or drinking contaminated water.