Types of exposure:
(1) environmental (see below)
(2) worker in a microbiology laboratory
Environmental factors:
(1) location of exposure
(2) exposure to warm, moist soil or dust rich in decaying organic material (recreation, building construction, etc)
Locations typically associated with infection:
(1) Mississippi river valley
(2) Ohio river valley
(3) along the St Lawrence River
(4) Kentucky, Virginia, West Virginia, Tennessee, North Carolina, South Carolina, northern Georgia, northern Alabama
Occasionally people have become infected outside of the United States in a tropical or subtropical location (Africa, Central America, South America, Middle East, India).
The incubation period is usually around 4 to 6 weeks.
