Infants, young children, and older persons, in particular those with chronic
lung disease are at increased risk
for severe disease. Disseminated disease is more frequently seen in people with cancer, AIDS or other forms of immunosuppression.
H. capsulatum grows in soil and material contaminated with bat or bird droppings. Spores become airborne when contaminated soil is disturbed. Breathing the spores causes infection. The disease is not transmitted from an infected person to someone else.