In certain soils, cocci grow as septate hyphae. As the mycelia age, some of the hyphae form arthroconidia, which are the barrel-shaped infectious units of cocci.
Unclear circumstances surround the formation of the arthroconidia as the fungus matures.
These units resist drying and easily become airborne, as some of the neighboring attached cells become empty and act as sails. When inhaled, as few as 10 arthroconidia can cause infection. Once inhaled, the arthroconidia that survive phagocytosis mature to form endospore-containing spherules. When the spherules dehisce, an endospore may mature as quickly as 48-72 hours into another spherule. Although cocci are not contagious, lab personnel handling specimens from cocci patients must follow class III precautions carefully to avoid contracting the illness.