According to my ancient copy of Volk (Medical Microbiology, 1978), Coccidiodes
immitis infects humans through inhalation. Volk further states that this
organism is endemic to the soil of arid regions, and that 60% of primary
infections are asymptomatic. If c. immitis were transmitted by human milk, the
large number of silent carriers would make this apparent.
Catherine Watson Genna, IBCLC NYC [log in to unmask]