A. fumigatus is a mold species that produces many minute conidia (spores) that become airborne like the seeds of this dandelion seed-head. These spores are everywhere in the atmosphere and it has been estimated that we inhale several hundred spores every day (Abad et al., 2010).
A healthy immune system will normally eliminate these before they can start to grow at body temperature. However, individuals who are immuno-compromised (organ transplant recipients, AIDS or leukemia patients) are much more at risk as the fungus is more likely to become pathogenic, over-running the host’s weakened defenses and entering the blood stream via the lungs ultimately causing a range of diseases generally termed “aspergillosis”.
For example, an aspergilloma (fungus ball) may develop in the lungs triggering cough, fever, chest pain, and difficulty breathing and once aspergillosis is disseminated through the blood
stream it can cause widespread organ damage resulting in kidney failure or liver failure.
Aspergillus species account for 600,000 deaths a year worldwide (Denning et al., 2013)
Fernández-Molina JV, Bikandi J, Ramírez A, Margareto J, Sendino J,
Hernando FL, Pontón J, Garaizar J, Rementeria A. (December 2010). “What makes Aspergillus fumigatus a successful pathogen? Genes and molecules involved in invasive aspergillosis.”
Denning, D. W.; Pleuvry, A.; Cole, D. C. (March 2013). “Global burden of chronic pulmonary aspergillosis complicating sarcoidosis”. European Respiratory Journal41 (3): 621–6.