Aspergillus spp. is a type of fungus that forms spores. It is normally found in soil,
water, and decaying vegetation. In the hospital environment, the spores settle in some
part of the ventilation system. Spores are also stirred up from construction and
renovation. Additional sources of the fungal spores could be contaminated or wet wood,
bird droppings in air ducts, or decaying fireproofing materials. The fungus causes
pneumonia in a host with a weak or otherwise compromised immune system. Patients at
risk are those undergoing organ transplant or bone marrow transplants, and depending on
the type of transplant, mortality rates are as high as 95%. Bone marrow transplant
patients, the highest risk group, should be treated like they are immunosuppressed for up
to four weeks after the procedure. The portal of entry is through the upper respiratory
track. The infection then becomes systemic and is spread into multiple deep organs.
Because few reliable tests are available for diagnosing pneumonia due to Aspergillus,
clinicians often use a lung biopsy. Blood culture techniques fail because antibody
responses in immunocompromised patients give false indications of infection.
Identification of a source of the fungi is difficult, but can be determined through careful
evaluation of each additional case. A better solution is to develop protected areas for high
risk patients. These protected areas would have special air filtration systems that direct air
flow only in certain directions. The doors to these rooms would have vacuum seals and
would have a higher pressure inside than outside. The end goal of the protected areas
would be to increase air flow in the room to the point that the air becomes essentially
sterile and to maintain a clean environment. The costs of implementing a "protected area"
system may be prohibitively high.