Columbus, Ohio (AP) -- Ohio State University is trying to determine if two co-workers with the same lung ailment were made sick by their campus office.

Both women have been diagnosed with a disease called histoplasmosis.

Spokeswoman Amy Murray says the university is moving college of engineering employees out of a suite of offices in Hitchcock Hall, though she says tests found no mold or evidence of animal infestation.

Murray says the fungus that causes histoplasmosis develops in bat and bird droppings.

One of the stricken employees says she paid for her own test of a ceiling tile and it came back positive for the fungus.

Murray says the university still considers the source of the illnesses a mystery.

She says the histoplasmosis fungus is common and found in soil.

(Copyright 2009 by the Associated Press. All rights reserved.)