This can be quickly noticed in people who are allergic to mold. They are usually the first to detect mold because it causes them irritation if they are anywhere near mold. Once they are out of the vicinity, these allergic symptoms stop. You could say that such people are somewhat lucky because their body indicates the presence of mold and they can get away from the area immediately.
A majority of the population is not allergic to mold and their bodies do not indicate any side effects initially. This might result in a false sense of safety, but in reality it is likely to have long term effects. Long term side effects may include learning disabilities, mental problems, heart problems, chronic fatigue syndrome and bleeding in the lungs.
Myotoxins can be deadly and mold is known to produce these harmful myotoxins, in order to destroy other species of mold. This is carcinogenic and deadly to humans.
Molds colonize by producing Spores. These are dangerous to human beings as the spores settle in the lungs and the body might not be able to throw them out. This results in spores getting trapped inside the body and leading to scar tissue.