Histoplasmosis is a fungal disease, growing in the guano of pigeons that has the potential to cause serious damage. It is particularly damaging due to the fact that many healthy people may carry the disease and be asymptomatic, but still infectious, having the potential to infect other, less healthy people. This disease primarily targets the respiratory system, namely the lungs. For relatively healthy people, the symptoms often are just minor respiratory problems, such as coughing and wheezing. However, if it is left untreated, and your immune system is weak, histoplasmosis has the potential to develop into disseminated histoplasmosis, spreading to other organs of the body, causing them to fail with potentially fatal consequences. Therefore, if you have an existing condition that weakens the immune system, such as AIDS, this can be a very serious disease. Smokers must also be aware, as the damage that smoking does to the lungs can prevent them from dealing with the fungus. Other complications may arise, such as pneumonia and the scarring of the retina. Usually, amongst those with mild symptoms, histoplasmosis does not need treatment, as the immune system will deal with it. If treatment is necessary, it comes in the form of antifungal medications. Thankfully, only 5% of those infected will need such treatments.