Histoplasmosis is a fungal infection that is caused by inhaling fungal spores into your lungs. The spores of a fungus are often found in the fecal matter of birds and bats which is often found in soil. People are most commonly exposed to histoplasmosis when these fungal spores are airborne during cleanup or demolition projects. It is most often found in the mid-Atlantic, southeastern, and central regions of the United States. The illness can either be mild or life-threatening. Histoplasmosis most often affects your lungs. However, if the infection is severe, it can spread throughout the entire body. There are about 250,000 people in the United States who get histoplasmosis each year.

Most people who develop histoplasmosis never experience symptoms. In fact, many people are not even aware that they have the infection. However, when the infection is severe (which most often occurs in babies or people with weak immune systems), it can become a serious and life-threatening condition.

Histoplasmosis can range from mild to severe. When the infection is mild, there are often no signs or symptoms. When the infection becomes severe and life-threatening, people usually do experience signs and symptoms. The signs and symptoms with a severe form of histoplasmosis usually appear three to seventeen days after being exposed to the infection. The signs and symptoms usually include fever, chills, headache, muscle aches, dry cough, and chest discomfort.

People with histoplasmosis may also experience joint pain and a rash. When people develop the infection and already have an underlying lung disease (such as emphysema), they may develop a chronic form of histoplasmosis. When histoplasmosis becomes chronic, the signs and symptoms may include weight loss and a cough that causes blood to come up. The symptoms of chronic histoplasmosis sometimes can be similar to the symptoms of tuberculosis.

People who develop a severe form of histoplasmosis usually include babies or people who have a weakened immune system. Severe histoplasmosis is called disseminated histoplasmosis. This type of infection can affect just about any part of your body, including your mouth, liver, central nervous system, skin and adrenal glands. If the infection is left untreated, it can be fatal.

The risk of developing histoplasmosis increases with the number of spores you inhale. People who are at the highest risk include those who work in certain professions such as farming, pest control, poultry keeping, construction, roofing, landscaping, and gardening.