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The Fungus Among Us: Valley Fever, Blastomycosis, and Histoplasmosis

These three fungi are common within our environment and have the potential to cause infection. It is important to know your risks and how to avoid the fungus among us.

From the depths of our soil, under rocks, in dirt and decaying plant matter, lies a hidden world of fungus that many have never heard of. This microscopic kingdom is responsible for a unique group of ailments ranging from mild flu-like symptoms to debilitating infections – Valley Fever, Blastomycosis, and Histoplasmosis. In this blog post we’ll take an in depth look at these unusual fungal infections – what causes them, how they can be prevented or treated, and just why it’s so important to understand how fungus affects us all.  

Coccidioidomycosis, or Valley Fever as it is more commonly known, is caused by a fungus that is known to live in the soil in the southwest United States, including Arizona and California, as well as parts of Mexico and Central and South America. Humans and animals get Valley Fever by breathing in microscopic spores, called Coccidioides, in the air, usually due to disturbed soil that kicks up dust. Symptoms of infection from Valley Fever may include fatigue, cough, fever, shortness of breath, headache, night sweats, muscle aches, joint pain, and rash on the upper body or legs. However, most people do not become sick from breathing in these spores, and those who do usually get better on their own within weeks or months. Those who don’t get better may need an antifungal medication. Those with weakened immune systems, pregnant women, diabetics, and Black or Filipino people are more likely to be affected by Valley Fever. 

Blastomycosis does not have an easy, roll of the tongue kind of name, but it is caused by the fungus Blastomyces. This fungus lives in moist soil and decomposing plant matter. In the United States, it is mostly found in the midwestern, south central, and southeastern states. Like Valley Fever, humans and animals breathe in the spores of this fungus and often do not become ill. Those who do may end up with similar symptoms to Valley Fever with the addition of skin lesions, such as blisters, ulcers, or raised bumps, and unintentional weight loss. These symptoms generally appear, if at all, between 3 weeks and 3 months after breathing in the spores. People who work in wooded areas or participate in outdoor activities such as hiking are more likely to become infected with Blastomycosis than those who do not. 

Another one without a common name is Histoplasmosis, caused by a fungus called Histoplasma.This one is found in soil that contains large amounts of bird and bat droppings. In the United States, Histoplasma is generally found in the central and eastern states. Just like the other 2, Histoplasmosis is caused by breathing in the spores of the fungus. Also, like the others, most people will not have any symptoms and will not become sick. However, those who do may have fever, cough, fatigue, chills, headache, chest pain, and body aches. If a person is to get these symptoms, they generally occur about 3 to 17 days after exposure and most will go away within a few weeks to a month. People with a weakened immune system, infants, and adults over age 55 are at higher risk for severe Histoplasmosis. 

Once someone is infected with any of these, it is very rare for them to relapse, that is to get it again. Our bodies’ immune systems will recognize the infection and fight it off before it becomes a problem. Luckily, too, none of these fungi are contagious from person to person, person to animal, or animal to person, unless spread through a wound, but that is also extremely rare. If you are among those at higher risk for infection from any of these fungi, it is important to avoid breathing in dust and working in or playing with soil. If this is unavoidable, wear a respirator mask, as an N95, wear gloves, and clean your hands or any wounds thoroughly. 

Valley Fever, Blastomycosis and Histoplasmosis are common health risks to be aware of. While they aren’t often a cause for concern, it’s still important to understand your risks when it comes to these pesky airborne spores. Keep an eye out for any chronic coughs or fever that may linger for weeks on end. If you’re noticing anything out of the ordinary, speak with your physician. 


Centers for Disease Control and Prevention. (2020, December 29). Histoplasmosis. Centers for Disease Control and Prevention. Retrieved April 19, 2023, from https://www.cdc.gov/fungal/diseases/histoplasmosis/index.html  

Centers for Disease Control and Prevention. (2022, February 9). Blastomycosis. Centers for Disease Control and Prevention. Retrieved April 19, 2023, from https://www.cdc.gov/fungal/diseases/blastomycosis/index.html  

Centers for Disease Control and Prevention. (2020, December 29). Valley fever (coccidioidomycosis). Centers for Disease Control and Prevention. Retrieved April 19, 2023, from https://www.cdc.gov/fungal/diseases/coccidioidomycosis/index.html 

Erin McGreal RN, BSN

Upper Echelon Medical in Fullerton, Orange County, East LA, and Inland Empire, California, provides comprehensive primary care services to patients of all ages living and working in the local community.
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