Histoplasmosis: A Common Fungal Lung Infection

Histoplasmosis is caused by a fungus that lives in soil, particularly where there’s a large amount of bird or bat poop. People can get histoplasmosis by breathing in fungal spores, and infection can be mild or life-threatening. It can be misdiagnosed because its symptoms are similar to those of other illnesses, like pneumonia caused by bacteria. This often results in delayed treatment. Here are some important things to know about histoplasmosis and Histoplasma, the fungus that causes this illness.

Histoplasmosis is a fungal infection that can affect anyone. It usually affects the lungs and causes pneumonia but also can affect other parts of the body. Learning about histoplasmosis can help you stay healthy and recognize symptoms early if you do get the infection.

Common Symptoms Can Lead to Delayed Diagnosis

Older man coughing

Symptoms of histoplasmosis include:

  • Fever
  • Cough
  • Fatigue (extreme tiredness)
  • Chills
  • Headache
  • Chest pain
  • Body aches

These symptoms usually appear 3 to 17 days after breathing in the fungus. Because other bacterial or viral diseases have similar symptoms, patients can experience delays in getting correctly diagnosed and treated.

Anyone can get infected, but most people who breathe in the fungus that causes histoplasmosis have no symptoms or only mild ones. Some people never know they’ve had histoplasmosis until a CT scan, X-ray, or other imaging test shows spots on their lungs. These spots can look identical to lung cancer, leading to unnecessary costs and emotional stress associated with finding the right diagnosis.

It is important to know that some people can develop severe histoplasmosis and get very sick. This includes:

  • People who have existing health problems or take medicines that lower the body’s ability to fight germs and sickness (people with weakened immune systems), and
  • People who are exposed to a large amount of the fungus.

A severe infection must be treated with prescription antifungal medicine.

If you have symptoms and suspect that you might have histoplasmosis, ask your doctor to test you for it.

How It Spreads: From Soil to Lungs

In the United States, the fungus that causes histoplasmosis mainly lives in soil in central and eastern states, especially in areas around the Ohio and Mississippi River valleys. It’s also present in other U.S. states, likely in small pockets that offer the right growing conditions (such as a large amount of bird or bat poop). The fungus also lives in parts of Central and South America, Africa, Asia, and Australia. People can get histoplasmosis by breathing in the fungus from the air in these areas. Histoplasmosis does not spread from person to person.

Be Safe Around Bird or Bat Poop

It can be difficult to avoid breathing in the fungus that causes histoplasmosis in areas where it’s common in the environment. In those areas, people who have weakened immune systems should consider avoiding activities associated with getting histoplasmosis, such as:

  • Disturbing material where there is a large amount of bird or bat poop (for example, digging in soil or chopping wood)
  • Cleaning, remodeling, or tearing down old buildings
  • Exploring caves
  • Cleaning chicken coops

Large amounts of bird or bat poop should be cleaned up by a professional company that specializes in handling hazardous waste. A small amount of bird or bat poop on a hard surface is much less likely to spread histoplasmosis than a larger amount around soil or plants.

Before starting a job or activity where there’s a possibility of being exposed to the fungus that causes histoplasmosis, review Histoplasmosis: Protecting Workers at Risk [PDF – 39 pages].

It’s important to know that people can also get histoplasmosis without being exposed to bird or bat poop.

Awareness Is Key

In areas where the fungus that causes histoplasmosis is common, it’s difficult to completely avoid exposure. That’s why knowing about histoplasmosis is one of the most important ways to avoid delays in diagnosis and treatment.

Greater awareness about histoplasmosis is needed in the United States and around the world. In Latin America and the Caribbean, histoplasmosis is one of the most common infections among people living with HIV. There, about 1 in 3 people with HIV who get histoplasmosis die from this condition. Learn more about CDC’s work to prevent deaths due to histoplasmosis by improving diagnosis and increasing access to lifesaving antifungal medications.

Estimated Areas With Histoplasmosis
This map shows CDC’s current estimate of where the fungi that cause histoplasmosis live in the environment in the US.

This map shows CDC’s current estimate of where the fungi that cause histoplasmosis live in the environment in the United States. These fungi are not distributed evenly in the shaded areas, might not be present everywhere in the shaded areas, and can also be outside the shaded areas. Darker shading shows areas where Histoplasma is more likely to live. Diagonal lines show the potential range of Histoplasma.

Fungal Disease Awareness Week
Fungal Disease Awareness Week 2022

Join CDC in sharing information to increase awareness in your community about fungal diseases during Fungal Disease Awareness Week.