Histoplasmosis is a disease caused by a fungus (or mold) called Histoplasma. The fungus is common in the eastern and central United States. It grows in soil and material contaminated with bat or bird droppings. You get infected by breathing the fungal spores. You cannot get the infection from someone else.

Histoplasmosis is often mild, with no symptoms. If you do get sick, it usually affects your lungs. Symptoms include feeling ill, fever, chest pains, and a dry cough. In severe cases, histoplasmosis spreads to other organs. This is called disseminated disease. It is more common in infants, young children, seniors, and people with immune system problems.

Your doctor might do a variety of tests to make the diagnosis, including a chest x-ray, CT scan of the lungs, or examining blood, urine, or tissues for signs of the fungus. Mild cases usually get better without treatment. Treatment of severe or chronic cases is with antifungal drugs.

Histoplasmosis is an infection caused by the fungus Histoplasma. The fungus lives in the environment, particularly in soil that contains large amounts of bird or bat droppings. In the United States, Histoplasma mainly lives in soil in the central and eastern states, especially areas around the Ohio and Mississippi River valleys. The fungus also lives in parts of Central and South America, Africa, Asia, and Australia.

People can get histoplasmosis after breathing in the microscopic fungal spores from the air, often after participating in activities that disturb the soil. Although most people who breathe in the spores don’t get sick, those who do may have a fever, cough, and fatigue. Many people who get sick will get better on their own without medication. In some people, such as those who have weakened immune systems, the infection can become severe, especially if it spreads from the lungs to other organs.

Who gets histoplasmosis?

Anyone can get histoplasmosis if they’ve been in an area where Histoplasma lives in the environment. Histoplasmosis is often associated with activities that disturb soil, particularly soil that contains bird or bat droppings. Certain groups of people are at higher risk for developing the severe forms of histoplasmosis:

• People who have weakened immune systems, for example, people who:
  • Have HIV/AIDS
  • Have had an organ transplant
  • Are taking medications such as corticosteroids or TNF-inhibitors
• Infants
• Adults aged 55 and older

Is histoplasmosis contagious?

No. Histoplasmosis can’t spread from the lungs between people or between people and animals. However, in extremely rare cases, the infection can be passed through an organ transplant with an infected organ.

If I’ve already had histoplasmosis, could I get it again?

It’s possible for someone who’s already had histoplasmosis to get it again, but the body’s immune system usually provides some partial protection so that the infection is less severe the second time. In people who have weakened immune systems, histoplasmosis can remain hidden in the body for months or years and then cause symptoms later (also called a relapse of infection).

Can my pets get histoplasmosis?

Yes. Pets, particularly cats, can get histoplasmosis, but it is not contagious between animals and people. Histoplasmosis in cats and dogs is similar to histoplasmosis in humans. Like humans, many cats and dogs that are exposed to Histoplasma never get sick. Cats and dogs that do develop symptoms often have symptoms that include coughing, lack of energy, and weight loss. The fungus that causes histoplasmosis grows well in soil that contains bird droppings, but birds don’t appear to be able to get histoplasmosis. If you’re concerned about your pet’s risk of getting histoplasmosis or if you think that your pet has histoplasmosis, please talk to a veterinarian.

How can I prevent histoplasmosis?

It can be difficult to avoid breathing in Histoplasma in areas where it’s common in the environment. In areas where Histoplasma is known to live, people who have weakened immune systems (for example, by HIV/AIDS, an organ transplant, or medications such as corticosteroids or TNF-inhibitors) should avoid doing activities that are known to be associated with getting histoplasmosis, including:

• Disturbing material (for example, digging in soil or chopping wood) where there are bird or bat droppings
• Cleaning chicken coops
• Exploring caves
• Cleaning, remodeling, or tearing down old buildings

Large amounts of bird or bat droppings should be cleaned up by professional companies that specialize in the removal of hazardous waste.

What are public health agencies doing about histoplasmosis?

• Surveillance. In some states, healthcare providers and laboratories are required to report histoplasmosis cases to public health authorities. Disease reporting helps government officials and healthcare providers understand how and why outbreaks occur and allows them to monitor trends in the number of histoplasmosis cases.
• Developing better diagnostic tools. The symptoms of histoplasmosis can be similar to those of other respiratory diseases. Faster, more reliable methods to diagnosis histoplasmosis are in development, which could help minimize delays in treatment, save money and resources looking for other diagnoses, and reduce unnecessary treatment for other suspected illnesses.
• Building laboratory capacity. Equipping laboratories in Latin America to be able to diagnose histoplasmosis and perform laboratory-based surveillance will help reduce the burden of HIV-associated histoplasmosis in these areas.

Where does Histoplasma live?

Histoplasma, the fungus that causes histoplasmosis, lives throughout the world, but it’s most common in North America and Central America. In the United States, Histoplasma mainly lives in soil in the central and eastern states, particularly areas around the Ohio and Mississippi River Valleys, but it can likely live in other parts of the U.S. as well. The fungus also lives in parts of Central and South America, Africa, Asia, and Australia.

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 shading shows the potential range of Histoplasma.

Life cycle of Histoplasma

Histoplasma spores circulate in the air after contaminated soil is disturbed. The spores are too small to see without a microscope. When people breathe in the spores, they are at risk for developing histoplasmosis. After the spores enter the lungs, the person’s body temperature allows the spores to transform into yeast. The yeast can then travel to lymph nodes and can spread to other parts of the body through the bloodstream.

Most people who are exposed to the fungus Histoplasma never have symptoms. Other people may have flu-like symptoms that usually go away on their own.

Symptoms of histoplasmosis include:

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

How soon do the symptoms of histoplasmosis appear?

Symptoms of histoplasmosis may appear between 3 and 17 days after a person breathes in the fungal spores.

How long do the symptoms of histoplasmosis last?

For most people, the symptoms of histoplasmosis will go away within a few weeks to a month. However, some people have symptoms that last longer than this, especially if the infection becomes severe.

Severe histoplasmosis

In some people, usually those who have weakened immune systems, histoplasmosis can develop into a long-term lung infection, or it can spread from the lungs to other parts of the body, such as the central nervous system (the brain and spinal cord).

How is histoplasmosis diagnosed?

Healthcare providers rely on your medical and travel history, symptoms, physical examinations, and laboratory tests to diagnose histoplasmosis. The most common way that healthcare providers test for histoplasmosis is by taking a blood sample or a urine sample and sending it to a laboratory.

Healthcare providers may do imaging tests such as chest x-rays or CT scans of your lungs. They may also collect a sample of fluid from your respiratory tract or perform a tissue biopsy, in which a small sample of affected tissue is taken from the body and examined under a microscope. Laboratories may also see if Histoplasma will grow from body fluids or tissues (this is called a culture).

Where can I get tested for histoplasmosis?

Most healthcare providers can order a test for histoplasmosis.

How long will it take to get my test results?

It depends on the type of test. Results from a blood test or a urine test will usually be available in a few days. If your healthcare provider sends a sample to a laboratory to be cultured, the results could take a couple of weeks.

How is histoplasmosis treated?

For some people, the symptoms of histoplasmosis will go away without treatment. However, prescription antifungal medication is needed to treat severe histoplasmosis in the lungs, chronic histoplasmosis, and infections that have spread from the lungs to other parts of the body (disseminated histoplasmosis). Itraconazole is one type of antifungal medication that’s commonly used to treat histoplasmosis. Depending on the severity of the infection and the person’s immune status, the course of treatment can range from 3 months to 1 year.

Histoplasmosis is an infection caused by a fungus called Histoplasma capsulatum. The fungus lives in the environment in the central and eastern United States, parts of Central and South America, and other areas of the world. People can get histoplasmosis after breathing in the microscopic fungal spores from the air, although most people who inhale the spores don’t get sick.

Histoplasmosis sometimes affects healthy people (particularly people who are exposed to soil in endemic areas that contains large amounts of bird or bat droppings), but the infection often goes away without antifungal medication. However, histoplasmosis can be very serious in people who have weakened immune systems, such as people with cancer or HIV/AIDS.

Why is histoplasmosis a problem?

• In Latin America, histoplasmosis is one of the most common opportunistic infections among people with HIV/AIDS, and the mortality rate ranges from 20–40%.
• The signs and symptoms of histoplasmosis are very similar to those of other respiratory infections such as tuberculosis (TB), which may lead to delays in diagnosing and treating histoplasmosis appropriately.
• The standard methods available to diagnose histoplasmosis, such as culture or histopathology, often require invasive procedures to obtain a sample for testing. In addition, culture can take days to weeks to produce results, and histopathology has limited sensitivity, meaning it doesn’t always detect the infection.
• Some antifungal medications to treat histoplasmosis are not widely available or are very expensive.

What CDC is doing to prevent deaths from histoplasmosis

• CDC is working with partners in the private sector and international government and non-governmental organizations to develop ways to diagnose histoplasmosis faster and more reliably.
• A new enzyme-linked immunosorbent assay (ELISA) can detect Histoplasma antigen in urine, and is potentially faster, cheaper, and more sensitive than traditional diagnostic methods. Earlier, more reliable diagnosis of histoplasmosis can prevent deaths by:
  • Minimizing delays in treatment
  • Saving money and resources spent looking for alternate diagnoses, and
  • Reducing unnecessary treatment for other suspected illnesses.
• CDC is helping build laboratory capacity to diagnose histoplasmosis and establish laboratory-based surveillance in Latin America and the Caribbean to better understand the public health burden of histoplasmosis.
• CDC is working to increase access to life-saving antifungal medications.