What is the skin infection from bird poop?

Histoplasmosis is a fungal infection caused by the fungus Histoplasma capsulatum. This fungus lives in the environment, often in soil that contains large amounts of bird or bat droppings. People can get sick with histoplasmosis if they breathe in the microscopic fungal spores. Histoplasmosis is sometimes called “cave disease” because people can get it from disturbing soil in caves that have bat droppings.

The most common symptoms of histoplasmosis infection are fever, cough, and fatigue. Most people exposed to the fungus don’t get sick. When illness does occur, it’s often mild with flu-like symptoms that go away without treatment. However, sometimes histoplasmosis can cause severe illness, especially in people with weakened immune systems.

Histoplasmosis is found throughout the world, but it’s most common in the central and eastern United States and parts of Central and South America. Bird droppings, especially from starlings and chickens, are an important source of the fungus. Outbreaks have happened when soil or materials contaminated with bird droppings are disturbed, such as during construction work.

What causes histoplasmosis?

Histoplasmosis is caused by the fungus Histoplasma capsulatum. The fungus grows as a mold in the environment, often in soil that contains bird or bat droppings. Birds don’t actually spread the disease – they aren’t affected by the fungus. But their droppings enrich the soil, providing nutrients that allow the fungus to thrive.

Histoplasma fungal spores become airborne when contaminated soil or droppings are disturbed. People can inhale the microscopic spores and become infected. Activities that can put you at risk for histoplasmosis include:

• Working in construction, demolition, landscaping, or agriculture involving soil that may have bird or bat droppings
• Cleaning or working in old buildings with bird nests in the rafters or attic
• Cave exploring where bats have left guano (droppings)
• Cleaning chicken coops or disturbing chicken run areas
• Raking, shoveling, or playing in areas underneath bird roosting sites like bridges

The biggest risk factor is exposing soil that contains a large quantity of dried bird or bat droppings. Outbreaks are often associated with disrupting roosting sites or cleaning up accumulations of guano. Just routine exposure to birds isn’t likely to cause histoplasmosis.

You can’t catch histoplasmosis directly from birds or other infected people. It’s only spread by inhaling the spores from contaminated soil or droppings.

Where is histoplasmosis found?

Histoplasmosis has been found all over the world, but it’s most common in certain parts of the United States and areas of Central and South America. In the U.S., it’s especially endemic in the central eastern states along the Ohio and Mississippi River valleys. This includes:

• Ohio
• Indiana
• Kentucky
• Tennessee
• Arkansas
• Louisiana
• Southern Missouri
• Southern Illinois
• Southern Mississippi
• Alabama

Histoplasmosis is also common along the St. Lawrence River in Canada. Areas with the highest rates of histoplasmosis have moist, acidic soil that provides ideal conditions for the fungus to thrive. Bird roosting sites in these areas allow large amounts of droppings to accumulate, further enriching the soil.

You can potentially be exposed to the fungus anywhere that has the right environmental conditions for it to grow. But infections are much less common outside of the endemic areas, except during outbreaks linked to contaminated work sites or buildings.

Histoplasmosis Rates in the U.S.

The table below shows the estimated incidence rates of histoplasmosis infections in states where it’s most common, based on CDC data:

Symptoms

Many people exposed to the histoplasma fungus don’t develop any symptoms. When illness does occur, symptoms usually appear 3 to 17 days after exposure. The most common symptoms are:

• Fever – often around 102°F (38.9°C)
• Cough – can be dry or produce phlegm
• Fatigue
• Headache
• Chest pain
• Muscle aches

Some people, especially children, may also have:

• Chills
• Joint pain
• Rash
• Mouth ulcers

These mild flu-like symptoms usually go away without treatment after a few weeks. The infection may resemble acute bronchitis or community-acquired pneumonia.

In a small number of cases, histoplasmosis can cause more severe illness. This is more common in infants, elderly adults, and people with weakened immune systems, such as from HIV/AIDS, cancer treatment, or immune disorders requiring medication. Severe symptoms can include:

• High fever
• Respiratory distress
• Severe pneumonia
• Sepsis
• Meningitis or brain infection
• Adrenal insufficiency
• Rheumatologic problems like arthritis

Disseminated histoplasmosis occurs when the infection spreads from the lungs to other organs and tissues. This serious form is fatal if left untreated, but is rare in healthy individuals.

Chronic Pulmonary Histoplasmosis

Some people develop chronic lung problems after acute histoplasmosis passes. This is more common in people over age 40. Symptoms of chronic pulmonary histoplasmosis can include:

• Cough
• Chest pain
• Fatigue
• Weight loss
• Fever

It may progress to serious lung disease requiring antifungal treatment.

Who is at risk of histoplasmosis?

Anyone can get histoplasmosis if exposed to the fungal spores. But some people are at increased risk of developing a severe infection:

• Infants and young children – Their immune systems haven’t fully developed.
• Elderly adults – They have a higher risk of severe pneumonia.
• Immunocompromised people – Such as those with HIV/AIDS, cancer, transplants, or on immunosuppressant medications. They have a high risk of disseminated histoplasmosis spreading to other organs.
• People with chronic lung disease – They may develop chronic pulmonary histoplasmosis after exposure.
• Pregnant women – Hormonal changes make them more susceptible to severe disseminated infection.
• Men exposed to large infective doses – Outbreaks show they are more likely to develop severe pulmonary symptoms than women.

People who work with soil contaminated by bird or bat droppings are also at higher risk due to repeated exposure. Jobs like construction, landscaping, poultry work, and cave exploration in bat habitats raise the risk.

Diagnosis

Histoplasmosis can be difficult to diagnose because symptoms resemble other common respiratory illnesses. Diagnostic tests for histoplasmosis include:

• Chest X-ray – May show pneumonia or pulmonary nodules.
• CT scan – Provides more detailed lung images to detect granulomas or calcified lesions.
• Lab culture – Fungal cultures from respiratory samples can grow Histoplasma organisms, but take several weeks.
• Histoplasma antigen test – Detects fungal proteins in blood, urine, or respiratory samples. Results come back in a few days.
• Biopsy – Microscopic examination and fungal stain of lung or other infected tissue can reveal Histoplasma.
• Serology blood test – Measures antibodies your immune system produces in response to the infection.

Testing for histoplasmosis antigens or antibodies is the most reliable method. Regular lab cultures often fail to detect the fungus even when it’s present. Distinguishing histoplasmosis from COVID pneumonia or tuberculosis can require multiple types of testing.

Treatment

Mild acute histoplasmosis usually clears up on its own without antifungal treatment, but people with moderate to severe infections require medication. Hospitalization may be needed for respiratory complications, disseminated disease, or infections in immunocompromised people.

Common antifungal medications for histoplasmosis include:

• Itraconazole – For milder cases, itraconazole capsules are often given for 6-12 weeks.
• Liposomal amphotericin B – Used intravenously to treat severe pulmonary and disseminated infections. Once the patient improves, treatment may switch to itraconazole.
• Posaconazole – For people intolerant to itraconazole or with severe infections.
• Voriconazole – Sometimes used off-label for histoplasmosis infections unresponsive to other antifungals.

Even after initial antifungal treatment, long-term itraconazole maintenance therapy may be needed to prevent recurrence in immunocompromised patients. Chronic pulmonary histoplasmosis also requires ongoing itraconazole to prevent progression.

Other aspects of care can include:

• Oxygen support for respiratory distress.
• Fluid replacement for dehydration.
• Medications to improve adrenal function if the adrenal glands are affected.
• Monitoring for complications like clotting issues, secondary infections, inflammatory syndrome, and septic shock.

If diagnosed and treated early, histoplasmosis generally has a good prognosis and complete recovery is common. But untreated disseminated disease in immunocompromised people is often fatal.

Prevention

Preventing histoplasmosis involves limiting exposure to the fungal spores in contaminated soil or bird/bat droppings. Protective measures include:

• Avoid areas with large amounts of bird or bat droppings. Use caution in chicken coops, caves, old attics, and under bridges where droppings accumulate.
• Wear protective equipment like respirators, gloves, disposable coveralls, and goggles when handling contaminated soil or droppings.
• Clean up guano or bird/bat droppings using wet methods – never dry sweep.
• Have soil testing done in areas suspicious for Histoplasma before beginning construction or landscaping work.
• During dust-generating activities in endemic areas, mist soil with water to reduce spread of fungal spores.
• Cover or seal off access to old stone bridges, chimneys, or buildings housing birds or bats.
• Provide engineer controls like air filtration, negative pressure, and venting systems when working in contaminated indoor areas.

Proper precautions are especially important for anyone at higher risk of severe infection, like people with HIV/AIDS. They should avoid activities with soil exposure in endemic areas. There’s no vaccine available for histoplasmosis.

Conclusion

Histoplasmosis is a fungal infection acquired by inhaling microscopic spores released from soil enriched with bird or bat droppings. While mild cases may have flu-like symptoms and resolve without treatment, severe infections can develop, especially in immunocompromised people. Outbreaks are associated with disturbing sites contaminated by guano. Diagnosis requires laboratory testing, and antifungal medications are used for treatment. Preventing exposures during activities like construction or cave exploration in endemic areas is key to avoid this respiratory infection. Proper precautions are crucial for anyone at higher risk of complications.