Histoplasmosis: symptoms and treatment – MAPFRE Blogs

Histoplasmosis is a fungal infection transmitted by inhaling spores in contaminated soil. Learn about symptoms, risk factors and treatment.

Histoplasmosis is an infection caused by the fungus Histoplasma capsulatum, which lives in soil contaminated with bird or bat droppings, especially in humid and poorly ventilated environments (such as caves, chicken coops, silos, basements or demolition sites).

This fungus releases microscopic spores into the air which, when inhaled, can reach the lungs and other organs and cause infection.

It is not transmitted from person to person. Contagion occurs exclusively by inhalation of the fungus in the environment, not through direct contact between humans or through food.

What causes this disease?

The direct cause is the inhalation of Histoplasma capsulatum spores. These spores are generally found in:

• Soil contaminated with bat guano or bird droppings such as pigeon coops, chicken coops (they are soils rich in nitrogen).
• Areas with accumulation of dust or dirt that has been removed (excavations, demolitions, barn cleaning, etc.).
• More frequent in temperate and humid climates.

Once inhaled, the spores enter the lungs and can lodge in the alveolicausing a infection, pulmonary or disseminateddepending on the patient’s immune response. After reaching the bronchi and alveoli of the lungs, in the following days they are phagocytosed by alveolar macrophages (cells of the immune system), but not destroyed. Infected macrophages migrate to the mediastinal lymph nodes, liver and spleen. In healthy people, these yeasts remain dormant. However, in immunocompromised individuals, they can reactivate and cause progressive disease.

Risk factors

The fungus can be inhaled and cause infection in anyone, but there are a series of factors that increase the risk of infection and/or its severity:

• Environmental exposure
  • Working in or visiting caves, mines, poultry farms or old buildings with bird/bat droppings.
  • Demolition workers, chimney sweeps, excavations or remodeling of old houses.
• Immunodeficiencies (weakened immune system): HIV/AIDS, transplant recipients, patients under prolonged immunosuppressive or corticosteroid treatment.
• Babies and elderlyAt extreme ages, immune systems are weaker.
• Patients with lung diseases chronic diseases such as COPD.

How to prevent contagion?

• Avoid removing soil or debris in areas infested by birds or bats without adequate protection.
• Use masks with filters (N95 or higher) in high-risk jobs.
• Humidify the soil before working with it, to prevent dust with spores from dispersing into the air.
• Seal windows, attics or tanks where birds or bats may nest.
• Disinfect areas contaminated with guano using specific products and personal protection.

What are the main symptoms?

In most cases, especially in healthy people, the infection is asymptomatic or has very mild symptoms. However, in some people it can cause a respiratory illness similar to the flu or pneumonia.

If you identify any of these symptoms and, above all, if you are a person at risk, consulting with specialists is vital; at MAPFRE Home Insurance you have great professionals at your disposal.

CALCULATE YOUR PRICE

Types of histoplasmosis

Acute pulmonary histoplasmosis

• Mild or asymptomatic infection. It is self-limiting and the symptoms disappear in a few weeks.
• It can cause a flu-like illness: fever, chills, headache, myalgia and dry cough. It usually resolves without specific treatment.

Chronic pulmonary histoplasmosis

• It affects people with previous lung disease, such as emphysema.
• It manifests with chronic respiratory symptoms and lung lesions that progress with fibrosis, granulomas and cavitations.

Disseminated histoplasmosis

It occurs when the immune system fails to contain the infection, allowing the spread of the fungus through the mononuclear phagocytic system.

• Acute disseminated
  • More common in children and young adults with massive exposure or immunosuppression.
  • It causes high fever, nausea, vomiting, diarrhea, respiratory distress, lymphadenopathy, and hepatomegaly.
• Disseminated chronicle
  • It mainly affects immunocompromised adults, especially with hematological diseases or on immunosuppressive treatment.
  • Symptoms: weight loss, fatigue, persistent fever, anemia, thrombocytopenia, hepatomegaly, splenomegaly and ulcers in the gastrointestinal tract.

Complications and possible evolution of the disease

If not detected and treated properly, especially in people with low immunity, histoplasmosis can cause:

• Disseminated histoplasmosis: affects organs such as the liver, bone marrow or nervous system.
• Pulmonary fibrosis: irreversible damage to lung tissue.
• Respiratory distress syndrome (severe respiratory failure).
• Death in very serious untreated cases.

How is the diagnosis made?

Diagnosing histoplasmosis can be difficult because its symptoms are confused with other respiratory infections.

The most used methods are:

• Blood or urine antigen test (rapid detection tests).
• X-ray or tomography of the chest to identify nodules or lung lesions.
• Sputum or tissue cultures (slower but confirm the infection).
• Lung biopsy if chronic disease or tumor is suspected.
• Antibody test specific against histoplasma.

The diagnosis should always be contextualized with the patient’s background and history, recent travel, or work or environmental exposures.

Treatment

Treatment depends on the severity of the infection and the patient’s immune status and is based on the use of specific antifungals:

Mild cases in healthy people

• May not require antifungal treatment.
• Medical surveillance and symptom control is recommended.
• 90% of patients recover spontaneously.

Moderate cases or with risk factors

• It is used oral antifungal as itraconazole, for 6 to 12 weeks.

Serious or widespread cases

• Hospital treatment with intravenous liposomal amphotericin B.
• It subsequently requires continuing oral maintenance treatment with itraconazole for several months.
• In immunocompromised patients, prolonged antifungal treatment or prophylaxis may be required.

What you should know…

• Histoplasmosis is an infection caused by inhaling spores of the fungus Histoplasma capsulita, present in soil contaminated with bird or bat droppings, and is not transmitted from person to person.
• Risk factors include exposure to contaminated environments, immunodeficiencies, extreme ages, and lung diseases; The disease can range from asymptomatic to severe and disseminated.
• Diagnosis is made through blood tests, imaging, and cultures, and treatment varies depending on severity, from surveillance in mild cases to oral or intravenous antifungals in severe cases.