Prevention of Aspergillosis in Children - An Overview

Introduction:

Aspergillus is a fungus found in all places (indoors and outdoors). The disease caused by the fungus is known as aspergillosis. The spores of aspergillus are present in the air, and people breathe in the spores without any health effects or getting sick. However, suppose people with low immunity, lung disease, or a weakened immune system breathe in the spores. In that case, they have a higher chance of developing aspergillosis, ranging from mild to severe infections.

How Does One Get Aspergillosis Disease?

Aspergillus spores are present in the environment. When someone breathes in the aspergillus spores, they can get infected and suffer from mild to severe disease. The different types of aspergillosis include:

1. ABPA (Allergic Bronchopulmonary Aspergillosis) - ABPA is more common in asthma and cystic fibrosis.

2. Aspergilloma (Fungus Ball) - This type affects people with lung diseases such as tuberculosis.

3. Chronic Pulmonary Aspergillosis - Chronic pulmonary aspergillosis is common in individuals with sarcoidosis, tuberculosis, COPD (chronic obstructive pulmonary disease), and other lung diseases.

4. Invasive Aspergillosis - It is a more severe infection in immunocompromised patients (stem cell transplant, corticosteroid use), immunocompromised children, or hospitalized patients suffering from other critical illnesses such as influenza.

Which Children Are at a Higher Risk of Aspergillosis?

Children with poor immunity and weakened immune system are more prone to develop aspergillosis fungal infection. Invasive aspergillosis infections occur in the following–

• Congenital immunodeficiencies (such as severe congenital neutropenia).

• Infections like HIV (human immunodeficiency virus) reduce the child's immunity.

• Use of immunosuppressive drugs (corticosteroids or chemotherapy).

• Acute leukemia.

• Undergoing procedures such as stem cell transplantation (allogenic).

What Are the Three Main Risk Factors of Aspergillosis in Children?

The following risk factors increase the chance of aspergillosis in children:

1. An absolute neutrophil count below 500 cells per cubic millimeter.

2. Use of immunosuppressive corticosteroids.

3. Mucosal tissue damage.

How to Prevent Aspergillosis?

It is difficult to avoid breathing in the spores of aspergillus as the fungus is found commonly in the environment. Individuals and children with weak immune systems can lower their risk of severe aspergillosis with simple steps:

Protection:

1. Avoid areas with dust (where there is more chance of spore inhalation), such as excavation or construction sites.

2. Wearing respirator-type face masks (such as N95 masks) in high-risk areas.

3. Avoiding activities that require working with dust and soil, such as gardening or yard work.

4. Wearing shoes, long-sleeved shirts, and long pants (fully covered) when participating in outdoor activities.

5. Wearing gloves when handling soil, manure, or moss.

6. If the skin gets injured and exposed to dust or soil, cleaning thoroughly with water and soap is essential.

Antifungal Medication: Individuals (those with stem cell or organ transplantation) are at a high risk of aspergillosis. Their healthcare provider might assess their condition and prescribe antifungal medications that prevent invasive aspergillosis and other fungal infections.

Testing for Infection: Individuals without obvious symptoms but at high risk can benefit from testing their blood to detect early invasive aspergillosis infection.

What Medications Are Given for Prophylaxis From Invasive Aspergillosis in Children?

Antifungal agents can be used as primary and secondary prophylaxis in children at high risk for developing severe or invasive aspergillosis. Those pediatric patients with leukemia (recurrent or de novo), bone marrow failure syndromes, chronic prolonged neutropenia, aplastic anemia, chronic granulomatous disease, allo-stem cell transplant recipients, and children undergoing procedures such as lung transplantation are considered for prophylaxis administration. In addition, the local epidemiology must be considered to decide on the appropriate prophylaxis strategy. Prophylaxis is not recommended for other individuals or children who do not belong to the high-risk group.

The following are recommended for stem cell transplantation patients with graft vs. host disease (GVHD):

1. Voriconazole - This medication is indicated for children older than two years.

2. Itraconazole - This medication is indicated for children older than two years.

3. Posaconazole - This medication is indicated for children over 13.

Other medications for prophylaxis in children include the following–

1. Liposomal Amphotericin B.

2. Micafungin.

3. Aerosolized liposomal Amphotericin B.

For those who have undergone lung transplantation:

1. Voriconazole.

2. Itraconazole.

3. Inhaled Amphotericin B (three to four months after transplantation).

What Are the Measures to Prevent Aspergillosis in Children’s Hospitals?

Apart from drug prophylaxis, several strategies for infection control can be used to prevent severe aspergillosis among immunocompromised children with leukemia or stem cell transplants. The strategies can help to decrease the children's exposure to sources of fungal spores. These include

1. Protective Environment for Hospitalized Patients: Strict criteria have to be implemented to accommodate high-risk children in a safe environment with:

   • Efficient protective room ventilation.

   • Use of HEPA filters (high energy particulate air).

   • Proper room sealing, proper isolation, and automatic doors.

   • Directed airflow and the positive pressure differential must be maintained between the patient's room and outside.

   • Restricted connections to the room.

   • Avoid permitting flowers and plants into the patient's room.

2. For Children Who Are Not Hospitalized: The high-risk children and their parents must be educated on the following:

   • Avoidance of construction areas.

   • Avoidance of stagnant waters.

   • Avoidance of areas with increased moisture.

   • Avoidance of gardening and lawn mowing.

   • Appropriate food hygiene.

   • Hand hygiene.

3. If renovation or construction works are ongoing in the hospital, it is essential to improvise and increase infection control strategies.

4. Microbiological analysis of the environment (environmental sampling strategies) can be done routinely in high-risk areas.

5. The function of hospital filters has to be routinely checked.

What Is the Treatment for Aspergillosis?

Medications and treatments for aspergillosis depend upon the type of aspergillosis.

• Invasive Aspergillosis - Treatment includes medications like Voriconazole.

• Cutaneous Aspergillosis - Micafungin is used for the treatment of cutaneous aspergillosis.

• Chronic Pulmonary Aspergillosis - Medications like Posaconazole, Lipid Amphotericin formulations, Itraconazole, and Caspofungin are mostly used.

• Aspergilloma - Aspergilloma may require antifungal medications and surgery.

• Allergic Bronchopulmonary Aspergillosis (ABPA) and Allergic Aspergillus Sinusitis - These are treated with Itraconazole.

Conclusion:

The spores of aspergillus are present in the air, and one cannot prevent the children from breathing in the spores. For high-risk children (immunocompromised, leukemia, and transplant patients), drug prophylaxis and other preventive measures are essential to prevent invasive aspergillosis. Prophylaxis is not recommended for other individuals or children who do not belong to the high-risk group. Strict criteria must be implemented in hospitals where high-risk children are accommodated to ensure a safe environment free from aspergillus spores.