Dr. Maria Zolotareva, Associate Professor in the Department of Biotechnology and Industrial Pharmacy at MIREA Russian Technical University, points out that the cough may be caused by the ventilation of the house.
According to her, fine particles, including flaky epithelial cells, pollen grains, textile fibers, and fungal spores, gradually accumulate on the inner walls of ventilation ducts. Under favorable conditions (high humidity and temperature), mold fungi of the genera Aspergillus and Penicillium grow, which can pose a risk to indoor air quality.
She explains: "The fungus forms a mycelium (a branching network of threads that grows within the porous surface of ventilation walls). A single mold colony can produce up to one million spores per square centimeter of surface area, which are carried by the airflow through the ventilation system and then enter the dwelling."
It notes that the spores of the Aspergillus fungus are 2-5 micrometers in size, and when inhaled, some remain in the nose or trachea, while others penetrate directly into the alveoli of the lungs. In a healthy person, phagocytic cells in the alveoli destroy these spores, but if the immune system is weakened—after a severe case of influenza, while taking hormonal medications, or in old age—the spores are not neutralized and can germinate, eventually leading to aspergillosis.
She says: "Aspergillosis is an infectious fungal disease caused by types of mold of the Aspergillus genus. It leads to tissue damage, blood clots, and other complications. Aspergillosis is associated with symptoms such as a nighttime cough without phlegm, shortness of breath when walking normally, and a fever ranging between 37 and 37.5 degrees Celsius that lasts for weeks. However, treatment with antibiotics or antihistamines is ineffective, as the reaction is infectious and not allergic."
