Most patients reporting breathing difficulties are suffering from asthma, emphysema or chronic bronchitis and respond to treatment, but a significant minority do not respond to treatment and are then referred to testing for fungal infection. 15-20% of all patients are found to be positive for Aspergillus fumigatus which causes symptoms similar to asthma.
Evidence is accumulating that A. fumigatus can grow in the lungs of some people, causing allergies in some, worsening the symptoms of asthma patients (Severe Asthma with Fungal Sensitivity, SAFS) and it is known that it can trigger long term illness in others (Allergic Bronchopulmonary Aspergillosis, ABPA) or much worse in patients who have recently had an organ transplant (Invasive Aspergillosis, IA) or who have pre-existing conditions such as Tuberculosis (Aspergilloma, Chronic Pulmonary Aspergillosis, CPA).
This hazard may well have had its cause contributed to by the smog in Mumbai. The hazards of smog have been reported before in connection with an increase in asthma rates, but levels of contact with Aspergillus have not been investigated in connection with this problem. Here we find that Aspergillus can be a major contributor to breathing problems caused by smog.