A severe lung infection caused by the common airborne mold Aspergillus fumigatus, known as aspergillosis, is on the rise, with experts warning of mounting challenges in diagnosis and treatment. The fungus, which grows on decaying organic matter such as compost and leaves, typically poses no threat to healthy individuals, but it can lead to a serious, potentially fatal condition in those with weakened immune systems or pre-existing lung conditions.
Ruth McQueen, a 61-year-old psychotherapist, experienced a prolonged and severe hacking cough that led to repeated emergency room visits. Initially treated with antibiotics for a suspected bacterial infection, her condition worsened, causing difficulty breathing and chest pain. Investigations revealed she had allergic bronchopulmonary aspergillosis, a severe immune response to the fungus in her lungs, which also appeared to be growing on her lung tissue. This condition can cause significant airway inflammation, excess mucus production, and permanent lung damage.
McQueen's experience highlights a broader issue: a lack of widespread understanding and diagnostic capacity for aspergillosis within many healthcare systems. Professor David Denning of Manchester University notes that the complexity of testing makes it difficult to collect comprehensive data on the condition, leaving policymakers unaware of its true scale. Diagnosis often requires a combination of lung scans and PCR tests to detect fungal DNA in the blood, as no single test is sufficient. Denning warns that many cases of invasive aspergillosis go undetected because clinicians are not actively looking for the infection.
A 2012 study examining UK post-mortem data identified aspergillosis as one of the two most common missed diagnoses in deceased patients. Compounding the diagnostic challenges, the fungus is becoming increasingly resistant to standard antifungal treatments, particularly azoles. A study published in The Lancet Microbe found that azole-resistant strains are prevalent, with one in six patients in Dutch hospitals between 1994 and 2022 infected with at least one such strain.
Individuals in intensive care units, especially those with conditions like COVID-19 or chronic obstructive pulmonary disease (COPD), are particularly vulnerable. Their structurally damaged lungs and weakened immunity make them susceptible to colonization by Aspergillus fumigatus. Research suggests that the risk of death for these patients can double when they contract an aspergillus infection. Professor Denning estimates that up to one-third of COPD-related deaths in the UK could be attributable to invasive pulmonary aspergillosis.
Flu epidemics also present a significant risk factor, with studies indicating that a substantial percentage of hospitalized flu patients develop aspergillosis. The World Health Organization has designated Aspergillus fumigatus a top-priority fungal threat due to its growing resistance to treatment and its global impact, urging for faster diagnosis, improved drugs, and enhanced medical training.
Despite the grim outlook, research offers a glimmer of hope. Scientists at the University of East Anglia have identified a mechanism within immune cells, involving a protein called RAB5c, that helps the body fight off aspergillosis infections. This discovery could pave the way for new therapies that bolster the patient's own immune system to combat the fungal disease.
Ruth McQueen, while awaiting further treatment, continues her work as a psychotherapist, expressing uncertainty about her long-term prognosis due to the complex nature of her illness and the evolving medical strategies available.