Asthma

Is it time to monitor fungal spore levels as well as pollen counts?


Exposure to outdoor fungal spores can cause acute respiratory effects in vulnerable individuals such as people with asthma, a Victorian study shows.

And the finding that fungal spore counts are related to adverse effects on lung function and airway inflammation suggests they should be included in aeroallergen monitoring systems, according to Melbourne University researchers.

In a retrospective study they looked at associations between levels of 12 outdoor fungal spore species and respiratory measures such as spirometry values and fractional exhaled nitric oxide, (FeNO)  in 936 participants in the Melbourne Atopy Cohort Study during September 2009 to December 2011.

Higher levels of outdoor fungal spores such as smut (ustilago) and Drechslera  were associated with immediate and delayed reduced FEV1 on the day of exposure and also after a three day lag.

The associations between different spores were variable, with some including Alteneria also causing increased risk of reduced bronchodilator response.

This “indicated that exposure to these fungal spores may be associated with triggering acute bronchoconstriction, further supported by the associations with reversibility of airflow limitation,” said the study investigators from the Allergy and Lung Health Unit at the Melbourne School of Population and Global Health.

No associations were found overall between any fungal spores and airway inflammation as assessed by higher FeNO measures, but significant effects were seen on airways inflammation in fungi-sensitised individuals and those with diagnosed asthma.

“Our findings suggest that not all fungal spores have the same effect on the airways and when we grouped the fungal taxa into total numbers, the signals found with individual fungal taxa were not evident. This highlights the importance of not grouping fungal taxa together when exploring their health effects,” the researchers wrote in Environmental Research.

“Outdoor fungal spores are ubiquitous and cannot be readily controlled but understanding their effects on respiratory function may help predict impairment in fungal sensitised or asthmatic individuals. People who are sensitised to fungi and/or living with asthma, may benefit from minimising their exposure to elevated levels of outdoor fungal spores.”

However, they said prediction of high-risk periods for fungal spores would be difficult given their diversity and the unpredictable effects of weather conditions on different spore species.

“A strategy to address this could involve including sentinel fungal spore counts in existing aeroallergen monitoring systems and providing warning information to high-risk individuals prior to high concentration days,” they suggested.

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