Gardening: Good For Your Health But Take Care With Compost and Bark Chippings

Disturbing rotting compost releasing spores into the air
Billions of spores are released when compost is disturbed

The Daily Telegraph recently highlighted the health benefits of gardening, likening it to a free gym workout every day. That is hugely beneficial to all of our longevity, our flexibility and our mental health too. If we have a respiratory illness it has been proven that exercise is vitally important for keeping our lung health in optimal condition, helping slow down or even prevent deterioration 

There are however a few hazards to be aware of, especially if you have an allergic respiratory condition such as asthma, a weakened immune system (e.g. if you have had a transplant) or even if your lungs have been damaged by smoking, your occupation or genetic illness. For some people there may be no warning as we do not yet fully understand why some people become allergic, or become infected with a fungus like Aspergillus. We suspect a genetic vulnerability may contribute but as yet we cannot screen out those who are slightly more prone to infection or allergy from those who are not - so we should try to protect everyone.

The Telegraph article mentions a broad range of hazards in the garden and includes the risk of contracting aspergillosis (an infection caused by the fungus Aspergillus) caused by disturbing rotting organic material eg compost and bark chippings. There have very rarely been reported cases (i.e. one reported case in 2015) where someone has been accidentally exposed to huge clouds of Aspergillus spores when opening bags of compost. On breathing in very large numbers of spores their immune system seems to have been overwhelmed and death followed within days. We are unsure why these cases happen but we do know that overwhelming of the immune system is possible in rats but it required huge numbers of spores to do it. We also know that some people are more susceptible than others (see above) so it is possible that combining the two may cause these cases.

Spores can be highly concentrated when composting in bags
Composting in bags

We can take steps to prevent being exposed to clouds of spores by being increasingly aware of situations where it may happen. Spores are produced when fungi have finished digesting all they can from organic material. If that material is piled up into a heap and left for days or even enclosed in bags all the spores that develop with be gathered together in one small space. If that compost is then disturbed or the bag opened then it is easy to imagine that a very high number of almost invisible spores will be projected into the face of the gardener. Some organic material is pre-packaged sealing into plastic bags (eg compost, bark chippings), some might have been recycled and kept over winter in bags by the gardener. In all cases be very cautious about opening the bags/disturbing the compost. Do so in the outside air so that spores numbers will be diluted quickly and wear appropriate HEPA facemasks. Better still, if you think you may be vulnerable get someone else to open the bags and distribute the contents.