Mike Firth was a very accomplished recreational diver who was technically capable of diving to depths of 50m (160 feet) in search of rarely found wrecks to explore - not a feat to be taken lightly unless highly trained with a lot of specialist equipment.
In 2008 he started having breathing problems`following dives with symptoms including hacking cough, shaking and intermittantly raised temperature. After some time this was identified as a huge Aspergillus infection (aspergillosis) of his lungs which soon resulted in him being unable to walk for 25m as he rapidly lost lung function.
He was referred to the National Aspergillosis Centre in Manchester, UK which managed to get some control over his symptoms but it was still something of a mystery how this highly fit & active man could be infected by a fungus that normally only affects those who are heavily immunocompromised.
We know that this type of infection can sometimes occurr in a fully fit person if they directly inhaled huge amounts of fungal spores. These spores are incredibly tiny, some being only 2-3micrometre in diameter and as such can penetrate our lung very deeply, ultimately into the smallest air sacs (alveoli) from where if enough spores are involved our immune systems can sometimes be overwhelmed. A recent case involving a person opening a sac of compost for his garden and being exposed to a cloud of spores was probably a similar situation.
In this situation Mike seems to have inhaled spores when testing past of his equipment was working fully. The Bouyancy Compensation Device (BCD) bladder is not part of the normal breathing apparatus (and thus was not subject to the normal routine of cleaning & sterilizing of all parts that are breathed through) but is used to provide bouyancy while the diver swims - it helps the diver maintain a 'flat' position as he swims through the water by being filled with air.
Mike admitted that he liked the safeguard of being able to take a few breaths from the BSD should his main source of air fail while underwater - it was an emergency measure. For this reason he liked to be sure that the tube it was manually filled and emptied from was clear and unobstructed. Prior to going diving he blew into the tube and also sucked to check it worked in both directions, and indeed it checked out perfectly but he remembered that there was a strange taste.
Mike's lungs were so badly damaged that his only chance of a cure would now be a lung transplant. He submitted his story to many Divers publications in order to raise awareness of this serious problem and to try to prevent anyone else suffering the same fate as himself. We do it here for the same reason