Back in the 80s hospital emergency units were confounded by a surge of patients with symptoms of severe asthma in Barcelona, Spain. This became a pattern and placed a considerable cost on resources. Every few weeks large numbers of patients would arrive in hospital emergency departments in several hospitals.
The authorities were perplexed and epidemiologists were called in for help, and thus a great epidemiological detective story began. This is where data comes in so handy.
Data revealed that all patients were young healthy adult males without known asthma. Almost all clusters of patients came from areas near the sea port. Further investigation showed that they all worked in the dockyards.
But what caused their symptoms was proving to be a riddle. They were tested for all causes known to cause symptoms but there were no conclusive answers.
After another episode, someone suggested that perhaps the cause was something which was unloaded at the port. Inquiry revealed that those exhibiting the most severe symptoms were involved in unloading shipment of soya bean oil. Checking data of shipments unloaded on earlier dates when those young men fell ill confirmed that they had unloaded soya bean oil on those dates too.
As a result methods of shipping and unloading soya bean oil were changed, and appropriate preventive measures provided to the workers. Happily there were no outbreaks of severe asthma after that.
This goes to show how important accurate records and an open mind are.