Module 4: Occupational Allergy - Exercise

EXERCISE:

Read through the following case study and answer the following questions:

In recent years phytase (and other enzymes) have been used increasingly in animal feed as a means of reducing phosphate emissions from animal farms. Phytase is a hydrolytic enzyme (phosphatase) that releases phosphate from indigestible phospho-carbohydrate (phytate/phytic acid). In the gut this would result in enhanced phosphate uptake and reduce the need for phosphate supplements in animal feed used on animal farms.

In a so-called "premix" factory, where such supplements are produced/formulated mixtures usually containing various enzymes including phytase, vitamins, antibiotics etc. was added either as a powder or as an aerosol of a fluid enzyme solution to batches of animal feed. The phytase is a product of a biotechnological company, which is derived from a recombinant strain of Aspergillus niger ("genetically modified organism"), and sold as powder or as solution.

In this plant there were approximately 60 production workers, of whom only 11 were frequently handling phytase. Two years after the introduction of the phytase in the production process one of the production workers reported severe chest problems - wheezing, shortness of breath - particularly during and after enzyme handling. The same worker had complained of itchy eyes and nose in the past year. Two workers in the packing department have also been complaining of an itchy skin rash.

Questions:

Question #1:: What symptoms were experienced by the workers and what body systems were affected?

(See the answer)

Question #2:: How would you differentiate between an allergic reaction versus an irritant reaction based on the symptoms?

(See the answer)

Question #3:: What are the possible agents responsible for the symptoms experienced by the workers in order of decreasing likelihood?

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Question #4:: Is phytase likely to be a high or low molecular weight agent? Explain your answer.

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Question #5:: Depending on your answer, what kind of allergic reaction is it likely to cause?

(See the answer)

Question #6:: Why were the other workers in the plant not symptomatic?

(See the answer)

Question #7:: How would you prove that the symptoms were indeed due to exposure to the enzyme?

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Question #8:: How could exposure to workers be reduced in this plant?

(See the answer)

Question #9:: If you were the occupational health and safety advisor to the employer, would you recommend that workers be screened for atopy before being hired in this factory?

(See the answer)