Abstract

Background
Exposure to insects used in pet food, scientific research or live fish bait can cause occupational allergy. The recent shift towards enhanced insect production for human consumption and animal feed will likely expose more employees.
Objective
To investigate sensitization and symptoms in employees exposed to edible insects in Flanders.
Methods
Fifteen insect-exposed employees were recruited and sensitization was explored by skin prick test (SPT), basophil activation test (BAT), and immunoblotting. Lung function, fractional exhaled nitric oxide (FeNO), histamine provocation and sputum induction were studied. Airborne dust sampling was performed and proteins were studied by silver stain and immunoblotting.
Results
Sixty percent of employees self-reported upper respiratory tract symptoms related to insect exposure. Ten employees (71.4%) had a positive histamine provocation test (PC20 <8 mg/mL) and four (26.7%) had FeNO levels above 25 ppb. Four employees (30.7%) had a positive SPT for at least one insect, and seven (58.3%) had a positive BAT. In 8 participants with insect sensitization, 4 (50%) had co-occurring house dust mite sensitization. Two participants had strong IgE binding to a 50 kDa migratory locust allergen, one participant to a 25 kDa mealworm allergen and one participant to mealworm alpha-amylase. In one center, facility adjustment resulted in a substantial decrease of the inhalable dust fraction.
Conclusion
Insect exposure leads to high levels of sensitization among employees. Most employees reported symptoms of the upper respiratory system and two thirds of the employees had bronchial hyperreactivity. Prevention and health surveillance will be key in the developing insect-rearing industry.

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