D2.426 - Occupational Asthma Due to Tenebrio Molitor in the Owner of a Mealworm Farm: A Case Report

Background: Tenebrio molitor (mealworm), is an insect in the Coleoptera family that is recognized as a potential cause of occupational asthma. This condition primarily affects fishermen, grain handlers, and workers in fish bait farms. The consumption of mealworms is gaining popularity due to their high protein content and the sustainability of insect farming.

Case: We present the case of a 33-year-old female biologist with a history of pollen allergic rhinitis who owns a T. molitor insect farm. Over the past year, she developed work-related symptoms, including a dry cough and dyspnea, which were notably worse at night and occurred without accompanying rhinitis symptoms. She did not report allergies to shellfish or any specific food items.

Results: After a period of not working with insects, baseline spirometry was normal, exhaled nitric oxide (FeNO) of 25 ppb and a negative methacholine bronchial provocation. Skin prick tests (SPT) were positive for grass and olive pollens but negative for other aeroallergens, shrimp and other seafood. Prick-by-prick tests showed positive reactions to T. molitor adults, larvae, and their excrement, while results were negative for locusts and grasshoppers. A specific inhalation challenge (SIC) using nebulized T. molitor adult extract elicited a 27% inmediate reduction in FEV1 and a significant change in FeNO levels. The total IgE level measured was 26.70 UI/mL. SDS-PAGE analysis was conducted on extracts from live T. molitor larvae, adults, excrement, and dry larvae flour. IgE immunoblotting with the patient's serum revealed IgE-binding bands at approximately 120 kDa and 50 kDa in the adult T. molitor extract. The 50 kDa band was also noted in larva and excrement extracts, potentially corresponding to alpha-amylase, which might be a T. molitor allergen. The 120 kDa protein may correspond to α-Actinin 4, another T. molitor protein previously identified by mass spectrometry.

Conclusion: we report a case of IgE-mediated occupational asthma caused by T. molitor in an insect farming setting, confirmed by SPT and SIC. With the rising trend of insect consumption and the expansion of the insect farming industry, there is a potential for increased sensitization to this insect.