Organic dust toxic syndrome caused by occupational exposure to shrimpshell powder

Abstract

Background: The employees in a seafood savory factory experienced fever, chill, and respiratory problems while producing shrimpshell powder. They had no specific IgE towards shrimp and no problems when working with powder from whole shrimp.

Aim: The aim of the study was to identify the cause of the symptoms associated with shrimpshell powder.

Methods: Standardized laboratory methods were used to measure the concentration of endotoxin and size fractions of the powder, as well as the total inflammatory potential with a granulocyte assay that quantifies reactive oxygen species (ROS). One worker had a specific inhalation challenge (SIC) with respiratory and immunological responses measured before (Day₀), and after each of the 4 challenges with 20-150 g shrimpshell powder (maximum 20 minutes exposure).

Results: The shrimpshell powder contained 1118 endotoxin units/gram and the aerosol consisted of 90%, 86% and 57% inhalable, thoracic and respirable size fractions, respectively. The ROS production of the cells as a response to the inhalable fraction of the shrimp shell powder was significantly higher than with fish powder (control). The ROS production profiles were similar for shrimpshell powder and endotoxin stimulation. After challenge with 150 g shrimp shell powder, the worker had a 23% decrease in FEV₁ compared to baseline (Day₀). The neutrophils and monocytes increased 84% and 59%, respectively, from Day₀ to after the last challenge (Day₃).

Conclusion: The SIC resulted in >20% decrease in FEV_1, which could be bronchoconstriction due to endotoxin and the high levels of respirable dust. Also considering the flu-like symptoms and the increase in monocytes, this may indicate organic dust toxic syndrome.