Modelling Pathways for Outbreaks in Field Occupational Epidemiology

Abstract

Background: The investigation of an occupational outbreak, once the index case has been identified, triggers a stress situation to epidemiologists. Modelling occupational outbreaks will be useful to guide the field investigation. Objective: To identify standard pathways for occupational epidemic outbreaks. Methods: In-depth critical appraisal of 57 occupational outbreaks. Standard pathways of occupational outbreaks were identified by analysing the similarity between out-breaks. The model’s accuracy and homogeneity were established through Fisher’s exact test and the Kappa Index. Results: The analysis allowed synthesizing the occupational outbreaks variability in 4 pathways. 92.98% of the analysed outbreaks could be allocated to one of those 4 types. The theoretical patterns showed a good adjustment with the analysed out-breaks: Type I (Kappa = 0.94 - 0.60), Type II (Kappa = 1.00), Type III (Kappa = 1.00 - 0.68) and Type IV (Kappa = 0.94 - 0.87). The probability of a given outbreak fitting with its three components in any of the theoretical pathways was 0.83. Conclusions: The incorporation of those pathways to the field occupational epidemiology will allow: 1) to provide early guidance to epidemiological, clinical and environmental studies focused on specific hypothesis of causality; 2) to anticipate preventive measures; 3) to contribute to an earlier and more efficient outbreak resolution.