Seasonality trends of scabies in a young adult population: A 20-year follow-up

Background: Scabies is not a notifiable disease in most countries. Therefore, its seasonality trends are usually estimated and may be inaccurate. Objectives: To determine the seasonality of scabies over the long term in a large military population, including all of the Israel Defence Forces personnel. Methods: For the last two decades, the Israel Defence Forces have mandated the routine reportage of every case of scabies infestation in soldiers to the Epidemiology Department of the Army Health Branch. This database was used in the present study to analyse the incidence of scabies by season. Scabies was defined according to the report by a military physician based on the typical clinical presentation, relevant epidemiological data and, in most cases, microscopic visualization of the mite. Results: The person-time incidence of scabies was higher in winter than summer (P < 0.001). The overall risk ratio was 1.31 (95% confidence interval 1.28-1.33). Sensitivity analysis indicated that no single year was an important source of disease heterogeneity. Conclusions: Scabies in a young adult population is more frequent in the cooler months of the year.