[Time series in the epidemiology of typhoid fever in Spain]

Abstract

Background: The incidence of typhoid fever in Spain from January 1982 to December 1993 was studied with the aim of analyzing how the disease has evolved over these years and predict its future behavior in order to facilitate prevention by the public health care organizations and centers.

Material and methods: The Box-Jenkins temporary series theory was used. The data corresponded to the declared disease cases throughout Spain published in the Epidemiology Bulletin by the Carlos III Health Center and the Department of Health and Welfare.

Results: The ARIMA (0,1,1) (0,1,1)12 model was selected to report the data obtained. The analytical results demonstrated a exponential decreasing tendency with an annual seasonal pattern in incidence observed in this disease peaking in the months of July, August and September and decreasing in the declared cases in December, January and February. A mathematical expression was also obtained to allow the prediction of the disease behavior in the future.

Conclusions: Prophylactic measures should be taken in the summer months. A disease incidence greater than that foreseen by the mathematical formula obtained would express a failure in epidemiologic surveillance, and thus the results of this study may be used as a quality control of the preventive measures.