ABSTRACT
One goal of a public health surveillance system is to provide a reliable forecast of epidemiological time series. This paper describes a study that used data collected through a national public health surveillance system in the United States to evaluate and compare the performances of a seasonal autoregressive integrated moving average (SARIMA) and a dynamic linear model (DLM) for estimating case occurrence of two notifiable diseases. The comparison uses reported cases of malaria and hepatitis A from January 1980 to June 1995 for the United States. The residuals for both predictor models show that they were adequate tools for use in epidemiological surveillance. Qualitative aspects were considered for both models to improve the comparison of their usefulness in public health. Our comparison found that the two forecasting modelling techniques (SARIMA and DLM) are comparable when long historical data are available (at least 52 reporting periods). However, the DLM approach has some advantages, such as being more easily applied to different types of time series and not requiring a new cycle of identification and modelling when new data become available.
Subject(s)
Epidemiologic Methods , Models, Statistical , Communicable Disease Control/methods , Forecasting/methods , Hepatitis A/epidemiology , Humans , Malaria/epidemiology , Population Surveillance/methods , Public Health , United States/epidemiologyABSTRACT
Two cases of cutaneous Pythiosis insidiosi were diagnosed in cattle from the Pantanal region, Brazil. The lesions were observed in the limbs of two 8-month-old beef calves. Close examination showed local swelling and focal ulceration of the skin. Microscopically, there was multifocal granulomatous dermatitis with intralesional Pythium insidivosum hyphae. The diagnosis was based on the morphological aspects, immunohistochemical findings and culture of the etiologic agent.
