Israel Medical Association Journal

Background: Syndromic surveillance systems have been developed for early detection of bioterrorist attacks, but few validation studies exist for these systems and their efficacy has been questioned.

Objectives: To assess the capabilities of a syndromic surveillance system based on community clinics in conjunction with the WSARE[1] algorithm in identifying early signals of a localized unusual influenza outbreak.

Methods: This retrospective study used data on a documented influenza B outbreak in an elementary school in central Israel. The WSARE algorithm for anomalous pattern detection was applied to individual records of daily patient visits to clinics of one of the four health management organizations in the country.

Results: Two successive significant anomalies were detected in the HMO’s[2] data set that could signal the influenza outbreak. If data were available for analysis in real time, the first anomaly could be detected on day 3 of the outbreak, 1 day after the school principal reported the outbreak to the public health authorities.

Conclusions: Early detection is difficult in this type of fast-developing institutionalized outbreak. However, the information derived from WSARE could help define the outbreak in terms of time, place and the population at risk.

Objectives: To estimate usual patterns of acute illness in the community as a baseline for integration into pandemic influenza and bioterrorism preparedness plans.

Methods: Between 2000 and 2003 we conducted 13 telephone surveys to estimate the usual incidence and prevalence of symptoms of acute illness in the community.

Results: On average, 910 households were included in each of the surveys, representing about 3000 people. The compliance rates for full interviews ranged from 72.3% to 86.0%. In winter, on average, about 2% of the Israeli population (individuals) suffered each day from fever of ≥ 38ºC, and about 0.8% during the other months. The prevalence of cough was higher, 9.2% in winter and 3% during summer. Daily incidence of fever ranged from about 0.4% per day in winter to about 0.2% in the fall. The prevalence and incidence of both fever and cough were highest for infants followed by children aged 1–5 years.

Conclusions: These background morbidity estimates can be used for planning the overall treatment requirements, in addition to actual cases, resulting from pandemic influenza or a bioterrorist incident.

Background: Between 1970 and 1979, there was an increase in the incidence of viral hepatitis in Israel with a shift of peak incidence to an older age in the Jewish population, followed by a declining trend during the early 1980s. In July 1999 universal immunization of infants against hepatitis A was introduced.

Objective: To evaluate the chan-ges in the epidemiology of viral hepatitis A in Israel during the past decade.

Methods: Viral hepatitis is a notifiable disease in Israel and cases are reported to the regional health offices, which in turn provide summary reports to the Ministry of Health's Department of Epidemiology. The data in this study were derived from the summary reports and from results of seroprevalence studies.

Results: Following the increase in the incidence of reported viral hepatitis (mainly due to type A) between 1970 and 1979, the rates then stabilized and around 1984 began to decline until 1992. Since then there has been a slight increase. Whereas until 1987 the rates were consistently higher in the Jewish population. since then they are higher in the Arab population. The shift in the peak age-specific incidence from the 1-4 to the 5-9 year age group observed in the Jewish population around 1970 occurred 20 years later in the Arab population. The previously described seasonality is no longer evident. Recent seroprevalence studies indicate that by age 18 years only about 30-40% of the Jewish population have anti-hepatitis A antibodies.

Conclusions: The decline in the incidence of hepatitis probably reflects the changing socioeconomic condition occurring at different times in the two major population groups. Since hepatitis A accounts for almost all the acute viral hepatitis in Israel, the universal vaccination of infants introduced in 1999 should substantially lower the morbidity within the next few years.