[Surveillance of hepatitis A in the Netherlands 1993-2002].
OBJECTIVE
To survey trends in data on hepatitis A using information from the notification system of the Municipal Medical and Health Services 1993-2002.


METHODS
Retrospective, descriptive.


METHODS
Data collected from the notification system of the Dutch Municipal and Medical Services were analyzed.


RESULTS
From 1993 to 2002, 64.4%, 6.5% and 11.5% of infections were contracted in the Netherlands, Turkey and Morocco, respectively. Although the absolute number of cases was highest for young people under the age of 16 infected in the Netherlands, incidence rates showed that the children of immigrants infected in Turkey or Morocco were at highest risk, followed by adult immigrants from Turkey and Morocco. In addition, a seasonal trend was observed starting with an increase in the number of notifications of young travellers infected in Turkey and Morocco during their summer holiday, followed by a steep increase in notifications of young people infected in the Netherlands in autumn. This was followed later in the year by a slight increase in notifications of adults who acquired the infection in the Netherlands. However, between 1993-2002 the total number of notifications was halved. This decrease was mainly restricted to infections acquired in the Netherlands. In recent years, fewer outbreaks have been reported in schools, households and families. In 2001, a peak of notifications from the homosexual scene was observed. There was a continued trend in the rise of the mean age of hepatitis-A onset.


CONCLUSIONS
Risk of hepatitis A is highest for the children of immigrants travelling to Turkey or Morocco in the summer months. Secondary cases in the Netherlands are in strong decline, especially in schools and families. However, the almost stable incidence of infections among young people of Turkish or Moroccan extraction stresses the continued importance of immunization of this group before they travel. The continuing trend in the rise of the mean age of hepatitis-A onset deserves attention because of the increasing risk of mortality of the disease amongst older people.
Van Der Eerden
L J M
LJ
Rijksinstituut voor Volksgezondheid en Milieu, Centrum Infectieziekten Epidemiologie, Postbus 1, 3720 BA Bilthoven. liesbeth.van.der.eerden@rivm.nl
Bosman
A
A
Van Duynhoven
Y T H P
YT
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D018563:Disease Notification; D005260:Female; D006306:Health Surveys; D006506:Hepatitis A / Q000453:epidemiology*; D006801:Humans; D008297:Male; D009018:Morocco / Q000208:ethnology; D009426:Netherlands / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D012621:Seasons; D014421:Turkey / Q000208:ethnology