Since 1982, the sentinel network of general practitioners registers all new cases of measles and mumps clinically diagnosed in their practice.  This network provides the only ongoing surveillance of both diseases.

In 1994-1995, measles incidence in the Flemish Region was comparable with the level in 1991-1993 (87/100 000 inhabitants).  In the Walloon Region the incidence was significantly higher in 1994-1995 (177/100 000) inhabitants) compared with the period 1991-1993 and compared with the incidence in the Flemish Region in 1994-1995.  The proportion of cases in children aged 10 years and older increased significantly over time in both Regions.  Complications were notified in 19% of the
; cases, with pneumonia as leading type of complication (43%);

In 1994-1995, the incidence of mumps in the Flemish Region (49/100 000 inhabitants) was significantly lower than in 1991-1993.  The incidence of mumps in the Walloon Region in 1994-1995 (207/100 000 inhabitants) was comparable with the incidence in 1991-1993, but was significantly higher than in the Flemish Region.  As for measles, the proportion of cases in children aged 10 years and older increased significantly over time in both Regions.

The sentinel network of GPs is still a useful tool for monitoring changes in the epidemiology of measles and mumps.  Data from this network must be tested by information on vaccination coverage in both Regions