Sure. The NIVEL network ‘Zorgregistraties Eerstelijn‘ monitors for all kinds of things, like regular influenza, and self reported complaints by people to GPs. They added alertness and actual testing for Corona from the end of January (4 weeks before the first confirmed Dutch case). An announcement of that was posted on their site 7 Feb. RIVM mentions positive tests found through the NIVEL network in their daily Corona updates every now and then. The incidence level of all complaints are reported weekly by NIVEL on their site. General method description, and map of GPs involved is available. Their weekly bulletins with incidence and test numbers, graphs with multi-year comparison are published as PDFs