A user friendly and powerful Web interface based on PHP, JAVA and AJAX technologies was developed. This interface is intended to facilitate: (i) protein and contextual based queries (ii) protein-protein interaction quality filtering and display; (iii) protein-protein interaction network query (viral and host neighbours, virus-virus, virus-host, host-host sub-networks); and (iv) protein network graphical visualization. Description and examples of the database features are available in the Wiki page of the VirHostNet Web site (http://pbildb1.univ-lyon1.fr/virhost net/wiki).