A bioinformatics pipeline was developed to fully integrate virus-virus, virus-host and host-host protein-protein interactions gathered from a wide range of public databases, with those mined from scientific literature and curated by VirHostNet experts (Figure 1 ). In addition to the management of this large protein interaction resource, VirHostNet integrates contextual information concerning interacting proteins, like structural and functional annotations of proteins: Gene Ontology term (28) , KEGG pathway (29) , INTERPRO domain (30) . All these data were integrated into a knowledge-based system implemented by using PostgreSQL DataBase Management System (release 8.2.6).