To our knowledge, VirHostNet provides the largest and the most confident infected cellular network. This network is composed of 2671 virus-virus and virus-host non-redundant protein-protein interactions concerning 180 distinct viral species. The curated protein-protein interactions were mainly defined by low-throughput and high-throughput yeast two-hybrid screens (40%), co-immunoprecipitation (24%) and pull-down (21%) (Figure 2A ). Even if only 65% of interactions rely on a single experimental procedure, a total of 944 proteinprotein interactions (35%) were defined by at least two independent methods, in good agreement with other high-confidence databases (36) ( Figure 2B ). All these interactions were defined in 36 distinct viral families, underlying the broad taxonomical diversity provided by VirHostNet ( Figure 3A ). In addition, the distribution of interactions observed among viral Baltimore groups should allow large-scale comparative study of virus-virus ( Figure 3B ) and virus-host networks ( Figure 3C ).