Fig. 4. : co-occurrence network of research areas (2000-2014). *Each node represents a research area (RA) and a connection between two RAs indicated they have occurred together in the same article. The size of the nodes indicates their degree centrality in the network. Bigger nodes are the most central. (A) Whole network. The 10 most central areas, according to their degree centrality, have their names indicated; (B) Virology ego-network; (C) Tropical Medicine ego-network.
