Fig. 2From: Global research trends in West Nile virus from 1943 to 2016: a bibliometric analysisVOSviewer co-occurrence term map. a Term map of title and abstract words in West Nile virus publications during 1943–1999 with research topics indicated (based on VOS Viewer). b Term map of title and abstract words in West Nile virus publications during 2000–2006 with research topics indicated (based on VOS Viewer). c Term map of title and abstract words in West Nile virus publications during 2007–2016 with research topics indicated (based on VOS Viewer)Back to article page