Phylogenetic network — Clade I includes European/North American strains, Clade II comprises East Asian strains and III, IV, V and VI are East African. HSV-2 was used as an outgroup. Splitstree 4 was used to generate the network. The viral isolates are colored according to country of origin and are as follows: U.S.A: light blue, U.K.: dark blue, China: red, South Korea: purple, Japan: orange, and Kenya: green. (Kolb, Brandt, et al/PLoS)