Figure 1. Phylogenetic analysis of the sequences of the nucleoprotein genes (450 nt) of the strains of measles virus from Menglian County, Yunnan Province, People’s Republic of China. The unrooted tree shows sequences from Menglian viruses (circles) compared with World Health Organization (WHO) reference strains for each genotype. Triangles indicate D7 WHO reference strains; diamonds, the 2 older non-Menglian strains. Genotype designation is in boldface. MV, measles virus; MVi, measles virus sequence from isolates; MVs, measles virus sequence from clinical specimens. Scale bar indicates base substitutions per site.