Figure. Maximum-likelihood tree of McHV-1 constructed by using highly variable 375-bp fragment of US5 and intergenic region between US5 and US6 genes. The genotypes recovered from free-ranging rhesus macaques (Macaca mulatta) in Florida (bold) separate into 2 clades that include laboratory strains of McHV-1. GenBank accession numbers are provided. Scale bar indicates number of base pair changes per nucleotide. McHV-1, macacine herpesvirus 1.