Phylogenetic tree of Rift Valley fever virus (RVFV) generated by the maximum likelihood method with bootstrap (500 replicates) based on 6404 nucleotides of the L genomic segment of RVFV. Analysis involved 94 nucleotide sequences available in GenBank. Compressed Cluster 1 includes 43 sequences from Kenya, Madagascar, Mayotte, South Africa, and Tanzania, collected in the period 2006–2009; Cluster 2: ten sequences from Kenya, Sudan, Tanzania, and Uganda collected in 2006–2016; Cluster 3: three sequences from Kenya and Saudi Arabia, collected in the period 1998–2001; Cluster 4: eleven sequences from Zimbabwe, Egypt, and Madagascar, collected in 1974–1979; Cluster 5: seven sequences from C.A.R, Guinea, and Zimbabwe, collected in 1969–1985. The strain names and accession numbers of the sequences included in the compressed clusters are listed in Table S2.