This definition appears rarely
One of the rats was processed as previously described  and viral RNA sourced directly from lung tissue was subjected to additional characterisation of the virus through standard Sanger sequencing on a 3130xl sequencer (Life Technologies). Sequencing of the S segment was achieved, confirming the virus was indeed a strain of SEOV similar, but not identical, to previously isolated UK SEOV strains: Humber (wild rats)  and IR461 (laboratory rats) . We have provisionally designated this strain ‘Cherwell’. Alignments of sequences from the virus strains were conducted using ClustalW and the molecular evolutionary genetics analysis (MEGA5) programme suite  was used to perform phylogenetic analysis. Comparisons between Cherwell and Humber S segments highlighted a total of 47 nucleotide differences, 36 within the open reading frame (ORF) resulting in one amino acid difference (methionine to isoleucine.