Figure 2. Phylogenetic tree based on 387 nucleotide sequences of the 5′ end of open reading frame 2 (encoding viral protein 1) of norovirus strains from Royal Liverpool Children’s National Health Service Foundation Trust (Alder Hey Hospital), Liverpool, UK. For each strain the source (healthcare-associated [HA] or community-acquired [CA]), specimen number, month/year of detection, and the name of the strain is indicated. Reference strains included on the tree are GII/1 U07611 Hawaii/71/US, GII/2 X81879 Melksham/89/UK, GII/3 U22498 Mexico/89/MX, GII/4 X86557 Lordsdale/93/UK, GII/5 AJ277607 Hillingdon/90/UK, GII/6AB039776 SaitamaU3/97/JP, GII/7 AJ277608 Leeds/90/UK, GII/8 AB067543 SaitamaU25/98/JP, GII/9 AY054299 IdahoFalls/378/96/US, GII/10 AY237415 Mc37/99/Thai, GII/11 AB112221 SaitamaT29GII/01/JP, GII/12 AB039775 SaitamaU1/97/JP, GII/13 AY130761 M7/99/US, GII/14 AB078334 Kashiwa47/00/JP, GII/15 AB058582 SaitamaKu80aGII/99/JP, GII/16 AB112260 SaitamaT53GII/02/JP, GII/17 AF195847 Alphatron/98/NE, GI/1 M87661 Norwalk/68/US, AJ313030 Queen’sArms/Leeds/92/UK, AJ277615 Sindlesham/95/UK. Horizontal lengths are proportional to the genetic distance calculated with the Kimura 2-parameter method. Scale bar shows genetic distance expressed as nucleotide substitutions per site. Bootstrap probabilities >80% (>800 of 1,000 pseudoreplicate trials) are indicated at each node. The nucleotide sequences used in the tree have been deposited under the strain name and accession number (in parentheses) as follows; 06AH107 (FJ797840), 06AH109 (FJ797841), 06AH187 (FJ797842), 06AH194 (FJ797843), 06AH225 (FJ797844), 06AH387 (FJ797845), 06AH395 (FJ797846), 06AH397 (FJ797847), 06AH040 (FJ797848), 06AH402 (FJ797849), 06AH406 (FJ797850), 06AH408 (FJ797851), 06AH410 (FJ797852), 07AH448 (FJ797853), 06AH050 (FJ797854), 07AH509 (FJ797855), 07AH517 (FJ797856) 07AH525 (FJ797857), 07AH551 (FJ797858), 07AH570 (FJ797859), 07AH571 (FJ797860), 07AH579 (FJ797861), 07AH590 (FJ797862), 07AH602 (FJ797863), 07AH604 (FJ797864), 07AH611 (FJ797865), 07AH612 (FJ797866), 07AH616 (FJ797867), 07AH619 (FJ797868), 07AH623 (FJ797869), 07AH633 (FJ797870), 07AH642 (FJ797871), 07AH643 (FJ797872), 07AH651 (FJ797873), 07AH653 (FJ797874), 07AH654 (FJ797875), 06AH097 (FJ797876).