Preliminary characterization of a non-haemagglutinating strain of rabbit haemorrhagic disease virus from the United Kingdom.

A variant strain of rabbit haemorrhagic disease virus, designated "Rainham', originally isolated from a small localized outbreak of the disease in southern England, has been further examined and compared with conventional reference strains. The virus originally failed to haemagglutinate in standard conditions at normal temperature and consistently lacked HA activity after two passages in experimental rabbits. It did haemagglutinate at 4 degrees C. It reacted with hyperimmune sera to normal isolates of RHDV from the UK and Italy, and showed no differential binding activity with a panel of monoclonal antibodies prepared from an Italian reference strain. The Rainham strain appears to be antigenically indistinguishable from other known isolates and this suggests that it may differ by only a few amino acid changes in its capsid protein sequence.