TYPING OF EUROPEAN STRAINS OF PARVOVIRUS B19 BY RESTRICTION-ENDONUCLEASE ANALYSES AND SEQUENCING - IDENTIFICATION OF EVOLUTIONARY LINEAGES AND EVIDENCE OF RECOMBINATION OF MARKERS FROM DIFFERENT LINEAGES

European isolates of parvovirus B19 were analyzed by restriction enzym e analysis of PCR products of the VP1/2 coding region and sequencing o f the same amplified region, five cloned fragments from each PCR produ ct. Two main groupings were found based on three perfectly linked poin t deviations. On the assumption that identical point deviations causin g the various restriction patterns regardless of time and origin of vi rus isolation were unlikely to emerge independently in different evolu tionary lineages, traits of evolutionary lineages were identified, sug gesting a clonal population structure of global circulating B19 strain s. However, combinations of markers from different evolutionary lineag es were also found, particularly in a strain derived from an individua l chronically infected with B19 for more than 7 years. As chronically infected individuals might be subject to superinfections due to contac ts or possibly due to blood transfusions or the administration of gamm a-globulin, it is suggested that coexistance of, and recombination bet ween variants of B19 of different phylogenetic origin incidentally occ ur in such individuals. (C) 1998 Elsevier Science B.V. All rights rese rved.