Two out of the 11 genes of an unusual human G6P[6] rotavirus isolate are of bovine origin.

In 2003, we described the first human G6P[6] rotavirus strain (B1711). To investigate further the molecular origin of this strain and to determine the possible reassortments leading to this new gene constellation, the complete genome of strain B1711 was sequenced. SimPlot analyses were conducted to compare strain B1711 with other known rotavirus gene segments, and phylogenetic dendrograms were constructed to analyse the origin of the eleven genome segments of strain B1711. Our analysis indicated that strain B1711 acquired its VP1-, VP2-, VP4-, VP6- and NSP1-5-encoding gene segments from human DS-1-like P[6] rotavirus strains, and its VP3 and VP7 gene segments from a bovine rotavirus strain through reassortment. The introduction of animal-human reassortant strains, which might arise in either of the hosts, into the human rotavirus population is an important mechanism for the generation of rotavirus diversity, and might be a challenge for the current rotavirus vaccines and vaccines under development.