Downloaded from www.microbiologyresearch.org by IP: 54.90.7.114 On: Sun, 15 May 2016 00:49:22 Two out of the 11 genes of an unusual human G6P[6] rotavirus isolate are of bovine origin Jelle Matthijnssens, 1 Mustafizur Rahman 1,2 and Marc Van Ranst 1 Correspondence Jelle Matthijnssens jelle.matthijnssens @uz.kuleuven.be 1 Laboratory of Clinical and Epidemiological Virology, Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium 2 Laboratory of Virology, ICDDR,B: Centre for Health and Population Research, Dhaka, Bangladesh Received 7 May 2008 Accepted 13 June 2008 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. INTRODUCTION Rotaviruses (RV) of group A are an important cause of diarrhoeal diseases, and cause significant morbidity and mortality in young children and animals worldwide, especially in developing countries (Estes & Kapikian, 2007). RVs belong to the family Reoviridae, and possess a genome of 11 segments of double stranded RNA, encoding six structural (VP) and six non-structural proteins. Based on the protease-sensitive VP4 and the glycosylated VP7 proteins forming the outer capsid of the rotavirus particles, a widely used dual classification system exists, dividing VP7 into 19 G genotypes and VP4 into 27 P genotypes (Estes & Kapikian, 2007; Khamrin et al., 2007; Martella et al., 2006, 2007; Matthijnssens et al., 2008a; Rahman et al., 2005; Rao et al., 2000; Steyer et al., 2007). Recently, the remaining rotavirus genes encoding VP1, VP2, VP3, VP6, NSP1, NSP2, NSP3, NSP4 and NSP5 have also been divided into respectively 4 R genotypes, 5 C genotypes, 6 M genotypes, 11 I genotypes, 14 A genotypes, 5 N genotypes, 7 T genotypes, 11 E genotypes, and 6 H genotypes, based on specific nucleotide sequence cut-off identity values for each gene segment (Matthijnssens et al., 2008a). At least 11 G and 11 P genotypes have been isolated from humans, but only G1P[8], G2P[4], G3P[8], G4P[8] and G9P[8] are currently of epidemiological importance worldwide (Estes & Kapikian, 2007; Matthijnssens et al., 2008b). G6 RVs are the most common rotavirus genotype among cattle and they are mainly found in combination with P[5],P[1] and P[11] (Matthijnssens et al., 2008b). A limited number of human rotaviruses with the G6 specificity have been described in literature. Human G6 RVs in combination with P[14] have been isolated in Italy (PA169, 111/05-27), Australia (MG6, MG6.01, aG6.01, ASG6.02), Hungary (Hun5) and Belgium (B10925-97) (Ba ´nyai et al., 2003; Gerna et al., 1992; Palombo & Bishop, 1995, Matthijnssens et al., unpublished data). A few G6P[9] human rotavirus strains have been found in the United States (Se584), Italy (PA151) and Hungary (Hun1-4, Hun6-8) (Ba ´nyai et al., 2003; Gerna et al., 1992; Griffin et al., 2002). A recent multiplex RT-PCR-based study identified G6 human rotaviruses in France, Italy, and Spain (Van Damme et al., 2007). So far, G6 in combination with P[6] has been described only once in the literature. This strain, B1711, was isolated in Belgium from a child who had just returned from a holiday in Mali in 2002 (Rahman et al., 2003). From a second human G6P[6] rotavirus strain, R353, isolated in France, only the partial VP7 gene sequence is available in GenBank (accession no. DQ122400). In recent years, an increasing number of papers have reported the sequencing of multiple complete rotavirus genomes in order to study rotavirus interspecies transmis- sion, reassortments and evolutionary relationships between human and animal rotavirus strains (Ito et al., 2001; Matthijnssens et al., 2006a, b, 2008a; Rahman et al., 2007; Small et al., 2007). To unravel the evolutionary history of The GenBank/EMBL/DDBJ accession numbers of the sequences determined in this work are EF554082–EF554092. Supplementary material is available with the online version of this paper. Journal of General Virology (2008), 89, 2630–2635 DOI 10.1099/vir.0.2008/003780-0 2630 2008/003780 G 2008 SGM Printed in Great Britain