Full genomic analysis and possible origin of a porcine G12 rotavirus strain RU172

Human group A rotavirus (GAR) G12 strains are regarded as potentially important pathogens for acute gastroenteritis. On the other hand, to date, the only report of detection of G12 in animals was that of a porcine G12P[7] strain RU172. Strain RU172 formed a separate G12 lineage, distinct from human G12 strains, and by analyses of deduced amino acid sequences, had a VP4, VP6, NSP4-5 of porcine origin. In the present study, we determined the full-length nucleotide sequences of VP1, VP3, and NSP1-3 genes and nearly full-length nucleotide sequence of VP2 gene of RU172. By nucleotide sequence identities and phylogenetic analyses, the VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5 genes of RU172 were assigned to G12-P[7]-I5-R1-C1-M1-A1-N1-T1-E1-H1 genotypes, respectively. Within their respective genotypes, (i) VP1 gene of RU172 exhibited higher genetic relatedness to Wa-like human G12 GARs than porcine strains, (ii) VP2-3 and NSP2 genes clustered separately from the Wa-like human (including G12) and porcine clusters, while (iii) the VP6, NSP1 and NSP3-5 genes clustered with porcine and porcine-like human strains. These observations suggested that (i) the porcine G12 strain might have originated from porcine–human reassortment events, or alternatively, (ii) the Wa-like human and porcine G12 strains might have originated from a common ancestor, and eventually evolved (by genetic drift and shift) with time. Our findings provided important insights into the possible patterns of evolution of the porcine G12 strain.     

Molecular characterization of a rare G9P[23] porcine rotavirus isolate from China

The fifth most important G genotype, G9 rotavirus, is recognized as an emerging genotype that is spreading around the world. Sequence analysis was completed of a rare group A rotavirus, strain G9P[23], that was designated rotavirus A pig/China/NMTL/2008/G9P[23] and abbreviated as NMTL. It was isolated from a piglet with diarrhea in China. Nucleotide sequence analysis revealed that the VP7 gene clustered within the G9 lineage VId. The VP4 gene clustered within the rare P[23] genotype. NMTL is the first porcine G9 stain reported in China. Thus, to further characterize the evolutionary diversity of the NMTL strain, all gene segments were used to draw a phylogenetic tree. Based on the new classification system of rotaviruses, the NMTL sequence revealed a G9-P[23]-I5-R1-C1-M1-A8-N1-T1-E1-H1 genotype with close similarity to human Wa-like and porcine strains. The results showed that (i) NSP2 and NSP4 genes of NMTL exhibited higher genetic relatedness to human group A rotaviruses than to porcine strains, (ii) the VP2 and VP4 genes clustered with porcine and porcine-like human strains, and (iii) VP1 genes clustered apart from the Wa-like human and porcine clusters. In view of rotavirus evolution, this report provides additional evidence to support the notion that the human and porcine rotavirus genomes might be related.     

Identification of a novel VP4 genotype carried by a serotype G5 porcine rotavirus strain

Rotavirus genome segment 4, encoding the spike outer capsid VP4 protein, of a porcine rotavirus (PoRV) strain, 134/04-15, identified in Italy was sequenced, and the predicted amino acid (aa) sequence was compared to those of all known VP4 (P) genotypes. The aa sequence of the full-length VP4 protein of the PoRV strain 134/04-15 showed aa identity values ranging from 59.7% (bovine strain KK3, P8[11]) to 86.09% (porcine strain A46, P[13]) with those of the remaining 25 P genotypes. Moreover, aa sequence analysis of the corresponding VP8* trypsin cleavage fragment revealed that the PoRV strain 134/04-15 shared low identity, ranging from 37.52% (bovine strain 993/83, P[17]) to 73.6% (porcine strain MDR-13, P[13]), with those of the remaining 25 P genotypes. Phylogenetic relationships showed that the VP4 of the PoRV strain 134/04-15 shares a common evolutionary origin with porcine P[13] and lapine P[22] rotavirus strains. Additional sequence analyses of the VP7, VP6, and NSP4 genes of the PoRV strain 134/04-15 revealed the highest VP7 aa identity (95.9%) to G5 porcine strains, a porcine-like VP6 within VP6 genogroup I, and a Wa-like (genotype B) NSP4, respectively. Altogether, these results indicate that the PoRV strain 134/04-15 should be considered as prototype of a new VP4 genotype, P[26], and provide further evidence for the vast genetic and antigenic diversity of group A rotaviruses.     

Relationships among porcine and human P[6] rotaviruses: evidence that the different human P[6] lineages have originated from multiple interspecies transmission events

Porcine rotavirus strains (PoRVs) bearing human-like VP4 P[6] gene alleles were identified. Genetic characterization with either PCR genotyping or sequence analysis allowed to determine the VP7 specificity of the PoRVs as G3, G4, G5 and G9, and the VP6 as genogroup I, that is predictive of a subgroup I specificity. Sequence analysis of the VP8* trypsin-cleavage product of VP4 allowed PoRVs to be characterized further into genetic lineages within the P[6] genotype. Unexpectedly, the strains displayed significantly higher similarity (up to 94.6% and 92.5% at aa and nt level, respectively) to human M37-like P[6] strains (lineage I), serologically classifiable as P2A, or to the atypical Hungarian P[6] human strains (HRVs), designated as lineage V (up to 97.0% aa and 96.1% nt), than to the porcine P[6] strain Gottfried, lineage II (<85.1% aa and 82.2 nt), which is serologically classified as P2B. Interestingly, no P[6] PoRV resembling the original prototype porcine strain, Gottfried, was detected, while Japanase P[6] PoRV clustered with the atypical Japanase G1 human strain AU19. By analysis of the 10th and 11th genome segments, all the strains revealed a NSP4B genogroup (Wa-like) and a NSP5/6 gene of porcine origin. These findings strongly suggest interspecies transmission of rotavirus strains and/or genes, and may indicate the occurrence of at least 3 separate rotavirus transmission events between pigs and humans, providing convincing evidence that evolution of human rotaviruses is tightly intermingled with the evolution of animal rotaviruses.     

Evidence for independent segregation of the VP6- and NSP4- encoding genes in porcine group A rotavirus G6P[13] strains

Summary. Molecular characterization of two porcine group A rotavirus strains (HP113 and HP140), detected from eastern India, revealed a VP7 closely related to those of human G6P[14] strains, VP4 with a borderline P[13] genotype, and VP6 related to bovine and human SGI strains rather than porcine SGI and/or SGII group A rotaviruses. Both strains had NSP4 and NSP5 of porcine origin. Therefore, to our knowledge, the present study is the first report of detection of group A rotavirus strains with G6P[13] genotype specificities and provides evidence for independent segregation of the VP6- and NSP4-encoding genes in porcine group A rotaviruses.     

Sequence analysis of Vietnamese P[6] rotavirus strains suggests evidence of interspecies transmission

Nucleotide and amino acid sequences of the VP8* gene of five Vietnamese P[6] rotavirus strains detected from hospitalized patients with acute gastroenteritis were analyzed and compared with other human and porcine P[6] rotaviruses. It is of interest that these strains had greatest identity with two Italian porcine rotavirus strains, 134/04-10 and 134/04-11. To our knowledge, these five Vietnamese rotaviruses are the rare P[6] rotavirus strains belonging to lineage I that cluster into sublineage Ic with porcine rotaviruses, and not into sublineage Ia, as other human P[6] rotaviruses have done so far. Sequence analysis of the VP7 gene of these P[6] rotavirus strains was also performed. The results showed that the Vietnamese G9P[6] strain had high similarity with other human G9 rotaviruses, confirming a human-animal reassortant virus, whereas other three G4P[6] strains had best identity with porcine G4 rotavirus strains, suggesting interspecies transmission of rotavirus between porcine and humans. This result provides the important data on molecular characteristics of Vietnamese rotaviruses, and highlights interspecies transmission events of rotaviruses in Vietnam as well as in Asia.     

Whole genomic analysis reveals the co-evolutionary phylodynamics of Korean G9P[8] human rotavirus strains

Three human rotavirus G9P[8] strains, RVA/Human-tc/KOR/CAU05-202/2005/G9P[8], RVA/Human-tc/KOR/CAU09-371/2009/G9P[8], and RVA/Human-tc/KOR/CAU09-376/2009/G9P[8], were isolated from female pediatric patients with diarrhea from 2005 to 2009 using a cell culture system, and their complete genomic sequences were analyzed. The 11 gene segments of the three Korean strains possessed the G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 genotype, which is closely related to the Wa-like genotype 1 constellation. Interestingly, the NSP2 and the NSP3 genes of strain RVA/Human-tc/KOR/CAU09-376/2009/G9P[8] were related to the G9 porcine or human-porcine reassortant strains, providing evidence for porcine-to-human interspecies transmission.     

Molecular characterization of a rare,human-porcine reassortant rotavirus strain,G11P[6], from Ecuador

The Pan-American Health Organization established a rotavirus pre-vaccination disease burden and strain surveillance network in Latin America and the Caribbean in 2004. During strain surveillance in Ecuador in 2005–2006, a rare rotavirus genotype, G11P[6], was detected among common strains. Sequencing and phylogenetic analysis of this strain identified a novel lineage of the G11 VP7 gene, most closely related to A253 (91.8% nt identity), a porcine rotavirus strain identified in Venezuela. Most genes of this strain clustered with porcine, human-porcine or bovine-porcine reassortant strains; only VP6 and perhaps NSP2 genes were more closely related to cognate genes of human rotaviruses. Thus, this strain was likely generated by gene reassortment between porcine and human parental strains. Our study provides further evidence that animal rotaviruses play an important role in genetic and antigenic diversity of rotaviruses pathogenic for humans.     

Phylogenetic analysis of novel G12 rotaviruses in the United States: A molecular search for the origin of a new strain

Rotavirus serotype G12 was initially identified in the Philippines in 1987 and was not described again until it reemerged more than 13 years later. G12 strains were first detected in the United States in 2002 and have recently assumed a worldwide distribution. The high similarity between the sequence of the major outer capsid VP7 gene of human G12 strains and the single porcine G12 isolate raised the prospect that human strains may have arisen through reassortment with porcine strains or, alternatively, that the porcine strain originally came from humans. We sequenced portions of the remaining 10 segments of two human G12 strains (G12P[8] and G12P[6]) and a currently circulating common strain (G1P[8]) identified during the 2005–2006 surveillance season and compared the sequences with those of strains available through GenBank. By comparison, the three strains were all Wa‐like and not porcine‐like. A newly outlined classification system proposed genotypes for each gene segment based on nucleotide similarity. Using this approach, gene segments VP1–3, VP6 and NSP1–5 grouped within the same genotype, indicating that the three strains analyzed were closely related. These results suggest that the novel G12P[8] strain could have been formed by the solitary introduction of a VP7 gene into a globally common rotavirus strain, G1P[8]. Classifying rotavirus strains based only on VP7 (G) and VP4 (P) genotype potentially underestimates diversity and sequence analysis of the other segments is required to assess the complete genetic relationships between strains. J. Med. Virol. 81:736–746, 2009 © 2009 Wiley‐Liss, Inc.     

Phylogenetic analysis of VP1, VP2, and VP3 gene segments of genotype G5 group A rotavirus strains circulating in Brazil between 1986 and 2005

Genotype G5 group A rotavirus (RV-A), which is common in pigs and also detected in horses and cattle, circulated as endemic genotype in the 1980s and early 1990s in Brazil. After 1996, G5 RV-A has been replaced by G9 RV-A, becoming only sporadically detected. Recently, G5 has been reported in children with severe diarrhea in Argentina, Cameroon, Paraguay, People's Republic of China, and Vietnam, suggesting that, although uncommon in humans, it has a worldwide distribution. In a previous study, Brazilian G5 RV-A VP7 gene analysis demonstrated the existence of three main lineages: I, II, and III; all Brazilian strains and three porcine strains from Thailand grouped inside Lineage I. The VP8(*) subunit of VP4 gene showed that all P[8] strains fell into three major genetic lineages: P[8]-1; P[8]-2; and P[8]-3. Partial sequencing and phylogenetic analysis of VP1, VP2 and VP3 genes of P[8]G5 human RV-A strains were determined from 28 Brazilian strains collected from 1986 to 2005. The VP1-VP3 partial sequences analysis showed that the Brazilian strains have high amino acid identity with the human RV-A prototype IAL28 and other Wa-like genogroup strains. It was also shown that G5 RV-A Brazilian VP1-VP3 and VP7 sequences have a similar pattern of gouping: The study strains and the G5 prototype strain IAL-28 grouped together, while other prototypes, like OSU grouped separately. These results suggest that the core protein genes (VP1-VP3) of the G5 RV-A Brazilian strains might have originated from porcine and human strains. Phylogenetic analyses of VP7, VP4, VP1, VP2, and VP3 genes of P[8]G5 strains revealed a conserved genomic constellation (G5-P[8]-R1-C1-M1) with sequence similarity to Wa-like strains: IAL28, Wa, BE00048, CK00032, CK00033, DC4772 and DC1898, suggesting that despite the differences in genotypes (i.e., G5, G1 and G3) these viruses are genetically similar. The results presented here are fundamental to understand the epidemiology and evolution of genotype G5 RV-A and demonstrate the importance of continuous monitoring and molecular characterization of RV-A strains circulating in human and animal populations.     

Molecular characterization of a human rotavirus reveals porcine characteristics in most of the genes including VP6 and NSP4

Summary. Long electropherotype with Subgroup I specificity is a common feature of animal rotaviruses. In an epidemic of infantile gastroenteritis in Manipur, India, long but SG I strains predominated in the outbreak in the year 1987–88. One such strain isolated from that region, following the outbreak had G9P [19] specificity. As this is a rare combination, the gene sequences encoding VP4, VP6, VP7, NSP1, NSP2, NSP3, NSP4 and NSP5 of this strain were analyzed. All these genes except VP7 were closely related to porcine rotaviruses (95–99% identity at amino acid level) and clustered with the porcine strains in phylogenetic analysis. In addition, it had subgroup I nature and belonged to NSP4 genotype B which is characteristic of animal rotaviruses. This is the first report of a rotavirus with VP6 and NSP4, two crucial proteins thought to be involved in host range restriction and pathogenicity, were of porcine origin and caused diarrhoea in a human host. Among the genes of this strain sequenced so far, only VP7 had highest identity to human strains at amino acid level. This study suggests reassortment may be occurring between human and other animal strains and some of the reassortant viruses may be virulent to humans.     

Prevalence of human rotavirus genotypes in Wuhan, China, during 2008-2011: changing trend of predominant genotypes and emergence of strains with the P[8]b subtype of the VP4 gene

Hospital-based surveillance of rotavirus genotypes was conducted in Wuhan, China, between March 2008 and May 2011. The detection rates of group A rotavirus were 24.6% (458/1859) and 12.1% (96/795) in children and adults, respectively, with diarrhea. Among the 554 positive specimens, the most frequent genotype was G3P[8] (57.9%), followed by G1P[8] (29.4%). Compared with previous studies in Wuhan (2000-2008), the relative frequency of G3P[8] has been decreasing year by year, while the predominant genotype G3 shifted to G1 in 2011. In the present study, a rare P[8]b subtype of the VP4 gene (OP354-like P[8]) was identified in nine strains. Full-length sequences of VP7, VP4, VP6 and NSP4 genes of two G9P[8]b strains (RVA/Human-wt/CHN/E1545/2009/G9P[8]b and RVA/Human-wt/CHN/Z1108/2008/G9P[8]b) were determined for phylogenetic analysis. The four genes of these strains were closely related to one another, and the G9-VP7 genes of these strains belonged to lineage III, which contains globally spreading G9 rotaviruses. The full-length sequence of VP4 gene segments of the P[8]b strains in Wuhan clustered with those of P[8]b strains in Vietnam, Russia and Belgium, while they were distinct from those of the OP354 strain from Malawi and Bangladeshi strains. The VP6 and NSP4 genes of two P[8]b strains belonged to the I1 and E1 genotype, respectively, and clustered with those of strains belonging to Wa-like human rotaviruses from various Asian countries. These findings indicate the changing epidemiologic trend of rotavirus genotypes in Wuhan, i.e., the shift of the predominant type from G3 to G1 and the emergence of P[8]b strains genetically related to those distributed in other Asian countries.     

Comparative sequence analysis of the VP7 genes of G6, G8 and G10 bovine group A rotaviruses and further characterization of G6 subtypes

Summary.  We previously reported the relatively high prevalence (15%) of bovine G6 subtypes (G6s) in the field using RT-PCR and restriction fragment length polymorphism (RFLP) analysis (Chang et al., Arch. Virol. 141: 1727–39). In the present study, we report the nucleotide and antigenic characterization of a G6s strain (C-8336). We also sequenced the VP7 genes of four additional bovine rotavirus (BRV) strains: another G6s (MC27), G6 (IND), G8 (C-8008) and G10 (2292B) and compared these with other bovine and human rotavirus strains. The C-8336 and MC27 strains were confirmed as P[11]G6s by RT-PCR and RFLP analysis. The VP7 genes of the C-8336 and MC27 strains showed high homology to each other (∼98%) and with other bovine G6s strains (greater than 95% homology in nucleotide and amino acid sequence with KN-4{P[11]G6s}) and also showed lower, but substantial sequence homology with human G6s strains and prototype G6 BRV (79–87% in nucleotide and 88–91% in amino acid). Serologic analysis of the cell culture adapted C-8336 strain showed that it was neutralized by a G6 monoclonal antibody (MAb IC3) to similar titers as the reference NCDV and IND G6 strains. In two-way cross-neutralization tests, strain C-8336 showed 4- to 16-fold differences in antibody titers with NCDV and IND G6 BRV. Moreover polyclonal antiserum against strain C-8336 neutralized the NCDV and IND strains weakly. Genetic variability was also observed among G8 and G10 bovine and human group A rotaviruses: the VP7 genes of the bovine C-8008 (P[5]G8) and 2292 B (P[11]G10) strains showed from 10 to 17% nucleotide divergence with those of Cody I801 (P[1]G8, bovine), A5 (P[1]G8, bovine), 69 M (P[10]G8, human) and Hal 1166 (P[14]G8, human), and I321(P[11]G10, human) and MC35 (P[14]G10, human) rotaviruses, respectively. The divergence of VP7 genes among bovine and human G6, G8 and G10 strains appears related to host species origin and their combination with VP4 (P type). The data presented in this report confirms the genetic variability among homotypic bovine and human strains and highlights the importance of continued monitoring of BRV G and P types circulating in the field for the future development and monitoring of effective vaccines. Received July 4, 1999/Accepted October 31, 1999     

Full genomic analysis of a porcine–bovine reassortant G4P[6] rotavirus strain R479 isolated from an infant in China

During the 2004 surveillance of rotaviruses in Wuhan, China, a G4P[6] rotavirus strain R479 was isolated from a stool specimen collected from a 2‐year‐old child with diarrhea. The strain R479 had an uncommon subgroup specificity I + II, and analysis of the VP6 gene suggested that it was related to porcine rotaviruses. In the present study, full‐length nucleotide sequences of all the RNA segments of R479 were determined and analyzed phylogenetically to identify the origin of individual RNA segments. According to the rotavirus genotyping system based on 11 RNA segments, the genotype of R479 was expressed as G4‐P[6]‐I5‐R1‐C1‐M1‐A1‐N1‐T7‐E1‐H1. This genotype includes the porcine‐like VP6 genotype (I5) and bovine‐like NSP3 genotype (T7). Phylogenetic analysis revealed that R479 genes encoding VP1, VP2, VP3, VP6, VP7, VP8*, NSP1, NSP4, and NSP5 were more closely related to those of porcine rotaviruses than human or other animal rotaviruses. In contrast, it was remarkable that the NSP3 gene of R479 was genetically closely related to only a bovine rotavirus strain UK. The NSP2 gene of R479 was also unique and clustered with only the G5P[8] human strain IAL28 and G3P[24] simian strain TUCH. These results suggested that R479 may be a reassortant virus having the NSP3 gene from a bovine rotavirus in the genetic background of a porcine rotavirus, with an NSP2 gene related to the porcine‐human reassortant strain IAL28. To our knowledge, R479 is the first porcine–bovine reassortant rotavirus isolated from a human. J. Med. Virol. 82:1094–1102, 2010. © 2010 Wiley‐Liss, Inc.     

Molecular characterization of a porcine Group A rotavirus strain with G12 genotype specificity

Summary. A porcine Group A rotavirus strain (RU172) was detected and molecularly characterized during a surveillance study conducted for rotavirus infection in a pig farm located in a suburban area of Kolkata City, India. The G12 genotype specificity of RU172 was revealed by PCR-based genotyping assays following addition of a G12 type-specific primer (designed in our laboratory to pick up G12 isolates from field samples) and was confirmed by sequence analysis of the VP7-encoding gene. The RU172 strain exhibited maximum VP7 identities of 93.6% to 94.5% with human G12 strains at the deduced amino acid level. In spite of its G12 genotype nature, RU172 appeared to be distinct from human G12 rotaviruses and, on phylogenetic analysis, formed a separate lineage with human G12 strains. Among the other gene segments analyzed, RU172 belonged to NSP4 genotype B, had a NSP5 and VP6 of porcine origin, and shared maximum VP4 identities with porcine P[7] rotaviruses (94.3%–95.4% at the deduced amino acid level). Therefore, to the best of our knowledge, this is the first report of detection of an animal rotavirus strain with G12 genotype specificity. Detection of strains like RU172 provides vital insights into the genomic diversity of Group A rotaviruses of man and animals.     

Characterization of human symptomatic rotavirus isolates MP409 and MP480 having ‘long’ RNA electropherotype and subgroup I specificity, highly related to the P6[1],G8 type bovine rotavirus A5, from Mysore, India

Summary.  In an epidemiological study of symptomatic human rotaviruses in Mysore, India during 1993 and 1994, isolates MP409 and MP480 were isolated from two children suffering from severe, acute dehydrating diarrhea. Both isolates exhibited ‘long’ RNA pattern and subgroup I specificity suggesting the likelihood of their animal origin. Both isolates did not react with monoclonal antibodies (MAbs) specific for serotypes G1 to G6 as well as G10. To determine the genetic origin of these isolates, complete nucleotide sequences of genes encoding the outer capsid proteins VP4 and VP7, nonstructural proteins NSP1 and NSP3 and viral enterotoxin protein NSP4 from MP409 and partial sequences of genes from MP480 were determined. Comparison of the 5′ and 3′ terminal sequences of 250 nucleotides revealed complete identity of the gene sequences in both strains suggesting that MP409 and MP480 are two different isolates of a single strain. Comparison of the nucleotide and deduced amino acid sequences of VP4, VP7, NSP1 and NSP3 of MP409 with published sequences of strains belonging to different serotypes revealed that both outer capsid proteins VP4 and VP7 and NSP1 are highly related to the respective proteins from the P6[1], G8 type bovine rotavirus A5 isolated from a calf with diarrhoea in Thailand and that the NSP3 is highly homologous to that of bovine rotaviruses. The NSP4 protein showed greatest sequence identity with NSP4s belonging to the KUN genetic group to which NSP4s from human G2 type strains and bovine rotaviruses belong. MP409 and MP480 likely signify interspecies transmission of P6[1], G8 type strains from cattle to humans and represent the first P6[1] type rotaviruses isolated in humans. These and our previous studies on the asymptomatic neonatal strain I321 are of evolutionary and epidemiological significance in the context of close association of majority of the Indian population with cattle. Received September 29, 1999 Accepted February 4     

Detection and full genomic analysis of G6P[9] human rotavirus in Japan

A rare genotype G6P[9] was identified in two human group A rotavirus strains designated as KF14 and KF17, that were detected in stool specimens from children with diarrhea in Japan. VP7 gene sequences of these two strains were identical and genetically closely related to G6 human rotavirus strains reported in European countries and the United States. To our knowledge, this is the first report of detection of a G6 human rotavirus in Japan. For further genetic analysis to elucidate the origin of the G6 rotavirus, nearly full-length sequences of all 11 RNA segments were determined for the KF17 strain. The complete genomic constellation of KF17 was determined as G6-P[9]-I2-R2-C2-M2-A3-N2-T3-E3-H3, a novel genotype constellation for human rotavirus. Phylogenetic analysis indicated that VP6, VP1-3, and NSP2 genes of KF17 clustered with bovine-like G6 human strains and some animal strains into sub-lineages distinct from those of common DS-1-like G2 human rotaviruses. On the other hand, KF17 genes encoding VP4, NSP1, and NSP3-5 showed high sequence identities to the human G3P[9] strain AU-1, and clustered with AU-1 and some feline strains within the same lineage. These findings suggested that the G6P[9] human rotavirus detected in Japan may have occurred through reassortment among uncommon bovine-like human rotaviruses and human/feline AU-1-like rotaviruses.     

Molecular characterization of G11P[25] and G3P[3] human rotavirus strains associated with asymptomatic infection in South India

Rotaviruses are the major etiological agents of diarrhea in children less than 5 years of age. Two unusual rotavirus strains not previously reported in India, G11P[25] (CRI 10795) and G3P[3] (CRI 33594) were isolated from faecal samples of asymptomatic children in India. The strains were characterized by sequence analysis of the genes encoding the VP7, VP4, VP6, and NSP4. The G11P[25] strain was closely related to the human G11P[25] strains from Bangladesh (with 98% identity at the nucleotide [nt] level and the amino acid [aa] level for the VP7 gene and 96% identity at the nt and 98% at the aa level for the VP4 gene). The G3P[3] strain was found to be related to a G3P[3] strain isolated in Thailand (CMH222; 88% identity at the nt level and 97% at aa level for the VP7 gene and 84% identity at the nt level and 90% at the aa level for the VP4 gene). Phylogenetic analysis of the VP6 and the NSP4 genes revealed that the Vellore G11P[25] strain was of VP6 subgroup II and NSP4 genotype B. The G3P[3] strain was identified as NSP4 genotype C and the VP6 gene showed 97% identity at the deduced amino acid level with strain CMH222 (Thailand) strain but did not cluster with sequences of SGI, SGII, SGI+II or SG-nonI/nonII. Both strains had gene segments of animal rotavirus origin suggesting inter-species transmission of rotavirus, and in the case of G11P[25] possibly underwent reassortment subsequently with human strains resulting in an animal-human hybrid strain.