Search

From October 2003 through September 2004, a total of 289 stool samples were collected from children <5 years of age who had severe diarrhea at admission to or when visiting the emergency department at the Navrongo War Memorial Hospital in rural Ghana during a study on rotavirus disease burden. Rotavirus antigen was detected in 115 stool samples (39.8%) tested for rotavirus. Four rotavirus-positive samples were found to bear G10P[6] specificity by reverse-transcription polymerase chain reaction, polymerase chain reaction-enzyme-linked immunosorbent assay, and oligonucleotide microarray hybridization. Two of these strains further exhibited serotype G10 specificity by neutralization and subgroup II specificity by enzyme immunoassay and possessed long electropheretic patterns by polyacrylamide gel electrophoresis. Their VP7 genes shared a much closer nucleotide identity with other African human Gb strains (>97%) than with human Gb strain from Asia or South America (<86%) or animal strains (<85%). The VP8* genes of the Ghanaian G10 strains exhibited >94% identity to that of human P[6] virus strains and belonged to the P[6] lineage la. The deduced VP7 amino acid sequence showed that the Ghanaian strains were more closely related to human G10 strains than to animal Gb strains. The possession of the typical human subgroup II specificity and the P[6] specificity (frequently found in Ghana and the rest of Africa) and the marked similarity in the VP7 antigenic sites suggest that these G10 strains may have evolved through genetic reassortment between bovine and human strains. [ABSTRACT FROM AUTHOR]

Background: It is universally acknowledged that genome segment 4 of group A rotavirus, the major etiologic agent of severe diarrhea in infants and neonatal farm animals, encodes outer capsid neutralization and protective antigen VP4. Results: To determine which genome segment of three group A equine rotavirus strains (H-2, FI-14 and FI-23) with P[12] specificity encodes the VP4, we analyzed dsRNAs of strains H-2, FI-14 and FI-23 as well as their reassortants by polyacrylamide gel electrophoresis (PAGE) at varying concentrations of acrylamide. The relative position of the VP4 gene of the three equine P[12] strains varied (either genome segment 3 or 4) depending upon the concentration of acrylamide. The VP4 gene bearing P[3], P[4], P[6], P[7], P[8] or P[18] specificity did not exhibit this phenomenon when the PAGE running conditions were varied. Conclusions: The concentration of acrylamide in a PAGE gel affected VP4 gene coding assignment of equine rotavirus strains bearing P[12] specificity. [ABSTRACT FROM AUTHOR]

Background. In a study performed in 1983, 18 adult volunteers received oral challenge with the virulent human rotavirus strain D (G1P1A[8],NSP4[B]). To identify correlates of resistance to rotavirus infection, we analyzed levels of serum immunoglobulin (Ig) A and IgG antibodies to various rotaviral antigens in 16 of the 18 volunteers. Methods. We used immunocytochemical assays that involved a total of 16 different recombinant baculoviruses, with each baculovirus expressing one of the following major serotype/genotype rotavirus proteins for the serologic assays: (1) viral protein (VP) 4 with P1A[8], P1B[4], P2A[6], P3[9], or P4[10] specificity; (2) VP7 with G1-G4 or G9 specificity; and (3) nonstructural viral protein (NSP) 4 with genotype A, B, C, or D specificity. Results. The prechallenge titers of IgG antibody to VP7 types G1, G3, G4, and G9; VP4 types P1A[8], P1B[4], P2A[6], and P4[10]; and NSP4 type [A] in the group of noninfected volunteers (n=11) were significantly higher than those in the group of infected volunteers (n=5; of these 5 volunteers, 4 were symptomatically infected). Moreover, logistic regression analysis showed that resistance to rotavirus infection most closely correlated with higher prechallenge titers of IgG antibody to homotypic VP7 (G1) and VP4 (P1A[8]). Conclusions. These results suggest that protection against rotavirus infection and disease is primarily VP7/VP4 homotypic and, to a lesser degree, heterotypic. [ABSTRACT FROM AUTHOR]

The author comments on the study "Neonatal Infection With G10P Rotavirus Did Not Confer Protection Against Subsequent Rotavirus Infection in a Community Cohort in Vellore, South India," conducted by I. Banerjee and colleagues. He argues that the study failed to provide protection to neonates from rotaviruses because most of the postneonatal illness were caused by non-G10P rotavirus serotypes. He asserts that vaccines of the virus should undergo evaluation in the setting of a developing country.

Abstract: A distinct rotavirus strain (PTRV) was isolated in cell cultures from a stool sample obtained from a diarrheic 3-year-old female pig-tailed macaque (Macaca nemestrina) that was born at the breeding colony of the University of Washington in Seattle. Unlike other known simian rotavirus strains including vervet monkey rotavirus SA11 which bears P5B[2]:G3 or P6[1]:G3 specificity, rhesus monkey rotavirus MMU18006 with P5B[3]:G3 specificity, pig-tailed macaque rotavirus YK-1 with P[3]:G3 specificity and rhesus monkey rotavirus TUCH with P[24]:G3 specificity, the cell-culture-grown PTRV strain was shown to bear P6[1]:G8 specificity as determined by VP4 (P)- and VP7 (G)-specific neutralization assays as well as gene sequence analyses. The virus in the original diarrhea stool was also shown to bear genotypes P[1] and G8. In addition, the PTRV strain exhibited a “long” electropherotype, subgroup I specificity and NSP4 genotype A specificity. The PTRV probe formed (i) 8–9 hybrid bands with genomic RNAs of various bovine rotavirus strains and (ii) only 2–3 hybrid bands with simian rotavirus RNAs as demonstrated by RNA–RNA hybridization, suggesting a possible bovine origin of the virus. Serologic analysis of serum samples obtained from selected pig-tailed macaques in the colony suggested that a rotavirus bearing P[1]:G8 specificity was endemic among macaques for at least 8 years (1987–1994). This is the first report describing an isolation of a simian rotavirus bearing a non-G3 VP7 and possibly a P6[1] specificities. Because of its unique simian serotype, this virus may prove to be valuable in challenge studies in a non-human primate model in studies of rotavirus immunity. [Copyright &y& Elsevier]

There is an urgent need for a rotavirus vaccine, because up to 592,000 infants and young children <5 years old die each year from rotavirus diarrhea, predominantly in the developing countries. We have developed a tetravalent human-bovine rotavirus (UK) reassortant vaccine with VP7 (G) specificity for serotypes 1, 2, 3, and 4, which has been shown to be safe, immunogenic, and effective in preventing severe rotavirus diarrhea. However, because of the emergence of VP7 (G) serotype 9 as an epidemiologically important serotype and the importance of VP7 (G) serotype 8 in focal areas, we are planning to add human-bovine (UK) reassortants with G8 and G9 specificity to the tetravalent vaccine, thereby formulating a "designed" hexavalent vaccine for universal use. In addition, we propose that the vaccine be administered orally in a 2-dose schedule, with the first dose given at 0-4 weeks of age and the second dose given at 4-8 weeks of age, when infants are relatively refractory to developing intussusception, thereby avoiding the age period when naturally occurring intussusception is most prevalent (i.e., ages 3-4 months through age 9 months). In this way, theremay be the potential to eliminate or at least significantly decrease the risk of intussusception associated with rotavirus vaccination. [ABSTRACT FROM AUTHOR]

Abstract: Rotavirus gastroenteritis remains the leading cause of severe diarrheal disease in infants and young children worldwide, and thus, a safe and effective rotavirus vaccine is urgently needed in both developing and developed countries. Various candidate rotavirus vaccines that were developed by us and others have been or are being evaluated in different populations in various parts of the world. We have recently confirmed that a porcine rotavirus Gottfried strain bears a P (VP4) serotype (P2B[6]) closely related to human rotavirus P serotype 2A[6] which is of epidemiologic importance in some regions of the world. Based on the modified Jennerian approach to immunization, we have constructed 11 Gottfried-based single VP7 or VP4 gene substitution reassortant vaccine candidates which could provide: (i) an attenuation phenotype of a porcine rotavirus in humans; and (ii) antigenic coverage for G serotypes 1–6 and 8–10 and P serotype 1A[8], 1B[4] and 2A[6]. In addition, following immunization of guinea pigs with Gottfried VP4, we found low but consistent levels of neutralizing antibodies to VP4 with P1A[8] or P1B[4] specificity, both of which are of global epidemiologic importance. Thus, porcine-based VP7 reassortant rotavirus vaccines may provide an advantage over rhesus- or bovine-based VP7 reassortant vaccines since the VP4s of the latter vaccines do not evoke antibodies capable of neutralizing the viruses bearing P1A[8], P1B[4] or P2A[6] VP4. [Copyright &y& Elsevier]

Abstract: Of five globally important VP7 (G) serotypes (G1–4 and 9) of group A rotaviruses (the single most important etiologic agents of infantile diarrhea worldwide), G9 continues to attract considerable attention because of its unique natural history. Serotype G9 rotavirus was isolated from a child with diarrhea first in the United States in 1983 and subsequently in Japan in 1985. Curiously, soon after their detection, G9 rotaviruses were not detected for about a decade in both countries and then reemerged in both countries in the mid-1990s. Unexpectedly, however, such reemerged G9 strains were distinct genetically and molecularly from those isolated in the 1980s. Thus, the origin of the reemerged G9 viruses remains an enigma. Sequence analysis has demonstrated that the G9 rotavirus VP7 gene belongs to one of at least three phylogenetic lineages: lineage 1 (strains isolated in the 1980s in the United States and Japan), lineage 2 (strains first isolated in 1986 and exclusively in India thus far), and lineage 3 (strains that emerged/reemerged in the mid-1990s). Currently, lineage 3 G9 viruses are the most frequently detected G9 strains globally. We characterized a porcine rotavirus (A2 strain) isolated in the United States that was known to belong to the P[7] genotype but had not been serotyped by neutralization. The A2 strain was found to bear serotype G9 and P9 specificities as well as NSP4 [B] and subgroup I characteristics. By VP7-specific neutralization, the porcine G9 strain was more closely related to lineage 3 viruses than to lineage 1 or 2 viruses. Furthermore, by sequence analysis, the A2 VP7 was shown to belong to lineage 3 G9. These findings raise intriguing questions regarding possible explanations for the emergence of variations among the G9 strains. [Copyright &y& Elsevier]

Rotavirus, a cause of severe gastroenteritis, contains a segmented double-stranded (ds)RNA genome that replicates using viral mRNAs as templates. The highly conserved 3'-consensus sequence (3'CS), UGUGACC, of the mRNAs promotes dsRNA synthesis and enhances translation. We have found that the 3'CS of the gene (g5) encoding NSP1, an antagonist of interferon signaling, undergoes rapid mutation when rhesus rotavirus (RRV) is serially passaged at high multiplicity of infection (MOI) in cells permitting high titer growth. These mutations increase the promoter activity of the g5 3'-sequence, but decrease its activity as a translation enhancer. The location of the mutations defines the minimal essential promoter for dsRNA synthesis as URN0-5CC. Under passage conditions where cell-to-cell spread of the virus is required to complete infection (low MOI), the 3'CS is retained due to the need for NSP1 to be expressed at levels sufficient to prevent establishment of the antiviral state. These data demonstrate that host cell type and propagation conditions affect the capacity of RRV to produce the virulence gene product NSP1, an important consideration in producing RRV-based vaccines. [ABSTRACT FROM AUTHOR]

A safe and effective group A rotavirus vaccine that could prevent severe diarrhea or ameliorate its symptoms in infants and young children is urgently needed in both developing and developed countries. Rotavirus VP7 serotypes G1, G2, G3, and G4 have been well established to be of epidemiologic importance worldwide. Recently, serotype G9 has emerged as the fifth globally common type of rotavirus of clinical importance. Sequence analysis of the VP7 gene of various G9 isolates has demonstrated the existence of at least three phylogenetic lineages. The goal of our study was to determine the relationship of the phylogenetic lineages to the neutralization specificity of various G9 strains. We generated eight single VP7 gene substitution reassortants, each of which bore a single VP7 gene encoding G9 specificity of one of the eight G9 strains (two lineage 1, one lineage 2 and five lineage 3 strains) and the remaining 10 genes of bovine rotavirus strain UK, and two hyperimmune guinea pig antisera to each reassortant, and we then analyzed VP7 neutralization characteristics of the eight G9 strains as well as an additional G9 strain belonging to lineage 1; the nine strains were isolated in five countries. Antisera to lineage I viruses neutralized lineage 2 and 3 strains to at least within eightfold of the homotypic lineage viruses. Antisera to lineage 2 virus neutralized lineage 3 viruses to at least twofold of the homotypic lineage 2 virus; however, neutralization of lineage 1 viruses was fourfold (F45 and AU32) to 16- to 64-fold (WI61) less efficient. Antisera to lineage 3 viruses neutralized the lineage 2 strain 16- to 64-fold less efficiently, the lineage 1 strains F45 and AU32 8- to 128-fold less efficiently, and WI61 (prototype G9 strain) 128. to 1,024-fold less efficiently than the homotypic lineage 3 viruses. These findings may have important implications for the development of G9 rotavirus vaccine candidates, as the strain with the broadest reactivity (i.e., a prime strain) would certainly be the ideal strain for inclusion in a vaccine. [ABSTRACT FROM AUTHOR]

A rotavirus VP4 gene P[6] allele has been documented in a number of countries to be characteristically associated with an endemic predominantly asymptomatic infection in neonates in maternity hospital nurseries. The mechanisms underlying the endemicity and asymptomatic nature of such neonatal infections remain unknown. Rotavirus strains sharing this same P genotype, however, have more recently been recovered from an increasing number of symptomatic diarrheal episodes in infants and young children in various parts of the world. Previously, we have shown that an asymptomatic P[6] rotavirus neonatal infection is not associated with a unique VP7 (G) serotype but may occur in conjunction with various G types. Although amino acid sequence comparisons of the VP4 gene between selected “asymptomatic” and “symptomatic” P[6] rotavirus strains have been reported and yielded information concerning their VP4 genotypes, serotypic comparisons of the outer capsid spike protein VP4 of such viruses have not been studied systematically by two-way cross-neutralizations. We determined the VP4 neutralization specificities of four asymptomatic and four symptomatic P[6] strains: two each of asymptomatic and symptomatic strains by two-way tests, and two each of additional asymptomatic and symptomatic strains by one-way tests. Both asymptomatic and symptomatic P[6] strains were shown to bear similar, if not identical, VP4 neutralization specificities. Thus, P[6] rotavirus strains causing asymptomatic or symptomatic infections did not appear to belong to unique P (VP4) serotypes. In addition, a close VP4 serotypic relationship between human P[6] rotavirus strains and the porcine P[6] rotavirus Gottfried strain was confirmed. [Copyright &y& Elsevier]

Group A rotaviruses are the single most important etiologic agents of severe diarrhea of infants and young children worldwide and have been estimated to be responsible for approximately 650,000–800,000 deaths annually in children <5-year-old in the developing countries. Thus, the development of a safe and effective rotavirus vaccine has been a global public health goal. Epidemiologic surveillance of rotavirus VP7 (G) serotypes–genotypes conducted in various populations throughout the world has repeatedly shown that approximately 90% of the typeable rotavirus isolates belong to G1–G4. For these reasons, we have developed a rhesus rotavirus (RRV)-based or bovine rotavirus (UK)-based quadrivalent vaccine which is designed to provide antigenic coverage for G1–G4. More recently, G serotypes–genotypes other than G1–G4, including G5, G8–G10, have been detected in various parts of the world. Although the occurrence of such uncommon G types, except for G9, has been focal, still, in order to “be ready and prepared”, we have constructed and characterized eight additional reassortant rotavirus vaccines, each of which bears a single human or bovine VP7 gene encoding G serotype 5, 8, 9 or 10 specificity and the remaining 10 genes of RRV strain MMU18006 or bovine rotavirus strain UK. These candidate vaccines could be evaluated singly in special populations or in combination with a RRV- or an UK-based quadrivalent vaccine to broaden its G serotype specificity. [Copyright &y& Elsevier]

During a phase 3 clinical trial of rhesus monkey rotavirus-based quadrivalent vaccine in Venezuela, 2207 infants received 3 oral doses of vaccine (4 × 10[sup 5] plaque-forming units/dose) or placebo at ages ∼2, 3, and 4 months; 219 (14%) of 1537 stools obtained during 1550 diarrheal episodes in postvaccination surveillance were rotavirus-positive by enzyme-linked immunosorbent assay. With the use of various VP7 and VP4 primers for genotyping purposes, 213 of 219 rotavirus-positive stools were analyzed by reverse-transcription polymerase chain reaction. Twenty-nine (14%) of 213 rotavirus-positive stools contained at least 2 distinct rotavirus strains: a low-titered vaccine strain(s) and a second strain that, when possible, was studied further and found to be a wild-type rotavirus strain. The titer of vaccine viruses in 19 stools that plaqued directly in cell cultures ranged from 10¹ to 10³ plaque-forming units/0.5 mL of a 10% stool suspension. Reassortants of vaccine virus and wild-type human rotavirus were not detected. [ABSTRACT FROM AUTHOR]

Group A equine rotavirus (ERV) is the main cause of diarrhea in foals and causes severe economic loss due to morbidity and mortality on stud farming worldwide. Molecular evolution of equine rotaviruses remains understudies. In this study, whole-genomic analysis of 2 group A ERV, FI-14 (G3P[12]), H-2 (G3P[12]) isolated from American, and FI23 (G14P[12]) from British was carried out and genotype constellations were determined as G3-P[12]-I6-R2-C2-M3-A10-N2-T3-E2-H7 for FI-14; G14-P[12]-I2-R2-C2-M3-A10-N2-T3-E2-H7 for FI23; and G3-P[12]-I6-R2-C2-M3-A10-N2-T3-E2-H7 for H-2, respectively. With the exception of the VP7 and VP6 gene, 2 G3P[12] strains (FI-14 and H-2) and one G14P[12] strain (FI23) were highly related genetically. Of note, the VP6 genotype of H-2 strain was previously reported to be I2, however, sequence and phylogenetic analyses demonstrated that it was I6. Therefore, it showed that G3P[12] ERV strains and G14P[12] ERV strains bore a distinct VP6 genotype: I6 for G3P[12] strains and I2 for G14P[12] strains. Moreover, it demonstrated that T-cell epitope 299P–300P/Q residues (PP/Q) of VP6 may be considered as I2 ERV typical molecular marker, which facilitates the analysis of the molecular evolution of equine rotaviruses. [ABSTRACT FROM AUTHOR]

An abstract of the article "Porcine Rotavirus Bearing an Aberrant Gene Stemming from an Intergenic Recombination of the NSP2 and NSP5 Genes Is Defective and Interfering," by Dianjun Cao, Mario Barro, and Yasutaka Hoshino is presented.

Rotaviruses are the single most important etiologic agents of severe diarrhea in infants and young children worldwide. They possess a triple capsid morphology and a genome of 11 segments of double-stranded (ds) RNA. During the course of the development of various live, attenuated reassortant rotavirus vaccines, we often experienced difficulty in identifying the parental origin of certain genome segment(s) of a reassortant vaccine candidate. Various assays have been utilized for determination of the parental origin of reassortant virus genes, including polyacrylamide gel electrophoresis (PAGE), DNA and/or RNA hybridization assays and gene sequence analysis. The traditional PAGE is simple and easy to perform, however, it is common to find that certain cognate dsRNA segment(s) cannot be differentiated by this assay due to a high degree of sequence homology among different rotavirus strains. Constant denaturant gel electrophoresis (CDGE) is one of several methods that have been used to screen DNA fragments for small sequence changes or point mutations. By using the CDGE, we were successful in partially denaturing rotavirus dsRNA thereby changing the physical properties of the genome segment(s) in the gel and thus differentiating the cognate genome segment(s) of rotavirus reassortants. The CDGE provides a simple and reliable assay system for identification of parental gene origins of a rotavirus reassortant. [Copyright &y& Elsevier]

Rotavirus replication and virulence are strongly influenced by virus strain and host species. The rotavirus proteins VP3, VP4, VP7, NSP1, and NSP4 have all been implicated in strain and species restriction of replication; however, the mechanisms have not been fully determined. Simian (RRV) and bovine (UK) rotaviruses have distinctive replication capacities in mouse extraintestinal organs such as the biliary tract. Using reassortants between UK and RRV, we previously demonstrated that the differential replication of these viruses in mouse embryonic fibroblasts is determined by the respective NSP1 proteins, which differ substantially in their abilities to degrade interferon (IFN) regulatory factor 3 (IRF3) and suppress the type I IFN response. In this study, we used an in vivo model of rotavirus infection of mouse gallbladder with UK x RRV reassortants to study the genetic and mechanistic basis of systemic rotavirus replication. We found that the low-replication phenotype of UK in biliary tissues was conferred by UK VP4 and that the high-replication phenotype of RRV was conferred by RRV VP4 and NSP1. Viruses with RRV VP4 entered cultured mouse cholangiocytes more efficiently than did those with UK VP4. Reassortants with RRV VP4 and UK NSP1 genes induced high levels of expression of IRF3-dependent p54 in biliary tissues, and their replication was increased 3-fold in IFN-α/β and -γ receptor or STAT1 knockout (KO) mice compared to wild-type mice. Our data indicate that systemic rotavirus strain-specific replication in the murine biliary tract is determined by both viral entry mediated by VP4 and viral antagonism of the host innate immune response mediated by NSP1. [ABSTRACT FROM AUTHOR]

Abstract: Background: During the course of development and characterization of various rotavirus reassortants, we found that the relative position of the gene encoding neutralization and protective antigen VP7 of certain rotavirus strains in a PAGE gel was influenced by the concentration of acrylamide. Objectives: We investigated systematically various factors that affected the relative position of the rotavirus VP7 gene in a PAGE gel. Study design: We analyzed dsRNAs of selected rotavirus strains bearing G1, G2, G3 or G9 specificity by PAGE at varying concentrations of acrylamide. Results: We demonstrated that the relative position of the VP7 gene of three G2 strains varied depending upon the concentration of acrylamide in a PAGE gel, which occurred not only in a homologous G2 virus gene background but also in a heterologous G3 virus gene background; and the VP7 gene bearing G1, G3, G4 or G9 specificity did not display this phenomenon when the PAGE running conditions were varied. Conclusions: The concentration of acrylamide in a PAGE gel was the major factor that influenced the relative position of the VP7 gene of G2 rotavirus strains (i.e., VP7 gene coding assignment by PAGE). [Copyright &y& Elsevier]

Using recombinant baculoviruses expressing rotavirus NSP4 [A], [B], [C], and [D] genotypes of bovine, porcine, human, simian, or murine origin, we analyzed serum antibody responses to NSP4s in gnotobiotic calves and piglets infected by the oral/alimentary or intraamniotic route with bovine (NSP4[A]) (Wyatt, R.G., Mebus, C.A., Yolken, R.H., Kalica, A.R., James, H.D., Jr., Kapikian, A.Z., Chanock, R.M., 1979. Rotaviral immunity in gnotobiotic calves: heterologous resistance to human virus induced by bovine virus. Science 203(4380), 548–550) or porcine (NSP4[B]) (Hoshino, Y., Saif, L.J., Sereno, M.M., Chanock, R.M., Kapikian, A.Z., 1988. Infection immunity of piglets to either VP3 or VP7 outer capsid protein confers resistance to challenge with a virulent rotavirus bearing the corresponding antigen. J. Virol. 62(3), 744–748) rotaviruses. Following primary infection and challenge with virulent rotaviruses, the animals developed higher or significantly higher antibody titers to homologous host homotypic NSP4s than to heterologous host homotypic or heterologous host heterotypic NSP4s, indicating that antibody responses were species specific rather than genotype specific. Antibody responses to NSP4s corresponded closely with the phylogenetic relationships of NSP4s within a species-specific region of amino acids (aa) 131–141. In contrast, NSP4 genotypes determined by amino acid full-length sequence identity predicted poorly their “serotypes”. In piglets, antibodies to NSP4 induced by previous oral infection failed to confer protection against challenge from a porcine rotavirus bearing serotypically different VP4 and VP7 but essentially identical NSP4 to the porcine rotavirus in primary infection. Thus, in an approach to immunization with a live oral rotavirus vaccine, the NSP4 protein does not appear to play an important role in protection against rotavirus disease and infection. [Copyright &y& Elsevier]

Rotaviruses are the single most important etiologic agents of severe diarrhea of infants and young children worldwide. Surveillance of rotavirus serotypes/genotypes (both VP7[G] and VP4[P]) is in progress globally in which polymerase chain reaction (PCR) has been the assay of choice. We investigated polymorphism of the VP7 gene of serotype G9 rotavirus strains and its impact on the determination of VP7 gene genotype by PCR assay. By VP7 gene sequence analysis, we and others have previously shown that the G9 rotavirus strains belong to one of three VP7 gene lineages. By PCR assay using three different sets of commonly used primers specific for G1-4, 8 and 9, 23 Brazilian G9 strains and 5 well-characterized prototype G9 strains which collectively represented all three VP7 gene lineages were typed as: (i) G3; (ii) G4; (iii) G9; (iv) G3 and G9; or (v) G9 and G4 depending on a primer pool employed. This phenomenon appeared to be due to: (i) a VP7 gene lineage-specific polymorphism, more specifically mutation(s) in the primer binding region of the VP7 gene of G9 strain; and (ii) the magnitude of difference in nucleotide homology at respective primer binding site between homotypic (G9) and heterotypic (G3 or G4) primers present in a primer pool employed. [Copyright &y& Elsevier]

Rotaviruses are the single most important etiologic agents of severe diarrhea of infants and young children worldwide. Surveillance of rotavirus serotypes/genotypes (both VP7[G] and VP4[P]) is in progress globally in which polymerase chain reaction (PCR) has been the assay of choice. We investigated polymorphism of the VP7 gene of serotype G9 rotavirus strains and its impact on the determination of VP7 gene genotype by PCR assay. By VP7 gene sequence analysis, we and others have previously shown that the G9 rotavirus strains belong to one of three VP7 gene lineages. By PCR assay using three different sets of commonly used primers specific for G1-4, 8 and 9, 23 Brazilian G9 strains and 5 well-characterized prototype G9 strains which collectively represented all three VP7 gene lineages were typed as: (i) G3; (ii) G4; (iii) G9; (iv) G3 and G9; or (v) G9 and G4 depending on a primer pool employed. This phenomenon appeared to be due to: (i) a VP7 gene lineage-specific polymorphism, more specifically mutation(s) in the primer binding region of the VP7 gene of G9 strain; and (ii) the magnitude of difference in nucleotide homology at respective primer binding site between homotypic (G9) and heterotypic (G3 or G4) primers present in a primer pool employed. [Copyright &y& Elsevier]

Although few simian rotaviruses (RVs) have been isolated, such strains have been important for basic research and vaccine development. To explore the origins of simian RVs, the complete genome sequences of strains PTRV (G8P[1]), RRV (G3P[3]), and TUCH (G3P[24]) were determined. These data allowed the genotype constellations of each virus to be determined and the phylogenetic relationships of the simian strains with each other and with nonsimian RVs to be elucidated. The results indicate that PTRV was likely transmitted from a bovine or other ruminant into pig-tailed macaques (its host of origin), since its genes have genotypes and encode outer-capsid proteins similar to those of bovine RVs. In contrast, most of the genes of rhesus-macaque strains, RRV and TUCH, have genotypes more typical of canine-feline RVs. However, the sequences of the canine and/or feline (canine/feline)-like genes of RRV and TUCH are only distantly related to those of modern canine/feline RVs, indicating that any potential transmission of a progenitor of these viruses from a canine/feline host to a simian host was not recent. The remaining genes of RRV and TUCH appear to have originated through reassortment with bovine, human, or other RV strains. Finally, comparison of PTRV, RRV, and TUCH genes with those of the vervet-monkey RV SA11-H96 (G3P[2]) indicates that SA11-H96 shares little genetic similarity to other simian strains and likely has evolved independently. Collectively, our data indicate that simian RVs are of diverse ancestry with genome constellations that originated largely by interspecies transmission and reassortment with nonhuman animal RVs. [ABSTRACT FROM AUTHOR]