Last data update: May 20, 2024. (Total: 46824 publications since 2009)
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Special issue on 'genetic diversity and evolution of rotavirus strains: possible impact of global immunization programs'.
Bányai K , Gentsch J . Infect Genet Evol 2014 28 375-6 Epidemiological surveillance of rotavirus strains dates back to mid-1980s with the initial objective to describe the globally common rotavirus serotypes that could have an impact on vaccine development. With over 100,000 genotyped human rotavirus strains in the pre vaccine era worldwide and with the availability of two vaccines, the monovalent Rotarix and the pentavalent RotaTeq, the objectives of strain surveillance have changed. We have learned much about human rotavirus strain diversity and the evolutionary forces driving strain variation in nature. However questions on how rotavirus strains under vaccine induced immune pressure evolve and what the impact of vaccine use on strain prevalence in vaccinated populations is, remain open. | | In the 1980s rotavirus typing protocols included monoclonal antibody based enzyme immunoassays, which were available to relatively few laboratories due to limited reagent resources. In addition, the antibodies mainly identified only four common G types. The introduction of nucleic acid based techniques (primarily multiplex RT-PCR assays) enhanced our ability to genotype both neutralizing antigen genes and advances in sequencing technology paved the way for more detailed analysis of circulating rotavirus strains. More recently, whole genome sequencing has become an alternative tool for researchers to describe the molecular epidemiology of rotaviruses. Access to high throughput sequencing technology has made molecular strain characterization an increasingly routine laboratory method without the need of cumbersome and costly pre-analytic steps, such as cloning and/or designing dozens of PCR and sequencing primers. We believe that as these technical advances mature the ultimate goals of routine surveillance in the post rotavirus vaccine era will become a reality. Strain characterization using improved methods not only allows the classification of strains into their antigenic types, but also permits whole genome based comparisons, determination of preferred genotype constellations, identification of vaccine strain derived genes in field strains, and tracking the evolution of vaccine strains. |
Etiology of severe acute watery diarrhea in children in the Global Rotavirus Surveillance Network using quantitative polymerase chain reaction
Operario DJ , Platts-Mills JA , Nadan S , Page N , Seheri M , Mphahlele J , Praharaj I , Kang G , Araujo IT , Leite JPG , Cowley D , Thomas S , Kirkwood CD , Dennis F , Armah G , Mwenda JM , Wijesinghe PR , Rey G , Grabovac V , Berejena C , Simwaka CJ , Uwimana J , Sherchand JB , Thu HM , Galagoda G , Bonkoungou IJO , Jagne S , Tsolenyanu E , Diop A , Enweronu-Laryea C , Borbor SA , Liu J , McMurry T , Lopman B , Parashar U , Gentsch J , Steele AD , Cohen A , Serhan F , Houpt ER . J Infect Dis 2017 216 (2) 220-227 Background: The etiology of acute watery diarrhea remains poorly characterized, particularly after rotavirus vaccine introduction. Methods: We performed quantitative polymerase chain reaction for multiple enteropathogens on 878 acute watery diarrheal stools sampled from 14643 episodes captured by surveillance of children <5 years of age during 2013-2014 from 16 countries. We used previously developed models of the association between pathogen quantity and diarrhea to calculate pathogen-specific weighted attributable fractions (AFs). Results: Rotavirus remained the leading etiology (overall weighted AF, 40.3% [95% confidence interval {CI}, 37.6%-44.3%]), though the AF was substantially lower in the Americas (AF, 12.2 [95% CI, 8.9-15.6]), based on samples from a country with universal rotavirus vaccination. Norovirus GII (AF, 6.2 [95% CI, 2.8-9.2]), Cryptosporidium (AF, 5.8 [95% CI, 4.0-7.6]), Shigella (AF, 4.7 [95% CI, 2.8-6.9]), heat-stable enterotoxin-producing Escherichia coli (ST-ETEC) (AF, 4.2 [95% CI, 2.0-6.1]), and adenovirus 40/41 (AF, 4.2 [95% CI, 2.9-5.5]) were also important. In the Africa Region, the rotavirus AF declined from 54.8% (95% CI, 48.3%-61.5%) in rotavirus vaccine age-ineligible children to 20.0% (95% CI, 12.4%-30.4%) in age-eligible children. Conclusions: Rotavirus remained the leading etiology of acute watery diarrhea despite a clear impact of rotavirus vaccine introduction. Norovirus GII, Cryptosporidium, Shigella, ST-ETEC, and adenovirus 40/41 were also important. Prospective surveillance can help identify priorities for further reducing the burden of diarrhea. |
Effectiveness of pentavalent rotavirus vaccine against a diverse range of circulating strains in Nicaragua
Manish Patel , Pedreira C , Oliveira LHde , Tate J , Leshem E , Mercado J , Umana J , Balmaceda A , Reyes M , Kerin T , McDonald S , Gentsch J , Bowen MD , Umesh Parashar . Clin Infect Dis 2016 62 S127-S132 Background. Because >60 rotavirus strains have been reported worldwide, concerns exist about strain replacement after the introduction of rotavirus vaccines, particularly in developing countries with diverse strains and lower efficacy. Methods. We used the case-control design in 4 hospitals in Nicaragua to assess strain-specific vaccine effectiveness (VE) of a pentavalent rotavirus vaccine (RotaTeq) against rotavirus diarrhea. Cases were identified through prospective strain surveillance with reverse transcription-polymerase chain reaction for 3 years among children hospitalized for diarrhea, and controls were children negative for rotavirus. Results. We enrolled 1178 case-patients, 1082 (92%) with G and P typing, and 4927 controls. A different strain predominated each year with increasing age of the vaccine-eligible cohort during the study period: G2P[4] in 2008 (97%; mean age, 11.9 months), G1P[8] in 2009 (55%; mean age, 17.0 months), and G3P[8] in 2010 (78%; mean age, 17.3 months). Overall VE was 45% (95% confidence interval, 25%-59%). Regardless of the strain, VE estimates were 12%-79% lower among children aged >=12 months relative to those 6-11 months of age. The lower VE for G3P[8] was related to the higher mean age of cases (17.3 months) compared with the G2P[4] strains (11.9 months), with a significant trend (R2=0.819; P<.001) of declining effectiveness with increasing mean age of the cases. Conclusions. Introduction of RotaTeq did not result in sustained emergence of any particular strain in Nicaragua. Variation in strain-specific effectiveness was due to an age-related decline in effectiveness rather than differences in protection against the observed strains. |
Long-term consistency in rotavirus vaccine protection: RV5 and RV1 vaccine effectiveness in US children, 2012-2013
Payne DC , Selvarangan R , Azimi PH , Boom JA , Englund JA , Staat MA , Halasa NB , Weinberg GA , Szilagyi PG , Chappell J , McNeal M , Klein EJ , Sahni LC , Johnston SH , Harrison CJ , Baker CJ , Bernstein DI , Moffatt ME , Tate JE , Mijatovic-Rustempasic S , Esona MD , Wikswo ME , Curns AT , Sulemana I , Bowen MD , Gentsch JR , Parashar UD . Clin Infect Dis 2015 61 (12) 1792-9 BACKGROUND: Using a multi-center, active surveillance network from two rotavirus seasons (2012 and 2013), we assessed the vaccine effectiveness of RV5 (RotaTeq) and RV1 (Rotarix) rotavirus vaccines in preventing rotavirus gastroenteritis hospitalizations and emergency department (ED) visits for numerous demographic and secular strata. METHODS: We enrolled children hospitalized or visiting the ED with acute gastroenteritis (AGE) for the 2012 and 2013 seasons at 7 medical institutions. Stool specimens were tested for rotavirus by enzyme immunoassay and genotyped, and rotavirus vaccination histories were compared for rotavirus-positive cases and rotavirus-negative AGE controls. We calculated the VE for preventing rotavirus associated hospitalizations and ED visits for each vaccine, stratified by vaccine dose, season, clinical setting, age, predominant genotype, and ethnicity. RESULTS: RV5-specific VE analyses included 2,961 subjects, 402 rotavirus cases (14%) and 2,559 rotavirus-negative AGE controls. RV1-specific VE analyses included 904 subjects, 100 rotavirus cases (11%) and 804 rotavirus-negative AGE controls. Over the two rotavirus seasons, the VE for a complete 3-dose vaccination with RV5 was 80% (CI= 74% - 84%), and VE for a complete 2-dose vaccination with RV1 was 80% (CI= 68% - 88%).Statistically significant VE was observed for each year of life for which sufficient data allowed analysis (7 years for RV5 and 3 years for RV1). Both vaccines provided statistically significant genotype-specific protection against predominant circulating rotavirus strains. CONCLUSION: In this large, geographically and demographically diverse sample of US children, we observed that RV5 and RV1 rotavirus vaccines each provided a lasting, and broadly heterologous protection against rotavirus gastroenteritis. |
Effect of monovalent rotavirus vaccine on rotavirus disease burden and circulating rotavirus strains among children in Morocco
Benhafid M , Elomari N , Azzouzi Idrissi M , Rguig A , Gentsch JR , Parashar U , Elaouad R . J Med Virol 2015 87 (6) 944-53 Rotarix vaccine was introduced into the National Program of Immunization of Morocco in October 2010, reaching quickly 87% of the target population of children nationally. The incidence of rotavirus gastroenteritis and the prevalence of circulating rotavirus strains has been monitored in three sentinel hospitals since June 2006. The average percentage of rotavirus positive cases among all children under 5 years old hospitalized for gastroenteritis during the pre-vaccine period (2006-2010) was 44%. This percentage dropped to 29%, 15% and 24% in the 3 years post vaccine introduction (2011, 2012 and 2013), which is a decline of 34%, 66%, and 45%, respectively. Declines in prevalence were greatest among children 0-1 years of age (53%) and were most prominent during the winter and autumn rotavirus season. The prevalence of the G2P[4] and G9P[8] genotype sharply increased in the post vaccine period (2011-2013) compared to the previous seasons (2006-2010). Rotavirus vaccines have reduced greatly the number of children hospitalized due to rotavirus infection at the three sentinel hospitals; it is however unclear if the predominance of G2P[4] and G9P[8] genotypes is related to the vaccine introduction, or if this is attributable to normal genotype fluctuations. Continued surveillance will be pivotal to answer this question in the future. |
Comparative genomic analysis of genogroup 1 (Wa-like) rotaviruses circulating in the USA, 2006-2009.
Roy S , Esona MD , Kirkness EF , Akopov A , Kyle McAllen J , Wikswo M , Cortese MM , Payne DC , Parashar U , Gentsch JR , Bowen MD . Infect Genet Evol 2014 28 513-23 Group A rotaviruses (RVA) are double stranded RNA viruses that are a significant cause of acute pediatric gastroenteritis. Beginning in 2006 and 2008, respectively, two vaccines, Rotarix and RotaTeq(R), have been approved for use in the USA for prevention of RVA disease. The effects of possible vaccine pressure on currently circulating strains in the USA and their genome constellations are still under investigation. In this study we report 33 complete RVA genomes (ORF regions) collected in multiple cities across USA during 2006-2009, including 8 collected from children with verified receipt of 3 doses of rotavirus vaccine. The strains included 16 G1P[8], 10 G3P[8], and 7 G9P[8]. All 33 strains had a Wa like backbone with the consensus genotype constellation of G(1/3/9)-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1. From maximum likelihood based phylogenetic analyses, we identified 3-7 allelic constellations grouped mostly by respective G types, suggesting a possible allelic segregation based on the VP7 gene of RVA primarily for the G3 and G9 strains. The vaccine failure strains showed similar grouping for all genes in G9 strains and most genes of G3 strains suggesting that these constellations were necessary to evade vaccine-derived immune protection. Substitutions in the antigenic region of VP7 and VP4 genes were also observed for the vaccine failure strains which could possibly explain how these strains escape vaccine induced immune response. This study helps elucidate how RVA strains are currently evolving in the population post vaccine introduction and supports the need for continued RVA surveillance. |
Full genomic characterization of a novel genotype combination, G4P[14], of a human rotavirus strain from Barbados.
Tam KI , Roy S , Esona MD , Jones S , Sobers S , Morris-Glasgow V , Rey-Benito G , Gentsch JR , Bowen MD . Infect Genet Evol 2014 28 524-9 Since 2004, the Pan American Health Organization (PAHO) has carried out rotavirus surveillance in Latin America and the Caribbean. Here we report the characterization of human rotavirus with the novel G-P combination of G4P[14], detected through PAHO surveillance in Barbados. Full genome sequencing of strain RVA/Human-wt/BRB/CDC1133/2012/G4P[14] revealed that its genotype is G4-P[14]-I1-R1-C1-M1-A8-N1-T1-E1-H1. The possession of a Genogroup 1 (Wa-like) backbone distinguishes this strain from other P[14] rotavirus strains. Phylogenetic analyses suggested that this strain was likely generated by genetic reassortment between human, porcine and possibly other animal rotavirus strains and identified 7 lineages within the P[14] genotype. The results of this study reinforce the potential role of interspecies transmission in generating human rotavirus diversity through reassortment. Continued surveillance is important to determine if rotavirus vaccines will protect against strains that express the P[14] rotavirus genotype. |
Review of global rotavirus strain prevalence data from six years post vaccine licensure surveillance: is there evidence of strain selection from vaccine pressure?
Doro R , Laszlo B , Martella V , Leshem E , Gentsch J , Parashar U , Banyai K . Infect Genet Evol 2014 28 446-61 Comprehensive reviews of pre licensure rotavirus strain prevalence data indicated the global importance of six rotavirus genotypes, G1P[8], G2P[4], G3P[8], G4P[8], G9P[8] and G12P[8]. Since 2006, two vaccines, the monovalent Rotarix (RV1) and the pentavalent RotaTeq (RV5) have been available in over 100 countries worldwide. Of these, 60 countries have already introduced either RV1 or RV5 in their national immunization programs. Post licensure vaccine effectiveness is closely monitored worldwide. This review aimed at describing the global changes in rotavirus strain prevalence over time. The genotype distribution of the nearly 47,000 strains that were characterized during 2007-2012 showed similar picture to that seen in the preceding period. An intriguing finding was the transient predominance of heterotypic strains, mainly in countries using RV1. Unusual and novel antigen combinations continue to emerge, including some causing local outbreaks, even in vaccinated populations. In addition, vaccine strains have been found in both vaccinated infants and their contacts and there is evidence for genetic interaction between vaccine and wild-type strains. In conclusion, the post-vaccine introduction strain prevalence data do not show any consistent pattern indicative of selection pressure resulting from vaccine use, although the increased detection rate of heterotypic G2P[4] strains in some countries following RV1 vaccination is unusual and this issue requires further monitoring. |
Rotavirus genotypes in Belarus, 2008-2012.
Semeiko G , Yermalovich M , Poliakova N , Mijatovic-Rustempasic S , Kerin T , Wasley A , Videbaek D , Gentsch JR , Bowen MD , Samoilovich E . Infect Genet Evol 2014 28 480-5 This study describes group A rotavirus (RVA) genotype prevalence in Belarus from 2008 to 2012. In 2008, data from 3 sites in Belarus (Brest, Mogilev, Minsk) indicated that G4P[8] was the predominant genotype. Data from Minsk (2008-2012) showed that G4P[8] was the predominant RVA genotype in all years except in 2011 when G3P[8] was most frequently detected. Other RVA genotypes common in Europe (G1P[8], G2P[4]) were detected each year of the study. This study reveals the dominance of genotype G4P[8] in Belarus and helps to establish the baseline genotype prevalence prior to RVA vaccine introduction in the country. |
Approach to molecular characterization of partially and completely untyped samples in an Indian rotavirus surveillance program.
Babji S , Arumugam R , Sarvanabhavan A , Gentsch JR , Kang G . Vaccine 2014 32 Suppl 1 A84-8 Surveillance networks for rotavirus document the burden of the disease using the proportion of children hospitalized with gastroenteritis positive for rotavirus by enzyme immunoassay. They also describe genotypes of circulating viruses by polymerase chain reaction for the VP7 and VP4 genes, which determine G and P types, respectively. A proportion of samples cannot be genotyped based on initial testing and laboratories need to assess further testing strategies based on resources and feasibility. To 365 samples obtained from an Indian rotavirus strain surveillance program, we applied an approach to determine the G and P types in antigen positive samples that failed to type initially with the standard laboratory protocol. Fifty-eight samples (19%) were negative for the VP6 gene, indicating that the antigen test was likely to have been false positive. Alternative extraction and priming approaches resulted in the identification of G and P types for 264 strains. The identity of one strain was determined by sequencing the first-round amplicons. Thirty-five strains were partially typed and seven strains could not be typed at all. The distribution of G and P types among strains that had initially failed to type, except one strain, did not differ from that in strains that were typed using the standard laboratory protocol. |
Distribution of rotavirus strains and strain-specific effectiveness of the rotavirus vaccine after its introduction: a systematic review and meta-analysis
Leshem E , Lopman B , Glass R , Gentsch J , Banyai K , Parashar U , Patel M . Lancet Infect Dis 2014 14 (9) 847-56 BACKGROUND: Concerns exist about whether monovalent (RV1) and pentavalent (RV5) rotavirus vaccines provide adequate protection against diverse strains and whether vaccine introduction will lead to selective pressure. We aimed to investigate the distribution of rotavirus strains and strain-specific rotavirus vaccine effectiveness after vaccine introduction. METHODS: We did a systematic review of published work to assess the strain-specific effectiveness of RV1 and RV5 rotavirus vaccines. We classified strains as homotypic, partly heterotypic, and fully heterotypic based on the amount of antigen-matching between strain and vaccine. When studies reported vaccine effectiveness against single antigens (G-type or P-type), we categorised them as either single-antigen vaccine type or single-antigen non-vaccine type. Our primary outcome was strain-specific vaccine effectiveness, comparing effectiveness of homotypic strains with fully or partly heterotypic strains. A secondary outcome was the prevalence of rotavirus strains after vaccine introduction. We estimated pooled odds ratios using random-effect regression models, stratified by country income level and vaccine type, and tested for differences in strain-specific vaccine effectiveness. We assessed strain distribution trends from surveillance reports. FINDINGS: In high-income countries, RV1 pooled vaccine effectiveness was 94% (95% CI 80-98) against homotypic strains, 71% (39-86) against partly heterotypic strains, and 87% (76-93) against fully heterotypic strains. In middle-income settings, respective pooled data were 59% (36-73), 72% (58-81), and 47% (28-61). In high-income countries, RV5 vaccine effectiveness was 83% (78-87) against homotypic strains, 82% (70-89) against single-antigen vaccine type strains, 82% (70-89) against partly heterotypic strains, and 75% (47-88) against single-antigen non-vaccine type strains. In middle-income settings, RV5 vaccine effectiveness was 70% (58-78) against single-antigen vaccine type strains, 37% (10-56) against partly heterotypic strains, and 87% (38-97) against single-antigen non-vaccine type strains. No difference was noted in vaccine effectiveness for either RV1 or RV5 in any setting (all p>0.05). Prevalent strains in countries using RV1 were G2P[4] (2198 of 4428, 50%) and G1P[8] (953, 22%), and those in countries using RV5 were G1P[8] (1280 of 3875, 33%) and G2P[4] (1169, 30%). Sustained predominance of a single strain was not recorded. INTERPRETATION: RV1 and RV5 exert similar effectiveness against homotypic and heterotypic rotavirus strains. Persistence of specific strains was not recorded, suggesting vaccine-induced selective pressure did not occur. Expansion of rotavirus surveillance efforts to low-income countries and ongoing surveillance are crucial to identify emergence of new strains and to assess strain-specific vaccine effectiveness in various settings. FUNDING: None. |
WHO Global Rotavirus Surveillance Network: a strategic review of the first 5 years, 2008-2012
Agocs MM , Serhan F , Yen C , Mwenda JM , de Oliveira LH , Teleb N , Wasley A , Wijesinghe PR , Fox K , Tate JE , Gentsch JR , Parashar UD , Kang G . MMWR Morb Mortal Wkly Rep 2014 63 (29) 634-7 Since 2008, the World Health Organization (WHO) has coordinated the Global Rotavirus Surveillance Network, a network of sentinel surveillance hospitals and laboratories that report to ministries of health (MoHs) and WHO clinical features and rotavirus testing data for children aged <5 years hospitalized with acute gastroenteritis. In 2013, WHO conducted a strategic review to assess surveillance network performance, provide recommendations for strengthening the network, and assess the network's utility as a platform for other vaccine-preventable disease surveillance. The strategic review team determined that during 2011 and 2012, a total of 79 sites in 37 countries met reporting and testing inclusion criteria for data analysis. Of the 37 countries with sites meeting inclusion criteria, 13 (35%) had introduced rotavirus vaccine nationwide. All 79 sites included in the analysis were meeting 2008 network objectives of documenting presence of disease and describing disease epidemiology, and all countries were using the rotavirus surveillance data for vaccine introduction decisions, disease burden estimates, and advocacy; countries were in the process of assessing the use of this surveillance platform for other vaccine-preventable diseases. However, the review also indicated that the network would benefit from enhanced management, standardized data formats, linkage of clinical data with laboratory data, and additional resources to support network functions. In November 2013, WHO's Strategic Advisory Group of Experts on Immunization (SAGE) endorsed the findings and recommendations made by the review team and noted potential opportunities for using the network as a platform for other vaccine-preventable disease surveillance. WHO will work to implement the recommendations to improve the network's functions and to provide higher quality surveillance data for use in decisions related to vaccine introduction and vaccination program sustainability. |
Characterization of rotavirus genotypes before and after the introduction of a monovalent rotavirus vaccine in Colombia
Pelaez-Carvajal D , Cotes-Cantillo K , Paternina-Caicedo A , Gentsch J , de la Hoz-Restrepo F , Patel M . J Med Virol 2014 86 (6) 1083-6 Strain monitoring for emergence of novel strains after the introduction of rotavirus vaccine is an integral component of routine rotavirus immunization programs. Using a laboratory based strain surveillance system between 2008 and 2012, a wide variation in strain pattern in Colombia was founded both before and after the introduction of a monovalent rotavirus vaccine in 2009. G2P[4], a strain fully heterotypic to the vaccine was predominant before vaccine introduction in 2008 (47%) and after vaccine introduction in 2010 (54%), 2011 (86%), and 2012 (32%). The presence of this strain before the introduction of vaccine and decreasing prevalence during the most recent surveillance year suggests secular variation rather than vaccine pressure as a cause for this fluctuation. While strain monitoring can be valuable after vaccine introduction, these surveillance data alone without information on disease incidence or strain specific vaccine effectiveness can be prone to misinterpretation with regard to the role of vaccine pressure on emergence of new or persistent strains. |
Molecular surveillance of rotavirus infection in the Democratic Republic of the Congo August 2009 to June 2012.
Pukuta ES , Esona MD , Nkongolo A , Seheri M , Makasi M , Nyembwe M , Mondonge V , Dahl BA , Mphahlele MJ , Cavallaro K , Gentsch J , Bowen MD , Waku-Kouomou D , Muyembe JJ . Pediatr Infect Dis J 2014 33 (4) 355-9 BACKGROUND: Rotavirus is a major cause of severe diarrhea worldwide. It causes 453,000 deaths in children annually. In the Democratic Republic of the Congo, sentinel site surveillance of rotavirus gastroenteritis started in 2009 and aimed to document burden of rotavirus diarrhea and identify circulating rotavirus genotypes. METHODS: Between August 2009 to June 2012, stool samples were collected in Kinshasa and Lubumbashi, from children <5 years of age who met the WHO case definition for rotavirus gastroenteritis. Rotavirus antigen detection was performed using an enzyme immunoassay technique and rotavirus strains were characterized using a multiplex reverse transcription polymerase chain reaction assay. RESULTS: During the study period, 1614 stool samples were screened for rotavirus by enzyme immunoassay and 990 (61%) were positive. Of these, the genotype was determined in 330 (33%) samples. The most common genotypes found in the samples analyzed were G1P[8] in 2009 (28%) and 2012 (33%), G2P[4] (33%) in 2010 and G2P[6] (28%) in 2011. Uncommon strains like G8P[6] (5%), G6P[6] (5%), G12P[6] (3%), G12P[8] (3%) and G8P[8] (2%) were also detected. CONCLUSIONS: In Democratic Republic of the Congo, 61% of the diarrhea in children in <5 years of age was caused by rotavirus infection and a variety of rotavirus genotypes were detected. Implementation of rotavirus genotyping at the national level has improved the timely identification of rotavirus strains. These results will help decision makers in Democratic Republic of the Congo plan the implementation of a rotavirus vaccination program. |
Genetic analysis of G12P[8] rotaviruses detected in the largest U.S. G12 genotype outbreak on record.
Mijatovic-Rustempasic S , Teel EN , Kerin TK , Hull JJ , Roy S , Weinberg GA , Payne DC , Parashar UD , Gentsch JR , Bowen MD . Infect Genet Evol 2013 21c 214-219 In 2006-07, 77 cases of gastroenteritis in Rochester, NY, USA were associated with rotavirus genotype G12P[8]. Sequence analysis identified a high degree of genetic relatedness among the VP7 and VP4 genes of the Rochester G12P[8] strains and between these strains and currently circulating human G12P[8] strains. Out of 77 samples, two and seven unique nucleotide sequences were identified for VP7 and VP4 genes, respectively. Rochester strain VP7 genes were found to occupy the G12-III lineage and VP4 genes clustered within the P[8]-3 lineage. Six strains contained non-synonymous nucleotide substitutions that produced amino acid changes at 6 sites in the VP8 * region of the VP4 gene. Two sites (amino acids 242 and 246) were located in or near a described trypsin cleavage site. Selection analyses identified one positively selected VP7 site (107) and strong purifying selection at 58 sites within the VP7 gene as well as 2 of the 6 variant sites (79 and 218) in VP4. |
Rotavirus vaccines: successes and challenges
Glass RI , Parashar U , Patel M , Gentsch J , Jiang B . J Infect 2014 68 Suppl 1 S9-s18 Since 2006, the availability of two new rotavirus vaccines has raised enthusiasm to consider the eventual control and elimination of severe rotavirus diarrhea through the global use of vaccines. Rotavirus remains the most severe cause of acute diarrhea in children worldwide responsible for several hundred thousands of deaths in low income countries and up to half of hospital admissions for diarrhea around the world. The new vaccines have been recommended by WHO for all infants and in more than 47 countries, their introduction into routine childhood immunization programs has led to a remarkable decline in hospital admissions and even deaths within 3 years of introduction. Challenges remain with issues of vaccine finance globally and the problem that these live oral vaccines perform less well in low income settings where they are needed most. Ongoing research that will accompany vaccine introduction might help address these issues of efficacy and new vaccines and novel financing schemes may both help make these vaccines universally available and affordable in the decade. |
Real-time RT-PCR assays to differentiate wild-type group A rotavirus strains from Rotarix(®) and RotaTeq(®) vaccine strains in stool samples.
Gautam R , Esona MD , Mijatovic-Rustempasic S , Ian Tam K , Gentsch JR , Bowen MD . Hum Vaccin Immunother 2013 10 (3) 767-77 Group A rotaviruses (RVA) are the leading cause of severe diarrhea in young children worldwide. Two live-attenuated RVA vaccines, Rotarix(R) and RotaTeq(R) are recommended by World Health Organization (WHO) for routine immunization of all infants. Rotarix(R) and RotaTeq(R) vaccines have substantially reduced RVA associated mortality but occasionally have been associated with acute gastroenteritis (AGE) cases identified in vaccinees and their contacts. High-throughput assays are needed to monitor the prevalence of vaccine strains in AGE cases and emergence of new vaccine-derived strains following RVA vaccine introduction. In this study, we have developed quantitative real-time RT-PCR (qRT-PCR) assays for detection of Rotarix(R) and RotaTeq(R) vaccine components in stool samples. Real-time RT-PCR assays were designed for vaccine specific targets in the genomes of Rotarix(R) (NSP2, VP4) and RotaTeq(R) (VP6, VP3-WC3, VP3-human) and validated on sequence confirmed stool samples containing vaccine strains, wild-type RVA strains, and RVA-negative stools. For quantification, standard curves were generated using dsRNA transcripts derived from RVA gene segments. Rotarix(R) NSP2 and VP4 qRT-PCR assays exhibited 92-100% sensitivity, 99-100% specificity, 94-105% efficiency, and a limit of detection of 2-3 copies per reaction. RotaTeq(R) VP6, VP3-WC3, and VP3-human qRT-PCR assays displayed 100% sensitivity, 94-100% specificity, 91-102% efficiency and limits of detection of 1 copy, 2 copies, and 140 copies, respectively. These assays permit rapid identification of Rotarix(R) and RotaTeq(R) vaccine components in stool samples from clinical and surveillance studies and will be helpful in determining the frequency of vaccine strain-associated AGE. |
Diagnostic performance of rectal swab versus bulk stool specimens for the detection of rotavirus and norovirus: Implications for outbreak investigations
Arvelo W , Hall AJ , Estevez A , Lopez B , Gregoricus N , Vinje J , Gentsch JR , Parashar U , Lindblade KA . J Clin Virol 2013 58 (4) 678-82 BACKGROUND: In January of 2008, during the peak of the rotavirus season in Guatemala, a gastroenteritis outbreak with high mortality among infants was reported in Guatemala. Despite extensive efforts, the investigation was limited by the lack of bulk stool specimens collected, particularly from the more severely dehydrated or deceased children. OBJECTIVES: We evaluated the diagnostic performance of rectal swab specimens compared with bulk stool for the detection of rotavirus and norovirus. STUDY DESIGN: Patients with diarrhea (≥3 loose stools in 24h) were enrolled through an ongoing surveillance system in Guatemala. From January through March 2009, we attempted to enroll 100 patients <5 years old captured by the diarrhea surveillance, and collected paired bulk stool and rectal swabs specimens from them. Specimens were tested for norovirus using real-time reverse transcription-polymerase chain reaction and for rotavirus via enzyme immunoassay. RESULTS: We enrolled 102 patients with paired specimens; 91% of 100 paired specimens tested for rotavirus yielded concordant results positive for rotavirus with a negativity rate of 83%. Among 100 paired specimens tested for norovirus, 86% were concordant norovirus detection and the negativity rate was 85%. The diagnostic performance for rotavirus and norovirus detection did not differ significantly between the two specimen types. CONCLUSIONS: Testing of properly collected fecal specimens using rectal swabs may be a viable alternative to bulk stool for detection of rotavirus and norovirus, particularly during outbreaks where collection of bulk stool may be difficult. |
Rotavirus G9P[4] in 3 countries in Latin America, 2009-2010
Quaye O , McDonald S , Esona MD , Lyde FC , Mijatovic-Rustempasic S , Roy S , Banegas DJ , Quinonez YM , Chinchilla BL , Santiago FG , Lozano HG , Rey-Benito G , de Oliveira LH , Gentsch JR , Bowen MD . Emerg Infect Dis 2013 19 (8) 1332-3 Group A rotaviruses are the most common viral cause of acute gastroenteritis in young children. The most frequently detected group A rotavirus genotype combinations include G1P[8], G2P[4], G3P[8], G4P[8], and G9P[8]. The G9 genotype has been associated with multiple P types, including P[8], P[6], and P[4], although genotype G9P[8] is predominant (1). | In Latin America, a large number of unusual G-P combinations have been reported, and among these is the rare G9P[4] genotype, which was identified in Brazil in the 1990s (2), and later reported infrequently elsewhere in Latin America (3). In 2010, cases of group A rotavirus gastroenteritis associated with genotype G9P[4] were reported in Mexico (4). Increases in the incidence of group A rotavirus gastroenteritis were reported in 2010 in Mexico and Guatemala and in 2009 in Honduras (http://new.paho.org/hq/dmdocuments/2010/Epi_Alerts_2010_mar_5_rotavirus.pdf). | In response to these reports of increased group A rotavirus disease, fecal samples collected in Chiapas State, Mexico (in 2010, 30% of the cases in Mexico were from Chiapas), Guatemala, and Honduras in 2009–2010 that were positive by enzyme immunoassay were sent to the US Centers for Disease Control and Prevention (Atlanta, GA, USA) for characterization. Viral protein 4 (VP4) (P) and VP7 (G) genotyping, nucleotide sequencing, and genotype identification were performed by using consensus and genotype-specific oligonucleotide primers (5), and sequences were subjected to phylogenetic analyses. VP6 and nonstructural protein 4 (NSP4) genes of selected samples were also sequenced. |
Comparison of 2 assays for diagnosing rotavirus and evaluating vaccine effectiveness in children with gastroenteritis
Tate JE , Mijatovic-Rustempasic S , Tam KI , Lyde FC , Payne DC , Szilagyi P , Edwards K , Staat MA , Weinberg GA , Hall CB , Chappell J , McNeal M , Gentsch JR , Bowen MD , Parashar UD . Emerg Infect Dis 2013 19 (8) 1245-52 We compared rotavirus detection rates in children with acute gastroenteritis (AGE) and in healthy controls using enzyme immunoassays (EIAs) and semiquantitative real-time reverse transcription PCR (qRT-PCR). We calculated rotavirus vaccine effectiveness using different laboratory-based case definitions to determine which best identified the proportion of disease that was vaccine preventable. Of 648 AGE patients, 158 (24%) were EIA positive, and 157 were also qRT-PCR positive. An additional 65 (10%) were qRT-PCR positive but EIA negative. Of 500 healthy controls, 1 was EIA positive and 24 (5%) were qRT-PCR positive. Rotavirus vaccine was highly effective (84% [95% CI 71%-91%]) in EIA-positive children but offered no significant protection (14% [95% CI -105% to 64%]) in EIA-negative children for whom virus was detected by qRT-PCR alone. Children with rotavirus detected by qRT-PCR but not by EIA were not protected by vaccination, suggesting that rotavirus detected by qRT-PCR alone might not be causally associated with AGE in all patients. |
Detection of novel rotavirus strain by vaccine postlicensure surveillance
Weinberg GA , Teel EN , Mijatovic-Rustempasic S , Payne DC , Roy S , Foytich K , Parashar UD , Gentsch JR , Bowen MD . Emerg Infect Dis 2013 19 (8) 1321-3 Surveillance for rotavirus-associated diarrhea after implementation of rotavirus vaccination can assess vaccine effectiveness and identify disease-associated genotypes. During active vaccine postlicensure surveillance in the United States, we found a novel rotavirus genotype, G14P[24], in a stool sample from a child who had diarrhea. Unusual rotavirus strains may become more prevalent after vaccine implementation. |
Sensitive and specific quantitative detection of rotavirus A by one-step real-time reverse transcription-PCR assay without antecedent double-stranded-RNA denaturation.
Mijatovic-Rustempasic S , Tam KI , Kerin TK , Lewis JM , Gautam R , Quaye O , Gentsch JR , Bowen MD . J Clin Microbiol 2013 51 (9) 3047-54 A real-time reverse transcription-polymerase chain reaction (qRT-PCR) assay using the recombinant thermostable Thermus thermophilus (rTth) enzyme was developed to detect and quantify rotavirus A (RVA). By using rTth polymerase, significant improvement was achieved over the existing real-time RT-PCR assays which require denaturation of the RVA double-stranded RNA (dsRNA) prior to assay set-up. Using a dsRNA transcript for segment 7 which encodes the assay target NSP3 gene, the limit of detection for the improved assay was calculated to be approximately 1 genome copy per reaction. The NSP3 qRT-PCR assay was validated using a panel of 1906 stool samples, 23 reference RVA strains, and 14 non-target enteric virus samples. The assay detected a diverse number of RVA genotypes and did not detect other enteric viruses demonstrating analytical sensitivity and specificity for RVA when testing stool samples. A XenoRNA internal process control was introduced and detected in a multiplexed qRT-PCR format. Because it does not require an antecedent dsRNA denaturation step, this assay reduces the possibility of sample cross-contamination and requires less hands-on time than other published qRT-PCR protocols for RVA detection. |
One year survey of human rotavirus strains suggests the emergence of genotype G12 in Cameroon.
Ndze VN , Papp H , Achidi EA , Gonsu KH , Laszlo B , Farkas S , Kisfali P , Melegh B , Esona MD , Bowen MD , Banyai K , Gentsch JR , Odama AM . J Med Virol 2013 85 (8) 1485-90 In this study the emergence of rotavirus A genotype G12 in children <5 years of age is reported from Cameroon during 2010/2011. A total of 135 human stool samples were P and G genotyped by reverse transcriptase PCR. Six different rotavirus VP7 genotypes were detected, including G1, G2, G3, G8, G9, and G12 in combinations with P[4], P[6] and P[8] VP4 genotypes. Genotype G12 predominated in combination with P[8] (54.1%) and P[6] (10.4%) genotypes followed by G1P[6] (8.2%), G3P[6] (6.7%), G2P[4] (5.9%), G8P[6] (3.7%), G2P[6] (0.7%), G3P[8] (0.7%), and G9P[8] (0.7%). Genotype P[6] strains in combination with various G-types represented a substantial proportion (N = 44, 32.6%) of the genotyped strains. Partially typed strains included G12P[NT] (2.2%); G3P[NT] (0.7%); G(NT)P[6] (1.5%); and G(NT)P[8] (0.7%). Mixed infections were found in five specimens (3.7%) in several combinations including G1 + G12P[6], G2 + G3P[6] + P[8], G3 + G8P[6], G3 + G12P[6] + P[8], and G12P[6] + P[8]. The approximately 10% relative frequency of G12P[6] strains detected in this study suggests that this strain is emerging in Cameroon and should be monitored carefully as rotavirus vaccine is implemented in this country, as it shares neither G- nor P-type specificity with strains in the RotaTeq(R) and Rotarix(R) vaccines. These findings are consistent with other recent reports of the global spread and increasing epidemiologic importance of G12 and P[6] strains. |
Human G9P[8] rotavirus strains circulating in Cameroon, 1999-2000: Genetic relationships with other G9 strains and detection of a new G9 subtype.
Esona MD , Mijatovic-Rustempasic S , Foytich K , Roy S , Banyai K , Armah G , Steele A , Volotao E , Gomez M , Silva M , Gautam R , Quaye O , Tam K , Forbi J , Seheri M , Page N , Nyangao J , Ndze V , Aminu M , Bowen M , Gentsch J . Infect Genet Evol 2013 18 315-24 Group A rotaviruses (RV-A) are the leading cause of viral gastroenteritis in children worldwide and genotype G9P[8] is one of the five most common genotypes detected in humans. In order to gain insight into the degree of genetic variability of G9P[8] strains circulating in Cameroon, stool samples were collected during the 1999-2000 rotavirus season in two different geographic regions in Cameroon (Southwest and Western Regions). By RT-PCR, 15 G9P[8] strains (15/89=16.8%) were identified whose genomic configurations was subsequently determined by complete or partial gene sequencing. In general, all Cameroonian G9 strains clustered into current globally-spread sublineages of the VP7 gene and displayed 86.6%-100% nucleotide identity amongst themselves and 81.2%-99.5% nucleotide identity with global G9 strains. The full genome classification of all Cameroonian strains was G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 but phylogenetic analysis of each gene revealed that the strains were spread across 4 or more distinct lineages. An unusual strain, RVA/Human-wt/CMR/6788/1999/G9P[8], which shared the genomic constellation of other Cameroonian G9P[8] strains, contained a novel G9 subtype which diverged significantly (18.8% nucleotide and 19% amino acid distance) from previously described G9 strains. Nucleotide and amino acid alignments revealed that the 3' end of this gene is highly divergent from other G9 VP7 genes suggesting that it arose through extensive accumulation of point mutations. The results of this study demonstrate that diverse G9 strains circulated in Cameroon during 1999-2000. |
Diversity of circulating rotavirus strains in children hospitalized with diarrhea in India, 2005-2009
Kang G , Desai R , Arora R , Chitamabar S , Naik TN , Krishnan T , Deshpande J , Gupte MD , Venkatasubramaniam S , Gentsch JR , Parashar UD . Vaccine 2013 31 (27) 2879-2883 BACKGROUND: India accounts for 22% of the 453,000 global rotavirus deaths among children <5 years annually. The Indian Rotavirus Strain Surveillance Network provides clinicians and public health partners with valuable rotavirus disease surveillance data. Our analysis offers policy-makers an update on rotavirus disease burden with emphasis on regional shifts in rotavirus strain epidemiology in India. METHODS: Children <5 years requiring hospitalization for acute gastroenteritis were selected from 10 representative hospitals in 7 cities throughout India between November 2005 through June 2009. We used a modified World Health Organization protocol for rotavirus surveillance; stool specimens were collected and tested for rotavirus using enzyme immunoassay and reverse-transcription polymerase chain reaction. RESULTS: A total of 7285 stool specimens collected were tested for rotavirus, among which 2899 (40%) were positive for rotavirus. Among the 2899 rotavirus detections, a G-type could not be determined for 662 (23%) and more than one G type was detected in 240 (8%). Of 1997 (69%) patients with only one G-type, the common types were G1 (25%), G2 (21%), G9 (13%), and G12 (10%). The proportion of rotavirus infections attributed to G12 infections rose from 8% to 39% in the Northern region and from 8% to 24% in the Western region. CONCLUSIONS: This study highlights the large, ongoing burden of rotavirus disease in India, as well as interesting regional shifts in rotavirus strain epidemiology, including an increasing detection of G12 rotavirus strains in some regions. While broad heterotypic protection from rotavirus vaccination is expected based on pre- and post-licensure data from other settings, effectiveness assessments and rotavirus strain monitoring after vaccine introduction will be important. |
Rotavirus encephalitis with basal ganglia involvement in an 8-month-old infant
Rath BA , Gentsch J , Seckinger J , Ward K , Deputy S . Clin Pediatr (Phila) 2013 52 (3) 260-4 Rotavirus disease has always been considered an intestinal infection, but viremia and extra-intestinal spread may be more common than expected.1,2 In a recent surveillance study, as many as 90% of children with rotavirus diarrhea had evidence of rotavirus antigenemia, compared with 12% of children with rotavirus-negative diarrhea. All children with rotavirus-positive stool samples showed infectious particles in their plasma.1 Lymphatic spread may be an alternative route of central nervous system (CNS) infection.3 | A total of 33 cases of rotavirus disease with CNS involvement have been reported to date.2-12 Less than half (10/24; 42%) of the patients with reported outcomes recovered completely. Five children (21%) died from the disease, whereas the remaining 37% experienced neurological sequelae. With increased awareness evidence has since grown stronger, and CNS involvement is slowly being recognized as a rare but potentially serious complication in rotavirus gastroenteritis.13-22 The clinical spectrum of CNS involvement with rotavirus infection includes convulsions (with or without fever and including status epilepticus), aseptic meningitis, Reye’s syndrome, encephalopathy syndrome, and encephalitis.2,4 Other patients present with hemorrhagic shock and disseminated intravascular coagulation. Individual case reports have described cerebral edema, diffuse electroencephalogram (EEG) background slowing lasting up to several months after the illness, cerebrospinal fluid (CSF) pleocytosis, unilateral hemispheric edema, decreased regional cerebral blood flow on SPECT, mildly elevated liver transaminases, and irritability with altered mental status.2,4,8,12 Little is known about neuroimaging findings during rotavirus encephalitis as well as long-term cognitive, neurological, and behavioral functioning. | We report a case of rotavirus encephalitis with basal ganglia involvement, persistent irritability and dystonia, loss of developmental milestones, and failure to thrive as long-term sequelae. |
Effectiveness of pentavalent and monovalent rotavirus vaccines in concurrent use among US children <5 years old, 2009-2011
Payne DC , Boom JA , Staat MA , Edwards KM , Szilagyi PG , Klein EJ , Selvarangan R , Azimi PH , Harrison C , Moffatt M , Johnston SH , Sahni LC , Baker CJ , Rench MA , Donauer S , McNeal M , Chappell J , Weinberg GA , Tasslimi A , Tate JE , Wikswo M , Curns AT , Sulemana I , Mijatovic-Rustempasic S , Esona MD , Bowen MD , Gentsch JR , Parashar UD . Clin Infect Dis 2013 57 (1) 13-20 BACKGROUND: We assessed vaccine effectiveness (VE) for RotaTeq(R) (RV5; 3 doses) and Rotarix(R) (RV1; 2 doses) at reducing rotavirus acute gastroenteritis (AGE) inpatient and emergency department (ED) visits in geographically and demographically diverse US children. METHODS: We enrolled children <5 years old hospitalized or visiting the ED with AGE symptoms from November 2009 through June 2010 and from November 2010 through June 2011 at 7 medical institutions. Fecal specimens were tested for rotavirus by enzyme immunoassay and genotyped. Vaccine receipt among laboratory-confirmed rotavirus cases was compared with AGE children negative for rotavirus (rotavirus-negative AGE controls). Regression models calculated VE estimates for each vaccine, age, ethnicity, predominant genotype, and clinical setting. RESULTS: RV5-specific analyses included 359 rotavirus cases and 1,811 rotavirus-negative AGE controls. RV1-specific analyses included 60 rotavirus cases and 155 rotavirus-negative AGE controls. RV5 and RV1 were 84% (CI=78%-88%) and 70% (CI=39%-86%) effective, respectively, against rotavirus-associated ED visits and hospitalizations combined. By clinical setting, RV5 VE against ED and inpatient rotavirus-associated visits was 81% (CI=70%-84%) and 86% (CI=74-91%), respectively. RV1 was 78% (CI= 46%-91%) effective against ED rotavirus disease; study power was insufficient to evaluate inpatient RV1 VE. No waning of immunity was evident during the first four years of life for RV5, nor during the first two years of life for RV1. RV5 provided statistically significant genotype-specific protection against each of the four major circulating rotavirus strains (G1P[8], G2P[4], G3P[8], G12P[8]), while RV1 also had a statistically significant VE for the most common genotype, G3P[8]. CONCLUSION: Both RV5 and RV1 significantly protected against medically-attended rotavirus gastroenteritis in this real-world assessment. |
Dose sparing and enhanced immunogenicity of inactivated rotavirus vaccine administered by skin vaccination using a microneedle patch
Moon S , Wang Y , Edens C , Gentsch JR , Prausnitz MR , Jiang B . Vaccine 2012 31 (34) 3396-402 Skin immunization is effective against a number of infectious diseases, including smallpox and tuberculosis, but is difficult to administer. Here, we assessed the use of an easy-to-administer microneedle (MN) patch for skin vaccination using an inactivated rotavirus vaccine (IRV) in mice. Female inbred BALB/c mice in groups of six were immunized once in the skin using MN coated with 5mcg or 0.5mcg of inactivated rotavirus antigen or by intramuscular (IM) injection with 5mcg or 0.5mcg of the same antigen, bled at 0 and 10 days, and exsanguinated at 28 days. Rotavirus-specific IgG titers increased over time in sera of mice immunized with IRV using MN or IM injection. However, titers of IgG and neutralizing activity were generally higher in MN immunized mice than in IM immunized mice; the titers in mice that received 0.5mcg of antigen with MN were comparable or higher than those that received 5mcg of antigen IM, indicating dose sparing. None of the mice receiving negative-control, antigen-free MN had any IgG titers. In addition, MN immunization was at least as effective as IM administration in inducing a memory response of dendritic cells in the spleen. Our findings demonstrate that MN delivery can reduce the IRV dose needed to mount a robust immune response compared to IM injection and holds promise as a strategy for developing a safer and more effective rotavirus vaccine for use among children throughout the world. |
Symptomatic infection and detection of vaccine and vaccine-reassortant rotavirus strains in 5 children: a case series
Boom JA , Sahni LC , Payne DC , Gautam R , Lyde F , Mijatovic-Rustempasic S , Bowen MD , Tate JE , Rench MA , Gentsch JR , Parashar UD , Baker CJ . J Infect Dis 2012 206 (8) 1275-9 Vaccine or vaccine-reassortant rotavirus strains were detected in fecal specimens from 5 of 106 (4.7%) immunocompetent children who required treatment for rotavirus gastroenteritis at a large pediatric hospital in Texas in 2009-2010. Four strains were related to pentavalent rotavirus vaccine, whereas one was related to monovalent rotavirus vaccine. The contribution of these strains to each patient's illness was unclear given that 2 patients had prominent respiratory symptoms and 2 were concurrently infected with another pathogen (group F adenovirus and norovirus). Continued monitoring is necessary to assess the role of vaccine strains and vaccine-reassortant strains in pediatric rotavirus infections. |
Identification of a G8P[14] rotavirus isolate obtained from a Taiwanese child: evidence for a relationship with bovine rotaviruses
Wu FT , Banyai K , Wu HS , Yang DC , Lin JS , Hsiung CA , Huang YC , Hwang KP , Jiang B , Gentsch JR . Jpn J Infect Dis 2012 65 (5) 455-7 Systematic hospital-based surveillance of rotavirus strains has been conducted in Taiwan to track baseline strain prevalence before and during the introduction of vaccines and to document any strain changes that occur as vaccine use increases (1). Both Rotarix and RotaTeq have been available via Taiwan's private pharmaceutical market since September 2006. As a result of more rigorous surveillance and the exclusive use of gene sequencing for strain genotyping, a variety of unusual strains were detected between 2005 and 2010 (2,3). A strain with rare VP7 and VP4 genotypes, RVA/Human-wt/TWN/04-97s379/2008/G8P[14] (hereafter referred to as 04-97s379), was identified in a 23-month-old boy treated for fever, diarrhea, and vomiting at an outpatient clinic in Changhua, Taiwan. This was the only G8P[14] strain identified among the 1,273 human rotaviruses that were genotyped during this 6-year surveillance period in Taiwan. Because human G8P[14] strains have only been reported in a few countries, including only a single country in the World Health Organization Western Pacific Region, Australia (4), it was of interest to characterize the G8P[14] rotavirus strain detected in Taiwan. | The oligonucleotide primers used to amplify and sequence full-length or partial open reading frames of the VP7 (1,062 bp), VP4 (831 bp), VP6 (1,356 bp), and NSP4 (738 bp) genes (GenBank accession numbers, JX1543843, JX1542665, JX1543853, and JX1542003, respectively) have been described elsewhere (3). For phylogenetic analysis, nucleotide sequences of related strains were retrieved from GenBank and compared with the Taiwanese strain 04-97s379 using the MEGA4 software (5). |
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