Rotavirus G and P types circulating in Brazil: characterization by RT-PCR, probe hybridization, and sequence analysis

Epidemiology of Group A Rotavirus Diarrhea among Children Hospitalized for Acute Gastroenteritis in Ondo State, Nigeria

Globally, infective group A rotavirus (RVA) enteric infection in children culminates in acute diarrheal disease, severe dehydration, and mortality in children under the age of 5 years, particularly in sub-Saharan Africa. This research sought to determine the prevalence of RVA diarrhea among children aged below 5 years in Ondo state, as one of the necessary frameworks before instituting a vaccine campaign, and to expand knowledge on the epidemiology of RVA diarrhea in Nigeria.

In a cross-sectional descriptive study between October 2012 and September 2014, convenience sampling was adopted to obtain demographic information, clinical details, and stool samples from accented under five children who sought treatment for acute gastroenteritis at designated hospitals in Akure and Owo, Nigeria. A total of 390 stool samples were collected from children with acute diarrhea and tested for VP6 RVA antigen using enzyme immunoassay. Data generated were analyzed using descriptive statistics and chi-square at α 0.05.

From the 390 children hospitalized for diarrhea, 240 samples (240/390; 61.5%) were from males, while 150 samples (150/390; 38.5%) were from females, representing a male:female ratio of 1.6:1. RVAs were found in 24.2% (58/240) males and 28% (42/150) females, giving a male-female ratio of 1:1.2 and total prevalence of 25.6% (100/390). RVA infection was inversely proportional to the age as a rate of 11.8% was observed in children aged above 36 months and 31.8% (35/110) in children 7 to 12 months, while the highest rate (45.7%) was among children ≤ 6 months old. No significant difference was found (chi-square = 0.712) in the induction of diarrhea in children from Akure and Owo, neither was there any significant difference in the rates of infection between the boys and girls in Akure (chi-square = 0.576) nor in Owo (chi-square = 0.333). Seasonal association (chi-square = 5.802) in RVA infection was observed in the rainy season of year 2013/2014 period.

RVA diarrhea occurred year-round at a prevalence of 25.6%, predominantly in females. A seasonal fluctuation was observed in the rainy and dry seasons of the 2-year period. RVA diarrhea occurred predominantly in children aged below 18 months of age, and may thus help in determining the optimal period/schedule of any immunization program.

Recent advances in rotavirus reverse genetics and its utilization in basic research and vaccine development

Rotaviruses are segmented double-stranded RNA viruses with a high frequency of gene reassortment, and they are a leading cause of global diarrheal deaths in children less than 5 years old. Two-thirds of rotavirus-associated deaths occur in low-income countries. Currently, the available vaccines in developing countries have lower efficacy in children than those in developed countries. Due to added safety concerns and the high cost of current vaccines, there is a need to develop cost-effective next-generation vaccines with improved safety and efficacy. The reverse genetics system (RGS) is a powerful tool for investigating viral protein functions and developing novel vaccines. Recently, an entirely plasmid-based RGS has been developed for several rotaviruses, and this technological advancement has significantly facilitated novel rotavirus research. Here, we review the recently developed RGS platform and discuss its application in studying infection biology, gene reassortment, and development of vaccines against rotavirus disease.

Unexpected Role of Rotavirus G3P[8] Infection in Causing Severe Diarrhea in a Major Tertiary Referral Hospital in the Prevaccine Era

Background: Rotavirus A species is associated with severe gastroenteritis in children. Rotavirus G1P[8] was the most prevalent genotype found in Kuwait in a study conducted between 2005 and 2006. The RotaTeq vaccine was included in the Kuwait national immunization program at the end of 2017. Objectives: Since there is no available data on the rotavirus genotypes circulating before the introduction of the vaccine, we conducted a study to investigate the role of rotaviruses in causing severe diarrhea in children hospitalized in a major tertiary referral hospital in Kuwait during the year 2016. Methods: Viral RNA was isolated from the stool samples of 101 children under five years of age, hospitalized for acute gastroenteritis. Rotavirus VP4 and VP7 dsRNA were detected by RT-PCR, and their partial sequences were analyzed by phylogenic analysis. Results: Rotavirus dsRNA was detected in 24.7% of children with median age of 1 year. The genotype G3P[8] accounted for 47% of cases, followed by G1P[8] (26%), G9P[8] (10.5%), G4P[8] (10.5%), and G9P[4] (5%). Only VP7 nucleotide sequences of rotavirus G3 or G4 type clustered in the same lineage as RotaTeq vaccine, while most VP4 nucleotide sequences of rotavirus P[8] type clustered in a different lineage compared to Rotarix and RotaTeq vaccines. Conclusions: Our findings highlight the role of rotavirus G3P[8] in causing severe diarrhea and invites future investigations to know whether the recent introduction of RotaTeq vaccine in Kuwait selects certain genotypes and subgenomic lineages.

Overview of the Development, Impacts, and Challenges of Live-Attenuated Oral Rotavirus Vaccines

Safety, efficacy, and cost-effectiveness are paramount to vaccine development. Following the isolation of rotavirus particles in 1969 and its evidence as an aetiology of severe dehydrating diarrhoea in infants and young children worldwide, the quest to find not only an acceptable and reliable but cost-effective vaccine has continued until now. Four live-attenuated oral rotavirus vaccines (LAORoVs) (Rotarix^®, RotaTeq^®, Rotavac^®, and RotaSIIL^®) have been developed and licensed to be used against all forms of rotavirus-associated infection. The efficacy of these vaccines is more obvious in the high-income countries (HIC) compared with the low- to middle-income countries (LMICs); however, the impact is far exceeding in the low-income countries (LICs). Despite the rotavirus vaccine efficacy and effectiveness, more than 90 countries (mostly Asia, America, and Europe) are yet to implement any of these vaccines. Implementation of these vaccines has continued to suffer a setback in these countries due to the vaccine cost, policy, discharging of strategic preventive measures, and infrastructures. This review reappraises the impacts and effectiveness of the current live-attenuated oral rotavirus vaccines from many representative countries of the globe. It examines the problems associated with the low efficacy of these vaccines and the way forward. Lastly, forefront efforts put forward to develop initial procedures for oral rotavirus vaccines were examined and re-connected to today vaccines.

Rotavirus A Infections in Community Childhood Diarrhea in the Brazilian Semiarid Region During Postvaccination Era

BACKGROUND

Rotavirus A (RVA) is one of the leading causes of acute gastroenteritis worldwide; however, few studies assessed RVA genetics with community surveillance.

OBJECTIVES

This study aimed to investigate clinical data, genetic diversity, and coinfection patterns of RVA infections in children from 2 to 36 months old with or without community childhood diarrhea in the Brazilian semiarid region during postvaccination era.

METHODS

We enrolled and collected socioeconomic/clinical information using a standardized questionnaire and fecal samples from 291 children. Viral RNA samples were extracted and analyzed using quantitative reverse transcription polymerase chain reaction to establish the diagnosis of RVA. Sequencing of VP7 and VP4 (VP8*) regions and phylogenetic analysis were performed.

RESULTS

RVA-negative diagnosis was associated with children 24 to 36 months old with complete vaccination schedule. Genotype G1P[8] was the most prevalent (57%), whereas unusual genotypes including G1P[4], G2P[8], and G3P[9] were also detected. G1- and P[8]-positive samples showed high degrees of similarity with the vaccine strain. RVA coinfections were frequently observed, and enteroaggregative Escherichia coli was the most prevalent copathogen.

CONCLUSIONS

These results demonstrate that genotype G1P[8] is the most prevalent strain. VP7 and/or VP8* gene segments arising from RV1 vaccine strain were documented in these children, suggesting shedding or herd vaccination. Moreover, our study indicates full vaccination is important for protection against RVA infections.

Genetic characterization of group-A rotaviruses among children in eastern India during 2014-2016: Phylodynamics of co-circulating genotypes

BACKGROUND

Group-A human rotaviruses (GARV) are among the major cause of childhood diarrhea worldwide. In lieu of monitoring the circulatory GARV strains and underscoring the burden of GARV related hospitalization, a systematic surveillance was conducted in three hospitals of eastern India. In this hospital-based diarrheal disease surveillance (2014-2016), GARV was the most common cause of acute infantile gastroenteritis. The strains were genotyped and characterized to understand their prevalence and phylodynamics prior to the introduction of vaccine in eastern India.

MATERIALS AND METHODS

A total of 3652 stool samples were screened from children (≤5 years) hospitalized with acute diarrhea during 2014-2016. Initial screening for VP6 antigen was done by ELISA. GARV positive samples were genotyped by multiplex semi-nested PCR and DNA sequencing and phylogenetic analyses were based on the capsid proteins VP4 and VP7.

RESULTS

Of 3652 samples, 1817 (49.8%) were GARV positive. G1, G2, G3 and G9 in conjunction with P[4], P[6]and P[8]genotypes were seen to co-circulate in the population. A sharp deflection from G1 to G3 occurred since 2016; upsurge of G9 strains was seen in alternate years, whereas G2 strains had a low frequency. All the circulating genotypes depicted a low phylogenetic relatedness to the vaccine strains. Differences in antigenic epitopes of VP4 and VP7 proteins in local strains were seen when compared to the vaccine strains. A significant difference in the degree of dehydration, duration of mean hospital stay and frequency of vomiting/24 h between GARV positive and negative children was evident.

CONCLUSION

The study provides a relevant set of base-line data on high burden of rotaviral gastroenteritis and the varied genotypic diversity among children prior to the introduction of GARV vaccine in this endemic region. Continuous monitoring during post-vaccination era will be required to assess the impact of vaccination in this region.

Phylogenetic analysis of G1P[8] and G12P[8] rotavirus A samples obtained in the pre- and post-vaccine periods, and molecular modeling of VP4 and VP7 proteins

Reduction in morbimortality rates for acute gastroenteritis (AGE) by Rotavirus A (RVA) has been observed after the introduction of vaccines, however the agent continues to circulate. The present study described the genomic characterization of the 11 dsRNA segments of two RVA samples G1P[8] obtained in the pre- and post-vaccination periods and one of G12P[8] sample (post-vaccine), compared to Rotarix™ vaccine. Analysis by molecular sequencing of the samples showed that the three samples belonged to genogroup I. In addition, the analysis of VP7 gene revealed that the samples G1 (pre-vaccine), G1 (post-vaccine) and G12 were characterized as lineages II, I and III, respectively. Regarding to VP4 and NSP4 gene it was observed that all samples belonged to lineage III, whereas for VP6 gene, the sample of the pre- and post-vaccine belonged to the lineage IV and I, respectively. Considering the VP7 gene, it was observed high nucleotide and amino acid identity for the two G1 samples when compared to Rotarix™ vaccine and lesser identity for the G12 sample. In relation to antigenic epitope of VP7 greater modifications were observed for the G12 sample in the 7-2 epitope that was confirmed by molecular modeling. On the other hand, for VP4, some changes in the 8-1 and 8-3 antigenic epitopes was observed for the three samples. This data could be interpreted as a low selective pressure exerted by vaccination in relation to G1P[8] samples and lesser protection in relation to G12P[8]. Thus, the continuous monitoring of RVA circulating samples remains important.

VP7 and VP8* genetic characterization of group A rotavirus genotype G12P[8]: Emergence and spreading in the Eastern Brazilian coast in 2014

Group A rotavirus (RVA) genotype G12 is habitually associated with diarrhea disease (DD) in African children and recently its detection has increased worldwide. A total of 970 stool samples collected from individuals with DD in the Northeastern, Southeastern, and Southern Brazilian regions, Eastern coast, were analyzed and 321 (33%) were positive for RVA and of these, 241 (75%) genotyped as G12P[8]. The rate of RVA positivity was higher among children aged 5-10 years old (60%). All RVA infections observed in adults aged >21 years were G12P[8] (n = 27) showing that this genotype affected older age groups during the year of 2014 in Brazil. Phylogenetic analysis of VP7 and VP8* G12P[8] strains demonstrated an elevated similarity among Brazilian and G12-III prototypes strains circulating worldwide recently, suggesting that this lineage is associated with the global spread of the G12 genotype, considered as the 6th most prevalent human RVA genotype nowadays; while other G12 lineages remain sporadically detected and usually detected in association with other P genotypes. VP8* analysis revealed that Brazilian strains belong to P[8]-3 lineage, the single P[8] lineage presently detected in the country. No major nucleotide/amino acid disparities were observed among strains recovered from children and adults for VP7 and VP8* genes. These data are essential to support the surveillance studies, particularly in countries where the RVA vaccine was introduced in their National Immunization Program enabling identification of potential alterations in the epidemiological profile that can impact its efficacy in vaccination programs. J. Med. Virol. 89:64-70, 2017. © 2016 Wiley Periodicals, Inc.

Epidemiology of rotavirus A diarrhea in Chókwè, Southern Mozambique, from February to September, 2011

Acute diarrhea disease caused by Rotaviruses A (RVA) is still the leading cause of morbidity and mortality in children ≤5 years old in developing countries. An exploratory cross-sectional study was conducted between February and September, 2011 to determine the proportion of acute diarrhea caused by RVA. A total of 254 stool specimens were collected from children ≤5 years old with acute diarrhea, including outpatients (222 children) and inpatients (32 children), in three local health centers in Chókwè District, Gaza Province, South of Mozambique. RVA antigens were detected using enzyme immunoassay (EIA); the RVA G (VP7) and P (VP4) genotypes were determined by RT-PCR or analysis sequencing. Sixty (24%) out of 254 fecal specimens were positive for RVA by EIA; being 58 (97%) from children ≤2 years of age. RVA prevalence peaks in June and July (coldest and drier months) and the G[P] binary combination observed were G12P[8] (57%); G1P[8] (9%); G12P[6] (6%); and 2% for each of the following genotypes: G1P[6], G2P[6] G4P[6], and G9P[8]. Non-Typeable (NT) G and/or P genotypes were observed as follows: G12P [NT] (6%); G1P [NT], G3P[NT] and GNTP[NT] (4%). Considering the different GP combinations, G12 represented 67% of the genotypes. This is the first data showing the diversity of RVA genotypes in Mozambique highlighting the epidemiological importance of these viruses in acute diarrhea cases in children ≤2 years old. In addition, these findings will provide a baseline data before the introduction of the RVA monovalent (Rotarix(®) ) vaccine in the National Immunization Program in September 2015. J. Med. Virol. 88:1751-1758, 2016. © 2016 Wiley Periodicals, Inc.

Rotavirus infections in Detroit, USA, a region of low vaccine prevalence

After a sharp drop of rotavirus (RV) infections at Children's Hospital of Michigan, Detroit, USA in 2010 season, we noted an increase in the number of cases during the 2011 season including some RV vaccine (RVV) recipients. This study was conducted to determine the circulating genotypes during 2011 season and whether the increase in RV diarrhea was caused by replacement genotypes. G and P genotypes were determined by RT PCR and nucleotide sequencing of selected strains was performed. The vaccination rate among study patients was 24 %. RV strains from 68 stool samples were genotyped including 18 from vaccinated children and 50 from unvaccinated children. The predominant G genotype was G1 (58.8 %) followed by G9 (17.7 %) and G4 (15.5 %). P[8] was the predominant P genotype (68 %) followed by P[6] (17.6 %) and P[4] (3 %). All G9 strains were associated with P[6]. The most prevalent G-P combination was G1P[8] (56 %), followed by G9P[6] (17.6 %). Similar proportions of RV genotypes were found among vaccinated and unvaccinated children. Our local data suggest that 5 years after the introduction of RVV there has been no genotype replacement. Although a small increase in G9P[6] frequency was noted, G1P[8] remained the predominant strain of RV in our inner city community in the Midwestern USA.

Rotavirus Gastroenteritis in a Neonatal Unit of a Greek Tertiary Hospital: Clinical Characteristics and Genotypes

INTRODUCTION

Rotavirus (RV) infection in neonatal age can be mild or even asymptomatic. Several studies have reported that RV is responsible for 31%-87% of pediatric nosocomial diarrhea and causes gastroenteritis outbreaks in pediatric and neonatal units.

OBJECTIVES

Study clinical characteristics, genotypes and risk factors of RV infection in neonatal age.

METHODS

A prospective study was conducted from April 2009 till April 2013 in the neonatal special care unit of the largest tertiary pediatric hospital of Greece. Fecal samples and epidemiological data were collected from each neonate with gastrointestinal symptoms. RV antigen was detected with a rapid immunochromatography test. RV positive samples were further genotyped with RT PCR and sequencing using specific VP7 and VP4 primers.

RESULTS

Positive for RV were 126/415 samples (30.4%). Mean age of onset was 18 days. Seventy four cases (58%) were hospital acquired. Seasonality of RV infection did not differ significantly throughout the year with the exception of 4 outbreaks. Genotypes found during the study period were G4P[8] (58.7%), G1P[8] (14.7%), G12P[8] (9.3%), G3P[8] (9.3%), G12P[6] (5.3%), G9P[8] (1.3%) and G2P[4] (1.3%). RV cases presented with: diarrhea (81%), vomiting (26.2%), fever (34.9%), dehydration (28.6%), feeding intolerance (39.7%), weight loss (54%), whilst 19% of cases were asymptomatic. Comparing community with hospital acquired cases differences in clinical manifestations were found.

CONCLUSIONS

Significant incidence of nosocomially transmitted RV infection in neonatal age including asymptomatic illness exists. Genotypes causing nosocomial outbreaks are not different from community strains. Circulating vaccines can be effective in prevention of nosocomial RV infection through herd immunity.

G1P[8] species A rotavirus over 27 years--pre- and post-vaccination eras--in Brazil: full genomic constellation analysis and no evidence for selection pressure by Rotarix® vaccine

Epidemiological data on species A rotavirus (RVA) infections have demonstrated the genetic diversity of strains circulating worldwide. Many G and P genotype combinations have been described over the years, varying regionally and temporally, especially in developing countries. However, the most common G and P genotype combinations identified in RVA human strains worldwide are G1P[8], G2P[4], G3P[8], G4P[8] and G9P[8]. RVA genotype G1P[8] strains are responsible for more than 50% of child infections worldwide and component of the two vaccines (Rotarix® [RV1] and RotaTeq® [RV5]) licensed globally. For a better understanding of the evolutionary mechanisms of this genotype in Brazil, phylogenetic analyses based on the 11 RVA genome segments (genomic constellation) from 90 G1P[8] RVA strains collected in two eras - (i) pre-vaccination with RV1 (1996-February 2006); (ii) post-vaccination (March 2006-2013) - in different Brazilian states were performed. The results showed the Wa-like genomic constellation of the Brazilian G1P[8] strains with a I1-R1-C1-M1-A1-N1-T1-E1-H1 specificity, except for two strains (rj14055-07 and ba19030-10) that belong to a I1-R1-C1-M1-A1-N1-T3-E1-H1 genomic constellation, evidencing the occurrence of reassortment (Wa-like×AU-1-like) of the NSP3 gene. Reassortment events were also demonstrated between Brazilian G1P[8] strains and the RV1 vaccine strain in some genes in vaccinated and unvaccinated children. VP7 and VP8* antigenic site analysis showed that the amino acid substitutions observed in samples collected after the introduction of RV1 in Brazil were already detected in samples collected in the 1980s and 1990s, suggesting that mass Brazilian RV1 vaccination had no impact on the diversity observed inside antigenic sites for these two proteins.

Rotaviruses: is their surveillance needed?

Rotaviruses, a major cause of gastroenteritis in children worldwide accounts for around 0.5 million deaths annually. Owing to their segmented genome and frequently evolving capability, these display a wide variation in their genotypes. In addition to commonly circulating genotypes (G1, G2, G3, G4, G9, P[4] and P[8]), a number of infrequent genotypes are being continuously reported to infect humans. These viral strains exhibit variation from one geographical setting to another in their distribution. Though the introduction of vaccines (RotaTeq and Rotarix) proved to be very effective in declining rotavirus associated morbidity and mortality, the number of infections remained same. Unusual genotypes significantly contribute to the rotavirus associated diarrhoeal burden, may reduce the efficacy of the vaccines in use and hence vaccinated individuals may not be benefited. Vaccine introduction may bring about a notable impact on the distribution and prevalence of these viruses due to selection pressure. Moreover, there is a sudden emergence of G2 and G3 in Brazil and United States, respectively, during the years 2006-2008 post-vaccination introduction; G9 and G12 became predominant during the years 1986 through 1998 before the vaccine introduction and now are commonly prevalent strains; and disparity in the predominance of strains after introduction of vaccines and their natural fluctuations poses a vital question on the impact of vaccines on rotavirus strain circulation. This interplay between vaccines and rotavirus strains is yet to be explored, but it certainly enforces the need to continuously monitor these changes in strains prevalence in a particular region. Furthermore, these fluctuations should be considered while administration or development of a vaccine, if rotavirus associated mortality is ever to be controlled.

Rotavirus genotypes associated with acute diarrhea in Egyptian infants

BACKGROUND

Before the introduction of rotavirus vaccine in Egypt, information on the burden of disease and the circulating rotavirus genotypes is critical to monitor vaccine effectiveness.

METHODS

A cohort of 348 Egyptian children was followed from birth to 2 years of age with twice-weekly home visits to detect diarrheal illness. VP7 and VP4 genes were genotyped by reverse-transcription polymerase chain reaction and DNA sequencing.

RESULTS

Forty percentage of children had rotavirus-associated diarrhea at least once by their second birthday. One hundred and twelve children experienced a single rotavirus diarrheal episodes (RDE) at a median age of 9 months; while 27 infants had their second RDE at a median age of 15 months and 1 infant had 3 RDE at the age of 2, 16 and 22 months. Of the 169 RDE, 82% could be assigned a G-type, while 58% had been identified a P-type. The most prevalent genotype was G2 (32%), followed by G1 (24%) and G9 (19%). G2P[4] rotavirus episodes were significantly associated with fever (P = 0.03) and vomiting (P = 0.06) when compared with other genotypes. G2 strains were the predominant genotype causing 50% of the second RDE while G9 represented 25% of the second RDE.

CONCLUSIONS

Genotypes identified are similar to those detected globally except for absence of G4. Our finding that 75% of the second RDE were due to G2 and G9 indicates a possible reduction in natural protection afforded by these types compared with G1, where 90% of G1 cases did not experience a second xposure, indicating greater protection against recurrent symptomatic infection.

Distribution of Human Rotaviruses, Especially G9 Strains, in Japan from 1996 to 2000

A 4-year (1996-2000) survey of rotavirus infection involving 2,218 diarrheal fecal specimens of children collected from five regions of Japan was conducted. A total of 642 (28.9%) specimens were found to be rotavirus positive. A changed prevalence pattern of rotavirus G serotype was found with an increase of G9 and G2 and a decrease of G1, although G1 remained the prevailing serotype. Serotype G9 was unexpectedly determined to be the prevailing serotype in Sapporo (62.5%) and Tokyo (52.9%) in 1998-1999, and in Saga (78.4%) in 1999-2000. G9 strains isolated from 1998-1999 belonged to the P[8]-NSP4-Wa-group with long RNA pattern, while, G9 strains isolated from 1999-2000 belonged to three groups, the P[8]-NSP4-Wa-group with long RNA pattern, the P[4]-NSP4-KUN-group with short RNA pattern and a mixed-type group (P[4]/P[8]-NSP4-KUN/Wa-group with long RNA pattern). Both sequence and immunological analysis of VP7 revealed that the G9 strains from 1999-2000 were much more closely related to the G9 strains isolated worldwide in the 1990s, including G9 strains found in Thailand in 1997. However, the G9 strains from 1998-1999 were distinct from these and more closely related to the G9 prototype strains F45, AU32 and WI61 discovered in Japan and the US in the 1980s. Thus the G9 strains isolated in 1998-1999 had progenitors common to the G9 prototype strains, while the strains isolated in 1999-2000 did not directly evolve from them but were related to global G9 strains that have emerged in recent years. These data supported our previous report that G9 rotavirus might exist as two or more subtypes with diverse RNA patterns, P-genotype and NSP4 genogroup combinations (Y.M. Zhou et al., J. Med. Virol. 65: 619-628, 2001) and suggested that G9 rotavirus prevalent in Japan during two successive years belonged to different subtypes. The nucleotide sequences presented in this paper were submitted to DDBJ, EMBL and GenBank nucleotide sequence databases. The accession numbers are: 00-Ad2863VP7 (AB091746), 00-OS2986VP7 (AB091747), 00-SG2509VP7 (AB091748), 00-SG2518VP7 (AB091749), 00-SG2541 (AB091750), 00-SG2864 (AB091751), 00-SP2737VP7 (AB091752), 99-SP1542VP7 (AB091753), 99-SP1904VP7 (AB091754), 99-TK2082VP7 (AB091755) and 99-TK2091VP7 (AB091756).

Pathogenicity of porcine G9P[23] and G9P[7] rotaviruses in piglets

G9 group A rotaviruses (RVAs) are considered important pathogens in pigs and humans, and pigs are hypothesized to be a potential host reservoir for human. However, intestinal and extra-intestinal pathogenicity and viremia of porcine G9 RVAs has remained largely unreported. In this study, colostrum-deprived piglets were orally infected with a porcine G9P[23] or G9P[7] strain. Histopathologically, both strains induced characteristic small intestinal lesions. Degeneration and necrosis of parenchymal cells were observed in the extra-intestinal tissues, but most predominantly in the mesenteric lymph nodes (MLNs). RVA antigen was continuously detected in the small intestinal mucosa and MLNs, but only transiently in cells of the liver, lung, and choroid plexus. Viral RNA levels were much higher in the feces and the MLNs compared to other tissues. The onset of viremia occurred at day post infection (DPI) 1 with the amount of viral RNA reaching its peak at DPI 3 or 5, before decreasing significantly at DPI 7 and remaining detectable until DPI 14. Our data suggest that porcine G9 RVAs have a strong small intestinal tropism, are highly virulent for piglets, have the ability to escape the small intestine, spread systemically via viremia, and replicate in extra-intestinal tissues. In addition, MLNs might act as a secondary site for viral amplification and the portal of systemic entry. These results add to our understanding of the pathogenesis of human G9 RVAs, and the validity of the pig model for use with both human and pig G9 RVAs in further studies.

Phylogenetic analysis of G1P[6] group A rotavirus strains detected in Northeast Brazilian children fully vaccinated with Rotarix™

In 2009 the World Health Organization recommended the use of group A rotavirus (RVA) vaccines in all national immunization programs (NIPs) in order to control severe RVA gastroenteritis disease. In Brazil, Rotarix™ was introduced in the NIP in March 2006, and a significant reduction in mortality rates among children ≤ 5 years old was observed, especially in the Northern and Northeastern Brazil. In the current study the 11 gene segments of six Brazilian G1P[6] RVA strains, isolated in 2009 and 2010 from vaccinated children, were analyzed in order to investigate if the genetic composition of these strains might help to elucidate why they were able to cause acute gastroenteritis in vaccinated children. All six Brazilian RVA strains revealed a complete Wa-like genotype constellation: G1-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1. Phylogenetic analysis showed that all six strains were nearly identical and showed a close genetic relationship with contemporary typical human Wa-like RVA strains. These results suggests that the fact that these strains were able to cause acute gastroenteritis in vaccinated children is likely not due to the genetic background of the strains, but rather to other factors such as host relating factors, co-infecting pathogens or vaccine efficacy. P[6] RVA strains are detected rather occasionally in humans in most regions of the world, except for South Asia and Sub-Saharan Africa. However, recently two studies conducted in Brazil showed the circulation of G12P[6] and G2P[6]. This is the first report on the detection and complete genome analyses of G1P[6] RVA strains in Brazil. Surveillance studies will be crucial to further investigate the prevalence of this genotype in the Brazilian population, and the efficacy of current licensed vaccines, which do not contain the P[6] genotype.

Molecular characterization of rotavirus isolates from select Canadian pediatric hospitals

BACKGROUND

We report the first multi-site rotavirus genotype analysis in Canada. Prior to this study, there was a dearth of rotavirus G and P genotyping data in Canada. Publically funded universal rotavirus vaccination in Canada started in 2011 and has been introduced by four provinces to date. Uptake of rotavirus vaccines in Canada prior to 2012 has been very limited. The aim of this study was to describe the genotypes of rotavirus strains circulating in Canada prior to widespread implementation of rotavirus vaccine by genotyping samples collected from selected paediatric hospitals. Secondly we identified rotavirus strains that differed genetically from those included in the vaccines and which could affect vaccine effectiveness.

METHODS

Stool specimens were collected by opportunity sampling of children with gastroenteritis who presented to emergency departments. Samples were genotyped for G (VP7) genotypes and P (VP4) genotypes by hemi-nested multiplex PCR methods. Phylogenetic analysis was carried out on Canadian G9 strains to investigate their relationship to G9 strains that have circulated in other regions of the world.

RESULTS

348 samples were collected, of which 259 samples were rotavirus positive and genotyped. There were 34 rotavirus antigen immunoassay negative samples genotyped using PCR-based methods. Over the four rotavirus seasons, 174 samples were G1P[8], 45 were G3P[8], 22 were G2P[4], 13 were G9P[8], 3 were G4P[8] and 2 were G9P[4]. Sequence analysis showed that all Canadian G9 isolates are within lineage III.

CONCLUSIONS

Although a limited number of samples were obtained from a median of 4 centres during the 4 years of the study, it appears that currently approved rotavirus vaccines are well matched to the rotavirus genotypes identified at these hospitals. Further surveillance to monitor the emergence of rotavirus genotypes in Canada is warranted.

Inaccurate identification of rotavirus genotype G9 as genotype G3 strains due to primer mismatch

Reverse transcription (RT)-PCR is now the standard method for typing group A rotaviruses (RVA) to monitor the circulating genotypes in a population. Selection of primers that can accurately type the circulating genotypes is crucial in the context of vaccine introduction and correctly interpreting the impact of vaccination on strain distribution. To our knowledge this study is the first report from Asia of misidentification of genotype G9 as G3 due to a primer-template mismatch. We tested two published G-genotype specific primers sets, designed by Gouvea and colleagues (Set A) and Iturriza‐Gomara and colleagues (Set B) on RVA from Hong Kong and Sri Lanka. Among 52 rotaviruses typed as G3 by set A primers, 36 (69.2%) were identified as G9 by nucleotide sequencing and set B primers. Moreover, of 300 rotaviruses tested, 28.3% were untypable by set A primers whereas only 12.3% were untypable by set B primers. Our findings reinforce the need to periodically monitor the primers used for RVA genotyping.

Whole-genomic analysis of a human G1P[9] rotavirus strain reveals intergenogroup-reassortment events

Group A rotavirus (RVA) strain K8 (RVA/Human-tc/JPN/K8/1977/G1P[9]) was found to have Wa-like VP7 and NSP1 genes and AU-1-like VP4 and NSP5 genes. To determine the exact origin and overall genetic makeup of this unusual RVA strain, the remaining genes (VP1–VP3, VP6 and NSP2–NSP4) of K8 were analysed in this study. Strain K8 exhibited a G1-P[9]-I1-R3-C3-M3-A1-N1-T3-E3-H3 genotype constellation, not reported previously. The VP6 and NSP2 genes of strain K8 were related closely to those of common human Wa-like G1P[8] and/or G3P[8] strains, whilst its VP1–VP3, NSP3 and NSP4 genes were related more closely to those of AU-1-like RVAs and/or AU-1-like genes of multi-reassortant strains than to those of other RVAs. Therefore, strain K8 might have originated from intergenogroup-reassortment events involving acquisition of four Wa-like genes, possibly from G1P[8] RVAs, by an AU-1-like P[9] strain. Whole-genomic analysis of strain K8 has provided important insights into the complex genetic diversity of RVAs.

Detection of rare reassortant G5P[6] rotavirus, Bulgaria

During the ongoing rotavirus strain surveillance program conducted in Bulgaria, an unusual human rotavirus A (RVA) strain, RVA/Human/BG/BG620/2008/G5P[6], was identified among 2200 genotyped Bulgarian RVAs. This strain showed the following genomic configuration: G5-P[6]-I1-R1-C1-M1-A8-N1-T1-E1-H1. Phylogenetic analysis of the genes encoding the neutralization proteins and backbone genes identified a probable mixture of RVA genes of human and porcine origin. The VP1, VP6 and NSP2 genes were more closely related to typical human rotavirus strains. The remaining eight genes were either closely related to typical porcine and unusual human-porcine reassortant rotavirus strains or were equally distant from reference human and porcine strains. This study is the first to report an unusual rotavirus isolate with G5P[6] genotype in Europe which has most likely emerged from zoonotic transmission. The absence of porcine rotavirus sequence data from this area did not permit to assess if the suspected ancestral zoonotic porcine strain already had human rotavirus genes in its genome when transmitted from pig to human, or, the transmission was coupled or followed by gene reassortment event(s). Because our strain shared no neutralization antigens with rotavirus vaccines used for routine immunization in children, attention is needed to monitor if this G-P combination will be able to emerge in human populations. A better understanding of the ecology of rotavirus zoonoses requires simultaneous monitoring of rotavirus strains in humans and animals.

Assessment of gastroenteric viruses frequency in a children's day care center in Rio De Janeiro, Brazil: a fifteen year study (1994-2008)

This 15-year study aimed to determine the role of the main viruses responsible for acute infantile gastroenteritis cases in a day care center in the city of Rio de Janeiro, Brazil. From 1994 to 2008, 539 fecal samples were obtained from 23 outbreaks as well as sporadic cases that occurred in this period. The detection of Rotavirus group A (RVA), norovirus (NoV) and astrovirus (AstV) was investigated both by classical and molecular methods of viral detection. RVA was detected by enzymatic immune assay and/or polyacrylamide gel electrophoresis and genotyped by using semi-nested multiplex PCR. NoV and AstV were subsequently tested by real time PCR in all RVA-negative samples and genotyped throughout genome sequencing. Three protocols for molecular characterization of NoV nucleotide sequencing were performed with the partial nucleotide sequencing of genomic regions known as region B (polymerase gen), C and D (capsid gen).Viruses were identified in 47.7% (257/539) of the cases, and the detection rates of RVA, NoV and AstV in16.1% (87/539), 33.4% (151/452), and 6.3% (19/301), respectively. Most gastroenteritis cases were reported in autumn and winter, although NoV presented a broader monthly distribution. Viruses' detection rates were significantly higher among children aged less than 24 months old, although NoV cases were detected in all age groups. RVA genotypes as G1P[8], G9P[8], G2P[4], G3P[8] and G1+G3P[8] and RVA was no longer detected after 2005. NoV characterization revealed genotypes variability circulating in the period as GI.2, GI.3, GI.8 GII.2, GII.3, GII.4, GII.4 variants 2001 and 2006b, GII.6, GII.7, GII.12 and GII.17. AstV genotypes 1, 2, 4 and 5 were also characterized. Those data demonstrate the impact of NoV infection in cases of infantile gastroenteritis, surpassing RVA infection responsible for high morbidity rate in children under five years old.

Pathogenicity characterization of a bovine triple reassortant rotavirus in calves and piglets

Rotaviruses are important human and animal pathogens with high impact on public health and livestock industry. There is little evidence about the cross-species pathogenicity and extra-intestinal infections of animal and human reassortant rotaviruses, particularly based on all 11 genotyping data. In this study, the bovine triple reassortant KJ56-1 strain harboring two bovine-like genome segments, eight porcine-like genome segments, and one human-like genome segment was used to evaluate the cross-species pathogenicity in its parent species, calves and piglets, and to determine its abilities of causing viremia and extra-intestinal tropisms in piglets. The KJ56-1 strain isolated from a calf diarrhea fecal sample replicated without causing diarrhea and severe intestinal pathology in calves. However, piglets inoculated with this strain showed persistent severe diarrhea and marked intestinal pathology. By SYBR Green real-time RT-PCR, viral RNA was detected in the sera, mesenteric lymph node, lung, liver, choroid plexus, and cerebrospinal fluid in the experimental piglets. An immunofluorescence assay confirmed viral replication in these extra-intestinal organs and tissues. These results indicated that the bovine triple reassortant KJ56-1 strain was virulent to piglets but not to calves. Our data also demonstrated that the reassortant rotaviruses had the ability to spread to the bloodstream from the gut, enter and amplify in the mesenteric lymph node, and disseminate to the extra-intestinal organs and tissues.

Whole genome analysis of multiple rotavirus strains from a single stool specimen using sequence-independent amplification and 454® pyrosequencing reveals evidence of intergenotype genome segment recombination

Infection of a single host cell with two or more different rotavirus strains creates conditions favourable for evolutionary mechanisms like reassortment and recombination that can generate novel strains. Despite numerous reports describing mixed rotavirus infections, whole genome characterisation of rotavirus strains in a mixed infection case has not been reported. Double-stranded RNA, exhibiting a long electropherotype pattern only, was extracted from a single human stool specimen (RVA/Human-wt/ZAF/2371WC/2008/G9P[8]). Both short and long electropherotype profiles were however detected in the sequence-independent amplified cDNA derived from the dsRNA, suggesting infection with more than one rotavirus strain. 454® pyrosequencing of the amplified cDNA revealed co-infection of at least four strains. Both genotype 1 (Wa-like) and genotype 2 (DS-1-like) were assigned to the consensus sequences obtained from the nine genome segments encoding NSP1-NSP5, VP1-VP3 and VP6. Genotypes assigned to the genome segments encoding VP4 were P[4] (DS-1-like), P[6] (ST3-like) and P[8] (Wa-like) genotypes. Since four distinct genotypes [G2 (DS-1-like), G8, G9 (Wa-like) and G12] were assigned to the four consensus nucleotide sequences obtained for genome segment 9 (VP7), it was concluded that at least four distinct rotaviruses were present in the stool. Intergenotype genome recombination events were observed in genome segments encoding NSP2, NSP4 and VP6. The close similarities of some of the genome segments encoding NSP2, VP6 and VP7 to artiodactyl rotaviruses suggest that some of the infecting strains shared common ancestry with animal strains, or that interspecies transmission occurred previously. The sequence-independent genome amplification technology coupled with 454® pyrosequencing used in this study enabled the characterisation of the whole genomes of multiple rotavirus strains in a single stool specimen that was previously assigned single genotypes, i.e. G9P[8], by sequence-dependent RT-PCR.

Rotavirus infection: a perspective on epidemiology, genomic diversity and vaccine strategies

For centuries, acute diarrhea has been a major cause of death in young children worldwide, and until 1973, before rotavirus was discovered; no infectious agents could be identified in about 80% of patients admitted to hospital with severe dehydrating diarrhea. Rotaviruses have now been shown to cause 40-50% of severe acute diarrhea in young children worldwide in both developing and developed countries. More than 600,000 young children die and approximately 2.4 million hospitalize annually from rotavirus disease, especially in South-East Asia and sub-Saharan Africa. Two safe and effective vaccines are now licensed in 100 countries but used in 17 countries. Rotarix (GSK) vaccine is derived from single attenuated human rotavirus G1P[8], representative of the most common serotype identified worldwide. RotaTeq (Merck) is a pentavalent mixture of naturally attenuated bovine/human rotavirus reassortants representing G1, G2, G3, G4, and P[8] serotypes. Though these vaccines have already dramatically decreased the morbidity associated with rotavirus in countries where they are widely used, the third generation of vaccines, based on inactivated viruses or recombinant virus like particle are already in pipeline. Continuous surveillance and the genetic and antigenic analysis of the various strains of rotavirus circulating worldwide will aid significantly in assessing the effectiveness of these vaccines and monitor emergence of new strains. Introduction of rotavirus vaccines in national vaccine policy along with other childhood vaccines may result in significant reduction in mortality in children in poor socioeconomic countries.

Burden and typing of rotavirus group A in Latin America and the Caribbean: systematic review and meta-analysis

The efficacy of licensed rotavirus vaccines has only been shown against certain rotavirus group A (RV-A) types. It is critical to understand the burden of rotavirus gastroenteritis (RVGE) and its prevalent types to assess the potential impact of these vaccines in Latin America and the Caribbean (LA&C). We performed a systematic review and meta-analyses of all the available evidence reported from 1990 to 2009 on the burden of rotavirus disease and strains circulating in LA&C. Eligible studies--185 country-level reports, 174 951 faecal samples--were selected from MEDLINE, Cochrane Library, EMBASE, LILACS, regional Ministries of Health, PAHO, regional proceedings, doctoral theses, reference lists of included studies and consulting experts. Arc-sine transformations and DerSimonian-Laird random-effects model were used for meta-analyses. The proportion of gastroenteritis cases due to rotavirus was 24.3% (95%CI 22.3-26.4) and the incidence of RVGE was 170 per 1000 children-years (95%CI 130-210). We estimated a global annual mortality for 22 countries of 88.2 (95%CI 79.3-97.1) deaths per 100 000 under 5 years (47 000 deaths).The most common G type detected was G1 (34.2%), followed by G9 (14.6%), and G2 (14.4%). The most common P types detected were P[8] (56.2%), P[4] (22.1%) and P[1] 5.4%, and the most prevalent P-G type associations were P[8]G1 17.9%, P[4]G2 9.1% and P[8]G9 8.8%. In the last 10 years, G9 circulation increased remarkably and G5 almost disappeared. More recently, G12 appeared and P[4]G2 re-emerged. To our knowledge, this is the first meta-analysis of rotavirus infection and burden of disease in LA&C.

Emergence of human rotavirus genotype G9 in metropolitan Detroit between 2007 and 2009

Between January 2007 and April 2009, rotavirus (RV)-positive stool samples from 238 children with acute gastroenteritis, seen at Children's Hospital of Michigan in Detroit, USA, were collected and RV genotyping was performed. G and P genotypes were determined by RT-PCR and nucleotide sequencing was conducted on selected G9 and P[6] strains. Correlation between the severity of gastroenteritis episode and the infecting G genotype was done using a 14-point scoring system. The predominant G genotype was G9 (39.5 %), followed by G1 (35.3 %) and G4 (15.5 %), while P[8] was the most prevalent P genotype (66.5 %), followed by P[4] (21.9 %) and P[6] (11.2 %). The gene combinations G1P[8] and G9P[8] were the most prevalent (21.4 % and 20.6 %, respectively), followed by G4P[8] (13 %) and G9P[6] (8.8 %). Immunization data showed that only 17/238 (7.1 %) children received ≥one dose of RV vaccine (the pentavalent vaccine RotaTeq or the monovalent vaccine Rotarix) and that 10/17 were infected with G4P[8] strains. Severity of RV gastroenteritis episodes was not related to the infecting G genotype. Our results suggest a high proportion of genotype G9 strains in combination with P[8], P[6] and P[4] specificity circulating in the metropolitan Detroit area. While the protective efficacy of the RV vaccines has been demonstrated against G9P[8] strains, the level of cross-protection offered by the vaccines against G9 strains with P[6] and P[4] genotypes in the Detroit paediatric population remains to be determined.

Changes in childhood diarrhea incidence in nicaragua following 3 years of universal infant rotavirus immunization

BACKGROUND

Although the pentavalent rotavirus vaccine was highly efficacious against rotavirus diarrhea in clinical trials, the effectiveness of vaccine under field conditions in the developing world is unclear. In October 2006, Nicaragua became the first developing nation to implement universal infant immunization with the pentavalent rotavirus vaccine. To assess the effect of the immunization program, we examined the incidence of diarrhea episodes between 2003 and 2009 among children in the state of León, Nicaragua.

METHODS

We extracted data on diarrhea episodes from health ministry records. We used scaled Poisson regression models to estimate diarrhea incidence rate ratios for the period following the program's implementation to the period before implementation.

RESULTS

Following implementation of the immunization program, diarrhea episodes among infants were reduced (incidence rate ratios: 0.85, 95% confidence interval: 0.71-1.02) during the rotavirus season, but appear to have increased during other months.

CONCLUSIONS

Although the immunization program appears effective in reducing diarrhea episodes during the rotavirus season, a large burden of diarrhea still persists during the remainder of the year.

Laboratory-based rotavirus surveillance during the introduction of a vaccination program, Brazil, 2005-2009

BACKGROUND

: Brazil introduced universal antirotavirus vaccination in March 2006. This article reports the results of rotavirus A (RV-A) surveillance from January 2005 to December 2009.

METHODS

: A total of 6109 fecal samples were collected in 18 Brazilian states. RV-A was detected by enzyme immunoassay and/or polyacrylamide gel electrophoresis, and genotyped through seminested reverse transcription-polymerase chain reaction.

RESULTS

: RV-A was detected in 20.3% (n = 1242) of the samples. Among children less than 2 years old, regardless the antirotavirus vaccination status, the rates of RV-A detection were 33.8% in 2005, 23.7% in 2006, 16.8% in 2007, 22.9% in 2008, and 18.3% in 2009 (P < 0.001; χ test for linear trend). Among RV-A-positive samples, genotype G1P[8] or G1P[not typed(NT)] was detected in 14% in 2005, 12.3% in 2006, 9.5% in 2007, 0.7% in 2008, and 20.4% in 2009; G2P[4]/G2P[NT] was characterized in 9% in 2005, 49% in 2006, 66% in 2007, 85% in 2008, and 37.5% in 2009; G3P[8]/G3P[NT] was observed in 8.7% in 2005, 3.5% in 2006, and 5.7% in 2009; G9P[8]/G9P[NT] was observed in 52% in 2005, 22% in 2006, 12.3% in 2007, 3.2% in 2008, and 3.4% in 2009.

CONCLUSIONS

: Our data demonstrate the reemergence of RV-A genotype G2P[4] in Brazil from 2005 to 2008, and that the rate of G2P[4] detection decreased in 2009, probably reflecting natural oscillations of RV-A genotypes.

Outbreak of acute gastroenteritis in young children with death due to rotavirus genotype G9 in Rio Branco, Brazilian Amazon region, 2005

BACKGROUND

An epidemic of acute gastroenteritis occurred in Rio Branco City, Acre State, in Brazil's Amazon region in 2005. An investigation was conducted to confirm the etiology and identify possible risk factors for death.

METHODS

Rio Branco municipality surveillance data for the period May to October 2005 were reviewed. In a case-control study, children who died following acute gastroenteritis were compared to age-matched controls with acute gastroenteritis who survived. Rotavirus A (RV-A) was investigated in 799 stool samples and genotyped by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

The cumulative incidence of diarrhea in children aged <5 years was 21%. A fatal outcome was significantly associated with uncovered household water storage containers. RV-A was identified in 88% of samples and G9 was the prevalent genotype (71%).

CONCLUSIONS

Oral rehydration solution and boiling or chlorinating drinking water likely limited mortality. This epidemic was caused by RV-A genotype G9. After the outbreak, a rotavirus vaccine was introduced into the official childhood immunization schedule in Brazil.

Surto de diarréia por rotavírus no município de Bom Jesus (PI)

O presente estudo trata de um surto de diarréia, por rotavírus, em um município piauiense, objetivando identificar a etiologia, protocolo para atendimento aos casos. Realizou-se um estudo do tipo série de casos, com 22 crianças atendidas com diarréia aguda em 2006, nas Unidades de Saúde do município de Bom Jesus. Os dados foram coletados mediante realização de entrevistas com formulário aplicado aos responsáveis pelas crianças e observações das fichas de atendimento. A maioria das famílias (59,1%) tinha renda inferior a um salário mínimo, 59,1% utilizavam fossa séptica, 77,3% consumiam água da rede de abastecimento pública e 54,5% não bebiam água filtrada. Com relação à idade, 54,5%, tinham entre um a quatro anos e maioria apresentava estado nutricional adequado. Dentre as 22 amostras de swab retal coletadas para coprocultura, isolaram-se E. coli (69,6%), Klebsiella sp. (95,6%), Proteus Mirabilis (47,8%). Em relação às dezesseis amostras de fezes in natura para pesquisa de rotavírus, 100% foram positivas para o genótipo G2; 93,7%, para o sorotipo P4 e 7,2% não foram tipadas. Conclui-se que o monitoramento contínuo dos genótipos circulantes na população é fundamental, o que implica a necessidade de capacitação dos profissionais da área da saúde para o enfrentamento das diarréias.

Detection and genotyping of Korean porcine rotaviruses

Porcine group A rotavirus (GARV) is considered to be an important animal pathogen due to their economic impact in the swine industry and its potential to cause heterologous infections in humans. This study examined 475 fecal samples from 143 farms located in 6 provinces across South Korea. RT-PCR and nested PCR utilizing primer pairs specific for the GARV VP6 gene detected GARV-positive reactions in 182 (38.3%) diarrheic fecal samples. A total of 98 porcine GARV strains isolated from the GARV-positive feces were analyzed for G and P genotyping. Based on the sequence and phylogenetic analyses, the most predominant combination of G and P genotypes was G5P[7], found in 63 GARV strains (64.3%). The other combinations of G and P genotypes were G8P[7] (16 strains [16.3%]), G9P[7] (7 strains [7.1%]), G9P[23] (2 strains [2.0%]), and G8P[1] (1 strain [1.0%]). The counterparts of G or P genotypes were not determined in three G5, five P[7], and one P[1] strains. Interestingly, phylogenetic analysis indicated that all Korean G9 strains were more closely related to lineage VI porcine and human viruses than to other lineages (I–V) of GARVs and to Korean human G9 strains (lineage III). These results show that porcine GARV infections are common in diarrheic piglets in South Korea. The infecting strains are genetically diverse, and include homologous (G5P[7]), heterologous (G8P[1]), and reassortant (G8P[7]), as well as emerging G9 GARV strains.

Diversidade genotípica de rotavírus suínos no Estado de São Paulo

Rotavírus é uma das causas mais comuns de diarréia tanto em humanos quanto em diferentes espécies animais. Foi conduzido um estudo transversal a partir de 144 amostras fecais diarréicas colhidas de leitões, provenientes de 16 criações comerciais distribuídas por 10 municípios do Estado de São Paulo, Brasil, com o objetivo de se detectar a ocorrência de rotavírus e realizar sua caracterização molecular quanto seus genotipos G e P. Um total de 43 amostras (29,86%) foram positivas para rotavírus por Eletroforese em Gel de Poliacrilamida (PAGE) e ELISA, num esquema de triagem em paralelo. A caracterização mediante reações do tipo nested-multiplex RT-PCR demonstrou que, isoladamente, o genotipo P[6] foi o mais frequente, detectado em 25,58% das amostras, seguido pelo P[1] (11,63%) e P[7] (9,3%). Infecções concomitantes de genotipos P[6]+P[7] (9,3%), P[1]+P[6] (4,65%), P[1]+P[6]+P[7] (2,33%) foram também observadas. Analogamente, o genotipo G[5] foi detectado em 30,23% das amostras, seguido pelo G[10] (20,93%) e G[6] (4,65%) e G[5]+G[10] (18,6%). O genotipo G[5]P[6] foi o mais frequente (11,63%), porém outras combinações e amostras não tipificáveis também foram observadas. Considerando-se a diversidade de rotavírus suínos encontrada na população estudada, medidas profiláticas específicas devem levar em conta, para sua efetividade, o grau de proteção cruzada entre os genotipos presentes nas formulações vacinais e aqueles que realmente são circulantes numa região.

Genetic characterization of rotavirus subtypes in Pakistan-first report of G12 genotype from Pakistan under WHO-Eastern Mediterranean region

Rotaviruses are among the major causes of gastroenteritis and diarrhea among children in developed as well as the developing countries. The rapidly evolving strain prevalence and circulation have resulted in the emergence of novel strains over the period worldwide. The introduction of G12 prototype in 1987 from Philippines and subsequently re-emergence among most of the Asian countries along with USA and Europe has provoked new research horizons to address the global distribution of rotavirus serotypes. These newly emerging subtypes and their sustenance among the population have posed tremendous challenge to the development of an effectual vaccine with heterotypic protective efficacy. In Pakistan, no data is available regarding the prevalent rotavirus serotypes; therefore, this is the first study to report the prevalence of G12 strain in Pakistan in hospitalized children with diarrhea addressing a dire need of further large-scale epidemiological surveys to resolve the underlying rotavirus isolates in both the hospitalized and the community neonatal and child population before formulating the vaccine introduction policies in the country's routine immunization program.

Rotavirus genotype distribution after vaccine introduction, Rio de Janeiro, Brazil

Brazil introduced rotavirus vaccination in March 2006. We studied 133 rotavirus-positive fecal samples collected from February 2005 through December 2007. Genotype G2P[4] was found in 1.4% of samples in 2005, in 44% in 2006, and in 96% in 2007. Rotavirus detection rate decreased from 38% in 2005 to 24% in 2007 (p = 0.012).