Rotavirus A Strains Research Articles

Generation of Simian Rotavirus Reassortants with VP4- and VP7-Encoding Genome Segments from Human Strains Circulating in Africa Using Reverse Genetics.

Human rotavirus A (RVA) causes acute gastroenteritis in infants and young children. The broad use of two vaccines, which are based on RVA strains from Europe and North America, significantly reduced rotavirus disease burden worldwide. However, a lower vaccine effectiveness is recorded in some regions of the world, such as sub-Saharan Africa, where diverse RVA strains are circulating. Here, a plasmid-based reverse genetics system was used to generate simian RVA reassortants with VP4 and VP7 proteins derived from African human RVA strains not previously adapted to cell culture. We were able to rescue 1/3 VP4 mono-reassortants, 3/3 VP7 mono-reassortants, but no VP4/VP7 double reassortant. Electron microscopy showed typical triple-layered virus particles for the rescued reassortants. All reassortants stably replicated in MA-104 cells; however, the VP4 reassortant showed significantly slower growth compared to the simian RVA or the VP7 reassortants. The results indicate that, at least in cell culture, human VP7 has a high reassortment potential, while reassortment of human VP4 from unadapted human RVA strains with simian RVA seems to be limited. The characterized reassortants may be useful for future studies investigating replication and reassortment requirements of rotaviruses as well as for the development of next generation rotavirus vaccines.

Genomic constellation of human Rotavirus A strains identified in Northern Brazil: a 6-year follow-up (2010-2016).

ABSTRACTSurveillance of Rotavirus A (RVA) throughout the national territory is important to establish a more complete epidemiological-molecular scenario of this virus circulation in Brazil. The aim of the present study was to investigate the genetic diversity of RVA strains circulating in Tocantins State (Northern Brazil) during six years of post-vaccination follow-up (2010-2016). A total of 248 stool samples were screened by next generation sequencing and 107 (43.1%) nearly full length RVA genome sequences were obtained; one sample was co-infected with two RVA strains (G2/G8P[4]). Six G and P genotypes combinations were detected: G12P[8] strains (78.6%), as well as the G3P[8] (9.3%) and G1P[8] (0.9%) were associated with a Wa-like genogroup backbone. All G2P[4] (5.6%) and G8P[4] (2.8%) strains, including the mixed G2/G8P[4] infection (0.9%) showed the DS-1-like genetic background. The two G12P[4] strains (1.9%) were associated with distinct genetic backbones: Wa-like and DS-1-like. The phylogenetic analysis revealed the circulation of lineages G1-I, G2-IV, G3-III, G8-I and G12-III, and P[4]-V and P[8]-III of the VP7 and VP4 genes, respectively. Conserved clustering pattern and low genetic diversity were observed regarding VP1-VP3 and VP6, as well as NSP1-5 segments. We identified the same RVA circulation pattern reported in other Brazilian regions in the period of 2010-2016, suggesting that rural and low-income areas may not have a different RVA genotypic distribution compared to other parts of the country. The unique presentation of whole-genome data of RVA strains detected in the Tocantins State provides a baseline for monitoring variations in the genetic composition of RVA in this area.

Molecular Characteristics of Novel Mono-Reassortant G9P[8] Rotavirus A Strains Possessing the NSP4 Gene of the E2 Genotype Detected in Tokyo, Japan.

Rotavirus A (RVA) has been detected in patients with gastroenteritis even after vaccine introduction in Japan. To investigate circulating RVA strains, RVA-positive stool specimens obtained in Tokyo in 2017 and 2018 were analyzed using next-generation sequencing. A total of 50 and 21 RVA samples were obtained in 2017 and 2018, respectively. In 2017, G2P[4] (40.0%) was the most prevalent strain, followed by G3P[8] (DS-1-like) (28.0%), G8P[8] (10.0%), G3P[8] (Wa-like) (8.0%), G9P[8]-E1 (8.0%), and mixed infection (6.0%). In 2018, G3P[8] (DS-1-like) (28.6%) and G9P[8]-E2 (28.6%) were the most prevalent strains, followed by G9P[8]-E1 (19.0%), G2P[4] (9.5%), G8P[8] (9.5%), and mixed infection (4.8%). Six G9P[8]-E2 strains detected in 2018 showed an atypical genotype constellation (G9P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1), which had not been reported previously. Phylogenetic analyses suggested that the RVA virus was generated by inter-genogroup reassortment between commonly circulating G9P[8] and G2P[4] strains in Japan. The G9P[8] strain seemed to be reassorted with only the NSP4 gene of the E2 genotype of the G2P[4] strain. Since this newly-emerged G9P[8]-E2 virus was detected in different locations in Tokyo, the virus appears to have already begun to spread to a wider area.

Sub-genotype phylogeny of the non-G, non-P genes of genotype 2 Rotavirus A strains.

Recent increase in the detection of unusual G1P[8], G3P[8], G8P[8], and G9P[4] Rotavirus A (RVA) strains bearing the DS-1-like constellation of the non-G, non-P genes (hereafter referred to as the genotype 2 backbone) requires better understanding of their evolutionary relationship. However, within a genotype, there is lack of a consensus lineage designation framework and a set of common sequences that can serve as references. Phylogenetic analyses were carried out on over 8,500 RVA genotype 2 genes systematically retrieved from the rotavirus database within the NCBI Virus Variation Resource. In line with previous designations, using pairwise comparison of cogent nucleotide sequences and stringent bootstrap support, reference lineages were defined. This study proposes a lineage framework and provides a dataset ranging from 34 to 145 sequences for each genotype 2 gene for orderly lineage designation of global genotype 2 genes of RVAs detected in human and animals. The framework identified five to 31 lineages depending on the gene. The least number of lineages (five to seven) were observed in genotypes A2 (NSP1), T2 (NSP3) and H2 (NSP5) which are limited to human RVA whereas the most number of lineages (31) was observed in genotype E2 (NSP4). Sharing of the same lineage constellations of the genotype 2 backbone genes between recently-emerging, unusual G1P[8], G3P[8], G8P[8] and G9P[4] reassortants and many contemporary G2P[4] strains provided strong support to the hypothesis that unusual genotype 2 strains originated primarily from reassortment events in the recent past involving contemporary G2P[4] strains as one parent and ordinary genotype 1 strains or animal RVA strains as the other. The lineage framework with selected reference sequences will help researchers to identify the lineage to which a given genotype 2 strain belongs, and trace the evolutionary history of common and unusual genotype 2 strains in circulation.

Genetic diversity and zoonotic potential of rotavirus A strains in the southern Andean highlands, Peru.

Interspecies transmission is an important mechanism of evolution and contributes to rotavirus A (RVA) diversity. In order to evaluate the detection frequency, genetic diversity, epidemiological characteristics and zoonotic potential of RVA strains in faecal specimens from humans and animals cohabiting in the same environment in the department of Cusco, Peru, by molecular analysis, 265 faecal specimens were obtained from alpacas, llamas, sheep and shepherd children, and tested for RVA by RT-PCR. Genotyping was performed by multiplex PCR and sequence analysis. Rotavirus A was detected in 20.3% of alpaca, 47.5% of llama, 100% of sheep and 33.3% of human samples. The most common genetic constellations were G3-P[40]-I8-E3-H6 in alpacas, G1/G3-P[8]-I1-E1-H1 in llamas, G1/G3/G35-P[1]/P[8]-I1-E1-H1 in sheep and G3-P[40]-I1/I8-E3-H1 in humans. The newly described genotypes P[40] and P[50] were identified in all host species, including humans. Genotyping showed that the majority of samples presented coinfection with two or more RVA strains. These data demonstrate the great genetic diversity of RVA in animals and humans in Cusco, Peru. Phylogenetic analysis suggested that the strains represent zoonotic transmission among the species studied. Due to the characteristics of the human and animal populations in this study (cohabitation of different host species in conditions of poor sanitation and hygiene), the occurrence of zoonoses is a real possibility.

G and P genotype profiles of rotavirus A field strains circulating in beef and dairy cattle herds in Brazil, 2006–2015

The aim of this retrospective study was to use RT-PCR and nucleotide sequencing analysis to determine the G (VP7 gene) and P (VP4 gene) genotypes of 155 Brazilian bovine rotavirus A (RVA) wild-type strains detected in diarrheic calves from all Brazilian geographical regions from 2006 to 2015. The RVA strains evaluated belonged to the G6, G10, P[5], and P[11] genotypes. The G6P[5] genotype was prevalent (65.5%; P < 0.05) in beef, and the G10P[11] (38.4%) and G6P[11] (30.8%) genotypes were more prevalent in dairy cattle herds. The Midwest was the region with the highest number of genotyped RVA strains, where the genotypes G6, P[5], and P[11] were identified. Genotype combination G6-IV/P[5]-IX, prevalent in beef herds, and G6-III/P[11]-III or G10-IV/P[11]-III, prevalent in dairy herds, were detected. In addition, for the first time in Brazil, we detected the P[5] and P[11] genotype RVA strains that belong to lineage II and VII, respectively.

Longitudinal surveillance of rotavirus A genotypes circulating in a high milk yield dairy cattle herd after the introduction of a rotavirus vaccine

Worldwide, neonatal diarrhea is one of the most important health issues affecting dairy calves, and rotavirus A (RVA) is one of its primary causes. Among the measures to mitigate the risk of diarrhea outbreaks, cow vaccination stands out as one of the most important. However, the immune pressure resulting from routine vaccination may be able to select specific G and P genotypes in RVA field strains. This study aimed to determine the frequency and intensity of neonatal diarrhea and the incidence of RVA and attempted to monitor the G and P genotypes present in the RVA strains circulating in a high milk yield cattle herd vaccinated with RVA G6P[5] strain. Fecal samples (n = 1220) from 122 Holstein heifer calves between 0–30 days old that were born from RVA-vaccinated cows were collected at 10 different time points, regardless of the presence or absence of diarrhea. The presence of RVA in fecal samples was determined by the polyacrylamide gel electrophoresis (PAGE) technique and confirmed by reverse transcription polymerase chain reaction (RT-PCR). G and P amplicons from 10 RVA-positive fecal samples from calves of different ages and collections were subjected to nucleotide sequencing. The proportion of the calves and fecal samples that were positive for RVA were 62.3% (76/122) and 8.1% (99/1220), respectively. Using sequence analysis, all 10 RVA field strains presented genotype G10P[11]. The protection of G6P[5] vaccination is clear, as this genotype was not detected in this study, and it is known that vaccination against RVA reduces the incidence of diarrhea independent of genotype involved. This result demonstrates the importance of epidemiological monitoring of RVA genotypes circulating in vaccinated dairy cattle herds to the early detection of new potential pathogenic RVA strains.

Whole genome characterisation of G11P[25] and G9P[19] rotavirus A strains from adult patients with diarrhoea in Nepal

Rotavirus A (RVA) causes acute diarrhoea in children and less frequently in adults. However, the knowledge about the genotype distribution of RVA strains circulating in adults is limited particularly in developing countries. This study aimed to characterise the RVA strains detected from adult patients with diarrhoea in Nepal. A total of 47 RVA positive stool samples from adult patients with diarrhoea in Kathmandu, Nepal during 2007–2008 were examined for the G and P genotypes by sequencing. Nearly half (49%) of the samples were genotyped as G9P[8] (n = 23), G1P[8], G2P[4] (n = 5 each), G12P[8] (n = 4), G12P[6] (n = 3), G1P[6] (n = 2), G3P[8] and G9P[6] (n = 1 each). Interestingly, two G11P[25] and one G9P[19] strains detected were further subjected to Illumina MiSeq next generation sequencing to determine their whole genome sequences. The genotype constellations of RVA/Human-wt/NPL/TK2615/2008/G11P[25] and RVA/Human-wt/NPL/TK2620/2008/G11P[25] were I12-R1-C1-M1-A1-N1-T1-E1-H1, whereas that of RVA/Human-wt/NPL/TK1797/2007/G9P[19] was I5-R1-C1-M1-A8-N1-T1-E1-H1. The 11 genes of TK2615 and TK2620 were virtually identical, and they were either porcine-like or unique except the VP2 and NSP1 genes which were of human RVA origin. The two G11P[25] strains were also very similar to KTM368, another G11P[25] isolated from a child in Nepal in 2004. On the other hand, no gene of TK1797 was likely to be of human RVA origin. The observation that porcine-like RVAs were detected from adult patients justifies further studies to explore the role of adults in the interspecies transmission of animal RVA to humans.

Genome constellations of 24 porcine rotavirus group A strains circulating on commercial Thai swine farms between 2011 and 2016.

Rotavirus A (RVA) infection is a major cause of diarrhea-related illness in young children. RVA is also one of the most common enteric viruses detected on pig farms and contributes to substantial morbidity and mortality in piglets. Long-term multi-site surveillance of RVA on Thai swine farms to determine the diversity of RVA strains in circulation is currently lacking. In this study, we characterized the 11 segments of the RVA genome from 24 Thai porcine RVA strains circulating between 2011 and 2016. We identified G9 (15/24) and P[13] (12/24) as the dominant genotypes. The dominant G and P combinations were G9P[13] (n = 6), G9P[23] (n = 6), G3P[13] (n = 5), G9P[19] (n = 3), G4P[6] (n = 2), G4P[19] (n = 1), and G5P[13] (n = 1). Genome constellation of the Thai strains showed the predominance of Wa-like genotype (Gx-P[x]-I1/I5-R1-C1-M1-A8-N1-T1/T7-E1/E9-H1) with evidence of reassortment between the porcine and human RVA strains (e.g., G4-P[6]-I1-R1-C1-M1-A8-N1-T1-E1-H1 and G9-P[19]-I5-R1-C1-M1-A8-N1-T7-E9-H1). To assess the potential effectiveness of rotavirus vaccination, the Thai RVA strains were compared to the RVA strains represented in the swine rotavirus vaccine, which showed residue variations in the antigenic epitope on VP7 and shared amino acid identity below 90% for G4 and G5 strain. Several previous studies suggested these variations might effect on virus neutralization specificity and vaccine efficacy. Our study illustrates the importance of RVA surveillance beyond the G/P genotyping on commercial swine farms, which is crucial for controlling viral transmission.

Cross-sectional study of the G and P genotypes of rotavirus A field strains circulating in regularly vaccinated dairy cattle herds.

Neonatal diarrhea is the main cause of morbidity and mortality in calves up to 30days old, and rotavirus A (RVA) is the main viral etiology. RVA vaccines are one of the main tools for diarrhea control in neonates. The aim of this cross-sectional study was to monitor by RT-PCR the G and P genotypes of RVA strains identified in dairy cattle herds regularly vaccinated with the RVA UK strain (G6P[5]). Of the 14 randomly selected herds, two were excluded because no calf was diagnosed with diarrhea on the day of fecal collection. Another six herds were also excluded from the study because all 20 diarrheic fecal samples evaluated were RT-PCR-negative. In the remaining six herds, 17 (25.4%) of the 67 diarrheic samples were RVA-positive. One G and P amplicon from each herd were selected for nucleotide sequencing. In the phylogenetic analysis, five RVA strains presented the G6P[11] genotype, and one presented the G10P[11] genotype. The G6 genotype present in all RVA field strains clustered into a distinct phylogenetic arrangement (lineage III) of the UK vaccine strain (lineage IV), characterizing the emergence of a phylogenetically distant G6 strain. In addition, we observed the emergence of strains with G10 and P[11] genotypes characterizing failure in heterologous immune protection. These results show the epidemiological importance of constant monitoring of RVA strains in vaccinated cattle herds and the low frequencies of diarrhea and diagnosis of RVA suggest that a regular vaccination program reduces the frequency and severity of RVA diarrhea in suckling calves.

Prevalence and clinical profile of rotavirus A infection among diarrhoeal children and phylogenetic analysis with vaccine strains in Chengdu, West China, 2009-2014.

Rotaviruses are the most common cause of severe diarrhoeal disease in young children. However, little is known about the epidemiological and clinical profile of rotavirus A (RVA) in diarrhoeal children or the efficacy of Lanzhou lamb rotavirus vaccine (LLR) in Chengdu, China. This study aimed to determine the prevalence and clinical profile of RVA in diarrhoeal children and provide gene analysis information for RVA vaccination programmes. A total of 1121 faecal samples were collected from outpatient children with diarrhoea between 2009 and 2014. RT-PCR was performed to detect RVA infection and other gastroenteritis viruses. VP4 and VP7 genes of 13 RVA strains were sequenced to compare their similarity with vaccine strains. The overall RVA infection rate was 17.48%. G1 (54.72%) and G3 (18.87%) were the predominant G genotypes; P[8] (72.36%) and P[4] (11.38%) were the main P genotypes. Sixteen genotypes were identified; G1P[8] (57.33%) and G9P[8] (12.00%) were the most prevalent. The proportion of coinfection with RVA and other gastroenteritis viruses was 18.88%. RVA was mostly detected in winter and in diarrhoeal children 1-2 years of age. The genotypes of Rotarix and RotaTeq vaccines were consistent with RVA strains prevalent in Sichuan and shared high identity. RVA was one of the major aetiological agents of diarrhoeal children in Chengdu. Genotype distribution differed within each year and the gene analysis implied low efficacy of LLR. Continuous epidemiological monitoring of RVA is essential for the national vaccination programme.

Full genotype constellations of six feline Rotavirus A strains isolated in Japan in the 1990s including a rare A15 NSP1 genotype.

Full genome sequencing of six feline Rotavirus A (RVA) strains isolated in Japan in the 1990s revealed three genotype constellations, one of which had a unique constellation of G3-P[3]-I3-R3-C3-M3-A15-N3-T3-E3-H6. Genotype A15, carried by RVA/Cat-tc/JPN/FRV348/1994/G3P[3], is a rare NSP1 genotype, and only one human and one canine RVA strains have thus far been reported to carry this genotype. The other three G3P[3] strains (FRV72, FRV73, and FRV303) possessed a constellation of I3-R3-C2-M3-A9-N2-T3-E3-H6, whereas two G3P[9] strains (FRV317 and FRV384) possessed a constellation of I3-R3-C3-M3-A3-N3-T3-E3-H3.

Porcine-like G3P[6] and G4P[6] rotavirus A strains detected from children with diarrhoea in Vietnam.

Animal rotavirus A (RVA) strains can infect children and cause diarrhoea. We determined the full genome sequences of one G3P[6] strain (NT0001) and five G4P[6] strains (NT0042, NT0077, NT0205, NT0599, and NT0621) detected from children with diarrhoea in Vietnam in 2007-2008. Strain NT0001 had a genotype constellation of: G3-P[6]-I5-R1-C1-M1-A8-N1-T1-E1-H1, strain NT0042: G4-P[6]-I1-R1-C1-M1-A8-N1-T1-E1-H1, strain NT0077: G4-P[6]-I5-R1-C1-M1-A8-N1-T7-E1-H1, and strains NT0205, NT0599, and NT0621: G4-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1. Sequence divergence data and phylogenetic analysis showed that they were different porcine RVA strains that independently and directly crossed the host species barrier to infect children.

Equine-like G3 rotavirus strains as predominant strains among children in Indonesia in 2015–2016

Rotavirus A (RVA) is a major cause of acute gastroenteritis in humans and animals worldwide. As a result of the segmented nature of the rotavirus genome, genetic reassortment commonly occurs. This study aims to clarify the genetic characteristics of RVAs circulating in Indonesia. From June 2015 through August 2016, stool samples were collected from 134 children aged <5 years (71 male and 63 female) with acute gastroenteritis who were inpatients at a private hospital in Surabaya, Indonesia. All stool samples were screened for RVA antigen using immunochromatography. Forty-two samples (31.3%, 42/134) were RVA antigen-positive. All RVA positive samples tested showed the unusual combinations of G3P[8] (n = 36) and G3P[6] (n = 3) with a short RNA pattern by G/P typing and polyacrylamide gel electrophoresis (PAGE). Whole genome analysis by next-generation sequencing (NGS) was performed for 11 strains to determine the RVA genotypes. Eleven rotavirus strains were found to carry a DS-like genetic backbone; nine strains showed a G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 genome constellation, which was recently reported in Australia, Hungary, Spain and Brazil; as well, two strains showed a G3-P[6]-I2-R2-C2-M2-A2-N2-T2-E2-H2 genome constellation. The phylogenetic tree based on the VP7 gene showed that all 11 strains were classified as equine-like G3, which is genetically distinct and different in origin from typical human G3 strains. The phylogenetic tree based on the NSP4 gene showed that six strains were classified as bovine-like strain and the remaining five were classified as human strain. In conclusion, we identified the strains which are intergenogroup reassortants containing an equine-like G3 VP7, a P[8])/P[6] VP4, with a DS-1-like genetic backbone. These findings suggest that equine-like G3P[8] and P[6] RVA strains have been circulating in the Indonesian population for at least 1 year and probably longer, indicating a diversity of RVAs in this area.

Molecular Characterization of Rotavirus Disclosed the First Introduction of G12P[8] Strain in Northern Italy

Aim: This paper discusses the unexpected findings from the RotaNet-Italy hospital-based surveillance study carried out in northern Italy. Materials &amp; methods: From September 2015 to August 2016, 51 rotavirus-A (RVA) positive fecal samples were collected from children aged less than 15 years, who were hospitalized for acute gastroenteritis in Lombardy, northern Italy. Results: Molecular characterization revealed the predominance of the uncommon G12P[8] RVA strain, which was detected in 49% of cases. Phylogenetic analysis showed that these G12 strains clustered into lineage 3. Conclusion: To our knowledge, this is the first study on the G12P[8] genotype’s introduction in northern Italy. Our findings emphasize the importance of the surveillance of RVA gastroenteritis with the aim of obtaining new insight into the unusual newly emerging RVA strains.

The dynamics of a Chinese porcine G9P[23] rotavirus production in MA-104 cells and intestines of 3-day-old piglets.

Rotavirus A (RVA) G9 genotype is recognized as an emerging genotype which is spreading worldwide, however, our knowledge on pathogenicity of this virus is limited. In this study, porcine RVA strain HN03 was successfully isolated on MA-104 cells, and the isolate was propagated continuously for 7 passages after a virus cloning at passage 3. The virus titers from 4 to 10 passages ranged from 107.1 to 108.1 TCID50/ml. The growth curve of HN03 strain in cell culture was determined, and the virus production dynamics was confirmed by immunoperoxidase monolayer assay (IPMA). Sequence and phylogenetic analyses based on full-length VP7 and partial VP4 genes indicated that HN03 strain belongs to genotype G9P[23]. In addition, the sixth passage of strain HN03 in cell culture was subjected to 3-day-old piglets. All infected piglets developed severe watery diarrhea within 24 hr post-inoculation (hpi), but recovered from disease after 72 hpi. RVA antigen could be detected by IHC in the cytoplasm of villous enterocytes as early as 2 hr after appearance of clinical symptoms and virus antigen load kept increasing in the next 30 hr. The dynamics of RVA HN03 strain proliferation on cells and in pigs extended our understanding of rotavirus pathogenicity.

Prevalence and diversity of rotavirus A genotypes cirulating in Turkey during a 2-year sentinel surveillance period, 2014-2016.

Human rotavirus A (RVA) is the main etiological agent of watery diarrhea among children under 5 years of age worldwide. The aims of this study were to investigate the prevalence and diversity of RVA genotypes circulating in Turkey during a 2-year sentinel surveillance study. A total of 1639 rotavirus antigen-positive stool samples were obtained from children younger than 5 years of age hospitalized with acute gastroenteritis. Rotavirus G and P genotypes were determined by reverse transcription polymerase chain reaction (RT-PCR) with consensus primers for the VP7 and VP4 genes, followed by semi-nested type-specific multiplex PCR. Rotavirus RNA was detected in 1396 (85.3%) of the samples tested. The highest detection rate (38.2%) was obtained among children in the 0-12 months age group, followed by children in the 13-24 months age group (36.2%). The most prevalent genotype was G1P[8] (24.6%) followed by G3P[8] (19.6%), G9P[8] (12.2%), G2P[4] (9.5%), G2P[8] (6.5%), and G4P[8] (4.8%). The proportions of uncommon and mixed genotypes were 21.5% and 1.14%, respectively. The large number of genotypes observed, including common, uncommon, and mixed types, indicates a high heterogeneity of RVA strains circulating in Turkey. The current study also exhibited dramatic fluctuations on the prevalences of the common genotypes, with increases in G3 and G1 and decreases in G9 and G2 from 2014-2016.

Group A rotaviruses circulating prior to a national immunization programme in Nigeria: Clinical manifestations, high G12P[8] frequency, intra-genotypic divergence of VP4 and VP7.

Nigeria having approximately 50 000 Rotavirus A (RVA) deaths annually is yet to introduce RVA vaccine into routine national immunization; therefore surveillance of RVA strains circulating before vaccine introduction is essential in evaluating impact of the intervention. Stool samples and sociodemographic data of diarrhoeic children, <5 years were collected between August 2012 and December 2013. While a high prevalence of RVA infection (47.6%; 49/103) was observed by quantitative reverse transcription real time PCR, only 25% (26/103) had high RVA genome concentrations and were antigen positive. G and P types were obtained for 31 and 37 samples respectively. G12P[8] strains were predominant (30.6%; 16/31); Other genotypes found included G9, G3, G2 and P[4], P[6], P[8]. A G12 + G2/P[8] + P[6] mixed infection was detected. The P[8] genotype showed divergence with strains distributed in lineage III and IV. Compared to the vaccines, changes in antigenic sites of VP8* and VP7 were found. The finding of the G2P[6] genotype combination and emergence of G12 strains support observations in most of the recent RVA studies from Africa. P[6] is common in many African countries, in contrast to countries in Europe and the Americas. In conclusion, this study shows the circulation of other RVA genotypes compared to the common RVA genotypes in Nigeria. PCR results should be interpreted with caution to avoid significant bias from samples with low RVA genome concentrations. These findings provide important information on the detection and molecular epidemiology of RVA prior to vaccination and contribute as a baseline for future evaluations after possible vaccine introduction.

Detection of uncommon G3P[3] rotavirus A (RVA) strain in rat possessing a human RVA-like VP6 and a novel NSP2 genotype

Rotavirus is one of the leading causes of acute gastroenteritis in infants and young children. RVAs infect not only humans but also a wide range of mammals including rats, which represent a reservoir of several other zoonotic pathogens.Due to the segmented nature of the RVA genome, animal RVA strains can easily adapt to the human host by reassortment with co-infecting human viruses.This study aims to detect and characterize RVA in the intestinal content of Italian sinantropic rats (Rattus rattus). Out of 40 samples examined following molecular approach, one resulted positive for RVA. The molecular characterization of VP1-4, 6 and 7, and NSP1-5 genes by sequencing revealed the genomic constellation G3-P[3]-I1-R11-C11-M10-A22-N18-T14-E18-H13. This uncommon genomic combination includes: the VP1-4,VP7, the NSP1, 3, 4 and 5 gene segments, closely related to those of RVA from rodents, the N18 novel genotype established for the NSP2 gene segment and the human Wa-like VP6 gene, suggesting interspecies reassortment.

Genotypic and epitope characteristics of group A porcine rotavirus strains circulating in Canada

Surveillance of Rotavirus A (RVA) infections in North America swine populations are limited and not performed over a significant time period to properly assess the diversity of RVA strains in swine. The VP7 (G) and VP4 (P) genes of 32 Canadian RVA strains, circulating between 2009 and 2015 were sequenced, identifying the G3P[13], G5P[7], G9P[7], G9[13], and G9[19] genotype combinations. The Canadian RVA strains were compared to the RVA strains present in the swine ProSystems RCE rotavirus vaccine. The comparison revealed multiple amino acid differences in the G and P antigenic epitopes, regardless of the G and P genotypes but specifically in the Canadian G3, P[13] and P[19] genotypes. Our study further contributes to the characterization of RVA's evolution and disease mitigation among swine, which may optimize target vaccine design, thereby minimizing RVA disease in this economically important animal population.