Full genomic characterization of a novel genotype combination, G4P[14], of a human rotavirus strain from Barbados

Epidemiological study of unusual rotavirus strains and molecular characterization of emerging P[14] strains isolated from children with acute gastroenteritis during a 15-year period

Rotavirus group A (RVA) is characterized by molecular and epidemiological diversity. To date, 42 G and 58 P RVA genotypes have been identified, some of which, like P[14], have a zoonotic origin. In this study, we describe the epidemiology of unusual RVA genotypes and the molecular characteristics of P[14] strains. Fecal samples from children ≤ 16 years of age with acute gastroenteritis (AGE) who were hospitalized during 2007-2021 in Greece were tested for RVA by immunochromatography. Positive RVA samples were G and P genotyped, and part of the VP7 and VP4 genes were sequenced by the Sanger method. Epidemiological data were also recorded. Phylogenetic analysis of P[14] was performed using MEGA 11 software. Sixty-two (1.4%) out of 4427 children with RVA AGE were infected with an unusual G (G6/G8/G10) or P (P[6]/P[9]/P[10]/P[11]/P[14]) genotype. Their median (IQR) age was 18.7 (37.3) months, and 67.7% (42/62) were males. None of the children were vaccinated against RVA. P[9] (28/62; 45.2%) was the most common unusual genotype, followed by P[14] (12/62; 19.4%). In the last two years, during the period of the COVID-19 pandemic, an emergence of P[14] was observed (5/12, 41.6%) after an 8-year absence. The highest prevalence of P[14] infection was seen in the spring (91.7%). The combinations G8P[14] (41.7%), G6P[14] (41.7%), and G4P[14] (16.6%) were also detected. Phylogenetic analysis showed a potential evolutionary relationship of three human RVA P[14] strains to a fox strain from Croatia. These findings suggest a possible zoonotic origin of P[14] and interspecies transmission between nondomestic animals and humans, which may lead to new RVA genotypes with unknown severity.

Prevalence and diversity of rotavirus A in pigs: Evidence for a possible reservoir in human infection

BACKGROUND

Rotavirus A (RVA) are a group of diverse viruses causing acute gastroenteritis (AGE) in humans and animals. Zoonotic transmission is an important mechanism for rotavirus evolution and strain diversity in humans, but the extent of pigs as a major reservoir for human infection is not clear.

METHODS AND FINDINGS

We have surveyed 153 pig farms across Taiwan with a total of 4588 porcine stool samples from three age groups from 2014 to 2017. Nursing piglets (less than one month of age) had higher detection rate for rotavirus than older age groups. Five VP7 (G) genotypes and 5 VP4 (P) genotypes were found in a total of 14 different G/P genotype combinations. In addition, porcine RVA strains had 2 NSP4 (E) genotypes and 3 VP6 (I) genotypes. A P[3]-like genotype was also discovered among strains collected in 2016 and 2017.

CONCLUSIONS

Most of the genes from Taiwanese porcine strains clustered with each other and the lineages formed by these strains were distinct from the sequences of numerous regional variants or globally circulating porcine strains, suggesting an independent evolutionary history for Taiwanese rotavirus genotypes. The close relationship among porcine RVA strains and some unique porcine-like genotypes detected sporadically among human children in swine farms illustrates that pigs might serve as a reservoir for potential zoonotic transmission and novel genotype evolution in Taiwan's insular environment.

Molecular characterization of the first human G15 rotavirus strain of zoonotic origin from the bovine species

Group A rotaviruses (RVAs) infect a wide variety of mammalian and avian species. Animals act as a potential reservoir to RVA human infections by direct virion transmission or by contributing genes to reassortants. Here, we report the molecular characterization of a rare human RVA strain Ni17-46 with a genotype G15P[14], isolated in Japan in 2017 during rotavirus surveillance in a paediatric outpatient clinic. The genome constellation of this strain was G15-P[14]-I2-R2-C2-M2-A13-N2-T9-E2-H3. This is the first report of an RVA with G15 genotype in humans, and sequencing and phylogenetic analysis results suggest that human infection with this strain has zoonotic origin from the bovine species. Given the fact that this strain was isolated from a patient with gastroenteritis and dehydration symptoms, we must take into account the virulence of this strain in humans.

Molecular characterization of unusual G10P[33], G6P[14] genomic constellations of group A rotavirus and evidence of zooanthroponosis in bovines

Group A rotaviruses (RVA) are a major cause of diarrhea in neonatal calves and children. The present study examined G/P combinations and genetic characteristics of RVAs in diarrheic bovine calves in Western India. RVAs were detected in 27 samples (17.64%) with a predominance of G10P[11] (51.85%), followed by previously unreported genomic constellations, G6P[14] (14.81%), and, G6P[4] (7.40%) and G10P[33] (3.70%). Sequencing and phylogenetic analysis revealed circulation of G10 (Lineage-5), G6 (Lineage-2), P[11] (Lineage-3), P[14] (proposed Lineage-8) and P[4] (Lineage-3) genotypes. The predominant G10P[11] strains were typical bovine strains and exhibited genotypic homogeneity. The rare, G10P[33] strain, had VP7 and VP4 genes of bovine origin but, a resemblance of the VP6 gene with simian strain indicated possible reassortment between bovine and simian (SA11-like) strains. The VP6 and VP7 genes of two rare strains, G6P[14] and G6P[4], were identical to those of bovine stains, but the VP4 was closely related to those of the human-bovine like and human strains, respectively. Additionally, in the VP4 gene phylogenetic tree, Indian P[14] strains constituted a closely related genetic cluster distinct from the other P[14] strains. Hence Lineage-8 was proposed for them. These findings indicated that bovines could serve as a source for anthropozoonotic transmission of G6P[14] strains while zooanthroponotic transmission followed by reassortment with human strain gave rise to G6P[4] strains. The observations of a present study reinforce the potential of rotaviruses to cross the host-species barrier and undergo reassortant to increase genetic diversity which, necessitates their continuous surveillance for development and optimization of prevention strategies against zoonotic RVAs.

Phylogenetic and immunoinformatic analysis of VP4, VP7, and NSP4 genes of rotavirus strains circulating in children with acute gastroenteritis in Indonesia

Rotavirus is a major cause of diarrhea in Indonesian children. However, rotavirus vaccines have not been introduced in the national immunization program of Indonesia. Understanding the genetic diversity and conserved antigenic regions of circulating strains are therefore essential to assess the potential efficacy of rotavirus vaccines. We collected fecal samples from hospitalized children less than 5 years of age with acute diarrhea. Rotavirus genotyping was performed by reverse transcriptase polymerase chain reaction, followed by sequencing of the VP4, VP7, and NSP4 genes of representative strains. Phylogenetic analysis was performed to investigate their relationship with globally circulating strains. Conservational analysis, immunoinformatics, and epitope mapping in comparison to vaccine strains were also performed. The sequence analyses showed that differences of multiple amino acid residues existed between the VP4, VP7, and NSP4 antigenic regions of the vaccine strains and the Indonesian isolates. However, many predicted conserved epitopes with higher antigenicity were observed in the vaccine and Indonesian strains, conferring the importance of these epitopes. The identified epitopes showed a higher potential of rotavirus vaccine to be employed in Indonesia. It could also be helpful to inform the design of a peptide vaccine based on the conserved regions and epitopes in the viral proteins.

Characterisation of a rare, reassortant human G10P[14] rotavirus strain detected in Honduras

BACKGROUND

Although first detected in animals, the rare rotavirus strain G10P[14] has been sporadically detected in humans in Slovenia, Thailand, United Kingdom and Australia among other countries. Earlier studies suggest that the strains found in humans resulted from interspecies transmission and reassortment between human and bovine rotavirus strains.

OBJECTIVES

In this study, a G10P[14] rotavirus genotype detected in a human stool sample in Honduras during the 2010-2011 rotavirus season, from an unvaccinated 30-month old boy who reported at the hospital with severe diarrhea and vomiting, was characterised to determine the possible evolutionary origin of the rare strain.

METHODS

For the sample detected as G10P[14], 10% suspension was prepared and used for RNA extraction and sequence independent amplification. The amplicons were sequenced by next-generation sequencing using the Illumina MiSeq 150 paired end method. The sequence reads were analysed using CLC Genomics Workbench 6.0 and phylogenetic trees were constructed using PhyML version 3.0.

FINDINGS

The next generation sequencing and phylogenetic analyses of the 11-segmented genome of the G10P[14] strain allowed classification as G10-P[14]-I2-R2-C2-M2-A3-N2-T6-E2-H3. Six of the genes (VP1, VP2, VP3, VP6, NSP2 and NSP4) were DS-1-like. NSP1 and NSP5 were AU-1-like and NSP3 was T6, which suggests that multiple reassortment events occurred in the evolution of the strain. The phylogenetic analyses and genetic distance calculations showed that the VP7, VP4, VP6, VP1, VP3, NSP1, NSP3 and NSP4 genes clustered predominantly with bovine strains. NSP2 and VP2 genes were most closely related to simian and human strains, respectively, and NSP5 was most closely related to a rhesus strain.

MAIN CONCLUSIONS

The genetic characterisation of the G10P[14] strain from Honduras suggests that its genome resulted from multiple reassortment events which were possibly mediated through interspecies transmissions.

Characterization of a triple-recombinant, reassortant rotavirus strain from the Dominican Republic

We report the genome of a novel human triple-recombinant G4P[6-8_R] mono-reassortant strain identified in a stool sample from the Dominican Republic during routine facility-based rotavirus strain surveillance. The strain was designated as RVA/Human-wt/DOM/2013840364/2013/G4P[6-8_R], with a genomic constellation of G4-P[6-8_R]-I1-R1-C1-M1-(A1-A8_R)-N1-(T1-T7_R)-E1-H1. Recombinant gene segments NSP1 and NSP3 were generated as a result of recombination between genogroup 1 rotavirus A1 human strain and a genotype A8 porcine strain and between genogroup 1 rotavirus T1 human strain and a genotype T7 bovine strain, respectively. Analyses of the RNA secondary structures of gene segment VP4, NSP1 and NSP3 showed that all the recombinant regions appear to start in a loop (single-stranded) region and terminate in a stem (double-stranded) structure. Also, the VP7 gene occupied lineage VII within the G4 genotypes consisting of mostly porcine or porcine-like G4 strains, suggesting the occurrence of reassortment. The remaining gene segments clustered phylogenetically with genogroup 1 strains. This exchange of whole or partial genetic materials between rotaviruses by recombination and reassortment contributes directly to their diversification, adaptation and evolution.

Molecular characterization of two rare human G8P[14] rotavirus strains, detected in Italy in 2012

Since 2007, the Italian Rotavirus Surveillance Program (RotaNet-Italy) has monitored the diversity and distribution of genotypes identified in children hospitalized with rotavirus acute gastroenteritis. We report the genomic characterization of two rare human G8P[14] rotavirus strains, identified in two children hospitalized with acute gastroenteritis in the southern Italian region of Apulia during rotavirus strain surveillance in 2012. Both strains showed a G8-P[14]-I2-R2-C2-M2-A11-N2-T6-E2-H3 genomic constellation (DS-1-like genomic background). Phylogenetic analysis of each genome segment revealed a mixed configuration of genes of animal and zoonotic human origin, indicating that genetic reassortment events generated these unusual human strains. Eight out of 11 genes (VP1, VP2, VP3, VP6, VP7, NSP3, NSP4 and NSP5) of the Italian G8P[14] strains exhibited close identity with a Spanish sheep strain, whereas the remaining genes (VP4, NSP1 and NSP2) were more closely related to human strains. The amino acid sequences of the antigenic regions of outer capsid proteins VP4 and VP7 were compared with vaccine and field strains, showing high conservation between the amino acid sequences of Apulia G8P[14] strains and human and animal strains bearing G8 and/or P[14] proteins, and revealing many substitutions with respect to the RotaTeq™ and Rotarix™ vaccine strains. Conversely, the amino acid analysis of the four antigenic sites of VP6 revealed a high degree of conservation between the two Apulia strains and the human and animal strains analyzed. These results reinforce the potential role of interspecies transmission and reassortment in generating novel rotavirus strains that might not be fully contrasted by current vaccines.

Molecular characterization of the first G24P[14] rotavirus strain detected in humans

Here we report the genome of a novel rotavirus A (RVA) strain detected in a stool sample collected during routine surveillance by the Centers for Disease Control and Prevention's New Vaccine Surveillance Network. The strain, RVA/human-wt/USA/2012741499/2012/G24P[14], has a genomic constellation of G24-P[14]-I2-R2-C2-M2-A3-N2-T9-E2-H3. The VP2, VP3, VP7 and NSP3 genes cluster phylogenetically with bovine strains. The other genes occupy mixed clades containing animal and human strains. Strain RVA/human-wt/USA/2012741499/2012/G24P[14] most likely is the product of interspecies transmission and reassortment events. This is the second report of the G24 genotype and the first report of the G24P[14] genotype combination in humans.

Zoonotic transmission of rotavirus: surveillance and control

Group A rotavirus (Rotavirus A, RVA) is the main cause of acute dehydrating diarrhea in humans and numerous animal species. RVA shows vast diversity and a variety of human strains share genetic and antigenic features with animal origin RVA strains. This finding suggests that interspecies transmission is an important mechanism of rotavirus evolution and contributes to the diversity of human RVA strains. RVA is responsible for half a million deaths and several million hospitalizations worldwide. Globally, two rotavirus vaccines are available for routine use in infants. These vaccines show a great efficacy profile and induce protective immunity against various rotavirus strains. However, little is known about the long-term evolution and epidemiology of RVA strains under selective pressure related to vaccine use. Continuous strain surveillance in the post-vaccine licensure era is needed to help better understand mechanisms that may affect vaccine effectiveness.

Full-Genome Sequence of the First G8P[14] Rotavirus Strain Detected in the United States

This is a report of the complete genomic sequence of a rare rotavirus group A G8-P[14]-I2-R3-C2-M2-A3-N2-T6-E2-H3 strain detected in a stool sample from a 57-year-old subject.

Full genomic characterization and phylogenetic analysis of a zoonotic human G8P[14] rotavirus strain detected in a sample from Guatemala

We report the genomic characterization of a rare human G8P[14] rotavirus strain, identified in a stool sample from Guatemala (GTM) during routine rotavirus surveillance. This strain was designated as RVA/Human-wt/GTM/2009726790/2009/G8P[14], with a genomic constellation of G8-P[14]-I2-R2-C2-M2-A13-N2-T6-E2-H3. The VP4 gene occupied lineage VII within the P[14] genotype. Phylogenetic analysis of each genome segment revealed close relatedness to several zoonotic simian, guanaco and bovine strains. Our findings suggest that strain RVA/Human-wt/GTM/2009726790/2009/G8P[14] is an example of a direct zoonotic transmission event. The results of this study reinforce the potential role of interspecies transmission and reassortment in generating novel and rare rotavirus strains which infect humans.