Full genomic analysis of a G8P[1] rotavirus strain isolated from an asymptomatic infant in Kenya provides evidence for an artiodactyl-to-human interspecies transmission event

Molecular Epidemiology of Rotavirus A in Calves: Evolutionary Analysis of a Bovine G8P[11] Strain and Spatio-Temporal Dynamics of G6 Lineages in the Americas

Rotavirus A (RVA) causes diarrhea in calves and frequently possesses the G6 and P[5]/P[11] genotypes, whereas G8 is less common. We aimed to compare RVA infections and G/P genotypes in beef and dairy calves from major livestock regions of Argentina, elucidate the evolutionary origin of a G8 strain and analyze the G8 lineages, infer the phylogenetic relationship of RVA field strains, and investigate the evolution and spatio-temporal dynamics of the main G6 lineages in American countries. Fecal samples (n = 422) from diarrheic (beef, 104; dairy, 137) and non-diarrheic (beef, 78; dairy, 103) calves were analyzed by ELISA and semi-nested multiplex RT-PCR. Sequencing, phylogenetic, phylodynamic, and phylogeographic analyses were performed. RVA infections were more frequent in beef (22.0%) than in dairy (14.2%) calves. Prevalent genotypes and G6 lineages were G6(IV)P[5] in beef (90.9%) and G6(III)P[11] (41.2%) or mixed genotypes (23.5%) in dairy calves. The only G8 strain was phylogenetically related to bovine and artiodactyl bovine-like strains. Re-analyses inside the G8 genotype identified G8(I) to G8(VIII) lineages. Of all G6 strains characterized, the G6(IV)P[5](I) strains from "Cuenca del Salado" (Argentina) and Uruguay clustered together. According to farm location, a clustering pattern for G6(IV)P[5] strains of beef farms was observed. Both G6 lineage strains together revealed an evolutionary rate of 1.24 × 10-3 substitutions/site/year, and the time to the most recent common ancestor was dated in 1853. The most probable ancestral locations were Argentina in 1981 for G6(III) strains and the USA in 1940 for G6(IV) strains. The highest migration rates for both G6 lineages together were from Argentina to Brazil and Uruguay. Altogether, the epidemiology, genetic diversity, and phylogeny of RVA in calves can differ according to the production system and farm location. We provide novel knowledge about the evolutionary origin of a bovine G8P[11] strain. Finally, bovine G6 strains from American countries would have originated in the USA nearly a century before its first description.

Genome analyses of species A rotavirus isolated from various mammalian hosts in Northern Ireland during 2013-2016

Rotavirus group A (RVA) is the most important cause of acute diarrhoea and severe dehydration in young mammals. Infection in livestock is associated with significant mortality and economic losses and, together with wildlife reservoirs, acts as a potential source of zoonotic transmission. Therefore, molecular surveillance of circulating RVA strains in animal species is necessary to assess the risks posed to humans and their livestock. An RVA molecular epidemiological surveillance study on clinically diseased livestock species revealed high prevalence in cattle and pigs (31 per cent and 18 per cent, respectively) with significant phylogenetic diversity including a novel and divergent ovine artiodactyl DS-1-like constellation G10-P[15]-I2-R2-C2-M2-A11-N2-T6-E2-H3. An RVA gene reassortment occurred in an RVA asymptomatic pig and identified as a G5-P[13] strain, and a non-structural protein (NSP)2 gene had intergenomically reassorted with a human RVA strain (reverse zoonosis) and possessed a novel NSP4 enterotoxin E9 which may relate to the asymptomatic RVA infection. Analysis of a novel sheep G10-P[15] strain viral protein 4 gene imparts a putative homologous intergenic and interspecies recombination event, subsequently creating the new P[15] divergent lineage. While surveillance across a wider range of wildlife and exotic species identified generally negative or low prevalence, a novel RVA interspecies transmission in a non-indigenous pudu deer (zoo origin) with the constellation of G6-P[11]12-R2-C2-M2-A3-N2-T6-E2-H3 was detected at a viral load of 11.1 log10 copies/gram. The detection of novel emerging strains, interspecies reassortment, interspecies infection, and recombination of RVA circulating in animal livestock and wildlife reservoirs is of paramount importance to the RVA epidemiology and evolution for the One Health approach and post-human vaccine introduction era where highly virulent animal RVA genotypes have the potential to be zoonotically transmitted.

Genomic Analysis of an Indian G8P[1] Caprine Rotavirus-A Strain Revealing Artiodactyl and DS-1-Like Human Multispecies Reassortment

The surveillance studies for the presence of caprine rotavirus A (RVA) are limited in India, and the data for the whole-genome analysis of the caprine RVA is not available. This study describes the whole-genome-based analysis of a caprine rotavirus A strain, RVA/Goat-wt/IND/K-98/2015, from a goat kid in India. The genomic analysis revealed that the caprine RVA strain K-98, possess artiodactyl-like and DS-1 human-like genome constellation G8P[1]-I2-R2-C2-M2-A3-N2-T6-E2-H3. The three structural genes (VP2, VP4, and VP7) were close to caprine host having nucleotide-based identity range between 97.5 and 98.9%. Apart from them, other gene segments showed similarity with either bovine or human like genes, ultimately pointing toward a common evolutionary origin having an artiodactyl-type backbone of strain K-98. Phylogenetically, the various genes of the current study isolate also clustered inside clades comprising Human-Bovine-Caprine isolates from worldwide. The current findings add to the knowledge on caprine rotaviruses and might play a substantial role in designing future vaccines or different alternative strategies combating such infections having public health significance. To the best of our knowledge, this is the first report on the whole-genome characterization of a caprine RVA G8P[1] strain from India. Concerning the complex nature of the K-98 genome, whole-genome analyses of more numbers of RVA strains from different parts of the country are needed to comprehend the genomic nature and genetic diversity among caprine RVA.

Identification of rotavirus A strains in small ruminants: first detection of G8P[1] genotypes in sheep in Turkey

Although members of rotavirus group A (RVA) are major enteric pathogens of humans and animals of many species, their impact on the health of small ruminants is not well documented. In this study, we conducted a molecular analysis of VP4, VP7, VP6 and NSP4 genes of RVAs detected using a commercial antigen ELISA in small ruminants with or without diarrhea in Turkey. Of the RVAs detected in sheep, one strain (Kutahya) was characterized as genotype G8P[1]-I2-E2. Two others (Ankara-1 and Ankara-2) were identified as NSP4 E2 and VP6 I2 genotypes, although they were untyped for the VP4 and VP7 genes. The RVAs from two goats were characterized as genotype G6P [1]-I2-E2. This is the first detection of in goats RVA genotypes G6P [1], which had previously only been found in cattle in Turkey, and of RVA in sheep. The study extends our current knowledge about the circulation of two RVA G genotypes, G6 and G8, in goat herds, and the detection of the G8 genotype in sheep in Turkey. This provides further information about the molecular epidemiology of RVAs in different animal species and indicates that additional surveillance programs are needed to determine the epidemiology of RVA in small ruminants and other species.

Full-length genome analysis of the first human G8P[14] rotavirus strain from Morocco suggests evidence of zoonotic transmission

An unusual group A rotavirus (RVA) strain MAR/ma31/2011/G8P[14] was detected for the first time in Morocco in a stool sample from hospitalized child aged 18 months suffering from acute gastroenteritis and fever in 2011. Complete genome sequencing of the ma31 strain was done using the capillary sequencing technology. The analysis revealed the G8-P[14]-I2-R2-C2-M2-A11-N2-T6-E2-H3 constellation and the backbone genes: I2-R2-C2-M2-A11-N2-T6-E2-H3 are commonly found in RVA strains from artiodactyls such as cattle. The constellation was shared with another Italian zoonotic G8P[14] strains (BA01 and BA02), two Hungarian human strains (182-02 and BP1062) and a sheep RVA strain OVR762. Phylogenetic analysis of each genome segment of ma31 revealed a mixed gene configuration originated from animals and human. Comparison of the antigenic regions of VP7 and VP4 amino acid sequences between ma31 strain and selected animal and human strains bearing G8 and or P[14], showed a high level of conservation, while many substitutions was observed in comparison with RotaTeq™ and Rotarix™ vaccine strains. In contrast, alignment analysis of the four antigenic sites of VP6 revealed a high degree of conservation. These findings reveal a typical zoonotic origin of the strain and confirm a high potential for RVA zoonotic transmission between bovine and humans, allowing the generation of novel rotavirus genotypes.

A Review of Zoonotic Pathogens of Dromedary Camels

Dromedary, or one-humped, camels Camelus dromedarius are an almost exclusively domesticated species that are common in arid areas as both beasts of burden and production animals for meat and milk. Currently, there are approximately 30 million dromedary camels, with highest numbers in Africa and the Middle East. The hardiness of camels in arid regions has made humans more dependent on them, especially as a stable protein source. Camels also carry and may transmit disease-causing agents to humans and other animals. The ability for camels to act as a point source or vector for disease is a concern due to increasing human demands for meat, lack of biosafety and biosecurity protocols in many regions, and a growth in the interface with wildlife as camel herds become sympatric with non-domestic species. We conducted a literature review of camel-borne zoonotic diseases and found that the majority of publications (65%) focused on Middle East respiratory syndrome (MERS), brucellosis, Echinococcus granulosus, and Rift Valley fever. The high fatality from MERS outbreaks during 2012-2016 elicited an immediate response from the research community as demonstrated by a surge of MERS-related publications. However, we contend that other camel-borne diseases such as Yersinia pestis, Coxiella burnetii, and Crimean-Congo hemorrhagic fever are just as important to include in surveillance efforts. Camel populations, particularly in sub-Saharan Africa, are increasing exponentially in response to prolonged droughts, and thus, the risk of zoonoses increases as well. In this review, we provide an overview of the major zoonotic diseases present in dromedary camels, their risk to humans, and recommendations to minimize spillover events.

Whole genomic analysis of human G8P[14] group A rotavirus detected from community gastroenteritis outbreak

Several suspected cases of zoonotic transmission of group A rotavirus (RVA)-related gastroenteritis were reported previously. In August 2012, G8P[14] RVA was detected in fecal specimens from a community gastroenteritis outbreak occurring during a school trip. In this study, additional analyses were performed and it was found that this strain had the G8-P[14]-I2-R2-C2-M2-A3-N2-T6-E2-H3 sequence, similar to bovine-like RVA strains. Some contamination by emesis and diarrheic feces was observed near a rest room in the lodging area. Contact history with animals was unknown in members of this school trip, and this case implied that the strain may have acquired the ability for person-to-person transmission.

Putative vaccine breakthrough event associated with heterotypic rotavirus infection in newborn calves, Turkey, 2015

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The circulation of G8 RVA strains in calves with diarrhea detected first time in Turkey.

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First report on whole genome of G8P[5] RVA strains from calves with diarrhea in Turkey.

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VP7 gene of the both Turkish bovine RVA strains showed the closest with human RVA strains detected in Europe and Africa.

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The genotype constellation of the strains is G8-P[5]-I2-R2-C2-M2-A3-N2-T6-E2-H3.

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The findings raise provocative questions related to strain-specific vaccine effectiveness in herds where commercial RVA vaccines are routinely utilized.

Group A rotaviruses (RVA) are regarded as major enteric pathogens of large ruminants, including cattle. Rotavirus vaccines administered to pregnant cows are commonly used to provide passive immunity that protects newborn calves from the clinical disease. In this study we report the detection of RVA from calves with severe diarrhea in a herd regularly vaccinated to prevent enteric infections including RVA. Diarrheic disease was observed in newborn calves aged 4–15 days, with high morbidity and mortality rates, but no diarrhea was seen in adult animals. Rotavirus antigen was detected by enzyme-immunoassay in the intestinal content or the fecal samples of all examined animals. Besides RVA, bovine coronavirus and bovine enteric calicivirus were detected in some samples. Selected RVA strains were characterized by whole genome sequencing. Two strains, RVA/Cow-wt/TUR/Amasya-1/2015/G8P[5] and RVA/Cow-wt/TUR/Amasya-2/2015/G8P[5] were genotyped as G8-P[5]-I2-R2-C2-M2-A3-N2-T6-E2-H3 and showed >99% nucleotide sequence identity among themselves. This genomic constellation is fairly common among bovine RVA strains; however, phylogenetic analysis of the G8 VP7 gene showed close genetic relationship to some European human RVA strains (up to 98.4% nt identity). Our findings is the first indication regarding the circulation of G8 RVA strains in Turkey. Given that the administered RVA vaccines contained type G6 and G10 VP7 antigens some concerns raised with regard to the level of heterotypic protection elicited by the vaccine strains against circulating bovine G8 RVA strains. Enhancement of surveillance of circulating RVA strains in calves across Turkey is needed to support ongoing vaccination programs.

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.

Whole Genomic Analysis of an Unusual Human G6P[14] Rotavirus Strain Isolated from a Child with Diarrhea in Thailand: Evidence for Bovine-To-Human Interspecies Transmission and Reassortment Events

An unusual rotavirus strain, SKT-27, with the G6P[14] genotypes (RVA/Human-wt/THA/SKT-27/2012/G6P[14]), was identified in a stool specimen from a hospitalized child aged eight months with severe diarrhea. In this study, we sequenced and characterized the complete genome of strain SKT-27. On whole genomic analysis, strain SKT-27 was found to have a unique genotype constellation: G6-P[14]-I2-R2-C2-M2-A3-N2-T6-E2-H3. The non-G/P genotype constellation of this strain (I2-R2-C2-M2-A3-N2-T6-E2-H3) is commonly shared with rotavirus strains from artiodactyls such as cattle. Phylogenetic analysis indicated that nine of the 11 genes of strain SKT-27 (VP7, VP4, VP6, VP2-3, NSP1, NSP3-5) appeared to be of artiodactyl (likely bovine) origin, while the remaining VP1 and NSP2 genes were assumed to be of human origin. Thus, strain SKT-27 was found to have a bovine rotavirus genetic backbone, and thus is likely to be of bovine origin. Furthermore, strain SKT-27 appeared to be derived through interspecies transmission and reassortment events involving bovine and human rotavirus strains. Of note is that the VP7 gene of strain SKT-27 was located in G6 lineage-5 together with those of bovine rotavirus strains, away from the clusters comprising other G6P[14] strains in G6 lineages-2/6, suggesting the occurrence of independent bovine-to-human interspecies transmission events. To our knowledge, this is the first report on full genome-based characterization of human G6P[14] strains that have emerged in Southeast Asia. Our observations will provide important insights into the origin of G6P[14] strains, and into dynamic interactions between human and bovine rotavirus strains.

Whole genomic constellation of the first human G8 rotavirus strain detected in Japan

Human G8 Rotavirus A (RVA) strains are commonly detected in Africa but are rarely detected in Japan and elsewhere in the world. In this study, the whole genome sequence of the first human G8 RVA strain designated AU109 isolated in a child with acute gastroenteritis in 1994 was determined in order to understand how the strain was generated including the host species origin of its genes. The genotype constellation of AU109 was G8-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2. Phylogenetic analyses of the 11 genome segments revealed that its VP7 and VP1 genes were closely related to those of a Hungarian human G8P[14] RVA strain and these genes shared the most recent common ancestors in 1988 and 1982, respectively. AU109 possessed an NSP2 gene closely related to those of Chinese sheep and goat RVA strains. The remaining eight genome segments were closely related to Japanese human G2P[4] strains which circulated around 1985-1990. Bayesian evolutionary analyses revealed that the NSP2 gene of AU109 and those of the Chinese sheep and goat RVA strains diverged from a common ancestor around 1937. In conclusion, AU109 was generated through genetic reassortment event where Japanese DS-1-like G2P[4] strains circulating around 1985-1990 obtained the VP7, VP1 and NSP2 genes from unknown ruminant G8 RVA strains. These observations highlight the need for comprehensive examination of the whole genomes of RVA strains of less explored host species.

Genetic diversity in three bovine-like human G8P[14] and G10P[14] rotaviruses suggests independent interspecies transmission events

The group A rotavirus (RVA) P[14] genotype has been detected sporadically in humans and is thought to be acquired through zoonotic transmission. The present study describes the full-length genome analysis of two G8P[14] and one G10P[14] human RVAs detected in Italy. The strains possessed the typical bovine-like I2-R2-C2-M2-A3/A11-N2-T6-E2-H3 genotype constellation. All the segments of the two G8P[14] RVAs were most closely related to bovine(-like) strains but were relatively distant to each other, suggesting two independent interspecies transmission events. Likewise, the G10P[14] RVA gene segments were most similar to bovine(-like) RVAs but distinct from the G8 strains. The history of these strains probably involved the interspecies transmission of these viruses to humans from an as-yet-unidentified animal host, without evidence of reassortment events involving human RVAs. These results reinforce the potential of animal viruses to cross the host-species barrier, causing disease and increased viral genetic diversity in humans.

Whole genomic analysis of porcine G10P[5] rotavirus strain P343 provides evidence for bovine-to-porcine interspecies transmission

Porcine group A rotavirus (RVA) strain P343 (RVA/Pig-tc/THA/P343/1991/G10P[5]) was suggested to have VP7 and VP4 genes of bovine origin. In order to obtain precise information on the exact origin and evolution of this unusual porcine strain, the remaining nine genes (VP6, VP1-3, and NSP1-5) of strain P343 were sequenced and analyzed in the present study. On whole genomic analysis, strain P343 was found to have a bovine RVA-like genotype constellation (G10-P[5]-I2-R2-C2-M2-A3-N2-T6-E2-H3) different from those of typical porcine RVA strains. Furthermore, on phylogenetic analysis, each of the 11 genes of strain P343 appeared to be of bovine origin. Therefore, strain P343 was suggested to be a bovine RVA strain that was transmitted to pigs.

Genomic characterization of a rotavirus G8P[1] detected in a child with diarrhea reveal direct animal-to-human transmission

Group A rotavirus is a major cause of severe gastroenteritis in children and young animals. During a retrospective analysis of samples collected from Paraguayan children under 5 years old with diarrhea, and previously negative for rotavirus and norovirus, we detected the presence of bovine rotavirus sequences by viral metagenomics. Nucleic acid was extracted direct from stool sample and determined to be G8P[1]. The genomic analyzes revealed that the strain presents an Artiodactyl-like genome (G8-P[1]-I2-R2-C2-M1-Ax-N2-T6-E12-H3) suggesting a direct animal-to-human transmission.

Identification of novel Ghanaian G8P[6] human-bovine reassortant rotavirus strain by next generation sequencing

Group A rotaviruses (RVAs) are the most important etiological agent of acute gastroenteritis in children <5 years of age worldwide. The monovalent rotavirus vaccine Rotarix was introduced into the national Expanded Programme on Immunization (EPI) in Ghana in May 2012. However, there is a paucity of genetic and phylogenetic data on the complete genomes of human RVAs in circulation pre-vaccine introduction. The common bovine rotavirus VP7 genotype G8 has been sporadically detected in Ghanaian children, usually in combination with the VP4 genotype P[6]. To investigate the genomic constellations and phylogeny of RVA strains in circulation prior to vaccine introduction, the full genomes of two unusual G8P[6] strains, GH018-08 and GH019-08, detected during burden of disease surveillance, were characterized by Illumina MiSeq sequencing. The Ghanaian isolates, GH018-08 and GH019-08, exhibited the unusual, previously unreported genotype constellation G8-P[6]-I2-R2-C2-M2-A2-N2-T2-E2-H3. Phylogenetic analyses confirmed that 10 out of the 11 genes of GH018-08 and GH019-08 were identical/nearly identical, with significant variation detected only in their VP1 genes, and clearly established the occurrence of multiple independent interspecies transmission and reassortment events between co-circulating bovine/ovine/caprine rotaviruses and human DS-1-like RVA strains. These findings highlight the contribution of reassortment and interspecies transmission events to the high rotavirus diversity in this region of Africa, and justify the need for simultaneous monitoring of animal and human rotavirus strains.

Rotavirus surveillance in Kisangani, the Democratic Republic of the Congo, reveals a high number of unusual genotypes and gene segments of animal origin in non-vaccinated symptomatic children

Group A rotavirus (RVA) infections form a major public health problem, especially in low-income countries like the Democratic Republic of the Congo (COD). However, limited data on RVA diversity is available from sub-Saharan Africa in general and the COD in particular. Therefore, the first aim of this study was to determine the genetic diversity of 99 RVAs detected during 2007–2010 in Kisangani, COD. The predominant G-type was G1 (39%) and the most predominant P-type was P[6] (53%). A total of eight different G/P-combinations were found: G1P[8] (28%), G8P[6] (26%), G2P[4] (14%), G12P[6] (13%), G1P[6] (11%), G9P[8] (4%), G4P[6] (2%) and G8P[4] (1%). The second aim of this study was to gain insight into the diversity of P[6] RVA strains in the COD. Therefore, we selected five P[6] RVA strains in combination with the G1, G4, G8 (2x) or G12 genotype for complete genome analysis. Complete genome analysis showed that the genetic background of the G1P[6] and G12P[6] strains was entirely composed of genotype 1 (Wa-like), while the segments of the two G8P[6] strains were identified as genotype 2 (DS-1-like). Interestingly, all four strains possessed a NSP4 gene of animal origin. The analyzed G4P[6] RVA strain was found to possess the unusual G4-P[6]-I1-R1-C1-M1-A1-N1-T7-E1-H1 constellation. Although the majority of its genes (if not all), were presumably of porcine origin, this strain was able to cause gastro-enteritis in humans. The high prevalence of unusual RVA strains in the COD highlights the need for continued surveillance of RVA diversity in the COD. These results also underline the importance of complete genetic characterization of RVA strains and indicate that reassortments and interspecies transmission among human and animal RVAs strains occur regularly. Based on these data, RVA vaccines will be challenged with a wide variety of different RVA strain types in the COD.

Whole-genome analyses of DS-1-like human G2P[4] and G8P[4] rotavirus strains from Eastern, Western and Southern Africa

Group A rotaviruses (RVAs) with distinct G and P genotype combinations have been reported globally. We report the genome composition and possible origin of seven G8P[4] and five G2P[4] human RVA strains based on the genetic evolution of all 11 genome segments at the nucleotide level. Twelve RVA ELISA positive stool samples collected in the representative countries of Eastern, Southern and West Africa during the 2007-2012 surveillance seasons were subjected to sequencing using the Ion Torrent PGM and Illumina MiSeq platforms. A reference-based assembly was performed using CLC Bio's clc_ref_assemble_long program, and full-genome consensus sequences were obtained. With the exception of the neutralising antigen, VP7, all study strains exhibited the DS-1-like genome constellation (P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2) and clustered phylogenetically with reference strains having a DS-1-like genetic backbone. Comparison of the nucleotide and amino acid sequences with selected global cognate genome segments revealed nucleotide and amino acid sequence identities of 81.7-100 % and 90.6-100 %, respectively, with NSP4 gene segment showing the most diversity among the strains. Bayesian analyses of all gene sequences to estimate the time of divergence of the lineage indicated that divergence times ranged from 16 to 44 years, except for the NSP4 gene where the lineage seemed to arise in the more distant past at an estimated 203 years ago. However, the long-term effects of changes found within the NSP4 genome segment should be further explored, and thus we recommend continued whole-genome analyses from larger sample sets to determine the evolutionary mechanisms of the DS-1-like strains collected in Africa.

The first caprine rotavirus detected in Argentina displays genomic features resembling virus strains infecting members of the Bovidae and Camelidae

Rotavirus group A (RVA) is a major cause of diarrhea in humans and young animals including small ruminants. The purpose of this study was to identify RVA in dairy goat kids, and to characterize the complete genomic constellation and genetic relatedness with other RVA strains. Four out of twenty fecal samples from diarrheic and non-diarrheic goat kids were positive for RVA by ELISA. A representative sample was selected for further genome analyses. The RVA strain RVA/Goat-wt/ARG/0040/2011/G8P[1] displayed the following genomic constellation: G8-P[1]-I2-R5-C2-M2-A3-N2-T6-E12-H3, reminiscent to guanaco and other bovine-like RVA strains detected in Argentina. Phylogenetic analyses revealed that most of the genome segments had a rather close relatedness with RVA strains typically obtained from cattle, sheep, South American camelids and goats. Interestingly, strain 0040 possessed the R5 and E12 genotypes which have up to date only been found in different animal species from Argentina. Overall, these findings suggest that strain 0040 could represent a typical goat RVA genome constellation similar to those previously found in other animal species within the order Artiodactyla.

Novel NSP1 genotype characterised in an African camel G8P[11] rotavirus strain

Animal-human interspecies transmission is thought to play a significant role in influencing rotavirus strain diversity in humans. Proving this concept requires a better understanding of the complete genetic constellation of rotaviruses circulating in various animal species. However, very few whole genomes of animal rotaviruses, especially in developing countries, are available. In this study, complete genetic configuration of the first African camel rotavirus strain (RVA/Camel-wt/SDN/MRC-DPRU447/2002/G8P[11]) was assigned a unique G8-P[11]-I2-R2-C2-M2-A18-N2-T6-E2-H3 genotype constellation that has not been reported in other ruminants. It contained a novel NSP1 genotype (genotype A18). The evolutionary dynamics of the genome segments of strain MRC-DPRU447 were rather complex compared to those found in other camelids. Its genome segments 1, 3, 7-10 were closely related (>93% nucleotide identity) to those of human-animal reassortant strains like RVA/Human-tc/ITA/PA169/1988/G6P[14] and RVA/Human-wt/HUN/Hun5/1997/G6P[14], segments 4, 6 and 11 shared common ancestry (>95% nucleotide identity) with bovine rotaviruses like strains RVA/Cow-wt/CHN/DQ-75/2008/G10P[11] and RVA/Cow-wt/KOR/KJ19-2/XXXX/G6P[7], whereas segment 2 was closely related (94% nucleotide identity) to guanaco rotavirus strain RVA/Guanaco-wt/ARG/Rio_Negro/1998/G8P[1]. Its genetic backbone consisted of DS-1-like, AU-1-like, artiodactyl-like and a novel A18 genotype. This suggests that strain MRC-DPRU447 potentially emerged through multiple reassortment events between several mammalian rotaviruses of at least two genogroups or simply strain MRC-DPRU447 display a unique progenitor genotypes. Close relationship between some of the genome segments of strain MRC-DPRU447 to human rotaviruses suggests previous occurrence of reassortment processes combined with interspecies transmission between humans and camels. The whole genome data for strain MRC-DPRU447 adds to the much needed animal rotavirus data from Africa which is limited at the moment.

G8P[6] rotaviruses isolated from Amerindian children in Mato Grosso do Sul, Brazil, during 2009: close relationship of the G and P genes with those of bovine and bat strains

During the 2009 national group A rotavirus (RVA) surveillance, five unusual strains of the human G8P[6] genotype were detected in Brazilian indian children with acute gastroenteritis. The aim of this study was to carry out sequence analysis of the two outer capsid proteins (VP4 and VP7) and the inner capsid protein (VP6) of the G8P[6] strains detected in order to provide further information on the genetic relationship between human and animal RVA. A total of 68 stool samples, collected in Mato Grosso do Sul during 2009, were tested for RVA using ELISA, following by reverse transcriptase-PCR and sequencing. RVA infection was detected in 7.3% of samples (5/68). The IAL-RN376 G8 sequence shares a clade with bovine and human strains, displaying highest nucleotide identity to African human strains DRC86 and DRC88, followed by African bovine strain NGRBg8. IAL-RN376 and IAL-RN377 P[6] sequences showed highest identity to human strain R330 from Ireland, and a close genetic relationship to African fruit bat RVA strain KE4852/07. Strains IAL-RN376 and IAL-RN377 display genogroup I VP6 specificity and the I2 genotype, and share high nucleotide identities with human strains B1711, 272-BF and 06-242, and moderate identities with bovine (RUBV81, 86 and KJ9-1) and porcine (HP140) strains. This study suggested that a reassortment between bovine and bat RVA strains could have occurred in animal host(s) preceding the transmission to humans. In the indigenous population, zoonotic transmission is probably fairly frequent as the inhabitants live in close contact with animals under conditions of poor hygiene.

Zoonotic transmission of reassortant porcine G4P[6] rotaviruses in Hungarian pediatric patients identified sporadically over a 15 year period

Genotype G4P[6] Rotavirus A (RVA) strains collected from children admitted to hospital with gastroenteritis over a 15 year period in the pre rotavirus vaccine era in Hungary were characterized in this study. Whole genome sequencing and phylogenetic analysis was performed on eight G4P[6] RVA strains. All these RVA strains shared a fairly conservative genomic configuration (G4-P[6]-I1/I5-R1-C1-M1-A1/A8-N1-T1/T7-E1-H1) and showed striking similarities to porcine and porcine-derived human RVA strains collected worldwide, although genetic relatedness to some common human RVA strains was also seen. The resolution of phylogenetic relationship between porcine and human RVA genes was occasionally low, making the evaluation of host species origin of individual genes sometimes difficult. Yet the whole genome constellations and overall phylogenetic analyses indicated that these eight Hungarian G4P[6] RVA strains may have originated by independent zoonotic transmission, probably from pigs. Future surveillance studies of human and animal RVA should go parallel to enable the distinction between direct interspecies transmission events and those that are coupled with reassortment of cognate genes.

G8 rotaviruses with conserved genotype constellations detected in Malawi over 10 years (1997-2007) display frequent gene reassortment among strains co-circulating in humans

Rotavirus A, the most common cause of severe diarrhoea in children worldwide, occurs in five major VP7 (G) and VP4 (P) genotype combinations, comprising G1P[8], G2P[4], G3P[8], G4P[8] and G9P[8]. However, G8, a common bovine rotavirus genotype, has been reported frequently among children in African countries. Surveillance of rotavirus gastroenteritis conducted in a sentinel hospital in Blantyre, Malawi between 1997 and 2007 provided a rare opportunity to examine the whole genotype constellation of G8 strains and their evolution over time. A sample of 27 (9.0 %) of 299 G8 strains was selected to represent each surveillance year and a range of P genotypes, which shifted in predominance from P[6] to P[4] and P[8] during the study period. Following cell culture adaptation, whole genome sequencing demonstrated that the genetic background of 26 strains possessed the DS-1 genotype constellation. A single G8P[6] strain was a reassortant in which both NSP2 and NSP5 genes from strains with the Wa genotype constellation had been inserted into a strain with the DS-1 genotype background. Phylogenetic analysis suggested frequent reassortment among co-circulating strains with the DS-1 genotype constellation. Little evidence was identified to suggest the introduction of contemporary bovine rotavirus genes into any of the 27 G8 strains examined. In conclusion, Malawian G8 strains are closely related to other human strains with the DS-1 genotype constellation. They have evolved over the last decade through genetic reassortment with other human rotaviruses, changing their VP4 genotypes while maintaining a conserved genotype constellation for the remaining structural and non-structural proteins.

Characterization of human rotaviruses circulating in Iraq in 2008: atypical G8 and high prevalence of P[6] strains

Fecal samples from 976 children with gastroenteritis were collected and analyzed for group A rotavirus (RVA), in three different cities in Iraq between January 2008 and December 2008. RVA antigen was detected in 394 (40%) of the samples, and 98 samples were available for further genotype analyses using multiplex RT-PCR and sequence analyses for untypeable strains. The G/P-genotype combination was determined for 69 samples, and 19, 2 and 8 samples remained P-untypeable, G-untypeable and G/P-untypeable (UT), respectively. The most prevalent genotype was G2 (40%, 39/98) most often associated with P[6]. G1 was the second most common genotype (16%, 16/98) mainly associated with P[8] and P[UT]. G3, G4 and G9 were detected at a lower prevalence (3%, 11%, 3%, respectively), mainly associated with P[6]. Surprisingly, five G8P[6], and seven G12 RVA strains in combination with P[6] and P[8] were also detected for the first time in Iraq. Overall, a striking high prevalence of 47% of the analyzed samples possessed the P[6] genotype (65% of the P-typed RVA strains). Atypical genotype combinations such as G1P[4], G1P[6], G2P[8] or strains with mixed G-types were detected sporadically. The detection of unusual G8P[6] RVA strains prompted us to further analyze the NSP2, NSP3, NSP4 and NSP5 gene segments of three selected G8P[6] strains, resulting in their designation to the N2, T2, E2 and H2 genotypes, respectively. The VP7, VP4, NSP2, NSP3 and NSP5 gene segments clustered closely with common human RVA strains, whereas the NSP4 gene sequences were found to cluster with animal derived RVA strains, suggesting a potential reassortment event. The high prevalence of RVA strains with the G8, G12 and P[6] genotypes in combination with a DS-1-like genotype constellation in Iraq, needs to be monitored closely as these RVA strains might challenge the effectiveness of current RVA vaccines.

First report of human rotavirus G8P[4] gastroenteritis in India: evidence of ruminants-to-human zoonotic transmission

Group A rotaviruses are the major cause of childhood gastroenteritis worldwide. Due to close proximity of human and cattle in rural areas of developing countries like India, interspecies transmission or zoonotic transmission is a major source of rapid generation of reassortants and genetic or antigenic variants. Previously, many human group A rotaviruses were found with porcine or bovine characteristics from eastern and north-eastern India. In this study, four unusual human G8P[4] strains were identified which had artiodactyl-like origins. During an ongoing community based surveillance for epidemiological profiling of diarrheal pathogens, these unusual human group A rotavirus G8P[4] strains were detected from the stool samples of 3-14 months old children with acute diarrhea in Sonarpur, eastern India. Analysis of eleven complete and/or partial gene segments of these unusual G8P[4] strains were done by reverse transcription-PCR (RT-PCR) followed by nucleotide sequencing and phylogenetic analysis. The VP7 nucleotide sequences revealed a close phylogenetic relationship to the G8P[7] porcine strain D-1 and bovine strain KJ59-2 from South Korea. Whereas the VP4 gene segments were also related closely to human rotavirus prototype strain DS-1. Other nine gene segments of these G8P[4] rotaviruses were related closely to either animal or animal-derived rotavirus members of the DS-1-like family. These results suggest that origin of these G8P[4] strains might have been resulted from multiple reassortment events between artiodactyls and ruminant-derived reassortant human rotaviruses. To date, this is the first report of G8P[4] rotavirus from India and the first genomic analysis of G8P[4] strains from Asian continent.

Identification by full-genome analysis of a bovine rotavirus transmitted directly to and causing diarrhea in a human child

The genome of rotaviruses consists of 11 segments of double-stranded RNA, and each genome segment has multiple genotypes. Thus, the genotype constellation of an isolate is often indicative of its host species. Albeit rarely, interspecies transmission occurs either by virions with nonreassorted or reassorted genomic segments. A rotavirus with the G6P[1] genotype, Ro8059, was isolated from the stool of a 1-year-old child during routine characterization of diarrheal specimens from a sentinel clinic in Israel in 1995. Since genotype G6P[1] is generally associated with bovine rotaviruses, and the child developed diarrhea within days of his first contact with calves at an urban farm, the aim of this study was to characterize the whole genomic constellation of Ro8059 and four G6P[1] bovine strains, BRV101, BRV105, BRV106, and CR231/39, by RNA-RNA hybridization and full genome sequencing to determine whether some or all of the segments were of bovine origin. The genome constellations of all four bovine G6P[1] strains were G6-P[1]-I2-R2-C2-M2-A3-N2-T6-E2-H3 for VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5, respectively. Ro8059 shared the same genotype constellation with these bovine strains, with high nucleotide sequence identities (95.84 to 100%) for each of the 11 segments indicating that Ro8059 represented a direct interspecies whole-genome transmission of a nonreassorted rotavirus from a calf to a human infant. We conclude that this was the earliest example with a complete epidemiological link in which an entirely bovine rotavirus directly infected a human child and caused a symptomatic diarrheal illness. Thus, not all bovine rotaviruses are always naturally attenuated to the human host.

Discovery and molecular characterization of a group A rotavirus strain detected in an Argentinean vicuña (Vicugna vicugna)

The wild vicuña (Vicugna vicugna) is one of the four species of native South American camelids (SACs) in addition to the wild guanaco, and their domesticated counterparts, alpaca and llama, respectively. Serological data have indicated the presence of group A rotaviruses (RVA) specific antibodies in all 4 members of the SAC, and so far, RVA has been detected from alpacas, llamas and guanacos. A total of 59 fecal samples from healthy wild newborn and juvenile vicuñas, raised in captivity in Jujuy, Argentina were collected and analyzed by ELISA to detect RVA antigen. Two samples (3%) were found to contain G8 RVA strains and one strain (RVA/Vicuña-wt/ARG/C75/2010/G8P[14]) was selected for further genome analyses, revealing the G8-P[14]-I2-R2-C2-M2-Ax-N2-T6-E3-Hx genotype constellation. Unfortunately, no sequence data could be obtained for NSP1 and NSP5. Except for the E3 NSP4 genotype, this partial genotype constellation is reminiscent to bovine RVA strains and bovine-like RVA strains isolated from sheep, guanaco, antelope and humans. This relationship was confirmed phylogenetically, providing further evidence of the widespread presence of this genotype constellation in animals belonging to the artiodactyls. In particular, a close phylogenetic relationship was found between C75 and guanaco RVA strain RVA/Guanaco-wt/ARG/Chubut/1999/G8P[14] for at least 5 gene segments, suggesting a partial conservation of the genotype constellation of RVA strains infecting different species of SACs, even though nowadays their natural habitats are not overlapping. The further monitoring of the sanitary health of wild newborn and juvenile vicuñas is essential to improve the management practices applied in their sustainable exploitation.

Whole genome sequence analyses of three African bovine rotaviruses reveal that they emerged through multiple reassortment events between rotaviruses from different mammalian species

Animal-to-human interspecies transmission is one of the evolutionary mechanisms driving rotavirus strain diversity in humans. Although quite a few studies emanating from Africa revealed evidence of bovine-to-human rotavirus interspecies transmission, whole genome data of African bovine rotavirus strains are not yet available. To gain insight into the complete genome constellation of African bovine rotaviruses, the full genomes of three bovine rotavirus strains were extracted from stool samples collected from calves, amplified using a sequence-independent procedure, followed by 454(®) pyrosequencing. Strains RVA/Cow-wt/ZAF/1603/2007/G6P[5] and RVA/Cow-wt/ZAF/1605/2007/G6P[5] were both genotyped as G6-P[5]-I2-R2-C2-M2-A3-N2-T6-E2-H3 and were probably two variants of the same rotavirus due to their close nucleotide sequence similarity. The genotype constellation of strain RVA/Cow-wt/ZAF/1604/2007/G8P[1] was G8-P[1]-I2-R2-C2-M2-A3-N2-T6-E2-H3. The genetic relationships and phylogenetic analyses suggested that these three bovine rotavirus strains may have emerged through multiple reassortment events between bovine, giraffe and antelope rotaviruses. Due to the close relatedness of genome segments 1 (encoding VP1), 7 (NSP2), 9 (VP7) and 10 (NSP4) of strain RVA/Cow-wt/ZAF/1604/2007/G8P[1] to those of the corresponding segments of human rotaviruses, RVA strain 1604 may represent bovine strains that were transmitted to humans and possibly reassorted with human rotaviruses previously. The complete nucleotide sequences of the bovine rotavirus strains reported in this study represent the first whole genome data of bovine rotaviruses from Africa.

A large outbreak of enteritis in goat flocks in Marmara, Turkey, by G8P[1] group A rotaviruses

Group A rotaviruses are regarded as major enteric pathogens of large ruminants, while their impact on the health of small ruminants is not well documented. We report the detection of group A rotavirus from a large outbreak of enteritis that occurred in two goat flocks in the town of Kırklareli, Marmara Region, Turkey, in 2007. The disease was observed in young kids, with high morbidity and mortality rates, but not in adult animals. Rotavirus antigen was detected in the stools of the examined animals, and rotaviruses were isolated in MA104 cells. Upon sequencing of the VP4, VP6, VP7 and NSP4 genes, the strain (RVA/goat-tc/TUR/Kirklareli/2007/G8P[1]) was characterized as G8P[1], with E2 NSP4 and VP6 I2 genotype. These findings indicate that group A rotavirus should be included in the diagnostic algorithms for enteric disease in small ruminants.

Whole-genomic analysis of rotavirus strains: current status and future prospects

Studies on genetic diversity of rotaviruses have been primarily based on the genes encoding the antigenically significant VP7 and VP4 proteins. Since the rotavirus genome has 11 segments of RNA that are vulnerable to reassortment events, analyses of the VP7 and VP4 genes may not be sufficient to obtain conclusive data on the overall genetic diversity, or true origin of strains. In the last few years following the advent of the whole-genome-based genotype classification system, the whole genomes of at least 167 human group A rotavirus strains have been analyzed, providing a plethora of new and important information on the complex origin of strains, inter- and intra-genogroup reassortment events, animal–human reassortment events, zoonosis, and genetic linkages involving different group A rotavirus gene segments. In addition, the whole genomes of a limited number of human group B, C and novel group rotavirus strains have been analyzed. This article briefly reviews the available data on whole-genomic analysis of human rotavirus strains. The significance and future prospects of whole-genome-based studies are also discussed.

Whole-genome analysis reveals the complex evolutionary dynamics of Kenyan G2P[4] human rotavirus strains

Although G2P[4] rotaviruses are common causes of acute childhood diarrhoea in Africa, to date there are no reports on whole genomic analysis of African G2P[4] strains. In this study, the nearly complete genome sequences of two Kenyan G2P[4] strains, AK26 and D205, detected in 1982 and 1989, respectively, were analysed. Strain D205 exhibited a DS-1-like genotype constellation, whilst strain AK26 appeared to be an intergenogroup reassortant with a Wa-like NSP2 genotype on the DS-1-like genotype constellation. The VP2-4, VP6-7, NSP1, NSP3 and NSP5 genes of strain AK26 and the VP2, VP4, VP7 and NSP1–5 genes of strain D205 were closely related to those of the prototype or other human G2P[4] strains. In contrast, their remaining genes were distantly related, and, except for NSP2 of AK26, appeared to originate from or share a common origin with rotavirus genes of artiodactyl (ruminant and camelid) origin. These observations highlight the complex evolutionary dynamics of African G2P[4] rotaviruses.

Uniformity of rotavirus strain nomenclature proposed by the Rotavirus Classification Working Group (RCWG)

In April 2008, a nucleotide-sequence-based, complete genome classification system was developed for group A rotaviruses (RVs). This system assigns a specific genotype to each of the 11 genome segments of a particular RV strain according to established nucleotide percent cutoff values. Using this approach, the genome of individual RV strains are given the complete descriptor of Gx-P[x]-Ix-Rx-Cx-Mx-Ax-Nx-Tx-Ex-Hx. The Rotavirus Classification Working Group (RCWG) was formed by scientists in the field to maintain, evaluate and develop the RV genotype classification system, in particular to aid in the designation of new genotypes. Since its conception, the group has ratified 51 new genotypes: as of April 2011, new genotypes for VP7 (G20-G27), VP4 (P[28]-P[35]), VP6 (I12-I16), VP1 (R5-R9), VP2 (C6-C9), VP3 (M7-M8), NSP1 (A15-A16), NSP2 (N6-N9), NSP3 (T8-T12), NSP4 (E12-E14) and NSP5/6 (H7-H11) have been defined for RV strains recovered from humans, cows, pigs, horses, mice, South American camelids (guanaco), chickens, turkeys, pheasants, bats and a sugar glider. With increasing numbers of complete RV genome sequences becoming available, a standardized RV strain nomenclature system is needed, and the RCWG proposes that individual RV strains are named as follows: RV group/species of origin/country of identification/common name/year of identification/G- and P-type. In collaboration with the National Center for Biotechnology Information (NCBI), the RCWG is also working on developing a RV-specific resource for the deposition of nucleotide sequences. This resource will provide useful information regarding RV strains, including, but not limited to, the individual gene genotypes and epidemiological and clinical information. Together, the proposed nomenclature system and the NCBI RV resource will offer highly useful tools for investigators to search for, retrieve, and analyze the ever-growing volume of RV genomic data.