Analysis of complete genome sequences of G9P[19] rotavirus strains from human and piglet with diarrhea provides evidence for whole-genome interspecies transmission of nonreassorted porcine rotavirus

Prevalence and genetic diversity of porcine rotavirus A from diarrheic piglets in Northern Thailand

BACKGROUND

Rotavirus A (RVA) is an important pathogen causing acute viral gastroenteritis in young children and various animals. RVA is also recognized as a common cause of gastroenteritis in piglets. Epidemiological studies of porcine RVA (PoRVA) conducted in different settings worldwide reported that the prevalence of PoRVA infection ranged from 9.4% to 74.0% with the predominance of G4P[6], G4P[7], and G5P[7] genotypes. In Thailand, long-term epidemiological surveillance of PoRVA infection is limited. Continuous monitoring of PoRVA infection is required to gain a better understanding the prevalence and evolution of PoRVA. In this study, the prevalence and genetic diversity of PoRVA were investigated by screening of 1,260 stool samples collected from 0 to 5-week-old piglets with acute diarrhea during 2016 to 2023 by using real-time RT-PCR. The G- and P-genotypes of RVA were identified by characterization of the partial VP7 and VP4 genes by using multiplex-PCR, nucleotide sequencing, and phylogenetic analysis.

RESULTS

A total of 303 out of 1,260 (24.0%) samples were positive for PoRVA. Overall, the G5P[23] (28.7%) and G4P[23] (28.4%) were detected as the co-predominant PoRVA genotypes, followed by G5P[13] (9.9%), G3P[23] (9.6%), G9P[23] (8.2%), G4P[13] (7.9%), G9P[13] (3.3%), G3P[13] (1.7%), G4P[6] (1.7%), and G2P[23] (0.3%) genotypes. Additionally, a rare G2P[27] (0.3%) genotype re-emerged approximately 22 years after the initial detection in 2000 in Chiang Mai, Thailand.

CONCLUSION

Our results revealed the prevalence of wide variety of PoRVA genotypes circulating in piglets with acute diarrhea in Thailand over a study period of seven years. Of these, G5P[23] and G4P[23] emerged as the most predominant genotypes, which were substantially different from previous reports in the same geographical area. The findings offer valuable contribution to a better understanding of molecular epidemiology and evolution of PoRVA in piglets with acute diarrhea.

Phylogenitc analysis and immunogenicity comparison of porcine genotype G9 rotavirus in China from 2020-2023

As an emerging genotype, the G9 genotype rotaviruses (RVs) are widespread among humans and pigs, and have been reported in many countries and regions in the recent years. Moreover, porcine G9 strains could cross the interspecies barrier to infect human. To investigate the epidemic trends of porcine G9 strains as well as the cross-immunoreactivity among different isolates, an epidemiological investigation about porcine G9 genotype RVs (PoRVs) was performed during the period 2020-2023 in multiple provinces of China. A total of nine representative strains were identified. The phylogenetic analysis based on viral VP7 gene showed that these strains mainly clustered with lineages III and VI, which revealed the predominant G9 PoRVs in China. Moreover, a new lineage, lineage VII, was identified, and strains of this lineage were found to be circulating in Guangdong and Taiwan. Except lineages I and IV, some isolates from other lineages could co-circulate in pigs and humans. Three G9 strains, namely 923H, 923E, and 923X, which belonged to the largest sub-lineage III, were isolated. Then, the significant cross-reactivity was observed among strains of the same or different lineages. This study is the first to systematically investigate the genetic and immunogenetic characteristics of porcine G9 genotype rotavirus in China, as well as the potential cross-species transmission between pigs and humans, providing a valuable direction for the effective prevention of porcine rotavirus.

Unusual G3P[10] bat-like rotavirus strains detected in children with acute gastroenteritis in Thailand

Rotavirus A (RVA) is the main cause of acute gastroenteritis among children under the age of five globally. The unusual bat-like human RVA strains G3P[10] (RVA/Human-wt/THA/CMH079/05/2005/G3P[10] and RVA/Human-wt/THA/CMH-S015-19/2019/G3P[10]) were detected in children with acute gastroenteritis in 2005 and 2019, respectively, in the same geographical area of Northern Thailand. To elucidate the genetic backgrounds of these unusual or bat-like human RVA strains, the complete genome of these RVA strains was sequenced and phylogenetically analyzed. All eleven genome segments of these G3P[10] strains were genotyped as G3-P[10]-I8-R3-C3-M3-A9-N3-T3-E3-H6, which is closely related to bat G3P[10] RVA strain (RVA/Bat-tc/CHN/MYAS33/2013/G3P[10]) and bat-like human RVA strain (RVA/Human-wt/THA/MS2015-1-0001/2015/G3P[10]). The findings indicate that human G3P[10] RVA strains detected in this study (RVA/Human-wt/THA/CMH079/05/2005/G3P[10] and RVA/Human-wt/THA/CMH-S015-19/2019/G3P[10]) contained all eleven genome segments similar to those of bat RVA strains and appeared to be human RVA strains of bat origin. Phylogenetic analysis revealed that several genome segments of these two RVA strains were also closely related with those of other species in addition to bats and had a zoonotic transmission history. The results of this study supported the roles of interspecies transmission of RVA strains among bats and humans in the natural environment and provided convincing evidence that the evolution of human RVAs was closely interrelated with those of animal RVAs. Continuing surveillance of RVAs in humans and animals is imperative to gain a better understanding of the origin and the evolution of these viruses.

Genetic Diversity of Rotaviruses Circulating in Pediatric Patients and Domestic Animals in Thailand

Rotavirus A is a highly contagious virus that causes acute gastroenteritis in humans and a wide variety of animals. In this review, we summarized the information on rotavirus described in the studies in the last decade (2008 to 2021) in Thailand, including the prevalence, seasonality, genetic diversity, and interspecies transmission. The overall prevalence of rotavirus infection in humans ranged from 15-33%. Rotavirus infection was detected throughout the year and most frequently in the dry and cold months, typically in March. The diversity of rotavirus genotypes varied year to year and from region to region. From 2008 to 2016, rotavirus G1P[8] was detected as the most predominant genotype in Thailand. After 2016, G1P[8] decreased significantly and other genotypes including G3P[8], G8P[8], and G9P[8] were increasingly detected from 2016 to 2020. Several uncommon rotavirus strains such as G1P[6], G4P[6], and G3P[10] have also been occasionally detected. In addition, most studies on rotavirus A infection in animals in Thailand from 2011 to 2021 reported the detection of rotavirus A in piglets and canine species. It was reported that rotavirus could cross the host species barrier between humans and animals through interspecies transmission and genetic reassortment mechanisms. The surveillance of rotavirus infection is crucial to identify the trend of rotavirus infection and the emergence of novel rotavirus genotypes in this country. The data provide information on rotavirus infection and the diversity of rotavirus genotypes circulating in the pre-vaccination period, and the data will be useful for the evaluation of the effectiveness of rotavirus vaccine implementation in Thailand.

Genetic diversity and Genomic analysis of G3P[6] and equine-like G3P[8] in Children Under-five from Southern Highlands and Eastern Tanzania

Rotavirus group A genomic characterization is critical for understanding the mechanisms of rotavirus diversity, such as reassortment events and possible interspecies transmission. However, little is known about the genetic diversity and genomic relationship of the rotavirus group A strains circulating in Tanzania. The genetic and genomic relationship of RVA genotypes was investigated in children under the age of five. A total of 169 faecal samples were collected from under-five with diarrhea in Mbeya, Iringa and Morogoro regions of Tanzania. The RVA were screened in children under five with diarrhea using reverse transcription PCR for VP7 and VP4, and the G and P genotypes were determined using Sanger dideoxynucleotide cycle sequencing. Whole-genome sequencing was performed on selected genotypes. The overall RVA rate was 4.7% (8/169). The G genotypes were G3 (7/8) and G6 (1/8) among the 8 RVA positives, while the P genotypes were P[6] (4/8) and P[8] (2), and the other two were untypeable. G3P[6] and G3P[8] were the identified genotype combinations. The genomic analysis reveals that the circulating G3P[8] and G3P[6] isolates from children under the age of five with diarrhea had a DS-1-like genome configuration (I2-R2-C2-M2-Ax-N2-T2-E2-H2). The phylogenic analysis revealed that all 11 segments of G3P[6] were closely related to human G3P[6] identified in neighboring countries such as Uganda, Kenya, and other African countries, implying that G3P[6] strains descended from a common ancestor. Whereas, G3P[8] were closely related to previously identified equine-like G3P[P8] from Kenya, Japan, Thailand, Brazil, and Taiwan, implying that this strain was introduced rather than reassortment events. We discovered amino acid differences at antigenic epitopes and N-linked glycosylation sites between the wild type G3 and P[8] compared to vaccine strains, implying that further research into the impact of these differences on vaccine effectiveness is warranted. The phylogenic analysis of VP7 also identified a bovine-like G6. For the first time in Tanzania, we report the emergence of novel equine-like G3 and bovine-like G6 RVA strains, highlighting the importance of rotavirus genotype monitoring and genomic analysis of representative genotypes.

Full genome-based characterization of G4P[6] rotavirus strains from diarrheic patients in Thailand: Evidence for independent porcine-to-human interspecies transmission events

The exact evolutionary patterns of human G4P[6] rotavirus strains remain to be elucidated. Such strains possess unique and strain-specific genotype constellations, raising the question of whether G4P[6] strains are primarily transmitted via independent interspecies transmission or human-to-human transmission after interspecies transmission. Two G4P[6] rotavirus strains were identified in fecal specimens from hospitalized patients with severe diarrhea in Thailand, namely, DU2014-259 (RVA/Human-wt/THA/DU2014-259/2014/G4P[6]) and PK2015-1-0001 (RVA/Human-wt/THA/PK2015-1-0001/2015/G4P[6]). Here, we analyzed the full genomes of the two human G4P[6] strains, which provided the opportunity to study and confirm their evolutionary origin. On whole genome analysis, both strains exhibited a unique Wa-like genotype constellation of G4-P[6]-I1-R1-C1-M1-A8-N1-T1-E1-H1. The NSP1 genotype A8 is commonly found in porcine rotavirus strains. Furthermore, on phylogenetic analysis, each of the 11 genes of strains DU2014-259 and PK2015-1-0001 appeared to be of porcine origin. On the other hand, the two study strains consistently formed distinct clusters for nine of the 11 gene segments (VP4, VP6, VP1-VP3, and NSP2-NSP5), strongly indicating the occurrence of independent porcine-to-human interspecies transmission events. Our observations provide important insights into the origin of zoonotic G4P[6] strains, and into the dynamic interaction between porcine and human rotavirus strains.

Presence and Diversity of Different Enteric Viruses in Wild Norway Rats (Rattus norvegicus)

Rodents are common reservoirs for numerous zoonotic pathogens, but knowledge about diversity of pathogens in rodents is still limited. Here, we investigated the occurrence and genetic diversity of enteric viruses in 51 Norway rats collected in three different countries in Europe. RNA of at least one virus was detected in the intestine of 49 of 51 animals. Astrovirus RNA was detected in 46 animals, mostly of rat astroviruses. Human astrovirus (HAstV-8) RNA was detected in one, rotavirus group A (RVA) RNA was identified in eleven animals. One RVA RNA could be typed as rat G3 type. Rat hepatitis E virus (HEV) RNA was detected in five animals. Two entire genome sequences of ratHEV were determined. Human norovirus RNA was detected in four animals with the genotypes GI.P4-GI.4, GII.P33-GII.1, and GII.P21. In one animal, a replication competent coxsackievirus A20 strain was detected. Additionally, RNA of an enterovirus species A strain was detected in the same animal, albeit in a different tissue. The results show a high detection rate and diversity of enteric viruses in Norway rats in Europe and indicate their significance as vectors for zoonotic transmission of enteric viruses. The detailed role of Norway rats and transmission pathways of enteric viruses needs to be investigated in further studies.

Prevalence and genome characterization of porcine rotavirus A in southern Mozambique

Rotavirus A (RVA) is an important pathogen causing gastroenteritis in many species, including humans and pigs. The objective of this study was to determine the prevalence of RVA in pigs from smallholdings and commercial farms in southern Mozambique and characterize the complete genomes of selected strains. RVA was detected at a rate of 11.8% (n = 288), of which 7.6% was detected at commercial farms and 4.2% at smallholdings. The whole genomes of eight rotavirus strains were determined using an Illumina MiSeq platform. Seven displayed a G9P[13] and one a G4P[6] genotype combination, all with a typical porcine backbone (I1/5-R1-C1-M1-A1/8-N1-T1/7-E1-H1). Phylogenetic analysis indicated that the seven G9P[13] strains were in fact one strain that circulated on a commercial pig farm. The genome segments of this strain clustered with diverse segments of human and porcine RVA strains from various Asian countries. Analysis of the G4P[6] strain revealed four distinct genome segments (VP2, VP4, VP6 and VP7) and five genome segments closely related to South African porcine rotavirus strains (NSP1, NSP3, NSP4, NSP5 and VP1). These results suggest that both the G4P[6] and the G9P[13] strains possibly emerged through multiple reassortment events. The presence of these strains on the commercial farms and smallholdings calls for a more in-depth surveillance of rotavirus in Mozambique.

Childhood diarrhoeal diseases in developing countries

Diarrhoeal diseases collectively constitute a serious public health challenge globally, especially as the leading cause of death in children (after respiratory diseases). Childhood diarrhoea affecting children under the age of five accounts for approximately 63% of the global burden. Accurate and timely detection of the aetiology of these diseases is very crucial; but conventional methods, apart from being laborious and time-consuming, often fail to identify difficult-to-culture pathogens. The aetiological agent of an average of up to 40% of cases of diarrhoea cannot be identified. This review gives an overview of the recent trends in the epidemiology and treatment of diarrhoea and aims at highlighting the potentials of metagenomics technique as a diagnostic method for enteric infections.

Synanthropic rodents as virus reservoirs and transmitters

This review focuses on reports of hepatitis E virus, hantavirus, rotavirus, coronavirus, and arenavirus in synanthropic rodents (Rattus rattus, Rattus norvegicus, and Mus musculus) within urban environments. Despite their potential impact on human health, relatively few studies have addressed the monitoring of these viruses in rodents. Comprehensive control and preventive activities should include actions such as the elimination or reduction of rat and mouse populations, sanitary education, reduction of shelters for the animals, and restriction of the access of rodents to residences, water, and food supplies.

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.

The potential of pectin to impact pig nutrition and health: feeding the animal and its microbiome

The increasing efforts to substitute antibiotics and improve animal health combined with the acknowledgement of the role of gut microbiota in health have led to an elevated interest in the understanding on how fibre with prebiotic potential, such as pectin, can improve animal growth and health via direct or gut microbiota mediated effects. Various reports exist on the antiviral and antibacterial effects of pectin, as well as its potency as a modulator of the immune response and gut microbial community. Comprehensive insights into the potential of pectin to improve animal growth and health are currently still hampered by heterogeneity in the design of studies. Studies differ with regard to the dosage, molecular structure and source of the pectin implemented, as well as concerning the set of investigations of its effects on the host. Harmonisation of the study design including an in-depth analysis of the gut microbial community and its metabolome will aid to extract information on how pectin can impact growth and overall animal health. Studies with an increased focus on pectin structure such as on pectin-derived rhamnogalacturonan I (RG-I) are just starting to unravel pectin-structure-related effects on mammalian health.

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.

Complete genome sequence analysis of rare G4P[6] rotavirus strains from human and pig reveals the evidence for interspecies transmission

Two rare human rotavirus strains, RVA/Human-wt/THA/CMH-N016-10/2010/G4P[6] and RVA/Human-wt/THA/CMH-N014-11/2011/G4P[6], were detected during the surveillance of group A rotavirus (RVA) in Chiang Mai, Thailand. Complete genome sequences of both strains were analyzed in comparison with that of the representative porcine G4P[6] RVA strain (RVA/Pig-wt/THA/CMP-011-09/2009/G4P[6]) detected in the same geographical area. Human RVA strain CMH-N016-10 containing the genotype constellation of G4-P[6]-I1-R1-C1-M1-A8-N1-T1-E1-H1 was identical to that of porcine RVA strain CMP-011-09. Another human RVA strain (CMH-N014-11) was also contained the genotype constellation of ten segments identical to those of CMH-N016-10 and of porcine RVA strain CMP-011-09 except for genotype I of VP6 gene which contained I5 instead of I1. The genotype constellation of CMH-N014-11, G4-P[6]-I5-R1-C1-M1-A8-N1-T1-E1-H1 was a novel genotype constellation that has not been reported previously in both human and pig. Phylogenetic analysis of all 11 genome segments revealed that both strains of human RVA were more closely related to porcine and porcine-like human than to human RVA reference strains, particularly those reported from Thailand and other Asian countries with very high nucleotide sequence identities ranging from 91.1-100% except for NSP4 gene from 86.1-92.2%. Based on complete genome constellation and overall phylogenetic analyses suggested that these two human G4P[6] strains may have probably originated from porcine RVA strains of independent ancestor. This study provided an evidence for direct interspecies transmission of porcine RVA from pig to human.

Farmed and companion animals as reservoirs of zoonotic rotavirus strains

Rotavirus (RV) infections are a major epidemiological problem in humans and farm animals. So far, a number of human and animal RV strains have been identified. Based on the antigenic properties of the VP6 capsid protein, they have been classified into eight serogroups (A-H). The most important of them are viruses from group A (RVA), which are responsible for more than 90% of cases of rotaviral diarrhoea. The segmented structure of the virus genome and the presence of animals in human neighbourhood favour genetic reassortment between RV strains originating from different hosts. This could result in an emergence of zoonotic virus strains. The increasing number of human infections caused by virus strains having genotypes which have only been identified in animals indicates the need for epidemiological surveillance of infections. Additionally, the identification of epidemic virus strains in the outbreaks of disease in humans should be conducted. The identification of RVA strains circulating in humans and animals will allow the assessment of the impact of vaccination on the selection and emergence of zoonotic RVA strains.

1. Introduction. 2. General characteristics and classification of rotaviruses. 3. Group A rotavirus infection in humans. 4. Group A rotavirus infection in animals. 5. Genetic changes and reassortment as factors leading to the formation of zoonotic rotavirus strains. 6. Impact of human immunization on changes in genotype profile of circulating rotavirus strains. 7. Conclusions

Genome Sequence Analysis of a G2P[4] Group A Rotavirus Strain with an Unusual Canine-Origin NSP1 A15 Genotype

Here, we disclose the complete genomic sequence of a rare rotavirus group A G2P[4]-I2-R2-C2-M2-A15-N2-T2-E2-H2 strain detected in a fecal specimen from a rotaviral acute gastroenteritis patient who had previously received the Rotarix vaccine.

Porcine Rotaviruses: Epidemiology, Immune Responses and Control Strategies

Rotaviruses (RVs) are a major cause of acute viral gastroenteritis in young animals and children worldwide. Immunocompetent adults of different species become resistant to clinical disease due to post-infection immunity, immune system maturation and gut physiological changes. Of the 9 RV genogroups (A–I), RV A, B, and C (RVA, RVB, and RVC, respectively) are associated with diarrhea in piglets. Although discovered decades ago, porcine genogroup E RVs (RVE) are uncommon and their pathogenesis is not studied well. The presence of porcine RV H (RVH), a newly defined distinct genogroup, was recently confirmed in diarrheic pigs in Japan, Brazil, and the US. The complex epidemiology, pathogenicity and high genetic diversity of porcine RVAs are widely recognized and well-studied. More recent data show a significant genetic diversity based on the VP7 gene analysis of RVB and C strains in pigs. In this review, we will summarize previous and recent research to provide insights on historic and current prevalence and genetic diversity of porcine RVs in different geographic regions and production systems. We will also provide a brief overview of immune responses to porcine RVs, available control strategies and zoonotic potential of different RV genotypes. An improved understanding of the above parameters may lead to the development of more optimal strategies to manage RV diarrheal disease in swine and humans.