Genetic characterization of a rare bovine-like human VP4 mono-reassortant G6P[8] rotavirus strain detected from an infant in Bangladesh

Genetic diversity of rotavirus A in Argentina during 2019-2022: detection of G6 strains and insights regarding its dissemination

One of the challenges associated with introducing a vaccine is monitoring its impact through clinical and molecular surveillance. The aims of this study were to analyze the genetic diversity of rotavirus A in Argentina between 2019 and 2022 and to assess the phylogenetic and phylodynamic features of the unusual G6 strains detected. A significant decline in the Wa-like genogroup strains was observed, and G6 strains were detected for the first time in Argentina, in association with P[8] and P[9]. Spatiotemporal analysis showed that the G6-lineage I strains detected recently in Argentina and Brazil might have emerged from European strains. This study provides recent evidence of the genetic diversity of rotaviruses in isolated cases. It is considered important to support continuous surveillance of rotavirus in the post-vaccine scenario, mainly to evaluate potential changes that may occur after the COVID-19 pandemic.

Rotavirus A during the COVID-19 Pandemic in Brazil, 2020-2022: Emergence of G6P[8] Genotype

Rotavirus A (RVA) remains a leading cause of acute gastroenteritis (AGE) hospitalizations in children worldwide. During the COVID-19 pandemic, a reduction in vaccination coverage in Brazil and elsewhere was observed, and some reports have demonstrated a reduction in AGE notifications during the pandemic. This study aims to investigate the diversity and prevalence of RVA genotypes in children and adults presenting with AGE symptoms in Brazil during the COVID-19 pandemic between 2020 and 2022. RVA was screened using RT-qPCR; then, G and P genotypes were characterized using one-step multiplex RT-PCR. A total of 2173 samples were investigated over the three-year period, and we detected RVA in 7.7% of samples (n = 167), being 15.5% in 2020, 0.5% in 2021, and 13.8% in 2022. Higher RVA prevalence was observed in the Northeastern region (19.3%) compared to the Southeastern (6.1%) and Southern regions (5.5%). The most affected age group was children aged between 0 and 6 months old; however, this was not statistically significant. Genotyping and phylogenetic analysis identified the emergence of G6P[8] during the period; moreover, it was detected in 10.6% of samples in 2020 and in 83.5% in 2022. In contrast, the prevalence of G3P[8], the previous dominant genotype, decreased from 72.3% in 2020 to 11.3% in 2022. We also identified unusual strains, such as G3P[9] and G9P[4], being sporadically detected during the period. This is the first report on the molecular epidemiology and surveillance of RVA during the COVID-19 pandemic period in Brazil. Our study provides evidence for the importance of maintaining high and sustainable levels of vaccine coverage to protect against RVA disease. Furthermore, it highlights the need to maintain nationwide surveillance in order to monitor future trends and changes in the epidemiology of RVA in Brazil.

Full genotype constellations analysis of unusual DS-1-like G12P[6] and G6P[8] rotavirus strains detected in Brazil, 2019

Rotavirus A (RVA) is a major cause of acute gastroenteritis (AGE) in children worldwide. We report unusual RVA G12P[6] and G6P[8] strains isolated from fecal samples from Brazilian children hospitalized for AGE. The characterized RVA have genome segments backbone: G12-P[6]/ G6-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 of DS-1-like genogroup. Our study describes the first identification of G6P[8], a DS-1-like genogroup strain. Nucleotide analysis of VP7 and VP4 genes revealed that all G12 Brazilian strains clustered into the sub-lineages IIIB, mostly associated with P[6] lineage I. Additionally, our G6 lineage I strains were closely related to German G6 genotypes, bound with P[8] lineage III, differing from both vaccine strains. The comparative sequence analysis of our strains with vaccine strains revealed amino acid substitutions located in immunodominant regions of VP7 and VP4 proteins. Continuous monitoring of RVA genotypes is essential to evaluate the impact of vaccination on the dynamic nature of RVA evolution.

Major zoonotic diseases of public health importance in Bangladesh

Zoonotic diseases cause repeated outbreaks in humans globally. The majority of emerging infections in humans are zoonotic. COVID‐19 is an ideal example of a recently identified emerging zoonotic disease, causing a global pandemic. Anthropogenic factors such as modernisation of agriculture and livestock farming, wildlife hunting, the destruction of wild animal habitats, mixing wild and domestic animals, wildlife trading, changing food habits and urbanisation could drive the emergence of zoonotic diseases in humans. Since 2001, Bangladesh has been reporting many emerging zoonotic disease outbreaks such as nipah, highly pathogenic avian influenza, pandemic H1N1, and COVID‐19. There are many other potential zoonotic pathogens such as Ebola, Middle East respiratory syndrome coronavirus, Kyasanur forest disease virus and Crimean–Congo haemorrhagic fever that may emerge in the future. However, we have a limited understanding of zoonotic diseases’ overall risk in humans and associated factors that drive the emergence of zoonotic pathogens. This narrative review summarised the major emerging, re‐emerging, neglected and other potential zoonotic diseases in Bangladesh and their associated risk factors. Nipah virus and Bacillus anthracis caused repeated outbreaks in humans. More than 300 human cases with Nipah virus infection were reported since the first outbreak in 2001. The highly pathogenic avian influenza virus (H5N1) caused more than 550 outbreaks in poultry, and eight human cases were reported so far since 2007. People of Bangladesh are frequently exposed to zoonotic pathogens due to close interaction with domestic and peri‐domestic animals. The rapidly changing intensified animal–human–ecosystem interfaces and risky practices increase the risk of zoonotic disease transmission. The narrative review's findings are useful to draw attention to the risk and emergence of zoonotic diseases to public health policymakers in Bangladesh and the application of one‐health approach to address this public health threat.

Phylogenetic analysis of open reading frame of 11 gene segments of novel human-bovine reassortant RVA G6P[1] strain in Pakistan

Multiple Rotavirus A (RVA) strains are linked with gastrointestinal infections in children that fall in age bracket of 0 to 60 months. However, the problem is augmented with emergence of unique strains that reassort with RVA strains of animal origin. The study describes the sequence analysis of a rare G6P[1] rotavirus strain isolated from a less than 1 year old child, during rotavirus surveillance in Rawalpindi district, Pakistan in 2010. Extracted RNA from fecal specimen was subjected to high throughput RT-PCR for structural and nonstructural gene segments. The complete rotavirus genome of one isolate RVA/Human-wt/PAK/PAK99/2010/G6P[1] was sequenced for phylogenetic analysis to elucidate the evolutionary linkages and origin. Full genome examination of novel strain RVA/Human-wt/PAK/PAK99/2010/G6P[1] revealed the unique genotype assemblage: G6-P[1]-I2-R2-C2-M2-A3-N2-T6-E2-H1. The evolutionary analyses of VP7, VP4, NSP1 and NSP3 gene segments revealed that PAK99 clustered with bovine, or cattle-like rotavirus strains from other closely related species, in the genotypes G6, P[1], A3 and T6 respectively. Gene segments VP6, VP1, VP2, VP3, NSP2 and NSP4 all possessed the DS-1-like bovine genotype 2 and bovine (-like) RVA strains instead of RVA strains having human origin. However, the NSP5 gene was found to cluster closely with contemporary human Wa-like rotavirus strains of H1 genotype. This is the first report on bovine-human (Wa-like reassortant) genotype constellation of G6P[1] strain from a human case in Pakistan (and the second description worldwide). Our results emphasize the significance of incessant monitoring of circulating RVA strains in humans and animals for better understanding of RV evolution.

Detection and molecular characterization of rotavirus of pigs in Kerala, India

Group A rotaviruses (GAR) are an important cause of diarrhoea in infants and newborn animals especially pigs. In this paper, we report the detection, G and P typing and phylogenetic analysis of GAR of pigs in Kerala. A total of 100 fecal samples from diarrhoeic piglets were collected from organized farms in Wayanad, Ernakulam, Thrissur, and Palakkad districts of Kerala. The samples were tested for the presence of GAR employing reverse transcriptase polymerase chain reaction (RT-PCR) targeting VP6 gene. Positive samples were tested by G and P genotyping primers and representative amplicons were sequenced. Of the 100 samples, 12 were positive for GAR. The G and P types detected were G2, G4, G5, G6, G9, P[6] and P[19]. An untypable P type (P21-5 like) was also detected. In some of the samples more than one G type was detected. The nucleotide sequences of G2, G4 and G5 types were similar to those seen in pigs and that of G6 was similar to bovine sequences. G9, P[6] and P[19] sequences showed similarity to human rotavirus sequences. The findings of this study provide the first information on the G and P genotypes of GAR of pigs in Kerala.

Epidemiology and genotypes of group A rotaviruses in cattle and goats of Bangladesh, 2009-2010

Group A rotavirus (RVA) is recognized as a major cause of severe gastroenteritis in newborn calves and goat kids. We estimated the proportion of ruminants infected with rotavirus and identified the circulating genotypes in cattle and goats in Bangladesh. Between May 2009 and August 2010, fecal samples were collected from 520 cattle and goats presenting with diarrhea at three government veterinary hospitals in three districts of Bangladesh. All samples were screened for RVA RNA using real-time, one-step, reverse transcription polymerase chain reaction (qRT-PCR). Of the 520 animals tested, 11.7% (61) were positive for RVA RNA, with 6.2% (15/241) and 16.5% (46/279) positivity in cattle and goats, respectively. RVA positive samples were further characterized by nucleotide sequence analysis of two structural protein gene fragments, VP7 (G genotype), and VP4 (P genotype). Among 17 successfully sequenced strains, G8 (17.9%) was the most prevalent G-genotype followed by G10 (8%) and G6 (1.6%). P[1] (11.3%) was the most frequently detected P-genotype followed by P[11] (3.2%) and P[15] (1.6%). The most common VP7/VP4 combinations for cattle were G10P[11], G10P[15], and G6P[11], and for goat, G8P[1], and G10P[1]. Phylogenetic analysis of the RVA strains showed clustering with bovine and caprine strains from neighboring India. The study adds to our understanding of the genetic diversity of bovine and caprine rotavirus strains in Bangladesh. Our findings highlight the importance of rotavirus surveillance in cattle and goat populations, which may serve as a potential source for genetic reassortment and zoonotic transmission.

Rotavirus Burden, Genetic Diversity and Impact of Vaccine in Children under Five in Tanzania

In Tanzania, rotavirus infections are responsible for 72% of diarrhea deaths in children under five. The Rotarix vaccine was introduced in early 2013 to mitigate rotavirus infections. Understanding the disease burden and virus genotype trends over time is important for assessing the impact of rotavirus vaccine in Tanzania. When assessing the data for this review, we found that deaths of children under five declined after vaccine introduction, from 8171/11,391 (72% of diarrhea deaths) in 2008 to 2552/7087 (36% of diarrhea deaths) in 2013. Prior to vaccination, the prevalence of rotavirus infections in children under five was 18.1–43.4%, 9.8–51%, and 29–41% in Dar es Salaam, Mwanza and Tanga, respectively, and after the introduction of vaccines, these percentages declined to 17.4–23.5%, 16–19%, and 10–29%, respectively. Rotaviruses in Tanzania are highly diverse, and include genotypes of animal origin in children under five. Of the genotypes, 10%, 28%, and 7% of the strains are untypable in Dar es Salaam, Tanga, and Zanzibar, respectively. Mixed rotavirus genotype infection accounts for 31%, 29%, and 12% of genotypes in Mwanza, Tanga and Zanzibar, respectively. The vaccine effectiveness ranges between 53% and 75% in Mwanza, Manyara and Zanzibar. Rotavirus vaccination has successfully reduced the rotavirus burden in Tanzania; however, further studies are needed to better understand the relationship between the wildtype strain and the vaccine strain as well as the zoonotic potential of rotavirus in the post-vaccine era.

Distribution of rotavirus genotypes in three Croatian regions among children ≤5 years of age (2012-2014)

OBJECTIVES

Rotavirus is the major cause of severe diarrhea in young children worldwide. In countries like Croatia, where rotavirus vaccine has not been introduced in the national immunization program, prospective surveillance is necessary to establish the diversity of rotavirus strains. The aim of this study was to describe the prevalence and geographical distribution of rotavirus strains in Croatia and to detect the possible emergence of novel strains.

METHODS

The study was conducted among children ≤5 years of age with acute gastroenteritis at three hospitals located in different geographical regions of Croatia, during the years 2012 to 2014. Rotavirus was detected in stools using an immunochromatographic assay and then sent for further molecular analysis.

RESULTS

Genotyping of 822 rotaviruses showed that the predominant circulating strain was G1P[8] (61.9%), followed by G2P[4] (19.5%), G1P[4] (3.9%), and G3P[8] (2.9%). A high prevalence of reassortants among common human rotavirus genotypes was detected (7.7%). Possible zoonotic reassortants were found, including G8 and G6 strains. The latter is described for the first time in Croatia.

CONCLUSIONS

This study represents pre-vaccination data that are important for decisions regarding immunization strategies in Croatia. The high prevalence of 'common' rotavirus strains circulating in Croatia may advocate for rotavirus vaccine introduction, but further surveillance is necessary to monitor the possible emergence of novel genotypes.

Post-vaccinated asymptomatic rotavirus infections: A community profile study of children in Surabaya, Indonesia

BACKGROUND

Rotavirus gastroenteritis accounts for significant childhood morbidity and mortality worldwide. Vaccination using RotarixTM (GSK) and RotaTeq^® (Merck) was introduced due to the tremendous disease burden. The possibility of asymptomatic infections following vaccinations was poorly understood. This study examined rotavirus cases in post-vaccinated children, their clinical manifestations and the genotypes of isolated strains.

METHODS

Stool samples of healthy, vaccinated children under 5 years of age in Surabaya were collected monthly for 1 year between January 2016 and February 2017. Episodes of gastroenteritis were reported, and samples were collected. Rotavirus was identified using multiplex reverse transcription Polymerase Chain Reaction (QIAGEN, Inc., Valencia, CA). Clinical manifestations were measured using the Vesikari score. The genotype was analyzed by Applied Biosystems (Foster, CA).

RESULTS

A total of 109 stool samples were collected from 30 subjects, of which 22 received Rotarix; 8 RotaTeq. Nine out of 109 samples were collected during diarrhea episodes of 8 subjects. Two asymptomatic rotavirus infections were identified by RT-PCR. The genotypes isolated were G1P[8] and G3P[8].

CONCLUSIONS

Asymptomatic rotavirus infections can occur in post-vaccinated children. Strains identified were homologous to serotypes eliciting gastroenteritis in unvaccinated children of the same community.

Rotavirus genotypes in children with gastroenteritis in Erzurum: first detection of G12P[6] and G12P[8] genotypes in Turkey

Introduction

Rotavirus is one of the leading pathogens which cause acute gastroenteritis in children and is responsible for a substantial proportion of childhood deaths worldwide.

Aim

To determine the group A rotavirus (RVA) prevalence and genotypes of circulating RVA strains in 0–5-year-old children with complaints of vomiting and diarrhoea in Eastern Anatolia in Turkey.

Material and methods

RNA extracted from stool specimens of 329 children aged 0–5 years with acute diarrhoea was subjected to reverse transcription polymerase reaction (RT-PCR) and multiplex-nested PCR. The genotypes were identified based on the expected size of the amplicon, which was amplified with a genotype-specific primer.

Results

Out of 329 stool samples analyzed, 109 (33.1%) were positive for RVA. G1P[8] was the dominant genotype combination (42.2%), followed by G9P[8] (21.1%) and G12P[6] (11.0%). Mixed infections were identified in 5 cases: G3,9 in 2 cases, G1,9 in 1 case, P[4,8] in 1 case, and P[6,8] in 1 case. The P genotype could not be typed in two patients.

Conclusions

In the study, we detected six different rotavirus G genotypes, 3 different P genotypes, 11 different G-P combinations and 5 different mixed genotypes combinations. G1, G9, G12 and P[8] were found to be the predominant genotypes. G12P[6] and G12P[8] genotypes, showing an increase as new rotavirus genotypes in the world, are reported for the first time for our regions. We determined the dominant genotypes, mixed genotypes and unconventional genotypes of rotavirus in our region.

Human fecal and pathogen exposure pathways in rural Indian villages and the effect of increased latrine coverage

Efforts to eradicate open defecation and improve sanitation access are unlikely to achieve health benefits unless interventions reduce microbial exposures. This study assessed human fecal contamination and pathogen exposures in rural India, and the effect of increased sanitation coverage on contamination and exposure rates. In a cross-sectional study of 60 villages of a cluster-randomized controlled sanitation trial in Odisha, India, human and domestic animal fecal contamination was measured in community tubewells and ponds (n = 301) and via exposure pathways in homes (n = 354), using Bacteroidales microbial source tracking fecal markers validated in India. Community water sources were further tested for diarrheal pathogens (rotavirus, adenovirus and Vibrio cholerae by quantitative PCR; pathogenic Escherichia coli by multiplex PCR; Cryptosporidium and Giardia by immunomagnetic separation and direct fluorescent antibody microscopy). Exposure pathways in intervention and control villages were compared and relationships with child diarrhea examined. Human fecal markers were rarely detected in tubewells (2.4%, 95%CI: 0.3-4.5%) and ponds (5.6%, 95%CI: 0.8-10.3%), compared to homes (35.4%, 95%CI: 30.4-40.4%). In tubewells, V. cholerae was the most frequently detected pathogen (19.8%, 95%CI: 14.4-25.2%), followed by Giardia (14.8%, 95%CI: 10.0-19.7%). In ponds, Giardia was most often detected (74.5%, 95%CI: 65.7-83.3%), followed by pathogenic E. coli (48.1%, 95%CI: 34.8-61.5%) and rotavirus (44.4%, 95%CI: 34.2-54.7%). At village-level, prevalence of fecal pathogen detection in community drinking water sources was associated with elevated prevalence of child diarrhea within 6 weeks of testing (RR 2.13, 95%CI: 1.25-3.63) while within homes, higher levels of human and animal fecal marker detection were associated with increased risks of subsequent child diarrhea (P = 0.044 and 0.013, respectively). There was no evidence that the intervention, which increased functional latrine coverage and use by 27 percentage points, reduced human fecal contamination in any tested pathway, nor the prevalence of pathogens in water sources. In conclusion, the study demonstrates that (1) improved sanitation alone may be insufficient and further interventions needed in the domestic domain to reduce widespread human and animal fecal contamination observed in homes, (2) pathogens detected in tubewells indicate these sources are microbiologically unsafe for drinking and were associated with child diarrhea, (3) domestic use of ponds heavily contaminated with multiple pathogens presents an under-recognized health risk, and (4) a 27 percentage point increase in improved sanitation access at village-level did not reduce detectable human fecal and pathogen contamination in this setting.

Complete genotyping of unusual species A rotavirus G12P[11] and G10P[14] isolates and evidence of frequent in vivo reassortment among the rotaviruses detected in children with diarrhea in Kolkata, India, during 2014

Species A rotaviruses (RVA) are the most important cause of acute gastroenteritis in the young of humans and many animal species globally. G1P[8], G2P[4], G3P[8], G4P[8], G9P[6/8] and G12P[6/8] are the predominantly isolated genotypes throughout the world including India. Unusual genotypes from different host species such as G5, G6, G8, G10 and G11 have also been reported in humans with low frequency. In the present study, among >650 RVA positive stool samples collected from children with diarrhea in Kolkata, India, during 2014, two isolates each of the genotype G12P[11] and G10P[14] were obtained and their genomes completely sequenced. The full genotype constellations were G12-P[11]-I1-R1-C1-M2-A1-N1-T2-E1-H1 and G12-P[11]-I1-R1-C1-M1-A5-N1-T1-E1-H1 for G12P[11] viruses, suggesting several reassortments between Wa- and DS-1-like human RVA strains, including possible reassortment of a simian NSP1 gene. The G10P[14] viruses (G10-P[14]-I2-R2-C2-M2-A11-N2-T6-E2-H3) were found to contain multiple genes closely related to RVAs of artiodactyl origin, highlighting the role of inter-host species transmissions of RVAs. From the G/P constellation of all RVA isolates, it could be concluded that approximately one quarter had likely arisen from reassortment events in vivo among RVAs of 'usual' genotypes.

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.

Molecular epidemiology of rotavirus in cats in the United Kingdom

Rotaviruses are leading causes of gastroenteritis in the young of many species. Molecular epidemiological studies in children suggest that interspecies transmission contributes to rotavirus strain diversity in people. However, population-based studies of rotaviruses in animals are few. We investigated the prevalence, risk factors for infection, and genetic diversity of rotavirus A in a cross-sectional survey of cats housed within 25 rescue catteries across the United Kingdom. Morning litter tray fecal samples were collected during the winter and summer in 2012 from all pens containing kittens and a random sample of those housing adult cats. Group A rotavirus RNA was detected by real-time reverse transcription-PCR, and positive samples were G and P genotyped using nested VP4 and VP7 PCR assays. A total of 1,727 fecal samples were collected from 1,105 pens. Overall, the prevalence of rotavirus was 3.0% (95% confidence interval [CI], 1.2 to 4.9%). Thirteen out of 25 (52%; 95% CI, 31.3 to 72.2%) centers housed at least one rotavirus-positive cat. The prevalence of rotavirus was associated with season (odds ratio, 14.8 [95% CI, 1.1 to 200.4]; P = 0.04) but not age or diarrhea. It was higher during the summer (4.7%; 95% CI, 1.2 to 8.3%) than in winter (0.8%; 95% CI, 0.2 to 1.5%). Asymptomatic epidemics of infection were detected in two centers. G genotypes were characterized for 19 (33.3%) of the 57 rotavirus-positive samples and P genotypes for 36 (59.7%). Two rotavirus genotypes were identified, G3P[9] and G6P[9]. This is the first population-based study of rotavirus in cats and the first report of feline G6P[9], which questions the previous belief that G6P[9] in people is of bovine origin.

Metagenomic identification of novel enteric viruses in urban wild rats and genome characterization of a group A rotavirus

Rats are known as reservoirs and vectors for several zoonotic pathogens. However, information on the viruses shed by urban wild rats that could pose a zoonotic risk to human health is scare. Here, intestinal contents from 20 wild Norway rats (Rattus norvegicus) collected in the city of Berlin, Germany, were subjected to metagenomic analysis of viral nucleic acids. The determined faecal viromes of rats consisted of a variety of known and unknown viruses, and were highly variable among the individuals. Members of the families Parvoviridae and Picobirnaviridae represented the most abundant species. Novel picornaviruses, bocaviruses, sapoviruses and stool-associated circular ssDNA viruses were identified, which showed only low sequence identity to known representatives of the corresponding taxa. In addition, noroviruses and rotaviruses were detected as potential zoonotic gastroenteritis viruses. However, partial-genome sequence analyses indicated that the norovirus was closely related to the recently identified rat norovirus and the rotavirus B was closely related to the rat rotavirus strain IDIR; both viruses clustered separately from respective human virus strains in phylogenetic trees. In contrast, the rotavirus A sequences showed high identity to human and animal strains. Analysis of the nearly complete genome of this virus revealed the known genotypes G3, P[3] and N2 for three of the genome segments, whereas the remaining eight genome segments represented the novel genotypes I20-R11-C11-M10-A22-T14-E18-H13. Our results indicated a high heterogeneity of enteric viruses present in urban wild rats; their ability to be transmitted to humans remains to be assessed in the future.

Sunlight-induced inactivation of human Wa and porcine OSU rotaviruses in the presence of exogenous photosensitizers

Human rotavirus Wa and porcine rotavirus OSU solutions were irradiated with simulated solar UV and visible light in the presence of different photosensitizers dissolved in buffered solutions. For human rotavirus, the exogenous effects were greater than the endogenous effects under irradiation with full spectrum and UVA and visible light at 25 °C. For porcine rotavirus, the exogenous effects with UVA and visible light irradiation were only observed at high temperatures, >40 °C. The results from dark experiments conducted at different temperatures suggest that porcine rotavirus has higher thermostability than human rotavirus. Concentrations of 3'-MAP excited triplet states of 1.8 fM and above resulted in significant human rotavirus inactivation. The measured excited triplet state concentrations of ≤0.45 fM produced by UVA and visible light irradiation of natural dissolved organic matter solutions were likely not directly responsible for rotavirus inactivation. Instead, the linear correlation for human rotavirus inactivation rate constant (kobs) with the phenol degradation rate constant (kexp) found in both 1 mM NaHCO3 and 1 mM phosphate-buffered solutions suggested that OH radical was a major reactive species for the exogenous inactivation of rotaviruses. Linear correlations between rotavirus kobs and specific UV254 nm absorbance of two river-dissolved organic matter and two effluent organic matter isolates indicated that organic matter aromaticity may help predict formation of radicals responsible for rotavirus inactivation. The results from this study also suggested that the differences in rotavirus strains should be considered when predicting solar inactivation of rotavirus in sunlit surface waters.