Molecular characterization of novel G5 bovine rotavirus strains

Ammi-visnaga extract; a novel phyto-antiviral agent against bovine rotavirus

The spread of bovine rotavirus has a great impact on animal productivity, milk products, and human public health. Thus, this study aimed to develop a novel, effective and accessible Phyto-antiviral treatment made from methanolic Ammi-visnaga seed extract against rotavirus infection. Rotaviruses were isolated from raw milk and cottage cheese samples randomly collected from Cairo and Qalubia governorates. They were all identified serologically, however, only three of them were both biologically and molecularly confirmed. The methanolic extract derived from Khella seeds (MKSE) was chemically analyzed with mass chromatography. The cellular toxicity of MKSE was tested on Caco-2 cells and its antiviral activity against one of the isolated bovine rotaviruses (BRVM1) was tested by both the cytopathic inhibition assay and the plaque reduction assay. Our results showed that 17.3% of the total collected 150 dairy samples were bovine rotavirus antigen positive. Three representatives of them were phylogenetically identified to be included in group A based on a 379 bp coat protein gene. Visnagin, Benzopyran, Khellin, and Benzenepropanoic acid were the major active components found in the MKSE. The maximum non-toxic concentration of MKSE was 5 µg/mL and the CC50 value was 417 µg/mL. The MKSE exhibited in-vitro antiviral activity against BRVM1 indicated by inhibition of the viral cytopathic effect (SI = 204.5, IP = 98%), causing a 1.5 log decrease in BVRM1 TCID50 and reducing the viral plaques count by the percentage of 93.14% at MNTC (5 ug/ml). In conclusion, our study showed that bovine rotavirus represents a severe health problem that needs attention in Egypt, and it supports using MKSE as a potential natural anti-rotavirus agent.

Genetic Diversity of Bovine Group A Rotavirus Strains Circulating in Korean Calves during 2014 and 2018

The purpose of this study was to investigate annual changes in BoRVA strains by examining the VP4 and VP7 genes of rotaviruses in Korean calves. Between 2014 and 2018, 35 out of 138 samples of calf diarrhea feces collected nationwide were positive for BoRVA. Further genetic characterization of the VP7 and VP4 genes of 35 BoRVA isolates identified three different G-genotypes (G6, G8, and G10) and two different P genotypes (P[5] and P[11]). The G6 genotype was most common (94.3%) in BoRVA-positive calves, followed by the P[5] genotype (82.9%). Four genotypes comprised combinations of VP4 and VP7: 80% were G6P[5], 14.2% were G6P[11], 2.9% were G8P[5], and 2.9% were G10P[11]. Susceptibility to infection was highest in calves aged < 10 days (35%) and lowest in calves aged 30−50 days (15.4%). The data presented herein suggest that the G6P[5] genotype is the main causative agent of diarrhea in Korean calves. In addition, it is predicted that G6P[5] will continue to act as a major cause of diarrhea in Korean calves.

Zoonotic RVA: State of the Art and Distribution in the Animal World

Rotavirus species A (RVA) is a pathogen mainly affecting children under five years old and young animals. The infection produces acute diarrhea in its hosts and, in intensively reared livestock animals, can cause severe economic losses. In this study, we analyzed all RVA genomic constellations described in animal hosts. This review included animal RVA strains in humans. We compiled detection methods, hosts, genotypes and complete genomes. RVA was described in 86 animal species, with 52% (45/86) described by serology, microscopy or the hybridization method; however, strain sequences were not described. All of these reports were carried out between 1980 and 1990. In 48% (41/86) of them, 9251 strain sequences were reported, with 28% being porcine, 27% bovine, 12% equine and 33% from several other animal species. Genomic constellations were performed in 80% (32/40) of hosts. Typical constellation patterns were observed in groups such as birds, domestic animals and artiodactyls. The analysis of the constellations showed RVA's capacity to infect a broad range of species, because there are RVA genotypes (even entire constellations) from animal species which were described in other studies. This suggests that this virus could generate highly virulent variants through gene reassortments and that these strains could be transmitted to humans as a zoonotic disease, making future surveillance necessary for the prevention of future outbreaks.

Molecular surveillance of rotavirus A associated with diarrheic calves from the Republic of Korea and full genomic characterization of bovine-porcine reassortant G5P[7] strain

Group A rotavirus (RVA) is the most common diarrhea-causing pathogen among humans and animals worldwide. Rotavirus infection in neonatal calves causes major problems in the livestock industry. This study aimed to determine the prevalence and genetic diversity of bovine rotavirus (BoRVA) infections in calves with diarrhea and to perform whole genome analysis of an unusual strain, designated as RVA/Calf-wt/KOR/KNU-GJ2/2020/G5P[7], that was detected in a 2-day-old diarrheic calf. From 459 diarrheic calves aged 1-40 days, fecal samples were collected and BoRVA infections were screened using real-time RT-PCR targeting VP6 gene. BoRVA was detected in 195 (42.4%) samples and was most prevalent in calves aged 1-10 days (47.2%). No significant difference in the BoRVA infection rate was observed between calves born in herds that were (42.1%) and were not (42.6%) vaccinated against BoRVA. A binomial regression analysis revealed that calves aged 1-10 days (95% confidence intervals [CI]:1.18-24.34; P = 0.000) and 11-20 days (95% CI: 0.76-16.83, P = 0.000) had a 5.37- and 3.58-fold higher BoRVA prevalence in comparison to those aged 31-40 days, respectively. The RVA-positive samples were subsequently subjected to amplification of the VP7 and VP4 genes for determining G and P genotypes. Overall, 45 (23.1%, 45/195) and 63 (32.3, 63/195) sequences for VP7 and VP4 were obtained. In this study, four G and three P genotypes were identified. G6 (86.7%) was the most prevalent genotype, followed by G8 (8.9%), G10 (2.2%), and G5 (2.2%). P[5] (92.1%) was the most frequently detected, followed by P[11] (6.3%), and P[7] (1.6%). The G6P[5] (82.2%) is the most common combination found in Korean native calves with diarrhea, whereas G6P[11] (4.4%) and G10P[11] (2.2%) had relatively low prevalence. G8P[5] (8.9%) was identified for the first time in diarrheic calves in the KOR. The uncommon strain KNU-GJ2 exhibited a G5-P[7]-I5-R1-C1-M2-A1-N1-T1-E1-H1 genotype constellation possessing a typical porcine RVA backbone, with the exception of the VP3 gene, which is derived from bovine. Phylogenetically, except for VP3, ten gene segments of KNU-GJ2 were closely related to porcine, porcine-like, and reassortant bovine strains. Interestingly, the VP3-M2 gene of KNU-GJ2 clustered with bovine-like strains as well as reassortant porcine and bovine strains. Comparison of the NSP4s within a species-specific region of amino acids 131-141 demonstrated that KNU-GJ2 belonged to genotype B with porcine RVAs; however, it differed from porcine RVAs by one to three amino acids. The present study is fundamental to understanding the epidemiology and genotypes of circulating RVAs throughout the KOR and underscoring the importance of continuous monitoring and molecular characterization of RVAs circulating within animal populations for future vaccine development.

Isolation and Characterization of Bovine RVA from Northeast China, 2017-2020

Group A rotaviruses (RVAs) are major enteric pathogens causing infections in calves. To investigate the epidemiological characteristics and genetic diversity of bovine rotavirus (BRV), 233 fecal samples were collected from calves with diarrhea in northeast China. The samples were analyzed for sequences encoding the inner capsid protein VP6 (subgroup) and the outer capsid proteins VP7 and VP4 (G and P type, respectively) using RT-PCR. Ten of the 233 samples (4.3%) were identified as BRV positive and were used for virus isolation and sequence analysis, revealing that all strains analyzed were of the G6P[1] genotype. The isolates exhibited high VP6 sequence identity to the USA cow RVA NCDV strain (>99% amino acid identity) and were further shown to be closely related to Japanese cow RVA BRV101 and Israelian human RVA G6P[1] strains, with >99% amino acid identity to VP7 and VP4 proteins, respectively. Comparative analyses of genome-predicted amino acid sequences between the isolates and the NCDV strains indicated that the antigenicity and infectivity of the strains isolated had changed. In this study, BRV genotypes and the genetic diversity among vaccinated cattle herds were monitored to provide epidemiological data and references for early diagnosis, allowing for early detection of new, potentially pathogenic RVA strains.

Opposite effects of apoptotic and necroptotic cellular pathways on rotavirus replication

Group A rotavirus (RVA), one of the leading pathogens causing severe acute gastroenteritis in children and a wide variety of young animals worldwide, induces apoptosis upon infecting cells. Though RVA-induced apoptosis mediated via the dual modulation of its NSP4 and NSP1 proteins is relatively well studied, the nature and signaling pathway(s) involved in RVA-induced necroptosis are yet to be fully elucidated. Here, we demonstrate the nature of RVA-induced necroptosis, the signaling cascade involved, and correlation with RVA-induced apoptosis. Infection with the bovine NCDV and human DS-1 RV strains was shown to activate receptor-interacting protein kinase 1 (RIPK1)/RIPK3/mixed lineage kinase domain-like protein (MLKL), the key necroptosis molecules in virus-infected cells. Using immunoprecipitation assay, RIPK1 was found to bind phosphorylated RIPK3 (pRIPK3) and pMLKL. pMLKL, the major executioner molecule in the necroptotic pathway, was translocated to the plasma membrane of RVA-infected cells to puncture the cell membrane. Interestingly, transfection of RVA NSP4 also induced necroptosis through the RIPK1/RIPK3/MLKL necroptosis pathway. Blockage of each key necroptosis molecule in the RVA-infected or NSP4-transfected cells resulted in decreased necroptosis but increased cell viability and apoptosis, thereby resulting in decreased viral yields in the RVA-infected cells. In contrast, suppression of RVA-induced apoptosis increased necroptosis and virus yields. Our findings suggest that RVA NSP4 also induces necroptosis via the RIPK1/RIPK3/MLKL necroptosis pathway. Moreover, necroptosis and apoptosis-which have proviral and antiviral effects, respectively-exhibited a crosstalk in RVA-infected cells. These findings significantly increase our understanding of the nature of RVA-induced necroptosis and the crosstalk between RVA-induced necroptosis and apoptosis. IMPORTANCE Viral infection usually culminates in cell death through apoptosis, necroptosis, and rarely, pyroptosis. Necroptosis is a form of programmed necrosis that is mediated by signaling complexes of the receptor-interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like protein (MLKL). Although apoptosis induction by rotavirus and its NSP4 protein is well known, rotavirus-induced necroptosis is not fully understood. Here, we demonstrate that rotavirus and also its NSP4 protein can induce necroptosis in cultured cells through the activation of the RIPK1/RIPK3/MLKL necroptosis pathway. Moreover, rotavirus-induced necroptosis and apoptosis have opposite effects on viral yield, i.e., they function as proviral and antiviral processes, respectively, and counterbalance each other in rotavirus-infected cells. Our findings provide important insights for understanding the nature of rotavirus-induced necroptosis and the development of novel therapeutic strategies against infection with rotavirus and other RNA viruses.

Isolation and Characterization of Coronavirus and Rotavirus Associated with Calves in Central Part of Oromia, Ethiopia

BACKGROUND

Coronavirus and rotavirus are most commonly associated etiologies for calves' diarrhoea, resulting in loss of productivity and economy of farmers. However, various facets of diarrheal disease caused by coronavirus and rotavirus in calves in Ethiopia are inadequately understood. A cross-sectional study was conducted with the aim of isolation and molecular characterization of coronavirus and rotavirus from calves in the central part of Oromia (Bishoftu, Sebata, Holeta, and Addis Ababa), Ethiopia, from November 2018 to May 2019. The four study areas were purposively selected and faecal samples were collected by simple random sampling for diagnosis of coronavirus and rotavirus infection by using the antigen detection enzyme-linked immunosorbent assay (Ag-ELISA) kit. In addition, this study was carried out to have insight in prevalence and associated risk factors of coronavirus and rotavirus infection in calves.

RESULT

During the study, 83 diarrheic and 162 nondiarrheic faecal samples collected from calves less than 4 weeks of age were screened for coronavirus and rotavirus. Of the 83 diarrheic samples, 1 sample (1.2%) was positive for coronavirus antigen and 6 samples (7.2%) were found to be positive for rotavirus antigen by Ag-ELISA. All the nondiarrheic samples were negative for both coronavirus and rotavirus Ag. The overall prevalence of coronavirus and rotavirus infection in calves was estimated at 0.4% (1/245) and 2.45% (6/245), respectively. All samples (7) of ELISA test positive of both coronavirus and rotavirus were propagated in Madin-Darby bovine kidney (MDBK) cells. After 3 subsequent passages, progressive cytopathic effect (CPE), i.e., rounding, detachment, and the destruction of monolayer cell of five samples (1 sample of coronavirus and 4 samples of rotavirus) (71.4%) were observed. At the molecular stage, reverse transcriptase polymerase chain reaction (RT-PCR) technique was used to determine the presence of coronavirus and rotavirus nucleic acid by using specific primers. The 5 samples that were coronavirus and rotavirus antigen positive by ELISA and develop CPE on cell culture were also positive on RT-PCR technique. The prevalence of infection peaked at 1st and 2nd weeks of age in male calves.

CONCLUSION

Diarrheal disease caused by coronavirus and rotavirus has a great health problem in calves that interrupts production benefits with reduced weight gain and increased mortality and its potential for zoonotic spread. So, the present findings show coronavirus and rotavirus infection in calves in Ethiopia that needs to be addressed by practising early colostrum feeding in newborn calves, using vaccine, or improving livestock management.

Development of a live attenuated trivalent porcine rotavirus A vaccine against disease caused by recent strains most prevalent in South Korea

Porcine rotaviruses cause severe economic losses in the Korean swine industry due to G- and P-genotype mismatches between the predominant field and vaccine strains. Here, we developed a live attenuated trivalent porcine group A rotavirus vaccine using 80 cell culture passages of the representative Korean predominant strains G8P[7] 174-1, G9P[23] PRG942, and G5P[7] K71. Vaccination with the trivalent vaccine or its individual components induced no diarrhea during the first 2 weeks post-vaccination, i.e., the vaccines were attenuated. Challenge of trivalent-vaccinated or component-vaccinated piglets with homologous virulent strain(s) did not induce diarrhea for 2 weeks post-challenge. Immunization with the trivalent vaccine or its individual components also alleviated the histopathological lesions in the small intestines caused by challenge with the corresponding original virulent strain(s). Fecal secretory IgAs specific for each of vaccine strains were detected starting at 14 days post-vaccination (dpv), and IgA levels gradually increased up to 28 dpv. Oral immunization with the trivalent vaccine or its individual components induced high levels of serum virus-neutralizing antibody by 7 dpv. No diarrhea was observed in any experimental piglets during five consecutive passages of each vaccine strain. Our data indicated that the live attenuated trivalent vaccine was safe and effective at protecting piglets from diarrhea induced by challenge exposure of homologous virulent strains. This trivalent vaccine will potentially contribute toward controlling porcine rotavirus disease in South Korea and other countries where rotavirus infections with similar G and P genotypes are problematic.

Porcine sapovirus Cowden strain enters LLC-PK cells via clathrin- and cholesterol-dependent endocytosis with the requirement of dynamin II

Caliciviruses in the genus Sapovirus are a significant cause of viral gastroenteritis in humans and animals. However, the mechanism of their entry into cells is not well characterized. Here, we determined the entry mechanism of porcine sapovirus (PSaV) strain Cowden into permissive LLC-PK cells. The inhibition of clathrin-mediated endocytosis using chlorpromazine, siRNAs, and a dominant negative (DN) mutant blocked entry and infection of PSaV Cowden strain, confirming a role for clathrin-mediated internalization. Entry and infection were also inhibited by the cholesterol-sequestering drug methyl-β-cyclodextrin and was restored by the addition of soluble cholesterol, indicating that cholesterol also contributes to entry and infection of this strain. Furthermore, the inhibition of dynamin GTPase activity by dynasore, siRNA depletion of dynamin II, or overexpression of a DN mutant of dynamin II reduced the entry and infection, suggesting that dynamin mediates the fission and detachment of clathrin- and cholesterol-pits for entry of this strain. In contrast, the inhibition of caveolae-mediated endocytosis using nystatin, siRNAs, or a DN mutant had no inhibitory effect on entry and infection of this strain. It was further determined that cell entry of PSaV Cowden strain required actin rearrangements for vesicle internalization, endosomal trafficking from early to late endosomes through microtubules, and late endosomal acidification for uncoating. We conclude that PSaV strain Cowden is internalized into LLC-PK cells by clathrin- and cholesterol-mediated endocytosis that requires dynamin II and actin rearrangement, and that the uncoating occurs in the acidified late endosomes after trafficking from the early endosomes through microtubules.

Activation of PI3K, Akt, and ERK during early rotavirus infection leads to V-ATPase-dependent endosomal acidification required for uncoating

The cellular PI3K/Akt and/or MEK/ERK signaling pathways mediate the entry process or endosomal acidification during infection of many viruses. However, their roles in the early infection events of group A rotaviruses (RVAs) have remained elusive. Here, we show that late-penetration (L-P) human DS-1 and bovine NCDV RVA strains stimulate these signaling pathways very early in the infection. Inhibition of both signaling pathways significantly reduced production of viral progeny due to blockage of virus particles in the late endosome, indicating that neither of the two signaling pathways is involved in virus trafficking. However, immunoprecipitation assays using antibodies specific for pPI3K, pAkt, pERK and the subunit E of the V-ATPase co-immunoprecipitated the V-ATPase in complex with pPI3K, pAkt, and pERK. Moreover, Duolink proximity ligation assay revealed direct association of the subunit E of the V-ATPase with the molecules pPI3K, pAkt, and pERK, indicating that both signaling pathways are involved in V-ATPase-dependent endosomal acidification. Acidic replenishment of the medium restored uncoating of the RVA strains in cells pretreated with inhibitors specific for both signaling pathways, confirming the above results. Isolated components of the outer capsid proteins, expressed as VP4-VP8* and VP4-VP5* domains, and VP7, activated the PI3K/Akt and MEK/ERK pathways. Furthermore, psoralen-UV-inactivated RVA and CsCl-purified RVA triple-layered particles triggered activation of the PI3K/Akt and MEK/ERK pathways, confirming the above results. Our data demonstrate that multistep binding of outer capsid proteins of L-P RVA strains with cell surface receptors phosphorylates PI3K, Akt, and ERK, which in turn directly interact with the subunit E of the V-ATPase to acidify the late endosome for uncoating of RVAs. This study provides a better understanding of the RVA-host interaction during viral uncoating, which is of importance for the development of strategies aiming at controlling or preventing RVA infections.

Viral particles must transport their genome into the cytoplasm or the nucleus of host cells to initiate successful infection. Knowledge of how viruses may pirate host cell signaling cascades or molecules to promote their own replication can facilitate the development of antiviral drugs. Group A rotavirus (RVA) is a major etiological agent of acute gastroenteritis in young children and the young of various mammals. RVA enters cells by a complex multistep process. However, the cellular signaling cascades or molecules that facilitate these processes are incompletely understood. Here, we demonstrate that infection with late-penetration RVA strains results in phosphorylation of PI3K, Akt, and ERK signaling molecules at an early stage of infection, a process mediated by the multistep binding of RVAs outer capsid proteins. Specific inhibitors for PI3K/Akt and MEK/ERK signaling pathways trap the viral particles in late endosome, and acidic replenishment restores and releases them. Moreover, the RVA-induced phosphorylated PI3K, Akt, and ERK directly interact with the subunit E of the V-ATPase proton pump, required for endosomal acidification and RVA uncoating. Understanding how RVA-induced early activation of cellular signaling molecules mediates the V-ATPase-dependent endosomal acidification required for uncoating of viral particles opens up opportunities for targeted interventions against rotavirus entry.

The molecular epidemiology of bovine rotaviruses circulating in Iran: a two-year study

Bovine group A rotavirus (bovine RVA) is recognized as a major cause of severe gastroenteritis in newborn calves. The purpose of this study was to estimate the prevalence and identify the genotypes of circulating bovine RVA in newborn diarrheic calves. Two hundred fifty-three stool samples of diarrheic calves up to 1 month old were collected from 42 industrial dairy farms in two Iranian provinces during March 2010 to February 2012. All collected samples were screened for the presence of bovine RVA by RT-PCR, and the G and P genotypes were determined by semi-nested multiplex RT-PCR assay. The results of RT-PCR indicated that 49.4 % (125 out of 253) of the samples were positive for bovine RVA. The G and P genotyping of a subset of positive samples (n = 85) by semi-nested multiplex RT-PCR revealed that G6 (55.3 %) and G10 (43.5 %) and P[5] (51.8 %) and P[11] (27 %) were the most prevalent G and P genotypes, respectively. G6P[5] was the dominant genotype (35.3 %), followed by G10P[5], G10P[11] and G6P[11], with prevalence rates of 16.5 %, 15.3 % and 10.6 %, respectively. Sequence analysis of 20 VP7 and four VP4 genes showed highest nucleotide sequence identity with the corresponding genes of strains RVA/Cow-tc/GBR/UK/1973/G6P7[5] and RVA/Cow-tc/USA/B223/XXXX/G10P[11]. The results of this study reveal the diversity of G and P genotypes in bovine RVA samples from diarrheic Iranian calves and expands our knowledge of bovine RVA infections in the Middle East. These results also highlight the importance of producing of an effective rotavirus vaccine and its inclusion in the national cattle immunization program.

Both α2,3- and α2,6-linked sialic acids on O-linked glycoproteins act as functional receptors for porcine Sapovirus

Sapovirus, a member of the Caliciviridae family, is an important cause of acute gastroenteritis in humans and pigs. Currently, the porcine sapovirus (PSaV) Cowden strain remains the only cultivable member of the Sapovirus genus. While some caliciviruses are known to utilize carbohydrate receptors for entry and infection, a functional receptor for sapovirus is unknown. To characterize the functional receptor of the Cowden strain of PSaV, we undertook a comprehensive series of protein-ligand biochemical assays in mock and PSaV-infected cell culture and/or piglet intestinal tissue sections. PSaV revealed neither hemagglutination activity with red blood cells from any species nor binding activity to synthetic histo-blood group antigens, indicating that PSaV does not use histo-blood group antigens as receptors. Attachment and infection of PSaV were markedly blocked by sialic acid and Vibrio cholerae neuraminidase (NA), suggesting a role for α2,3-linked, α2,6-linked or α2,8-linked sialic acid in virus attachment. However, viral attachment and infection were only partially inhibited by treatment of cells with sialidase S (SS) or Maackia amurensis lectin (MAL), both specific for α2,3-linked sialic acid, or Sambucus nigra lectin (SNL), specific for α2,6-linked sialic acid. These results indicated that PSaV recognizes both α2,3- and α2,6-linked sialic acids for viral attachment and infection. Treatment of cells with proteases or with benzyl 4-O-β-D-galactopyranosyl-β-D-glucopyranoside (benzylGalNAc), which inhibits O-linked glycosylation, also reduced virus binding and infection, whereas inhibition of glycolipd synthesis or N-linked glycosylation had no such effect on virus binding or infection. These data suggest PSaV binds to cellular receptors that consist of α2,3- and α2,6-linked sialic acids on glycoproteins attached via O-linked glycosylation.

Exotic rotaviruses in animals and rotaviruses in exotic animals

Group A rotaviruses (RVA) are a major cause of viral diarrhea in the young of mammals and birds. RVA strains with certain genotype constellations or VP7-VP4 (G-P) genotype combinations are commonly found in a particular host species, whilst unusual or exotic RVAs have also been reported. In most cases, these exotic rotaviruses are derived from RVA strains common to other host species, possibly through interspecies transmission coupled with reassortment events, whilst a few other strains exhibit novel genotypes/genetic constellations rarely found in other RVAs. The epidemiology and evolutionary patterns of exotic rotaviruses in humans have been thoroughly reviewed previously. On the other hand, there is no comprehensive review article devoted to exotic rotaviruses in domestic animals and birds so far. The present review focuses on the exotic/unusual rotaviruses detected in livestock (cattle and pigs), horses and companion animals (cats and dogs). Avian rotaviruses (group D, group F and group G strains), including RVAs, which are genetically divergent from mammalian RVAs, are also discussed. Although scattered and limited studies have reported rotaviruses in several exotic animals and birds, including wildlife, these data remain to be reviewed. Therefore, a section entitled "rotaviruses in exotic animals" was included in the present review.

Different virulence of porcine and porcine-like bovine rotavirus strains with genetically nearly identical genomes in piglets and calves

Direct interspecies transmissions of group A rotaviruses (RVA) have been reported under natural conditions. However, the pathogenicity of RVA has never been directly compared in homologous and heterologous hosts. The bovine RVA/Cow-tc/KOR/K5/2004/G5P[7] strain, which was shown to possess a typical porcine-like genotype constellation similar to that of the G5P[7] prototype RVA/Pig-tc/USA/OSU/1977/G5P9[7] strain, was examined for its pathogenicity and compared with the porcine G5P[7] RVA/Pig-tc/KOR/K71/2006/G5P[7] strain possessing the same genotype constellation. The bovine K5 strain induced diarrhea and histopathological changes in the small intestine of piglets and calves, whereas the porcine K71 strain caused diarrhea and histopathological changes in the small intestine of piglets, but not in calves. Furthermore, the bovine K5 strain showed extra-intestinal tropisms in both piglets and calves, whereas the porcine K71 strain had extra-intestinal tropisms in piglets, but not in calves. Therefore, we performed comparative genomic analysis of the K71 and K5 RVA strains to determine whether specific mutations could be associated with these distinct clinical and pathological phenotypes. Full-length sequencing analyses for the 11 genomic segments for K71 and K5 revealed that these strains were genetically nearly identical to each other. Two nucleotide mutations were found in the 5′ untranslated region (UTR) of NSP5 and the 3′ UTR of NSP3, and eight amino acid mutations in VP1-VP4 and NSP2. Some of these mutations may be critical molecular determinants for RVA virulence and/or pathogenicity.

Detection of rare reassortant G5P[6] rotavirus, Bulgaria

During the ongoing rotavirus strain surveillance program conducted in Bulgaria, an unusual human rotavirus A (RVA) strain, RVA/Human/BG/BG620/2008/G5P[6], was identified among 2200 genotyped Bulgarian RVAs. This strain showed the following genomic configuration: G5-P[6]-I1-R1-C1-M1-A8-N1-T1-E1-H1. Phylogenetic analysis of the genes encoding the neutralization proteins and backbone genes identified a probable mixture of RVA genes of human and porcine origin. The VP1, VP6 and NSP2 genes were more closely related to typical human rotavirus strains. The remaining eight genes were either closely related to typical porcine and unusual human-porcine reassortant rotavirus strains or were equally distant from reference human and porcine strains. This study is the first to report an unusual rotavirus isolate with G5P[6] genotype in Europe which has most likely emerged from zoonotic transmission. The absence of porcine rotavirus sequence data from this area did not permit to assess if the suspected ancestral zoonotic porcine strain already had human rotavirus genes in its genome when transmitted from pig to human, or, the transmission was coupled or followed by gene reassortment event(s). Because our strain shared no neutralization antigens with rotavirus vaccines used for routine immunization in children, attention is needed to monitor if this G-P combination will be able to emerge in human populations. A better understanding of the ecology of rotavirus zoonoses requires simultaneous monitoring of rotavirus strains in humans and animals.

Pathogenicity characterization of a bovine triple reassortant rotavirus in calves and piglets

Rotaviruses are important human and animal pathogens with high impact on public health and livestock industry. There is little evidence about the cross-species pathogenicity and extra-intestinal infections of animal and human reassortant rotaviruses, particularly based on all 11 genotyping data. In this study, the bovine triple reassortant KJ56-1 strain harboring two bovine-like genome segments, eight porcine-like genome segments, and one human-like genome segment was used to evaluate the cross-species pathogenicity in its parent species, calves and piglets, and to determine its abilities of causing viremia and extra-intestinal tropisms in piglets. The KJ56-1 strain isolated from a calf diarrhea fecal sample replicated without causing diarrhea and severe intestinal pathology in calves. However, piglets inoculated with this strain showed persistent severe diarrhea and marked intestinal pathology. By SYBR Green real-time RT-PCR, viral RNA was detected in the sera, mesenteric lymph node, lung, liver, choroid plexus, and cerebrospinal fluid in the experimental piglets. An immunofluorescence assay confirmed viral replication in these extra-intestinal organs and tissues. These results indicated that the bovine triple reassortant KJ56-1 strain was virulent to piglets but not to calves. Our data also demonstrated that the reassortant rotaviruses had the ability to spread to the bloodstream from the gut, enter and amplify in the mesenteric lymph node, and disseminate to the extra-intestinal organs and tissues.

VP7 Gene of human rotavirus A genotype G5: Phylogenetic analysis reveals the existence of three different lineages worldwide

Group A rotavirus (RV-A) genotype G5, which is common in pigs, was also detected in children with severe diarrhea in Brazil, Argentina, Paraguay, Cameroon, China, Thailand, and Vietnam. To evaluate the evolutionary relationship among RV-A G5 strains, the VP7 and VP4 genes of 28 Brazilian RV-A G5 human strains, sampled between 1986 and 2005, were sequenced and compared with other RV-A G5 strains currently circulating worldwide in animals and humans. The phylogenetic analysis of RV-A G5 VP7 gene strains demonstrates the existence of three main lineages: (a) Lineage I: Brazilian strains grouped with three porcine strains from Thailand; (b) Lineage II: porcine, bovine, and equine strains from different regions; (c) Lineage III: human strains isolated in Asia and Africa, and two porcine strains from Argentina. The VP8* (*non-typable) subunit of VP4 gene sequencing showed that all P[8] strains fell into three major genetic lineages: P[8]-1; P[8]-2; and P[8]-3. These results showed that the RV-A G5 strains circulating in humans are the result of two independent zoonotic transmission events, most likely from pigs.

Human rotavirus genotypes circulating in Brazil before and after a nationwide rotavirus vaccination program established in 2006

Accounting for an estimated 600,000 deaths worldwide each year, rotaviruses are recognized as the most important etiologic agents causing severe acute gastroenteritis among children under the age of five years. In Brazil, until rotavirus vaccination was established in the public health system in 2006, acute gastroenteritis striking children under five years and caused by these viruses was clearly associated with 3.5 million episodes of diarrhea, 650,000 visits to outpatient health care facilities, 92,000 hospitalizations, and 850 deaths each year. After the introduction of the rotavirus vaccine in Brazil in March 2006, studies all over the country have been comparing rotavirus genotypes circulating in the recent pre- and postvaccination era. Most of these studies have reported a high prevalence of the G2P[4] genotype and also a decrease in rotavirus detection all over Brazil after the introduction of the vaccine. So far, these are preliminary studies, as a longer period of time is necessary to establish if this high prevalence of G2P[4] is due to selective pressure by the vaccine on the circulating viruses or to a normal genotype fluctuation, and if it will have any impact on vaccine efficacy in the future. This review describes results from the most recent studies addressing this issue and on rotavirus genotypic variability in Brazil.

Tylosema esculentum (Marama) Tuber and Bean Extracts Are Strong Antiviral Agents against Rotavirus Infection

Tylosema esculentum (marama) beans and tubers are used as food, and traditional medicine against diarrhoea in Southern Africa. Rotaviruses (RVs) are a major cause of diarrhoea among infants, young children, immunocompromised people, and domesticated animals. Our work is first to determine anti-RV activity of marama bean and tuber ethanol and water extracts; in this case on intestinal enterocyte cells of human infant (H4), adult pig (CLAB) and adult bovine (CIEB) origin. Marama cotyledon ethanolic extract (MCE) and cotyledon water extract (MCW) without RV were not cytotoxic to all cells tested, while seed coat and tuber extracts showed variable levels of cytotoxicity. Marama cotyledon ethanolic and water extracts (MCE and MCW, resp.) (≥0.1 mg/mL), seed coat extract (MSCE) and seed coat water extract (MSCW) (0.01 to 0.001 mg/mL), especially ethanolic, significantly increased cell survival and enhanced survival to cytopathic effects of RV by at least 100% after in vitro co- and pre-incubation treatments. All marama extracts used significantly enhanced nitric oxide release from H4 cells and enhanced TER (Ω/cm²) of enterocyte barriers after coincubation with RV. Marama cotyledon and seed coat extracts inhibited virion infectivity possibly through interference with replication due to accumulation of nitric oxide. Marama extracts are therefore promising microbicides against RV.

Inhibition of rotavirus infectivity by a neoglycolipid receptor mimetic

Group A rotaviruses are a major cause of diarrhea in the young of many mammalian species. In rotavirus infected piglets mortality can be as high as 60%. Previous research in this laboratory has identified a porcine intestinal GM₃ ganglioside receptor that is required for sialic acid-dependent rotavirus recognition of host cells. In addition, we previously demonstrated exogenously added GM₃ can competitively inhibit porcine rotavirus binding and infectivity of host cells in vitro. Sialyllactose, the carbohydrate moiety of GM₃, is approximately 3 orders of magnitude less effective than GM₃ at inhibiting rotavirus binding to cells. Furthermore, production of therapeutic quantities of GM₃ ganglioside for use as an oral carbomimetic in swine is cost prohibitive. In an effort to circumvent these problems, a sialyllactose-containing neoglycolipid was synthesized and evaluated for its ability to inhibit rotavirus binding and infectivity of host cells. Sialyllactose was coupled to dipalmitoylphosphatidylethanolamine (PE) by reductive amination and the product (SLPE) purified by HPLC. Characterization of the product showed a single primulin (lipid) and resorcinol (sialic acid) positive band by thin layer chromatography and quantification of phosphate and sialic acid yielded a 1:1 molar ratio. Mass spectroscopy confirmed a molecular weight coinciding with SLPE. Concentration-dependent binding of rotavirus to SLPE was demonstrated using a thin-layer overlay assay. Using concentrations comparable to GM₃, SLPE was also shown to inhibit rotavirus binding to host cells by 80%. Furthermore, SLPE was shown to decrease rotavirus infection of host cells by over 90%. Finally, preliminary results of in vivo animal challenge studies using newborn piglets in their natural environment, demonstrated SLPE afforded complete protection from rotavirus disease. The efficacy of SLPE in inhibiting rotavirus binding and infection in vitro and in vivo, coupled with its relatively low-cost, large-scale production capabilities make SLPE a promising candidate for further exploration as a possible prophylactic or therapeutic nutriceutical for combating rotavirus disease in animals. Most importantly, the results presented here provide proof of concept that the nutriceutical approach of providing natural or synthetic dietary receptor mimetics for protection against gastrointestinal virus infectious disease in all species is plausible.

Antiviral activity of Alpinia katsumadai extracts against rotaviruses

In vitro anti-rotavirus activity of Alpinia katsumadai (AK) extracts were evaluated against bovine G8P[7] and porcine G5P[7] rotaviruses in two different assay strategies, a mixed treatment assay and a post treatment assay. In the mixed treatment assay, six AK extracts [AK-1 (EtOH extract), AK-3 (H₂O layer), AK-5 (40% methanol fraction), and AK-9–11 (H₂O extract, polysaccharide fraction, supernatant fraction)] exhibited inhibitory activities against G5P[7] rotavirus with the EC₅₀ values ranging from 0.7 ± 0.4 to 33.7 ± 6.5 μg/mL. Extracts AK-1, AK-3, and AK-5 inhibited rotavirus infection against G8P[7] rotavirus, the with EC₅₀ values of 8.4 ± 2.2 μg/mL, 6.5 ± 0.8 μg/mL and 8.4 ± 5.0 μg/mL, respectively. By hemagglutination inhibition (HI) assay, six AK extracts completely inhibited viral adsorption onto human RBCs in both strains of rotaviruses at less than 11 μg/mL. However, in the post treatment assay, there was no anti activity shown against both strains of rotaviruses. As a result, six AK extracts were attributed mainly to having a strong interaction with hemagglutinin protein on the outer surface of rotavirus, resulting to blockage of viral adsorption.

Ovine rotavirus strain LLR-85-based bovine rotavirus candidate vaccines: construction, characterization and immunogenicity evaluation

Group A bovine rotaviruses (BRVs) are the most important cause of diarrheal diseases in neonatal calves and cause significant morbidity and mortality in the young animals, and epidemiologic surveillance of bovine rotavirus G genotypes conducted in various cattle populations throughout the world has shown that approximately 90% of the bovine rotavirus isolates belong to G6 and G10. Based on the modified Jennerian approach to immunization, we constructed and characterized a reassortant rotavirus stain, which bears a single bovine rotavirus VP7 gene encoding G genotype 6 specificity while the remaining 10 genes are derived from the ovine attenuated rotavirus LLR-85. The reassortant rotavirus strain, named as R191, and its parental virus strain LLR-85 were combined as bivalent vaccine candidates to inoculate the colostrums-deprived neonatal calves for evaluation of the immunogenicity. The calves were orally inoculated with the reassortant R191 (group 1), the parental rotavirus LLR-85 (group 2), or combined the R191 and LLR-85 (group 3), and serum specimens were detected to determine the immune response of IgG and IgA antibodies. Results showed that seroconversion to positivity for IgG and IgA antibodies occurred at postinoculation day (PID) 10 in all of the inoculated calves, and the highest titers of the serum IgG (range 1:800 to 1:6400) and IgA (range 1:800 to 1:3200) antibodies were obtained at PID 21 for all calves. Meanwhile, virus shedding was detected after inoculation, showing that the inoculated virus was positive in 2 of 77 fecal specimens (2.6%) collected from the inoculated calves during the first 7 days of oral inoculation with the rotavirus vaccine candidates. The results suggested that the rotavirus strains R191 and LLR-85 are promising bivalent vaccine candidates for the prevention of bovine G6 and G10 rotavirus infection.

Full genomic analysis of a porcine-bovine reassortant G4P[6] rotavirus strain R479 isolated from an infant in China

During the 2004 surveillance of rotaviruses in Wuhan, China, a G4P[6] rotavirus strain R479 was isolated from a stool specimen collected from a 2-year-old child with diarrhea. The strain R479 had an uncommon subgroup specificity I + II, and analysis of the VP6 gene suggested that it was related to porcine rotaviruses. In the present study, full-length nucleotide sequences of all the RNA segments of R479 were determined and analyzed phylogenetically to identify the origin of individual RNA segments. According to the rotavirus genotyping system based on 11 RNA segments, the genotype of R479 was expressed as G4-P[6]-I5-R1-C1-M1-A1-N1-T7-E1-H1. This genotype includes the porcine-like VP6 genotype (I5) and bovine-like NSP3 genotype (T7). Phylogenetic analysis revealed that R479 genes encoding VP1, VP2, VP3, VP6, VP7, VP8*, NSP1, NSP4, and NSP5 were more closely related to those of porcine rotaviruses than human or other animal rotaviruses. In contrast, it was remarkable that the NSP3 gene of R479 was genetically closely related to only a bovine rotavirus strain UK. The NSP2 gene of R479 was also unique and clustered with only the G5P[8] human strain IAL28 and G3P[24] simian strain TUCH. These results suggested that R479 may be a reassortant virus having the NSP3 gene from a bovine rotavirus in the genetic background of a porcine rotavirus, with an NSP2 gene related to the porcine-human reassortant strain IAL28. To our knowledge, R479 is the first porcine-bovine reassortant rotavirus isolated from a human.

Detection and genotyping of Korean porcine rotaviruses

Porcine group A rotavirus (GARV) is considered to be an important animal pathogen due to their economic impact in the swine industry and its potential to cause heterologous infections in humans. This study examined 475 fecal samples from 143 farms located in 6 provinces across South Korea. RT-PCR and nested PCR utilizing primer pairs specific for the GARV VP6 gene detected GARV-positive reactions in 182 (38.3%) diarrheic fecal samples. A total of 98 porcine GARV strains isolated from the GARV-positive feces were analyzed for G and P genotyping. Based on the sequence and phylogenetic analyses, the most predominant combination of G and P genotypes was G5P[7], found in 63 GARV strains (64.3%). The other combinations of G and P genotypes were G8P[7] (16 strains [16.3%]), G9P[7] (7 strains [7.1%]), G9P[23] (2 strains [2.0%]), and G8P[1] (1 strain [1.0%]). The counterparts of G or P genotypes were not determined in three G5, five P[7], and one P[1] strains. Interestingly, phylogenetic analysis indicated that all Korean G9 strains were more closely related to lineage VI porcine and human viruses than to other lineages (I–V) of GARVs and to Korean human G9 strains (lineage III). These results show that porcine GARV infections are common in diarrheic piglets in South Korea. The infecting strains are genetically diverse, and include homologous (G5P[7]), heterologous (G8P[1]), and reassortant (G8P[7]), as well as emerging G9 GARV strains.

Sequence analysis of unusual P[7]G5 bovine rotavirus strains reveals evidence of interspecies transmission

By sequence and phylogenetic analyses, the 11 genomic segments of two bovine rotaviruses isolated from clinically infected calves were proven to be derived from the swine-like P[7]G5 genotype. This finding reinforced the hypothesis that interspecies transmission of completely heterologous strains can occur in nature.

Comparison of the efficacy of rotavirus VLP vaccines to a live homologous rotavirus vaccine in a pig model of rotavirus disease

Rotavirus-like particles (VLPs) have shown promise as rotavirus vaccine candidates in mice, rabbits and pigs. In pigs, VLP vaccines reduced rotavirus shedding and disease but only when used in conjunction with live attenuated human rotavirus. Using a porcine rotavirus pig model, rotavirus antigen shedding was reduced by up to 40% after vaccination with VLPs including the neutralizing antigens VP7 and VP8* when used in combination with the adjuvant polyphosphazene poly[di(carbozylatophenoxy)phoshazene] (PCPP). In contrast, complete protection from rotavirus antigen shedding and disease was induced by vaccination with the virulent porcine rotavirus PRV 4F. This is the first study to demonstrate some post-challenge reductions in rotavirus antigen shedding in a pig model of rotavirus disease after vaccination with VLPs without combining with infectious rotavirus.

Rotavirus diarrhea in bovines and other domestic animals

Rotavirus diarrhea is the major cause of death of millions of children in developing countries besides causing economically significant malady in neonates of many domestic animals. In neonates, the infection is non-viremic, have very short incubation period, and manifests profuse diarrhea and severe dehydration. Concurrent infection with secondary pathogens may augment the disease severity. Diarrhea occurs due to virus-mediated destruction of absorption efficient enterocytes, activation of enteric nervous system, or due to a rotavirus enterotoxin. Diagnosis of the infection relies on conventional techniques like isolation in MA 104 cell lines, electron microscopy, electro-pherotyping, and various serological tests. Presently, diagnosis and molecular typing is performed using serotype specific RT-PCR, sequencing or genomic hybridization techniques. As the rotaviruses are known to exhibit extreme genetic diversity and outplay disinfection procedures, eradication of the pathogen is often difficult. Hence, for prevention, good management practices coupled with vaccination of dam for protecting young ones, has to be practiced. Recently, new generation prophylactic strategies including DNA vaccines, subunit vaccines, virus-like particles (VLPs) and edible vaccines have been found to induce sufficient levels of passive immunity. Aside to the infection in animals, zoonotic significance of the animal rotaviruses has to be further unearthed. In this review, efforts have been made to highlight the importance and prevalence of the disease in bovines, its pathogenesis along with preventive measures, salient features of rotaviruses and their inter-species transmission abilities, zoonotic implications, and a concise account of the infection in various domestic animals and poultry.

A novel genomic constellation (G10P[3]) of group A rotavirus detected from buffalo calves in northern India

Group A bovine rotaviruses cause gastroenteritis and calf mortality leading to significant economic losses to dairy farmers in India. Due to segmented nature of the RNA genome and wide host range, vast genetic and antigenic diversity exists among different isolates of rotavirus. Molecular characterization of locally prevalent group A rotavirus strains in buffalo population in north India was undertaken. Out of a total of 455 faecal samples, 21 samples (4.61%) were positive for bovine rota virus (BRV) as determined by PAGE and ELISA, whereas of these only 15 isolates yielded specific products for VP4 and VP7 genes by RT-PCR. Genotyping by nested PCR typed G6, G10 and P[11] genotypes but VP4 genes of 11 isolates remained untyped. The phylogenetic and evolutionary analysis of nucleotide and predicted amino acid sequences of the cloned products of VP4 and VP7 genes confirmed typing results obtained by nested PCR for G6, G10 and P[11] and classified the untyped isolates as P[3] genotypes. In this study, it was observed that G6P[11] (26.66%) and G10P[3] (73.34%) group A rotaviruses are circulating in buffalo herds of organized farms in north India. Unusual reassortants G10P[3] of group A rotaviruses isolated from buffalo calves show novel genomic constellations indicative of interspecies reassortment.

Molecular characterization of rare bovine group A rotavirus G15P[11] and G15P[21] strains from eastern India: identification of simian SA11-like VP6 genes in G15P[21] strains

During a surveillance study (November 2001-March 2005), one rare G15P[11] and two rare G15P[21] bovine group A rotavirus strains were detected in diarrhoeic calves in Eastern India. Sequence analysis of the VP8*, VP6, NSP4 and NSP5 genes of the G15P[11] strain confirmed its bovine origin. Although the NSP4 and NSP5 genes of the two G15P[21] strains were of bovine origin, their VP6 genes shared higher nucleotide and amino acid identities with simian strain SA11 (92.5-93.1% and 98.5-98.7%) than bovine strains (88.5-88.9% and 97-97.2%), and by phylogenetic analysis, exhibited clustering with SA11, distantly related to bovine strains. All these pointed towards a possible reassortment event of VP6 gene between bovine and simian (SA11-like) strains. Therefore, the present study provided molecular evidence for bovine origin of G15 strains and revealed a rare instance of genetic diversity in the bovine VP6 gene, otherwise conserved in group A rotavirus strains from cattle.

Recommendations for the classification of group A rotaviruses using all 11 genomic RNA segments

Recently, a classification system was proposed for rotaviruses in which all the 11 genomic RNA segments are used (Matthijnssens et al. in J Virol 82:3204-3219, 2008). Based on nucleotide identity cut-off percentages, different genotypes were defined for each genome segment. A nomenclature for the comparison of complete rotavirus genomes was considered in which the notations Gx-P[x]-Ix-Rx-Cx-Mx-Ax-Nx-Tx-Ex-Hx are used for the VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5/6 encoding genes, respectively. This classification system is an extension of the previously applied genotype-based system which made use of the rotavirus gene segments encoding VP4, VP7, VP6, and NSP4. In order to assign rotavirus strains to one of the established genotypes or a new genotype, a standard procedure is proposed in this report. As more human and animal rotavirus genomes will be completely sequenced, new genotypes for each of the 11 gene segments may be identified. A Rotavirus Classification Working Group (RCWG) including specialists in molecular virology, infectious diseases, epidemiology, and public health was formed, which can assist in the appropriate delineation of new genotypes, thus avoiding duplications and helping minimize errors. Scientists discovering a potentially new rotavirus genotype for any of the 11 gene segments are invited to send the novel sequence to the RCWG, where the sequence will be analyzed, and a new nomenclature will be advised as appropriate. The RCWG will update the list of classified strains regularly and make this accessible on a website. Close collaboration with the Study Group Reoviridae of the International Committee on the Taxonomy of Viruses will be maintained.

Full genome-based classification of rotaviruses reveals a common origin between human Wa-Like and porcine rotavirus strains and human DS-1-like and bovine rotavirus strains

Group A rotavirus classification is currently based on the molecular properties of the two outer layer proteins, VP7 and VP4, and the middle layer protein, VP6. As reassortment of all the 11 rotavirus gene segments plays a key role in generating rotavirus diversity in nature, a classification system that is based on all the rotavirus gene segments is desirable for determining which genes influence rotavirus host range restriction, replication, and virulence, as well as for studying rotavirus epidemiology and evolution. Toward establishing such a classification system, gene sequences encoding VP1 to VP3, VP6, and NSP1 to NSP5 were determined for human and animal rotavirus strains belonging to different G and P genotypes in addition to those available in databases, and they were used to define phylogenetic relationships among all rotavirus genes. Based on these phylogenetic analyses, appropriate identity cutoff values were determined for each gene. For the VP4 gene, a nucleotide identity cutoff value of 80% completely correlated with the 27 established P genotypes. For the VP7 gene, a nucleotide identity cutoff value of 80% largely coincided with the established G genotypes but identified four additional distinct genotypes comprised of murine or avian rotavirus strains. Phylogenetic analyses of the VP1 to VP3, VP6, and NSP1 to NSP5 genes showed the existence of 4, 5, 6, 11, 14, 5, 7, 11, and 6 genotypes, respectively, based on nucleotide identity cutoff values of 83%, 84%, 81%, 85%, 79%, 85%, 85%, 85%, and 91%, respectively. In accordance with these data, a revised nomenclature of rotavirus strains is proposed. The novel classification system allows the identification of (i) distinct genotypes, which probably followed separate evolutionary paths; (ii) interspecies transmissions and a plethora of reassortment events; and (iii) certain gene constellations that revealed (a) a common origin between human Wa-like rotavirus strains and porcine rotavirus strains and (b) a common origin between human DS-1-like rotavirus strains and bovine rotaviruses. These close evolutionary links between human and animal rotaviruses emphasize the need for close simultaneous monitoring of rotaviruses in animals and humans.

Molecular characterization of bovine group A rotavirus G3P[3] strains

During a surveillance study, four of 130 group A rotavirus strains, detected from diarrheic calves in Eastern India, exhibited G3P[3] specificities. Molecular characterization of VP7 and VP8(*) genes of one such strain [named as RUBV3 (RU: ruminant and BV: bovine)] revealed genetic relatedness to a G3P[3] simian strain, RRV, and RRV-related caprine strain GRV. Strain RUBV3 had VP6, NSP4 and NSP5 genes of bovine origin. Therefore, the present study provides evidence for multiple reassortment events involving ruminant and simian strains and, to our knowledge, is the first report of detection of bovine group A rotavirus strains with G3P[3] specificities.

Group A rotavirus genotypes in Germany during 2005/2006

During the 2005/2006 winter season a total of 802 group A positive rotavirus specimens of patients from different regions throughout Germany were genotyped. Amplicons from a one-tube RT-PCR were typed by analysis of their (type-specific) size using type-specific primers, fluorescent consensus primers and a capillary sequencer for detection. While G1P[8] was predominant (45.8%), G9P[8] has emerged as the second most frequent genotype combination (37.7%). The distribution of genotypes was heterogeneous, regional frequencies regarding G1 and G9 were ranging from 15.0 to 89.3% and from 7.1 to 67.7%, respectively. Furthermore, a few human rotavirus G10P[6] and G10P[8] infections were observed.