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PubMed2002

Early response to rotavirus infection involves massive B cell activation.

Rotavirus is an acute enteric pathogen which induces severe diarrhea in infants and children. To determine the immune response to rotavirus in vivo, we used a mouse model of rotavirus infection. We observed dramatic increases in the sizes of both Peyer's patches and mesenteric lymph nodes, but not spleen, between 1 and 6 days after infection with a homologous strain of murine rotavirus, EC wild type. Histological analysis showed large increases in the numbers of lymphocytes in these same tissues in rotavirus-infected mice. Flow cytometric analysis confirmed the increase in numbers of lymphocytes and revealed a large increase in the percentage of activated B, but not T, lymphocytes in both Peyer's patches and mesenteric lymph nodes of rotavirus-infected mice compared with control mice. Fragment cultures from these tissues established at 3-4 days postinfection contain rotavirus-specific IgM but not IgA Ab. A similar degree of lymphoid hyperplasia and percentage of activated B cells were observed in rotavirus-infected TCR knockout mice. Taken together, our findings show that rotavirus infection, in the context of a normal immune response, induces a large increase in the percentages of activated B cells in the absence of any detectable increase in the percentage of activated T cells, implicating a T cell-independent B cell response as the primary mechanism for initial rotavirus clearance.

Animals↗

PubMed2004

Epidemiology and clinical manifestation of rotavirus and norwalk-like viruses in Thai children.

Acute gastroenteritis is one of the most common diseases affecting children and rotavirus is the major etiological agent worldwide. Although the role of rotavirus as a causal agent of gastroenteritis has been previously established in Thailand, little is known about the epidemiology of Norwalk-like viruses. The present study was designed to determine the epidemiology and clinical manifestation of Norwalk-like viruses in comparison with rotavirus in Thailand. One hundred and one children with watery diarrhea between November 2002 and October 2003 were recruited into the study. The clinical data and stool specimens were collected for clinical analysis and rotavirus and Norwalk-like virus detection. Rotavirus and Norwalk-like viruses were detected viral agent by RT-PCR method. Of 101 stool samples obtained, rotavirus was detected in 25/101 (24.7%). Norwalk-like viruses were detected in 23/101 (22.7%). Dual infections were detected in 6/101 (5.9%). Rotavirus and Norwalk-like viruses peaked in the winter time. Clinical manifestations of rotavirus and Norwalk-like viruses were watery stool, nausea, vomiting, abdominal pain and fever Norwalk-like viruses and rotavirus were the most common etiologic agents in children with acute gastroenteritis in Thailand Epidemiology and clinical manifestations of rotavirus and Norwalk-like viruses were not different.

Caliciviridae Infections↗

PubMed2004

Safety, efficacy, and immunogenicity of a live, quadrivalent human-bovine reassortant rotavirus vaccine in healthy infants.

OBJECTIVES: To investigate safety, efficacy, and immunogenicity of live quadrivalent rotavirus vaccine (QRV) containing human-bovine (WC3) reassortant rotavirus serotypes G1, G2, G3, and P1a. STUDY DESIGN: This was a randomized, double-blinded, placebo-controlled trial. During 1993 to 1994, at 10 US study sites, 439 healthy infants approximately 2 to 6 months of age, were enrolled to receive 3 doses of oral QRV or placebo at approximately 8-week intervals. RESULTS: The vaccine was generally well tolerated; no serious vaccine-related adverse experiences were reported. Risk differences and 95% confidence intervals suggested no differences between vaccine and placebo recipients in the incidences of fever, irritability, vomiting, or diarrhea during the 14 days after any dose. QRV was 74.6% efficacious (95% CI: 49.5%, 88.3%) in preventing rotavirus acute gastroenteritis (AGE), regardless of severity and 100% efficacious (95% CI: 43.5%, 100%) in preventing severe rotavirus AGE through one rotavirus season. Serotype G1 was identified in most infants with rotavirus AGE. A >or=3-fold rise in serum neutralizing antibody to G1 was observed in 57% (45/79) of vaccinees. A >or=3-fold rise in serum anti-rotavirus IgA and fecal anti-rotavirus IgA was observed in 88% (162/185) and 65% (104/159) of vaccinees, respectively. CONCLUSIONS: QRV was generally well tolerated, immungenic, and highly effective against rotavirus gastroenteritis.

Animals↗

PubMed1999

Efficacy of live, attenuated, human rotavirus vaccine 89-12 in infants: a randomised placebo-controlled trial.

BACKGROUND: Rotavirus is the most common cause of severe, dehydrating diarrhoea in infants worldwide. We assessed the safety, immunogenicity, and efficacy of a live, oral human rotavirus vaccine, 89-12, in US children in a randomised, placebo-controlled, double-blind multicentre trial. METHODS: 215 healthy infants were enrolled, of whom 213 were given two doses of 89-12 (containing 1x10(5) plaque-forming units) or placebo, and 213 were followed up through one rotavirus season. The frequency of side-effects was compared for 7 days after each dose of vaccine. Immune responses to rotavirus were assessed by serum and stool IgA, and by serum 89-12 neutralising titres. The primary outcome variable (protection from rotavirus disease) was evaluated by comparing the frequencies of rotavirus gastroenteritis in an intention-to-treat analysis. FINDINGS: Adverse reactions were mild. Low-grade fever (> or = 38.1 degrees C) after the first dose was the only side-effect significantly more common in the vaccine group than in the placebo group (21 [19%] vs 5 [5%], p=0.001). An immune response to vaccine was detected in 94.4% of vaccinees. Rotavirus disease occurred in 18 of 107 placebo recipients and two of 108 vaccine recipients (vaccine efficacy 89.0% [95% CI 65.4-94.5]). Ten infants in the placebo group but none in the vaccine group were presented for medical care. INTERPRETATION: The 89-12 rotavirus vaccine was safe and immunogenic and provided a high degree of protection against rotavirus disease. Further investigations of this vaccine are needed to confirm these findings in other settings.

Administration, Oral↗

PubMed2004

Evaluation of anatomic changes in young children with natural rotavirus infection: is intussusception biologically plausible?

BACKGROUND: Several studies have shown an association between vaccination with the rotavirus vaccine and the development of intussusception. We evaluated the plausibility of a causal association between natural rotavirus infection and intussusception. METHODS: We performed ultrasound measurements, in infants with confirmed rotavirus infection and in healthy control subjects, of the ileum wall thickness and mesenteric lymph nodes, at enrollment and 1 month later. RESULTS: Thirteen pairs of patients with rotavirus infection and control subjects were enrolled. The mean distal ileum wall thickness at the first examination was 3.0 mm in patients with rotavirus infection and 2.0 mm in control subjects (P = .037). The maximum lymph node size in patients with rotavirus infection was 11.6 mm at the first examination and 7.4 mm at the second examination (P = .017). Nodal aggregates and free fluid were also observed more commonly among patients with rotavirus infection (54% vs. 9%; P = .033 for both). CONCLUSION: Rotavirus infection was associated with increased distal ileum wall thickness and lymphadenopathy during the illness period. These changes suggest a plausible mechanism by which rotavirus infection could cause intussusception.

Case-Control Studies↗

PubMed2001

Protective efficacy of rotavirus 2/6-virus-like particles combined with CT-E29H, a detoxified cholera toxin adjuvant.

Identifying a safe and efficacious mucosal adjuvant is crucial for the development of subunit vaccines against rotavirus and other mucosal pathogens. Moreover, recognition of determinants of protective immunity to rotavirus infection is essential to the design of the means to prevent or control this viral gastrointestinal disease. We have studied the kinetics of systemic and mucosal antibody responses elicited upon mucosal immunization of mice with rotavirus recombinant virus-like particles (rVLPs) alone or combined with a detoxified version of cholera toxin, CT-E29H. CT-E29H has been shown to maintain the adjuvant effect of parental cholera holotoxin. Both inbred BALB/c and outbred CD-1 mice were immunized with rotavirus VP2/6-rVLPs (2/6-VLPs) combined with CT-E29H, orally or intranasally (i.n.), and the comparative efficacy of different formulations was then determined. Rotavirus-specific serum and fecal IgA, IgM, and IgG antibodies were determined by enzyme-linked immunoadsorbent assay (ELISA) weekly (or every other week) following vaccination. Animals then were challenged with a murine rotavirus strain, EDIM. The degree to which vaccinated animals were protected from the wild-type rotavirus challenge was reflected in the levels of viral antigen shed in stools (percent reduction in antigen shedding, PRAS). BALB/c mice immunized by either route produced rotavirus-specific serum IgA, IgM and IgG, as well as fecal IgA and IgG, but not IgM; however, the intranasal immunization induced stronger systemic IgG and IgM responses than did oral immunization. Similar levels of prechallenge rotavirus-specific fecal and serum IgA were detected in both the orally and the i.n. immunized groups. Two immunizations with 2-6VLPs and CT-E29H were sufficient to protect BALB/c mice, regardless of the route of administration. PRAS was 99.6, 98.8, and 98.8% for oral, i.n. and the oral + i.n. groups, respectively; in contrast vaccination with 2/6-VLPs alone was not protective (PRAS = 39%), indicating the critical role of CT-E29H in inducing protective levels of immune responses. Two of four outbred CD-1 mice that were immunized orally with 2/6-VLPs-CT-E29H showed no humoral responses (PRAS, 65%), but four of four i.n. immunized CD-1 mice displayed humoral responses (PRAS, 97.9%). Serum anti-VP6 and VP2 antibodies were detected in all immunoresponsive mice. The combined results in two strains of mice indicate that CTE29H is an effective mucosal adjuvant capable of inducing protective immune responses and suggest that intranasal administration is the preferred route of immunization.

Adjuvants, Immunologic↗

PubMed2002

Rotavirus G serotypes and p[],G genotypes identified in cases of reinfection among children participating in a trial with rhesus-human reassortant tetravalent vaccine (RRV-TV) in Belém, Brazil.

Group A rotaviruses are the most important agents of severe diarrhea in children and infants worldwide. The aim of present study was to identify rotavirus G serotypes and P[],G genotypes in cases of reinfection among children who participated in a vaccine trial with the tetravalent rhesus-human reassortant rotavirus vaccine (RRV-TV 4 x 10(4) pfu/dose) in Belém, Brazil. From July 1990 to June 1992, 540 children received, at their first, third and fifth months of life, oral doses of either vaccine or placebo. A total of 90 rotavirus diarrheal episodes among children who completed the three-dose vaccination schedule were recorded. We studied 11 reinfection rotavirus cases among five children (three female and two male). Fecal specimens were tested by using a enzyme immunoassay (IDEIA Rotavirus), followed by EIA with monoclonal antibodies to determine infecting serotypes Gl, G2, G3 and G4 and subgroups I and II. The viral dsRNA was extracted and electrophoresed through polyacrylamide gel and then subjected to reverse-transcription-polymerase chain reaction and nested-PCR for the determination of Gl, G2, G3, G4, G5 and G9 and P[4], P[6], P[8] and P[9] rotavirus genotypes. A total of 11 cases of reinfection (12 per cent) occurred among five children, three from the placebo group and two from the vaccine group. In four of the cases of reinfection G serotypes and P[],G genotypes were as follows: for the first and second infections, respectively: (1) G2/P[4],G2 and Gl/P[4],G1; (2) G2/P[4],G2 and G2/P[6],G5; (3) G2/P[4],G2 and G1/P[8],G1; and (4) G2/P[8],G1 and G1/P[8],G1. A fifth child had three successive infections caused by serotypes/genotypes G1/P[8],G1, in the first and second infections, and G2/P[4],G2 in the third infection. The common genotypes and unusual genotypes were detected in 8 (73 per cent) and 3 (27 per cent) of the isolates, respectively. With regards to the clinical severity, in two children a score indicated moderate/severe disease in both first and second infections. One child had three successive infections; the first episode was moderate/severe, the second very severe and the third was not available. In contrast, in two other children, the first episode was very severe, and the second episode was moderate/severe in one child and data was not available for the other child. The results obtained in the present investigation underscore the need to broaden our knowledge of the immunity in rotavirus reinfection. This should be useful regarding future rotavirus vaccination strategies in Brazil.

Brazil↗

PubMed2006

Rotavirus types in Europe and their significance for vaccination.

The degree of diversity of cocirculating human rotavirus wild-type strains is high. This article reviews the occurrence and frequency of rotavirus types in European children younger than 5 years of age during the past 10-15 years. To enable greater understanding of the overall epidemiologic situation, rotavirus types found in animals in Europe are described. In addition, rotavirus types occurring in children outside Europe are considered. Taken together, these data provide an essential background to the development of rotavirus vaccines. The different concepts of immunization with the 2 main rotavirus candidate vaccines are briefly discussed, and their potential impact on the epidemiology of cocirculating rotavirus wild-type viruses is considered. A case is made for comprehensive surveillance of cocirculating human rotavirus types in Europe after the implementation of rotavirus vaccination.

Age Distribution↗

PubMed2005

Novel rotavirus VP7 typing assay using a one-step reverse transcriptase PCR protocol and product sequencing and utility of the assay for epidemiological studies and strain characterization, including serotype subgroup analysis.

Rotavirus is the most common cause of severe dehydrating gastroenteritis in infants. To date, 10 different serotypes of rotavirus have been identified in human stools. While four or five serotypes dominate, serotype circulation varies with season and geography. Since our laboratory has been involved in the development of a multivalent rotavirus vaccine, it is important to identify the serotypes of rotavirus encountered during our clinical trials. We have developed methodologies for the molecular identification of rotavirus strains based on VP7 gene segment sequence. A 365-bp reverse transcriptase PCR product was generated from the VP7 gene segment using a pair of novel degenerate primers. All serotypes tested (both animal and human) yielded an identically sized product after amplification. Sequencing of these products is performed using truncated versions of the original primers. The sequence generated is compared against a database of rotavirus VP7 sequences, with the G type determined, based on the sequence homology. Using this assay, we have correctly identified human VP7 strains from a panel of available serotypes, as well as numerous animal strains. The assay was qualified using rotavirus positive stool samples, negative stool samples, and rotavirus-spiked stool samples. In addition, samples from cases of acute gastroenteritis collected at Children's Hospital of Philadelphia have been evaluated and indicate that the assay is able to discriminate subtle differences within serotypes. The assay has been utilized in the testing of >3,000 antigen-positive (enzyme immunoassay) samples collected during clinical trials of a rotavirus vaccine (RotaTeq) and identified a serotype in approximately 92% of samples (3, 17, 19).

Amino Acid Sequence↗

PubMed2006

Rotavirus infection enhances lipopolysaccharide-induced intussusception in a mouse model.

Unexpected reports of intussusception after vaccination with the live tetravalent rotavirus vaccine RotaShield resulted in voluntary withdrawal of the vaccine. Intussusception, a condition in which the intestine acutely invaginates upon itself, is the most common cause of intestinal obstruction in children. We report here the development of a mouse model to study rotavirus-induced intussusception. In this model, both homologous murine and heterologous simian rotavirus strains significantly enhanced the rate of lipopolysaccharide (LPS)-induced intussusception, and this enhancement was replication dependent, requiring rotavirus doses of greater than one 50% infectious dose. Rotavirus-induced intussusceptions did not have observable lymphoid lead points, despite the induction of intestinal lymphoid hyperplasia after rotavirus infection. Intussusceptions are also postulated to result from altered intestinal motility, but rotavirus infection had no effect on gastrointestinal transit. LPS-induced intussusception is associated with the induction of inflammatory mediators, and intussusception rates can be modified by inflammatory antagonists. We show that rotavirus infection significantly enhanced serum tumor necrosis factor alpha and gamma interferon cytokine levels after LPS treatment compared to uninfected mice. Together, these data suggest that rotavirus infection sensitized mice to the inflammatory effects of subsequent LPS treatment to enhance intussusception rates.

Animals↗

PubMed2026

A rotavirus vaccine candidate attenuated by codon deoptimization protects neonatal mice against wild-type virus infection.

Rotavirus infection is a leading cause of acute viral gastroenteritis and diarrhea in infants and young children. Owing to the limited development of effective antiviral therapies, vaccination has become the primary and most efficient strategy to reduce rotavirus-associated morbidity and mortality. Compared with classical virus attenuation strategies, reverse genetics approaches such as codon deoptimization are safer, more time-saving, more cost-effective, and more controllable. The present study describes the development of an oral live-attenuated rotavirus vaccine candidate using codon deoptimization. Based on a simian rotavirus SA11 strain, eight gene segments, encoding the structural proteins VP1, VP2, VP3, and VP6, and the non-structural proteins NSP2, NSP3, NSP4, and NSP5, were subjected to codon deoptimization. Attenuated rotavirus by multi-segment codon deoptimization (MS8cd) exhibited markedly attenuated replication both in vitro and in vivo, attributable to reduced protein production independent of mRNA stability. Despite the attenuation, MS8cd elicited robust systemic and mucosal antibody responses which were sufficient to protect neonatal mice against challenge with wild-type rotavirus in a maternal immunization model. To alter the immunogenicity, MS8cd was manipulated to encapsidate outer capsid proteins of several prevalent human rotaviruses. These reassortants exhibited altered antigenic and immunogenic properties associated with the differing genotypes of the outer capsid proteins. In conclusion, this study describes the generation of promising rotavirus vaccine candidates attenuated by codon deoptimization. They are capable of eliciting genotype-specific and broad-spectrum protective immunity against circulating strains of rotavirus. This represents a rapid-response platform for the development of novel vaccines against emerging variants.

Animals↗

PubMedDate not supplied

[Rotavirus A infections and reinfections: genotyping and vaccine implications].

OBJECTIVE: To identify rotavirus A and the most prevalent G and P genotypes in children with acute diarrhea, and to the describe the occurrence of rotavirus infection and reinfection. METHODS: Group A rotavirus specimens were obtained from fecal samples from children with acute diarrhea in Goiânia, state of Goiás, Brazil from July 2000 to October 2002. Rotavirus A positive children and a control group (children of the same age and sex, without diarrhea and with no evidence of rotavirus in the first fecal samples) were followed prospectively during one year. All rotavirus A positive samples were genotyped using RT-PCR/nested-PCR. RESULTS: A total of 77 group A rotavirus strains (37.2%) were identified in the diarrheic samples of 207 children. The following G genotypes were identified: G1 (62.3%), G9 (34.4%) and G4 (3.3%). With regard to P genotyping, 59% were characterized as P[8], 7.7% as P[6], 23.1% as P[6]+P[8], 7.7% as P[4]+P[8] and 2.6% as P[4]+P[8]. The following associations were observed: G1P[8] (77.8%), G9P[8] (11.1%), G4P[8] (5.6%) and G1P[6] (5.6%). No reinfection was observed in the 40 rotavirus A (+) children. However, but two of 40 children who were initially negative for this agent developed rotavirus infection during the same period. CONCLUSIONS: The predominant G and P genotypes observed were similar to those found in new vaccines. No reinfection occurred during one-year of follow-up for any of the genotypes identified.

Acute Disease↗

PubMed1995

Direct detection and characterization of rotavirus into subgroups by dot blot hybridization and correlation with 'long' and 'short' electropherotypes.

BACKGROUND: Enzyme-linked immunosorbent assay (ELISA) and polyacrylamide gel electrophoresis (PAGE) of viral RNA are well-established methods for detection of rotavirus in stool samples. Dot-blot hybridization has also been found to be a sensitive and specific technique for detection and characterization of rotaviruses. OBJECTIVES: To compare the performance of dot blot hybridization with ELISA and PAGE for detection of rotavirus in stool samples. To assess the use of dot blot hybridization for characterization of rotaviruses into subgroups. STUDY DESIGN: Stool samples were collected from 214 children presenting to the hospital with acute diarrhoea. These were assayed for rotavirus by ELISA and PAGE. Dot-blot hybridization was done with full length cloned radiolabelled c-DNA probes of gene segment 6 of SA-11 (subgroup I) and Wa (subgroup II) rotaviruses. RESULTS: Out of 214 stool samples 134 were found to be positive for rotavirus by one of the three methods. Among these 134 positive specimens 114 were positive by dot blot hybridization, this included 18 specimens which were positive only by dot blot assay. One-hundred-and-twelve of these 114 specimens could be subgrouped. Fifteen of these were classified as subgroup I, 97 as subgroup II and two had a dual subgroup specificity. Three subgroup 1 strains had a 'long' RNA pattern, whereas one subgroup II strain had a 'short' RNA pattern which has not been reported earlier for human rotaviruses. CONCLUSION: Dot blot hybridization as described here is a sensitive and specific assay for detection and subgrouping of rotaviruses. However, as there is a considerable genomic diversity among rotaviruses, the panel should include probes from all the genotypes of gene segment 6.

Journal Article↗

PubMed1994

Seasonality and prevalence of rotavirus in Al-Ain, United Arab Emirates.

BACKGROUND: Rotaviruses are the single most important causative agent of acute neonatal enteritis in most avian and mammalian species including humans. Rotaviruses infections have also been shown to be associated with the elderly, immunocompromised individuals and more recently with epidemic diarrheal illness in adults. OBJECTIVES: To study the incidence and the effect of seasonality on the prevalence of rotaviruses in Al-Ain, United Arab Emirates. STUDY DESIGN: A total of 650 stool samples submitted to the laboratories of two University Teaching Hospitals (Al-Ain and Tawam) and a private hospital (Oasis) were examined for the presence of rotaviruses from January 1990-December, 1992, using a commercially available latex agglutination assay. The meteorological data (temperature, relative humidity and rainfall) recorded during the sampling period was analyzed statistically to examine the effect of seasonality on the prevalence of rotavirus cases in Al-Ain, United Arab Emirates. RESULTS: Rotavirus was detected in 21.4% of the samples examined. The predominant number of positive cases (35%) were in the 7-12 months age group. It was interesting to find rotavirus-positive cases in as low an age group as < 3 months (3.6%) and as high as 10 years (8.04%). There was no significant difference on infection rates between male and female groups in the study. However, there was a significant difference between the national (38.18%) and non-national children (61.28%). The higher rate of the latter may be due to import of infections. There appeared to be a seasonal pattern of rotavirus occurrence in the cases studied, with a marked increase in the number of positive cases during the months when the relative humidity was low (25-45%) and there was no rainfall. CONCLUSIONS: Rotavirus was detected in all age groups with a predominance in 7-12 month age groups, and a higher incidence in non-nationals. There was a marked increase in the number of positive cases during the months when the relative humidity was low (25-45%) and there was no rainfall. These findings are discussed in relation to the epidemiology and prophylaxis of rotavirus infections.

Journal Article↗

PubMed1995

Economic impact of immunization against rotavirus gastroenteritis. Evidence from a clinical trial.

OBJECTIVE: To estimate the economic impact of immunization against rotavirus gastroenteritis in an infant population in the United States. DESIGN: Cost identification and break-even analyses from the perspective of society, nested within a phase 3, randomized, double-blind, placebo-controlled trial. PATIENTS: Infants (N = 1278), aged 6 to 22 weeks, enrolled during the summer and fall of 1991 and followed up until July 1, 1992. INTERVENTION: Immunization schedule of three doses of orally administered tetravalent or serotype 1 rhesus rotavirus vaccine, or placebo. MAIN OUTCOME MEASURES: Incidence of rotavirus gastroenteritis, total direct medical costs, direct nonmedical costs, and indirect costs of rotavirus and nonrotavirus gastroenteritis for the duration of the study and of any illness during 5 days after each dose. The cost of the vaccine was not included. RESULTS: Median total cost per infant among the 1187 infants who completed the immunization schedule was $9 in the tetravalent vaccine group, $9 in the serotype 1 vaccine group, and $49 in the placebo group (P = .01). Rotavirus gastroenteritis occurred in 195 infants (16%): 13% (51/398) in the tetravalent group, 12% (47/404) in the serotype 1 group, and 25% (97/385) in the placebo group (P < .0001). Of infants with an episode of rotavirus gastroenteritis, the proportion who incurred cost during the episode and the median cost during the episode did not differ by treatment group. The baseline net cost savings for treatment of rotavirus gastroenteritis and break-even cost of immunization were $11 per infant for the tetravalent vaccine and $12 for the serotype 1 vaccine. In sensitivity analysis, savings ranged from $40 to -$6, because of a large variance in the costs of rotavirus gastroenteritis. CONCLUSION: The results of the baseline analysis suggest that society should be willing to pay between $11 and $12 for immunization against rotavirus. It might be willing to pay an additional amount for the intangible benefits of reduced parental inconvenience or anxiety associated with this illness in infants.

Cost Savings↗

PubMed1985

Genetic relatedness among human rotaviruses.

The genetic relatedness of 81 clinical rotavirus isolates to the human rotavirus prototype strains Wa (subgroup 2, serotype 1) and DS-1 (subgroup 1, serotype 2) was examined by RNA hybridization techniques. Labeled single-stranded (+) transcripts of Wa or DS-1 virus were incubated with denatured genomic rotaviral RNAs, and the resulting hybrids were subjected to gel electrophoresis and autoradiography. Nineteen of the specimens contained subgroup 1 rotavirus with a "short" RNA migration pattern. These viruses were found to be closely related to the DS-1 strain and were associated with illness of short duration. The remaining 62 isolates belonged to subgroup 2 and exhibited a "long" RNA migration pattern. Fifty-four of these isolates exhibited significant hybridization with the Wa strain probe. Four isolates yielded multiple hybrid bands with the Wa probe but also possessed at least one gene segment homologous to the DS-1 strain. The remaining four subgroup 2 rotaviruses did not exhibit significant homology in the form of labeled hybrid bands when tested with either the Wa or DS-1 probe. These findings suggest that most clinical rotavirus isolates belong to one of two human rotavirus "families" defined as Wa-like or DS-1-like. Our observations also suggest that reassortment occurs in vivo between rotaviruses belonging to the two human rotavirus "families" and that there are one or more additional families of human rotavirus.

Genes, Viral↗

PubMed2004

Epidemiology of rotavirus diarrhoea in Iranian children.

Human rotavirus is the most important cause of severe diarrhoea in infants and young children worldwide. We describe the aetiology of viral diarrhoea and the characteristics of rotavirus infection in Shahrekord, Iran. Two hundred and fifty nine children <5 years old admitted to Hajar Hospital, 245 children with acute diarrhoea attending primary health centres in Shahrekord, and 114 children hospitalised for elective surgery were selected from October 2001 to August 2002. Stool samples were screened for enteric viruses using EM. Rotaviruses were characterised using ELISA, reverse transcription-polymerase chain reaction (RT-PCR), and electropherotyping. One hundred and eighty six viruses were identified, of which 146 (78%) were rotavirus. The second most frequent virus was coronavirus, followed by calicivirus. Rotaviruses exhibited a marked seasonal variation, being most frequently isolated from November to February (50% of rotavirus recovered) and affected mostly children <2 years old. The RT-PCR successfully typed 139 of the 146 (95%) rotavirus G types and 124 (85%) P types. The most frequent P type was, P[8] in 108 (74%), P[4] in 16 (11%), and was P non-typeable in 22 (15%). Among the G types, G1 was identified in 120 (82%), G2 in 19 (13%), and was G-non-typeable in 7 (5%). Our results are the first report of rotavirus genotypes affecting Iranian children. The most frequent G and P types (G1, G2, P[8], and P[4]) are similar to those reported from around the world and will be covered by existing rotavirus vaccines targeting G types G1-G4.

Antigens, Viral↗

PubMed2006

Molecular characterization of a rare G3P[3] human rotavirus reassortant strain reveals evidence for multiple human-animal interspecies transmissions.

An unusual strain of human rotavirus G3P[3] (CMH222), bearing simian-like VP7 and caprine-like VP4 genes, was isolated from a 2-year-old child patient during the epidemiological survey of rotavirus in Chiang Mai, Thailand in 2000-2001. The rotavirus strain was characterized by molecular analysis of its VP4, VP6, VP7, and NSP4 gene segments. The VP4 sequence of CMH222 shared the greatest homology with those of caprine P[3] (GRV strain) at 90.6% nucleotide and 96.4% amino acid sequence identities. Interestingly, the VP7 sequence revealed highest identity with those of simian G3 rotavirus (RRV strain) at 88% nucleotide and 98.1% amino acid sequence identities. In contrast, percent sequence identities of both the VP4 and VP7 genes were lower when compared with those of human rotavirus G3P[3] reference strains (Ro1845 and HCR3). Analyses of VP6 and NSP4 sequences showed a close relationship with simian VP6 SG I and caprine NSP4 genotype C, respectively. Phylogenetic analysis of VP4, VP6, VP7, and NSP4 genes of CMH222 revealed a common evolutionary lineage with simian and caprine rotavirus strains. These findings strongly suggest multiple interspecies transmission events of rotavirus strains among caprine, simian, and human in nature and provide convincing evidence that evolution of human rotaviruses is tightly intermingled with the evolution of animal rotaviruses.

Animals↗