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PubMed2006

Rotavirus viremia and extraintestinal viral infection in the neonatal rat model.

Rotaviruses infect mature, differentiated enterocytes of the small intestine and, by an unknown mechanism, escape the gastrointestinal tract and cause viremia. The neonatal rat model of rotavirus infection was used to determine the kinetics of viremia, spread, and pathology of rotavirus in extraintestinal organs. Five-day-old rat pups were inoculated intragastrically with an animal (RRV) or human (HAL1166) rotavirus or phosphate-buffered saline. Blood was collected from a subset of rat pups, and following perfusion to remove residual blood, organs were removed and homogenized to analyze rotavirus-specific antigen by enzyme-linked immunosorbent assay and infectious rotavirus by fluorescent focus assay or fixed in formalin for histology and immunohistochemistry. Viremia was detected following rotavirus infection with RRV and HAL1166. The RRV 50% antigenemia dose was 1.8 x 10(3) PFU, and the 50% diarrhea dose was 7.7 x 10(5) PFU, indicating that infection and viremia occurred in the absence of diarrhea and that detecting rotavirus antigen in the blood was a more sensitive measure of infection than diarrhea. Rotavirus antigens and infectious virus were detected in multiple organs (stomach, intestines, liver, lungs, spleen, kidneys, pancreas, thymus, and bladder). Histopathological changes due to rotavirus infection included acute inflammation of the portal tract and bile duct, microsteatosis, necrosis, and inflammatory cell infiltrates in the parenchymas of the liver and lungs. Colocalization of structural and nonstructural proteins with histopathology in the liver and lungs indicated that the histological changes observed were due to rotavirus infection and replication. Replicating rotavirus was also detected in macrophages in the lungs and blood vessels, indicating a possible mechanism of rotavirus dissemination. Extraintestinal infectious rotavirus, but not diarrhea, was observed in the presence of passively or actively acquired rotavirus-specific antibody. These findings alter the previously accepted concept of rotavirus pathogenesis to include not only gastroenteritis but also viremia, and they indicate that rotavirus could cause a broad array of systemic diseases in a number of different organs.

Animals↗
PubMed1988

Clinical and immunological studies of rotavirus vaccines.

The RIT 4237 bovine rotavirus vaccine has served as a useful model for rotavirus vaccination, but the vaccine will not be further developed or tested. The main problem encountered with this vaccine was its poor "take" rate in developing countries. The reasons for this are unclear, and it is not known whether other bovine rotavirus vaccines are more efficacious in this respect. WC-3 bovine rotavirus vaccine will shortly be tested at several sites in developing countries. The rhesus rotavirus vaccine RRV-1 does not appear by itself to be a practical vaccine either. It has induced only moderate protection against human rotavirus serotypes other than the vaccine type. However, the fact that RRV-1 vaccine has induced substantial protection against severe diarrhoea caused by serotype 3 rotavirus, even in young infants, is promising and supports the concept that serotype-specific neutralizing antibodies play a role in protection against human rotavirus disease. Based on this concept, it has been possible to develop reassortant rhesus rotaviruses in which one RNA segment of human rotavirus, which encodes the expression of VP7 antigen, has been incorporated (Kapikian et al., 1986; 1987). Such rhesus-human reassortant rotaviruses, representing serotypes 1, 2 and 4 of human rotavirus and serotype 3 of rhesus rotavirus, can be combined to make a tetravalent vaccine that might induce neutralizing antibodies against each of the main serotypes of human rotavirus. Although its efficacy is unproven, such a combination vaccine is presently regarded as the most promising candidate rotavirus vaccine for the prevention of human rotavirus disease.

Drug Interactions↗
PubMed2003

Molecular epidemiology of rotaviruses in India.

Rotaviruses cause an estimated 140 million cases of gastroenteritis and 800,000 deaths in children between the ages of 6 months to 2 yr in developing countries. In India, one of every 250 children or about 100-150,000 children die of rotavirus diarrhoea each year. The prevalence of rotavirus diarrhoea in India has been found to vary from 5-71 per cent in hospitalized children <5 yr of age with acute gastroenteritis. The seasonal variation of rotavirus diarrhoea in India varies in different geographical regions with high incidence in winter months at low relative humidity in north India. The distinctive features of rotavirus infection in India include the occurrence of severe disease at an early age and common neonatal rotavirus infections which are often asymptomatic. Rotavirus shows genetic and antigenic diversity in terms of subgroup, electropherotypes and G and P serotypes/genotypes. There are a few studies in terms of prevalence of different antigenic and genetic variants from various regions of India. In most studies on subgroup distribution from India a higher prevalence of subgroup II was reported compared to subgroup I. Electropherotyping has also demonstrated that a number of multiple electropherotypes co-circulate at one time in a particular community leading to extensive genomic variation and the appearance of new strains which may become the predominant electropherotype during the peak season. The most common G types reported from India are G1 and G2 and P types are P[4] and P[8]. A significant number of children also have mixed rotavirus infections. G9 strains are also quite commonly seen in Indian children. In addition P6 strains of probable bovine origin have been reported from India. A novel neonatal strain P type 11 human rotavirus (116 E) was isolated from neonates in Delhi, the VP4 of which was closely related to the bovine serotype G10P[11] strain B223 and VP7 was closely related to the human serotype G9 strain. Another neonatal strain G10P[11] was reported from Bangalore. G10P[11] strains also have a high prevalence in calves with diarrhoea, in India. The occurrence of these unusual rotavirus strains which are natural reassortants of human and bovine rotaviruses, suggests that reassortment may be an important mechanism for generation of rotavirus strains of newborns. This is catalyzed by the age old traditions of calves and humans living in the same household and socio-economic conditions in India. The diversity of rotavirus strains and the high prevalence of mixed infections in India are unique features of rotavirus epidemiology in India and emphasizes that vaccines should be formulated against a broad range of strains. Another important aspect is that vaccines in India should also target G9 strains. Since neonates acquiring rotavirus infection are protected against severe diarrhoea, neonatal rotavirus strains can be effective potential vaccine candidates and vaccines based on these neonatal strains are being indigenously developed in India.

Child↗
PubMed2000

Rotavirus vaccines and vaccination in Latin America.

Worldwide, rotaviruses account for more than 125 million cases of infantile gastroenteritis and nearly 1 million deaths per year, mainly in developing countries. Rather than other control measures, vaccination is most likely to have a major impact on rotavirus disease incidence. The peak incidence of rotavirus diarrhea occurs between 6 and 24 months of age. In developing countries, however, cases are not uncommon among children younger than 6 months. G serotypes 1 to 4 are responsible for most disease, but there are indications that in Brazil that G type 5 is of emerging epidemiological importance. Both homotypic and heterotypic responses are elicited during natural rotavirus infection, and the immunological response at the intestinal mucosal surface is probably the more consistent predictor of clinical immunity. With the primary objective of protecting children against life-threatening dehydrating diarrhea, many approaches to rotavirus vaccine development have been attempted. One vaccine, the tetravalent rhesus-human reassortant rotavirus vaccine (RRV-TV), was given licensing approval in the United States of America, introduced to the market, and later withdrawn. A number of studies have found better efficacy of RRV-TV in developed countries than in developing ones. Field trials with a 4 x 10(4) plaque-forming units (PFU) preparation of RRV-TV have been carried out in two countries in Latin America, Brazil and Peru. Those trials yielded protective efficacy rates against all rotavirus diarrhea ranging from 18% to 35%. Data from a large catchment trial in Venezuela with a higher RRV-TV dose, of 4 x 10(5) PFU/dose, indicated an efficacy rate of 48% against all rotavirus diarrhea and 88% against severe rotavirus diarrhea. It appears that breast-feeding does not compromise the efficacy of RRV-TV if three doses of the vaccine are administered. Similarly, possible interference of oral poliovirus vaccine with the "take" of the rotavirus vaccine can be overcome by giving three doses of the rotavirus vaccine or by using a higher-titer formulation of it. Wild enteroviruses, however, may cause primary rotavirus vaccine failure in developing countries. Studies in Peru with RRV-TV have shown a trend towards higher vaccine efficacy rates against "pure" (rotavirus-only) diarrheal episodes. Economic analyses made in the United States indicate that a vaccine that costs less than US$ 9 per dose would lead to a net savings in medical costs. To date, however, cost-benefit studies have not been done in developing countries. In the future, it is possible that some Latin American countries might adapt their polio production facilities to the preparation of rotavirus vaccines for human use. A year after RRV-TV was licensed for vaccination of infants in the United States, the occurrence of intussusception as an adverse event led to the vaccine's withdrawal from the market. The implications of that action, particularly for Latin America, will be addressed in this article, including the need to explore alternative rotavirus candidate vaccines, particularly through the conduct of parallel clinical trials in both developed and developing countries.

Animals↗
PubMed2004

Rotavirus vaccine for preventing diarrhoea.

BACKGROUND: Rotaviruses cause viral gastroenteritis and result in more deaths from diarrhoea in children under 5 years of age than any other single agent, particularly in low- and middle-income countries. OBJECTIVES: To assess rotavirus vaccines in relation to preventing rotavirus diarrhoea, death, and adverse events. SEARCH STRATEGY: We searched the Cochrane Infectious Diseases Group's trial register (October 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2003), MEDLINE (1966 to October 2003), EMBASE (January 1980 to October 2003), LILACS (1982 to October 2003), Biological Abstracts (January 1982 to October 2003), reference lists of articles, and contacted researchers and rotavirus vaccine manufacturers. SELECTION CRITERIA: Randomized controlled trials comparing rotavirus vaccines to placebo, no intervention, or other rotavirus vaccines in children and adults. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed trial methodological quality, and contacted trial authors for additional information. MAIN RESULTS: Sixty-four trials provided information on efficacy and safety of three main types of rotavirus vaccine (bovine, human, and rhesus) for 21,070 children. Different levels of efficacy were demonstrated with different vaccines varying from 22 to 89% to prevent one episode of rotavirus diarrhoea, 11 to 44% to prevent one episode of all-cause diarrhoea, and 43 to 90% to prevent one episode of severe rotavirus diarrhoea. Rhesus vaccine demonstrated a similar efficacy against one episode of rotavirus diarrhoea (37 and 44% respectively), and one episode of all-cause diarrhoea (around 15%) for trials performed in high and middle-income countries. Results on mortality and safety of the vaccines were scarce and incomplete. We noticed important heterogeneity among the pooled studies and were unable to discard a biased estimation of effect. REVIEWER'S CONCLUSIONS: Current evidence shows that rhesus rotavirus vaccines (particularly RRV-TV) and the human rotavirus vaccine 89-12 are efficacious in preventing diarrhoea caused by rotavirus and all-cause diarrhoea. Evidence about safety, and about mortality or prevention of severe outcomes, is scarce and inconclusive. Bovine rotavirus vaccines were also efficacious, but safety data are not available. Trials of new rotavirus vaccines will hopefully improve the evidence base. Randomized controlled trials should be performed simultaneously in high-, middle-, and low-income countries.

Adult↗
PubMed1996

The gnotobiotic piglet as a model for studies of disease pathogenesis and immunity to human rotaviruses.

Gnotobiotic piglets serve as a useful animal model for studies of human rotavirus infections, including disease pathogenesis and immunity. An advantage of piglets over laboratory animal models is their prolonged susceptibility to human rotavirus-induced disease, permitting cross-protection studies and an analysis of active immunity. Major advances in rotavirus research resulting from gnotobiotic piglet studies include: 1) the adaptation of the first human rotavirus to cell culture after passage and amplification in piglets; 2) delineation of the independent roles of the two rotavirus outer capsid proteins (VP4 and VP7) in induction of neutralizing antibodies and cross-protection; and 3) recognition of a potential role for a nonstructural protein (NSP4) in addition to VP4 and VP7, in rotavirus virulence. Current studies of the pathogenesis of group A human rotavirus infections in gnotobiotic piglets in our laboratory have confirmed that villous atrophy is induced in piglets given virulent but not cell culture attenuated human rotavirus (G1, P1A, Wa strain) and have revealed that factors other than villous atrophy may contribute to the early diarrhea induced. A comprehensive examination of these factors, including a proposed role for NSP4 in viral-induced cytopathology, may reveal new mechanisms for induction of viral diarrhea. Finally, to facilitate and improve rotavirus vaccination strategies, our current emphasis is on the identification of correlates of protective active immunity in the piglet model of human rotavirus-induced diarrhea. Comparison of cell-mediated and antibody immune responses induced by infection with a virulent human rotavirus (to mimic host response to natural infection) with those induced by a live attenuated human rotavirus (to mimic attenuated oral vaccines) in the context of homotypic protection has permitted an analysis of correlates of protective immunity. Results of these studies have indicated that the magnitude of the immune response is greatest in lymphoid tissues adjacent to the local site of viral replication (small intestine). Secondly, there was a direct correlation between the degree of protection induced and the level of the intestinal immune response, with significantly higher local immune responses and complete protection induced only after primary exposure to virulent human rotavirus. These studies thus have established basic parameters related to immune protection in the piglet model of human rotavirus-induced disease, verifying the usefulness of this model to examine new strategies for the design and improvement of human rotavirus vaccines.

Animals↗
PubMed1996

Trials of oral bovine and rhesus rotavirus vaccines in Finland: a historical account and present status.

Live oral rotavirus vaccine strain RIT 4237, derived from group A bovine rotavirus NCDV, was given to human volunteers in Tampere, Finland in 1982. Efficacy studies of this vaccine in 6-12 month-old children gave results characteristic of the performance of oral rotavirus vaccines in general: 58% protective efficacy against any rotavirus gastroenteritis and 82% against "clinically significant" gastroenteritis. Four trials of RIT 4237 bovine rotavirus vaccine, one trial of group A RRV-1 rhesus rotavirus vaccine, and one trial of rhesus-human reassortant rotavirus vaccines D x RRV and DS1 x RRV were carried out between 1983-1989. A meta-analysis of the protective efficacy of these vaccines indicated a 67% (95% C.I. 55-77%) efficacy against moderately severe rotavirus disease and an 81% (95% C.I. 60-91%) efficacy against severe rotavirus disease. There was no apparent difference between bovine and rhesus-based rotavirus vaccines in the protective efficacy against severe rotavirus gastroenteritis. Problems associated with the use of any oral rotavirus vaccine include acid lability of the vaccine virus, which requires buffering, and a slight but significant interference of oral poliovirus vaccine with the uptake of rotavirus vaccine. In the near future, oral heterologous rotavirus vaccines may be available for prevention of severe rotavirus gastroenteritis.

Administration, Oral↗
PubMed1992

The effect of dexamethasone-induced immunosuppression on the development of faecal antibody and recovery from and resistance to rotavirus infection.

Rotavirus-naive and rotavirus-immune gnotobiotic calves were treated with high doses of dexamethasone (DX) to suppress the immune system. Calves were then infected with a virulent rotavirus inoculum, J-160, to investigate the role of immune responses both in recovery from primary rotavirus infection and in resistance to secondary rotavirus infection. Treatment of calves with DX markedly suppressed in vitro responsiveness of peripheral blood lymphocytes to mitogens within 48 h of the start of DX treatment. Suppression was similar in rotavirus-naive and rotavirus-immune calves. In contrast, the effect of DX treatment on specific antibody responses differed depending on when DX treatment started in relation to rotavirus infection. When DX treatment commenced prior to primary rotavirus infection both systemic and local specific antibody responses were inhibited. These calves, in which mitogen and antibody responses were suppressed, exhibited greater clinical signs than did control calves after infection with virulent rotavirus, but virus excretion was affected in only one of the two calves. When DX treatment was started after primary rotavirus infection but before secondary infection, systemic and local antibody responses to the primary infection and to the challenge infection were not affected. These calves resisted challenge with virulent virus as did DX-untreated rotavirus-immune calves, even though mitogen responses were suppressed. We conclude that in a primary rotavirus infection, virus excretion ceased when both antibody and mitogen responses were suppressed. Resistance to secondary rotavirus infection occurred when mitogen responsiveness was suppressed, but when antibody levels were normal. Thus, no evidence was obtained that fully functional cell-mediated immune mechanisms are essential for resistance to rotavirus infection. Evidence was provided for the ability of parenteral treatment with DX to suppress mucosal as well as systemic antibody responses.

Animals↗
PubMed1994

Prevalence of P types among porcine rotaviruses using subgenomic VP4 gene probes.

Nucleic acid probes were developed to differentiate VP4 (P) types among porcine rotaviruses. These probes were then used to determine the relative prevalence of P types 6 (Gottfried-like) and 7 (OSU-like) in cultivated rotaviruses and field specimens. The variable regions between bases 205-551 of the VP4 gene of rotavirus strains OSU and Gottfried were amplified by the polymerase chain reaction and radiolabeled with 32P by random primer extension. Radiolabeled probes were tested in a dot blot hybridization assay. The subgenomic probes prepared from VP4 gene detected as little as 5 ng oF rotavirus RNA and were specific for differentiating the two porcine rotavirus P types. The probes were used to determine the P type of several reference rotavirus strains and recently cultivated porcine rotavirus strains. Eight of the 10 cultivated, previously untyped, rotaviruses isolates tested were of P type 7 (OSU-like). Two rotavirus strains neither reacted with OSU nor with the Gottfried probe, therefore, their P type could not be determined. Seventeen out of the 26 rotavirus (65.4%) field samples tested had a P type 6 (Gottfried-like) whereas 5 out of 26 (19.2%) had a P type 7 (OSU-like). Four of the 26 samples (15.4%) reacted neither with the OSU nor with the Gottfried probe and possibly represent previously unrecognized P types in swine. Data in this study suggests that (1) rotaviruses with P type 7 are most common among the cultivated rotaviruses, (2) rotaviruses with P type 6 are the most abundant type of rotavirus in natural infections and (3) rotaviruses with additional P types are also associated with diarrheic swine.

Animals↗
PubMed1986

Conservation of amino acid sequence of VP8 and cleavage region of 84-kDa outer capsid protein among rotaviruses recovered from asymptomatic neonatal infection.

Within the past few years, rotavirus strains were recovered from four discrete prolonged outbreaks of infection in newborn nurseries in which affected infants failed to develop significant symptoms. The virus strains recovered from each outbreak belonged to a different human rotavirus serotype and thus each of the four human rotavirus serotypes was associated with asymptomatic infection of neonates. Marked conservation of sequence was observed among the fourth genes of the nursery rotavirus strains in a previous study using RNA X RNA hybridization, while a different conserved set of fourth gene sequences was identified among virulent human rotaviruses representing the four known serotypes. In the present study, this sequence dimorphism was further evaluated by comparing the sequence of the region of the fourth gene of virulent and asymptomatic human rotaviruses that codes for the VP8 protein, downstream cleavage sites, and the NH2 terminus of VP5. The corresponding sequences of a simian rotavirus were also determined. The fourth segment (+) strand RNA has a 5' conserved nontranslated sequence of nine nucleotides and encodes a VP8 protein of 240 amino acids in human rotavirus strains and 241 amino acids in simian rotavirus strains. Human and simian rotaviruses exhibit many similarities in this region of their genome, including identical NH2-terminal amino acid sequences, conservation of arginine at the two trypsin cleavage sites, and the position of a cysteine residue. Alignment of amino acid sequences of the VP8 protein, the downstream cleavage region, and the NH2 terminus of VP5 of asymptomatic and virulent human rotavirus strains indicates a high degree of homology (96% or more) among the asymptomatic viruses (serotypes 1, 2, 3, and 4), while homology between asymptomatic strains and virulent viruses is considerably less (68-72%). A high degree of conservation of amino acid sequence (92-97%) is also observed among three of the virulent strains (serotypes 1, 3, and 4). At 48 positions in the protein sequence of VP8, the cleavage region, and the NH2 terminus of VP5, an amino acid is conserved among asymptomatic rotaviruses, while a different amino acid is conserved among virulent rotaviruses. Notably, three of these differences are located within the cleavage region between VP8 and VP5. These findings suggest that the fourth genes of virulent and asymptomatic human rotavirus strains represent two lines of divergent evolution from a common ancestor. Also, it is possible that this sequence dimorphism may be responsible in part for the difference in virulence between these two groups of human rotaviruses.

Amino Acid Sequence↗
PubMed1985

Rotavirus antibodies in the mother and her breast-fed infant.

The transfer of rotavirus antibodies from 25 healthy mothers to their breast-fed infants was investigated during the period of lactation (mean, 3.9 months; range, 1-9 months). Furthermore, the destiny of these antibodies in the infants' gastrointestinal tract and serum was examined. Rotavirus-specific immunoglobulins were analyzed by the ELISA (enzyme-linked immunosorbent assay) technique. All the mothers had rotavirus IgA and IgG in serum. About 80% of the mothers had low concentrations of rotavirus ScIg (i.e., antirotavirus immunoglobulin containing secretory component) in serum at the beginning of the lactation period declining to about 45% at the end of the period. From a few days after delivery to about 2 weeks later, the concentrations of rotavirus IgA and ScIg in milk declined. Thereafter, they remained unchanged. There was a positive correlation among the concentrations of rotavirus IgA in serum and rotavirus IgA as well as ScIg in milk. Rotavirus IgG in the infants' serum correlated with that of the mothers. Few samples of the infants' duodenal fluid contained rotavirus IgA or ScIg. On the other hand, about 80% of the infants' fecal samples contained rotavirus ScIg and IgA. Rotavirus IgA and ScIg disappeared from the infants' feces after cessation of lactation. Hence, it may be concluded that infants receive rotavirus IgG through the placenta, and rotavirus ScIg and IgA in constant amounts via milk throughout the period of lactation. The small intestine is flushed with rotavirus ScIg and IgA at each breast-meal, and these antibodies survive proteolysis in the gut. A possible protectional effect of rotavirus ScIg or IgA requires frequent breast-meals, and the effect is limited to the period of lactation.

Adult↗
PubMed2006

Mice develop effective but delayed protective immune responses when immunized as neonates either intranasally with nonliving VP6/LT(R192G) or orally with live rhesus rotavirus vaccine candidates.

Rotavirus vaccines are delivered early in life, when the immune system is immature. To determine the effects of immaturity on responses to candidate vaccines, neonatal (7 days old) and adult mice were immunized with single doses of either Escherichia coli-expressed rotavirus VP6 protein and the adjuvant LT(R192G) or live rhesus rotavirus (RRV), and protection against fecal rotavirus shedding following challenge with the murine rotavirus strain EDIM was determined. Neonatal mice immunized intranasally with VP6/LT(R192G) were unprotected at 10 days postimmunization (dpi) and had no detectable rotavirus B-cell (antibody) or CD4(+) CD8(+) T-cell (rotavirus-inducible, Th1 [gamma interferon and interleukin-2 {IL-2}]-, Th2 [IL-5 and IL-4]-, or ThIL-17 [IL-17]-producing spleen cells) responses. However, by 28 and 42 dpi, these mice were significantly (P >or= 0.003) protected and contained memory rotavirus-specific T cells but produced no rotavirus antibody. In contrast, adult mice were nearly fully protected by 10 dpi and contained both rotavirus immunoglobulin G and memory T cells. Neonates immunized orally with RRV were also less protected (P=0.01) than adult mice by 10 dpi and produced correspondingly less rotavirus antibody. Both groups contained few rotavirus-specific memory T cells. Protection levels by 28 dpi for neonates or adults were equal, as were rotavirus antibody levels. This report introduces a neonatal mouse model for active protection studies with rotavirus vaccines. It indicates that, with time, neonatal mice develop full protection after intranasal immunization with VP6/LT(R192G) or oral immunization with a live heterologous rotavirus and supports reports that protection depends on CD4(+) T cells or antibody, respectively.

Adjuvants, Immunologic↗
PubMed2003

Human group C rotaviruses identified in Kenya.

BACKGROUND: Rotavirus is associated with acute infantile gastro-enteritis in infants and young children worldwide. Rotavirus is associated with the high cases of morbidity and mortality and it is estimated that up to 650,000 deaths in young children occur annually in the less developed countries. Approximately a quarter of these deaths occur in African children yet minimal data exist on the circulating rotavirus strains in Africa. OBJECTIVE: To characterise the circulating rotavirus strains in Kenya. DESIGN: A prospective study to investigate rotavirus infection in infants and young children with acute diarrhoea in different areas of Kenya. Between September 2001 and February 2002, 119 faecal specimens were collected from children aged between 1 and 60 months with acute infantile gastro-enteritis. SETTING: Faecal samples were collected from clinics around Nairobi and its suburbs including Karen, Ngong, Ongata Rongai. SUBJECTS AND METHODS: Faecal samples were collected from 119 infants and young children with diarrhoea and were analysed by commercial ELISA and polyacrylamide gel electrophoresis (SDS-PAGE) to identify possible non-group A rotaviruses. Extraction of any potential rotavirus double-stranded RNA from faeces and characterisation by SDS-PAGE showed the presence of human group C rotaviruses. RESULTS: Examination of these samples with a commercial ELISA assay for the presence of group A rotavirus antigen showed that 13 specimens (11%) were positive. An analysis of all stool specimens was performed by polyacrylamide gel electrophoresis to identify possible non-group A rotaviruses. Extraction of any potential rotavirus double-stranded RNA from faeces and characterisation by SDS-PAGE showed the presence of human group C rotaviruses. CONCLUSION: This is the first report of group C rotaviruses in Kenya. Further studies are underway to continue the surveillance of rotavirus strains in Kenya; as this information will be useful in planning rotavirus vaccine trials in Africa.

Child, Preschool↗
PubMed2004

[Molecular epidemiologic survey of rotaviruses from infants and children with diarrhea in Shanghai].

OBJECTIVE: To investigate molecular epidemiologic features of rotaviruses circulating in Shanghai, China. METHODS: Stool samples were collected from 1230 hospitalized children with community-acquired and nosocomially acquired diarrhea in Children's Hospital Affiliated to Fudan University between November 1, 1999 and December 31, 2001. Polyacrylamide gel electrophoresis (PAGE) was used to detect rotavirus genomic RNA and identify electropherotypes of group A rotavirus RNAs. Reverse transcription polymerase chain reaction (RT-PCR) was performed to amplify full length VP7 gene and dot blot hybridization was performed to identify rotavirus G serotypes using digoxigenin-labelled variable regions from VP7 genes as probes. These probes were amplified by PCR from recombinant plasmids containing full length G1, G2, G3 and G4 VP7 genes from rotavirus field strains detected in Beijing and digoxigenin labelled dUTP was integrated into the PCR products. The Kruskal-Wallis analysis of variance was employed to analyze whether there were significant differences in variables. RESULTS: Out of 1230 samples investigated, 493 (40.1%) were group A rotavirus gene positive by PAGE, among which 397 (80.5%) showed long electropherotypes, 55 (11.2%) showed short electropherotypes, 18 (3.7%) showed mixed electropherotypes which suggested that the children were co-infected by rotaviruses with different electropherotypes, 23 (4.7%) were non-typable because of degradation of some of the genomic RNA fragments. No group B or group C rotavirus was found. RT-PCRs were performed for 328 fecal specimens containing sufficient rotavirus RNAs and VP7 gene products were obtained from 254 (77.4%) samples. Dot blot hybridization showed serotype G1 accounted for 55.5% (141) of these samples, serotype G3 accounted for 27.6% (70), serotype G2 accounted for 9.4% (24), co-infection by 2 rotaviruses with different G types accounted for 6.3% (16), only 1 G4 was detected and 2 were non-typable. The genomic RNA patterns of all G2 strains were short and those of G1, G3 and G4 strains were long. There were no statistically significant differences for age distribution and clinical manifestations among those infants and children infected by rotaviruses with different G serotypes. CONCLUSION: Group A rotavirus is the major pathogen for diarrhea in infants and children in Shanghai during the period of Nov. 1999 to Dec. 2001. Rotaviruses with long electropherotype were dominant during these years. Serotypes G1 to G3 constituted 98.8% of all 254 strains tested, and G1 was the most common serotype followed by G3 and G2, whereas serotype G4 was seldom found. Some of the children were co-infected by rotaviruses with different G serotypes. Clinical manifestations were not related to the infecting rotavirus with different G serotypes.

Age Factors↗
PubMed1990

[Epidemiological study of group C rotavirus].

By electron microscopy survey of acute gastroenteritis of children in Matsuyama, rotaviruses were detected in 561 of 2479 fecal samples obtained between October, 1984 and September, 1988, in which 60 atypical and 259 typical rotaviruses, so far tested, were detected by polyacrylamide gel electrophoresis (PAGE) of viral RNA. Out of 60 atypical rotaviruses, 5 were observed in 1985, 7 in 1986, none in 1987 and 48 in 1988. These atypical rotaviruses were morphologically indistinguishable from typical ones and showed very similar RNA migration patterns of PAGE to those of group C rotavirus. Furthermore, one atypical virus (86-542) reacted with antiserum against a porcine group C rotavirus in immune electron microscopy, while it did not react with anti-group A rotavirus serum. On the other hand, hyperimmune guinea pig antiserum against 86-542 reacted with a couple of atypical rotavirus including viruses isolated in 1988, so far tested, but did not react with any of the typical viruses. These findings showed that atypical rotaviruses which were endemic in Matsuyama city in 1988 were defined as group C rotavirus. Moreover, these group C rotaviruses showed two kind of RNA migration patterns in PAGE, which clearly discriminated the virus were isolated before and after 1987. Epidemiological features of group C rotavirus were as follows. Children from whom group C rotavirus was isolated were older than those from of whom group A rotavirus was isolated. The epidemic season was in February through April, compared to December through March in group A virus. Retrospective seroepidemiological study by immune adherence hemagglutination test (IAHA) using the purified 86-542 virus as antigen indicated that 15 of 78 sera of children obtained in 1971 already possessed IAHA antibody against group C rotavirus.

Adolescent↗
PubMed2003

A human vaccine strain of lamb rotavirus (Chinese) NSP4 gene: complete nucleotide sequence and phylogenetic analyses.

A lamb strain of rotavirus has recently been licensed for use in China as a live vaccine to prevent rotavirus diarrhea in children. As rotavirus NSP4, especially the cytotoxic domain alone is considered to be associated with diarrhea, we sequenced gene segment 10, which encodes NSP4, of lamb rotavirus. Comparative analyses was performed to identify differences from human rotavirus strains, that might be associated with attenuation, and to ascertain whether the lamb rotavirus gene fits among the NSP4 of other sequenced rotavirus strains. Our comparative nucleotide sequence analysis suggests its close identity (91.17% homology) with that of group-A equine rotavirus (strain HI23). Multiple alignment of the deduced amino acid sequence of lamb NSP4 with that of other group A rotaviruses demonstrated homology ranging from 63.42% with that of porcine YM strain to 93.71% with equine HI23 strain of rotavirus. A group A-specific NSP4 monoclonal antibody recognized the glycosylated and unglycosylated forms of the protein from virus-infected lysates, suggesting a well-conserved group-specificity of the lamb NSP4. Phylogenetic analysis of the lamb rotavirus gene, with 60 other NSP4 gene sequences of human and animal rotavirus strains, demonstrated that the lamb rotavirus strain belongs to genotype A. Comparative analysis also revealed that although it is a vaccine strain, the NSP4 cytotoxic domain of lamb strain demonstrated an overall amino acid conservation similar to that of other strains, whose NSP4 alone causes diarrhea in animal models. These results taken together with our previous observations clearly reaffirm the idea that the attenuation phenotype of rotaviruses does not involve NSP4 cytotoxic domain, perhaps due to the suppression of NSP4 cytotoxic activity by other rotaviral proteins.

Amino Acid Sequence↗
PubMed2005

Epidemiological profile of rotavirus infection in the Republic of Korea: results from prospective surveillance in the Jeongeub District, 1 July 2002 through 30 June 2004.

To facilitate future decisions regarding the usefulness of rotavirus vaccines in the Republic of Korea, active surveillance was conducted in a network of clinics, emergency departments, and hospitals serving Jeongeub District, Korea. Children with diarrhea underwent standard clinical evaluations, and stool specimens were collected to test for the presence of rotavirus. Parents were interviewed to collect demographic and family information. From 1 July 2002 through 30 June 2004, a total of 4106 children, representing 1 (50%) of every 2 children <5 years old in the study population, were evaluated for rotavirus diarrhea. Of the 2232 stool specimens obtained throughout the year, 460 (20.6%) were rotavirus positive; however, the monthly prevalence of rotavirus infection peaked at 49.5% in February 2004. Of the 460 rotavirus-positive stool specimens, 366 were obtained from children who visited outpatient clinics, and 94 were obtained from children who were hospitalized. By extrapolating the proportion of rotavirus-positive patients to all children with diarrhea in the surveillance system, we calculate that 882 children in Jeongeub District had rotavirus infection (which would predict that there would be 702 associated clinic visits and 180 hospitalizations). Genotyping of rotavirus strains showed that 39% of strains were type G9P[8], 24% were type G1P[8], 17% were type G3P[8], and 13% were type G2P[4]. The incidence of rotavirus diarrhea peaked at age 13-24 months, and 94% of cases occurred during the first 3 years of life. The annual incidence of all rotavirus disease-associated outcomes was 56.9 cases/1000 children <5 years old (95% confidence interval [CI], 51.9-62.2 cases/1000 children <5 years old). The incidence of rotavirus disease-associated hospitalizations was 11.6 cases/1000 children <5 years old (95% CI, 9.5-14.2 cases/1000 children <5 years old). In Korea, diarrhea is common during childhood, and the incidence of diarrhea due to rotavirus infection suggests that improved programs for the prevention and control of both rotavirus diarrhea and diarrhea due to other causes are needed.

Ambulatory Care Facilities↗
PubMed1985

Intestinal and serum immune response to a naturally acquired rotavirus gastroenteritis in children.

Seventeen children (mean age: 2.0 years, range: 36 days-8 years) hospitalized with acute gastroenteritis were investigated. Thirteen children had a rotavirus infection while four did not. Rotavirus serum IgA as well as ScIg, i.e., antirotavirus immunoglobulin containing secretory component, increased rapidly after rotavirus infection. While rotavirus IgA persisted in serum for at least 6 months, rotavirus ScIg disappeared from serum in less than 4 months. Rotavirus IgG could be detected in serum during the early stage of the infection and was still high after 6 months. The patients with nonrotavirus acute gastroenteritis did not show any of the above-mentioned serological hallmarks of those with rotavirus infection. The amounts of rotavirus ScIg found in serum about 1 week after the infection correlated to the amounts of rotavirus ScIg in duodenal fluid. Six months after the infection, rotavirus IgA was found in the feces of the majority of the patients while rotavirus ScIg could be detected only in one patient. The amounts of rotavirus IgA in sera and intestinal secretions showed identical patterns in the acute phase of the disease as well as after recovery. The same applied to rotavirus ScIg. These findings could be useful in future evaluations of vaccines and immunity against rotavirus infections.

Antibody Formation↗