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PubMed1992

Evidence of serologic diversity within group C rotaviruses.

The Cowden strain of porcine group C rotavirus and the Shintoku strain of bovine group C rotavirus were classified as different serotypes by two-way cross-neutralization tests. Two neutralization patterns against the Cowden and Shintoku strains were observed when hyperimmune or convalescent-phase antisera to three noncultivatable porcine group C rotaviruses and a human group C rotavirus were used in one-way cross-neutralization tests. Antisera to two porcine group C rotaviruses and the human group C rotavirus neutralized the Cowden strain at high titers but did not neutralize the Shintoku strain, suggesting that these three strains are serotypically related to the Cowden strain. The remaining antisera to a porcine group C rotavirus (HF strain) reacted with the Cowden and Shintoku group C rotaviruses in cell culture immunofluorescence tests but did not neutralize either virus in one-way cross-neutralization, suggesting that the HF strain belongs to a third serotype. However, confirmation of these findings requires additional analysis by two-way cross-neutralization. Our findings support the existence of at least two distinct serotypes of group C rotaviruses, and possibly a third, among animals and humans. The serotypic similarity observed between the Cowden strain and a human group C rotavirus suggests that the cultivatable Cowden strain and antiserum to this virus may provide important reagents for the diagnosis of group C rotaviruses in humans.

Animals↗
PubMed2006

G8 rotavirus strains isolated in the Democratic Republic of Congo belong to the DS-1-like genogroup.

Several G8P[6] and G8P[8] rotavirus strains were isolated from hospitalized patients in the Democratic Republic of Congo in 2003. To investigate their overall genomic relatedness and to determine to which genogroup they belonged, the complete genomes of strains DRC88 (G8P[8]) and DRC86 (G8P[6]) were determined. Genomic comparison of these two African G8 strains revealed that 10 out of their 11 gene segments, except for VP4, were nearly identical (>98.9% identical at the nucleotide level), suggesting that this rare G8P[8] rotavirus strain originated recently from a reassortment between a common G8P[6] strain and a strain with a P[8] specificity. A very close evolutionary relationship between 9 out of the 11 gene segments of DRC88 and DRC86 and rotavirus strains belonging to the DS-1-like (G2P[4]) "genogroup" was found, and several possible reassortment events preceding the occurrence of G8P[8] and G8P[6] human rotaviruses were hypothesized. Since the genes of G2P[4] rotavirus strains are very well adapted to infect humans, the acquirement of a new VP7 (G8) gene, and especially the replacement of P[6] (believed to be of animal origin) by P[8] (most common in human rotaviruses), might make DRC88-like rotaviruses very well equipped to become a predominant human rotavirus strain and an important pathogen on the African continent and the rest of the world. These findings have important implications for rotavirus vaccine development and highlight that typing of new rotavirus strains by merely sequencing their VP7 and VP4 genes provides us with only the tip of the iceberg regarding rotavirus diversity.

Animals↗
PubMed1985

Neutralizing monoclonal antibodies to human rotavirus and indications of antigenic drift among strains from neonates.

Cells producing neutralizing monoclonal antibodies to a serotype 3 human neonatal rotavirus strain RV-3 were derived by fusion of hyperimmunized mouse spleen cells with mouse myeloma cells. As ascites fluid, three rotavirus-neutralizing monoclonal antibodies were characterized by hemagglutination inhibition and reacted with 17 cultivable mammalian rotaviruses representing five virus serotypes, by fluorescent focus neutralization and enzyme immunoassay. Two antibodies, Mab RV-3:1 and Mab RV-3:2, reacted with the seven serotype 3 rotaviruses only. Mab RV-3:1 was shown to bind to the outer capsid glycoprotein gp34 of rotavirus when variants of SA 11 rotavirus were used, and it therefore appears to react with the major neutralization epitope of serotype 3 rotaviruses. The antibody Mab RV-3:3 was specific for an epitope of RV-3 rotavirus not present on any other rotavirus of any serotype tested, including another neonatal isolate of identical RNA electropherotype isolated from the same ward of the same hospital as RV-3 3 months earlier. These two viruses were also distinguishable by fluorescent focus neutralization, using antiserum to RV-3 virus. Western blot analysis showed binding of Mab RV-3:3 to the trypsin cleavage product of the outer capsid protein p86 of RV-3. This suggests that antigenic drift may have occurred among neonatal rotaviruses in Melbourne. These monoclonal antibodies will be useful in serotyping assays of rotaviruses directly in stool samples, and in further analysis of antigenic variation within the serotype.

Antibodies, Monoclonal↗
PubMed1994

Comparison of mucosal and systemic humoral immune responses and subsequent protection in mice orally inoculated with a homologous or a heterologous rotavirus.

Rotaviruses are the single most important cause of severe diarrhea in young children worldwide, and vaccination is probably the most effective way to control the disease. Most current live virus vaccine candidates are based on the host range-restricted attenuation of heterologous animal rotaviruses in humans. The protective efficacy of these vaccine candidates has been variable. To better understand the nature of the heterologous rotavirus-induced active immune response, we compared the differences in the mucosal and systemic immune responses generated by heterologous (nonmurine) and homologous (murine) rotaviruses as well as the ability of these infections to produce subsequent protective immunity in a mouse model. Sucking mice were orally inoculated with a heterologous simian or bovine rotavirus (strain RRV or NCDV) or a homologous murine rotavirus (wild-type or tissue culture-adapted) strain EHP at various doses. Six weeks later, mice were challenged with a virulent murine rotavirus (wild-type strain ECW) and the shedding of viral antigen in feces was quantitated. Levels of rotavirus-specific serum immunoglobulin G (IgG) and fecal IgA prior to challenge were measured and correlated with subsequent viral shedding or protection. Heterologous rotavirus-induced active protection was highly dependent on the strain and dose of the virus tested. Mice inoculated with a high dose (10(7) PFU per mouse) of RRV were completely protected, while the protection was diminished in animals inoculated with NCDV or lower doses of RRV. The ability of a heterologous rotavirus to stimulate a detectable intestinal IgA response correlated with the ability of the virus to generate protective immunity. Serum IgG titer did not correlate with protection. Homologous rotavirus infection, on the other hand, was much more efficient at inducing both mucosal and systemic immune responses as well as protection regardless of the virulence of the virus strain or the size of the immunizing dose.

Administration, Oral↗
PubMed1997

Evidence for CD8+ T-cell immunity to murine rotavirus in the absence of perforin, fas, and gamma interferon.

We recently showed that class I-restricted CD8+ T cells mediate clearance of primary rotavirus infection in mice: JHD knockout (JHD -/-) (B-cell-deficient) mice depleted of CD8+ T cells become chronically infected with murine rotavirus, and beta2 microglobulin knockout (beta2m -/-) mice have delayed but complete clearance of primary rotavirus infection. In the present work we have analyzed the mechanism used by CD8+ T cells to clear rotavirus infection. We first determined that perforin knockout (perforin -/-) mice and lpr (fas-deficient) mice clear rotavirus infection with the same kinetics as control mice. When perforin -/- or perforin +/+ mice were depleted of CD8+ T cells by administration of an anti-CD8 monoclonal antibody, they showed a delay of 1 to 2 days in the clearance of rotavirus infection compared to the clearance time for untreated control mice, indicating that CD8+ T cells in both groups of mice participate in the resolution of primary rotavirus infection. In addition, passively transferred CD8+ T cells from rotavirus-infected perforin +/+ and perforin -/- mice were able to mediate viral clearance in Rag 2 knockout (Rag 2 -/-) mice chronically infected with rotavirus with similar kinetics, suggesting that CD8+ T cells from perforin -/- mice are as efficient as CD8+ T cells from perforin +/+ mice in clearing a rotavirus infection. Gamma interferon (IFN-gamma) was also shown to be unnecessary for the antirotavirus effect of CD8+ T cells: IFN-gamma knockout (IFN-gamma -/-) mice and JHD -/-, perforin -/-, and perforin +/+ mice depleted of IFN-gamma by administration of an anti-IFN-gamma monoclonal antibody cleared rotavirus infection with the same kinetics as those for control mice. Hence, CD8+ T cells have an antirotaviral effect that is not mediated by perforin and appears to be independent of fas and the release of IFN-gamma.

Animals↗
PubMed1998

Improvement of the specificity of enzyme immunoassays for the detection of rotavirus and adenovirus in fecal specimens.

A variable rate of false-positive results may be observed with commercial enzyme immunoassays (EIAs) for the detection of rotavirus and adenovirus antigen in stool specimens, depending on the quality of the reagents and the presence of potentially interfering substances in stool samples. The present study was performed in an attempt to improve the specificity of current commercial rotavirus and adenovirus EIAs without significant loss of sensitivity by optimizing the cut-off value. A collective of 174 stool samples obtained from children suffering from acute gastroenteritis was tested. Electron microscopy (EM) and PAGE were used as reference methods for rotavirus detection. For the evaluation of the adenovirus kits, virus isolation in cell culture and the polymerase chain reaction served as reference standards. The highest sensitivity for rotavirus and adenovirus detection was achieved by the Ridascreen(R) Rotavirus and Ridascreen Adenovirus. However, the Ridascreen(R) Rotavirus and Ridascreen Adenovirus produced the highest number of false-positive results (n = 9) for each rotavirus and adenovirus detection. Cross-reactivities to coronaviruses and reoviruses were observed with the rotavirus antigen EIAs. For Rotazyme II, Ridascreen Rotavirus and Ridascreen Adenovirus, the specificity could be markedly increased without loss of sensitivity by doubling the cut-off value. For the alternative immunoassays, which were overall more specific, it was not possible to significantly decrease the rate of false-positive results without impairment of sensitivity by raising the cut-off value. In conclusion, at least for some rotavirus and adenovirus antigen EIAs, the cut-off value set by the manufacturer may not permit an optimal differentiation between true-positive and -negative samples. By raising the cut-off value from 50 to 100%, the specificity of two rotavirus antigen and one adenovirus antigen EIA can be improved markedly without significant loss of sensitivity.

Adenoviridae Infections↗
PubMed1995

The lesions of rotavirus infection in 1- and 10-day-old gnotobiotic calves.

Age-related resistance to rotavirus disease has been described with some rotaviruses. In the present study, we investigated age-related resistance to rotavirus disease by defining extent of intestinal infection, virus replication, and severity of intestinal lesions in groups of three 1- and 10-day-old gnotobiotic calves of mixed breed inoculated orally with a cloned bovine rotavirus of low virulence for calves (strain C3-160) and in two groups of three uninoculated control calves of mixed breed. One-day-old calves inoculated with rotavirus developed diarrhea 26 hours after inoculation, and their feces contained 10(8.5)-10(9.2) TCID50/g feces; inoculated 10-day-old calves did not develop diarrhea, virus excretion commenced on the second or third day after inoculation, and peak concentrations of virus in feces were 10(5.7)-10(7.9) TCID50/g feces. Calves were euthanatized within 8-30 hours after the attainment of peak virus shedding while they were still shedding virus at peak levels. The mean percentage of small intestinal epithelium that was immunostained for rotavirus was three times greater in 1-day-old calves than in 10-day-old calves, and the large intestine was infected more extensively in 1-day-old calves. Immunostaining for rotavirus was maximal in the mid small intestine. Staining of mucin was substantially less in the epithelium of the small intestines and colon of rotavirus-inoculated 1-day-old calves than in age-matched controls. The mean height of villi was reduced to approximately half that of controls in the mid and distal small intestine of rotavirus-inoculated 1-day-old calves and was unchanged in 10-day-old calves. Mean crypt cell production rates were greater than that in controls in both groups of rotavirus-inoculated calves, indicating increased enterocyte loss. Age-related resistance to disease was not due to an inability of rotavirus to infect and replicate in enterocytes with lethal effects but appeared to be associated with a slowing of the pathogenic process, which occurred because insufficient enterocytes became infected and destroyed for lesions to develop.

Aging↗
PubMed2006

Isolation and characterization of a new simian rotavirus, YK-1.

BACKGROUND: To effectively analyze the requirements for protection to rotavirus infection, a reliable animal model that reasonably mimics infection and disease in humans is needed. A requirement for an effective animal model is the availability of appropriate rotavirus stocks for challenge. RESULTS: A new simian rotavirus, designated YK-1, was isolated from a 2-year-old immunodeficient pigtailed macaque with chronic diarrhea. YK-1 was distinguishable by electropherotype from the other simian rotavirus strains, SA11 and RRV. One variant of YK-1, clone 311, which was isolated after adaptation and plaque purification in cell cultures, displayed an unusual RNA electropherotype with an abnormally migrating gene 11 segment. Sequence analysis demonstrated a genetic rearrangement that involved a partial duplication of the gene 11 ORF encoding NSP5. YK-1 was identified as a Group A rotavirus belonging to subgroup 1. To further characterize the YK-1 strain, the genes encoding VP4, VP7, and NSP4 were sequenced. Analysis of VP4 and VP7 gene fragments suggests that this strain is a G3P3 rotavirus and is closely related to the simian rotavirus strain RRV. Serotype analysis also identified YK-1 as a G3 rotavirus. The NSP4 genotype of YK-1 is C, the same genotype as RRV. CONCLUSION: This newly isolated rotavirus, YK-1, is being used to establish a nonhuman primate model for studying the infectivity, immunity, and pathogenesis of rotavirus and for evaluating candidate rotavirus vaccines.

Animals↗
PubMed1998

Human group C rotavirus in children with diarrhea in the Federal District, Brazil.

Group C rotaviruses are fastidious in their in vitro cell culture requirements. Recent serosurveys indicate that antibody to group C rotavirus is present in 3-45% of the human population in certain geographic locations, suggesting that rotavirus group C infection is more prevalent than previously believed and that the low rate of detection of these agents is probably due to the lack of sensitive diagnostic assays. From March to December 1994, 406 fecal specimens were collected from children under five years of age who were outpatients at the emergency services of nine public hospitals in Brasília, Federal District, Brazil. In addition to the samples from children, one public outpatient unit requested virological investigation of a stool sample from an HIV-seropositive adult male with diarrhea of sudden onset. All samples were analyzed by enzyme immunoassay for group A rotavirus and adenovirus (EIARA) and by polyacrylamide gel electrophoresis (PAGE). One hundred and seven (26%) were positive for group A rotavirus. Four samples from children and the sample from the HIV-seropositive patient, although negative by EIARA, showed a group C rotavirus profile by PAGE and were positive for rotavirus by electron microscopy. Using specific VP6 and VP7 primers for group C rotavirus, a reverse transcriptase-polymerase chain reaction (RT-PCR) was performed and products were detected by agarose gel electrophoresis and ethidium bromide staining. These products were confirmed to be specific for group C rotavirus by using digoxigenin-oligonucleotide probes, Southern hybridization and chemiluminescent detection. The five positive group C rotavirus samples were detected in August (3 samples) and September (2 samples). To the best of our knowledge, this is the first report of group C rotavirus detected in the Federal District, Brazil and in an HIV-seropositive patient with acute gastroenteritis.

Adult↗
PubMed2001

Epidemiological aspects of rotavirus infections in Minas Gerais, Brazil.

In order to develop good polices regarding public health measures and vaccine use to prevent rotavirus induced gastroenteritis, the epidemiology of the illness in various regions of Brazil is necessary. Accordingly, this study was to detect the frequency and types of rotavirus in one city in a tropical part of Brazil. This is an epidemiological survey of pediatric gastroenteritis caused by rotavirus conducted in Juiz de Fora, Minas Gerais State, Brazil. We analyzed 656 in-patient (190) and out-patient (466) stool samples from children ages 0 to 5 years during 1998. Rotavirus detection was performed using polyacrylamide gel electrophoresis (PAGE). Rotavirus was isolated from 62/190 stool samples (32.6%) from hospitalized children and 16/466 (3.4%) from out-patients. The overall rotavirus frequency in this population was 11.9%. The highest rotavirus detection was found in hospitalized children ages 6 to 24 months. Rotaviruses were detected from March to September, with a peak incidence in June (33.3%), the coldest and driest month in the region. Electrophoretic analysis identified 10 different profiles, all long and compatible with group A rotavirus, termed L(A) through LJ. The L(B) and L(D) profiles circulated throughout most of the study period. However, in June, when the highest detection rate occurred, the vast majority (92.5%) of the positive samples displayed the L(B) profile, thus suggesting an outbreak caused by this rotavirus profile. Rotavirus induced gastroenteritis is common in one tropical region of Brazil, it is an important cause of diarrhea in hospitalized children ages 6 to 24 months, it is most common during dry, cold months of the year, and it may occur in electrophoretype restricted epidemics. Such analyses throughout Brazil will assist in developing sound guidelines regarding its prevention.

Age Distribution↗
PubMed2006

Rotavirus vaccine (RotaTeq).

RotaTeq is a live, oral, pentavalent human-bovine reassortant rotavirus vaccine approved for use in the prevention of G1-G4 rotavirus gastroenteritis in infants and children. Rotavirus vaccine demonstrated good immunogenicity in healthy infants. Three oral doses of rotavirus vaccine had a protective efficacy against G1-G4 rotavirus gastroenteritis of any severity of 74%, and a protective efficacy against severe G1-G4 rotavirus gastroenteritis of 98%, in the randomized, double-blind, placebo-controlled, multicenter REST (Rotavirus Efficacy and Safety Trial) study; the per-protocol efficacy analysis included >4500 infants. Healthcare resource use was reduced by rotavirus vaccine, with a 94.5% reduction in the incidence of hospitalization or emergency department care because of G1-G4 rotavirus gastroenteritis. This analysis of the REST trial included >57,000 infants. Rotavirus vaccine did not increase the risk of intussusception within 42 days of any dose, according to an analysis of the REST trial including almost 70,000 infants. Rotavirus vaccine and placebo were associated with serious adverse events in <3% of infants in either group.

Administration, Oral↗
PubMed2006

Rotavirus vaccine RIX4414 (Rotarix).

RIX4414 is a human, live attenuated rotavirus vaccine containing a rotavirus strain of G1P[8] specificity; it is administered orally using a two-dose schedule. RIX4414 showed good immunogenicity in healthy infants in several well designed trials in terms of both seroconversion rates and vaccine take. Moreover, RIX4414 did not impair the immune response of infants to other vaccines. RIX4414 provided significant protection against severe rotavirus gastroenteritis. In a subgroup analysis (n = 20 169) of a large (n = 63 225), well designed, placebo-controlled, phase III trial (conducted in Latin America and Finland), the efficacy of RIX4414 against severe rotavirus gastroenteritis was 85% in healthy infants, with an efficacy against hospitalization for severe rotavirus gastroenteritis of 85%. RIX4414 provided cross-protection against non-G1 serotypes containing the P[8] antigen. Moreover, in this trial, RIX4414 had a protective efficacy against severe gastroenteritis of any cause of 40%, with an efficacy against hospitalization because of severe gastroenteritis of any cause of 42%. In another well designed, placebo-controlled, phase III trial (conducted in Europe; n = 3874), RIX4414 had an efficacy against rotavirus gastroenteritis of any severity of 87%, an efficacy against severe rotavirus gastroenteritis of 96%, and an efficacy against hospitalization because of rotavirus gastroenteritis of 100%. RIX4414 protected against rotavirus gastroenteritis from the first dose onwards. A meta-analysis revealed that RIX4414 had a protective efficacy against rotavirus gastroenteritis of any severity caused by the G2P[4] serotype of 81% and against severe rotavirus gastroenteritis caused by the G2P[4] serotype of 71%. RIX4414 was generally well tolerated in healthy infants. The vaccine did not appear to be associated with an increased risk of intussusception.

Clinical Trials as Topic↗
PubMed1999

[Rotavirus gastroenteritis in infants and children. Results of a prospective study in the area of Geneva and Basel 1997/1998 (RoMoS). RoMoS Study Group].

BACKGROUND: In Europe information is scarce about the impact of rotavirus, probably the most important cause of acute gastroenteritis in children up to the age of 4 years. The aim of this study was to collect data on the frequency and symptoms of community-acquired rotavirus-positive acute gastroenteritis in Switzerland. PATIENTS AND METHODS: In 6 paediatric practices, 3 each in the Geneva and Basle areas, every child up to the age of 48 months presenting with acute gastroenteritis between December 1997 and May 1998 was eligible for inclusion in the study. The symptoms, course of the disease and treatment were recorded in a standardized fashion after informed consent had been obtained. Stool specimens were screened for rotavirus by ELISA, and PCR was performed for serotyping in ELISA-positive samples. RESULTS: 294 of 6672 children under observation were taken to their paediatrician because of acute gastroenteritis during the study period. Informed consent was obtained in 256 cases (mean age 19.2 months). 234 stool specimens were available of which 96 (41%) were rotavirus-positive. The incidence of rotavirus-positive acute gastroenteritis was 1.6 per 100 children and winter season. Acute gastroenteritis due to rotavirus was more severe than rotavirus-negative acute gastroenteritis, with diarrhoea and vomiting in 84% versus 54%, and dehydration in 42% versus 28%, 5% of the acute gastroenteritis cases compared to 11% of the rotavirus-positive cases were hospitalized. In the Geneva and Basle areas the predominant rotavirus types, as identified by PCR in ELISA-positive stool specimens, were G4 P[8] and G1 P[8] respectively (67% each). CONCLUSION: Rotavirus infection was a relevant cause of acute gastroenteritis in our study population, resulting in more severe symptoms than rotavirus-negative acute gastroenteritis. All G-types identified in our study are included in the recently developed tetravalent vaccine. Cost-benefit analysis and ethical issues will need to be considered in evaluating the impact of the vaccine in Switzerland.

Child, Preschool↗
PubMed1992

Laboratory-based surveillance for rotavirus United States, January 1989-May 1991.

Geographic and temporal trends of rotavirus detections in the United States for the period January 1989-May 1991 were determined by analyzing data reported monthly by 47 virology laboratories participating in the North American Rotavirus Surveillance System. Reports included complete information on the number of specimens tested, the number of test results positive for rotavirus, and the method used to detect rotavirus. Consistent trends in regional and geographic area were identified, with distinctly different peaks of rotavirus activity in the western and eastern states. Each year in the western states, rotavirus activity began in November and peaked in December-January, whereas in the eastern states activity began in January and peaked in February-March. These differences do not correlate with obvious trends in strain variation of rotavirus and remain unexplained. Unexpected reporting of summer rotavirus activity by some laboratories in 1989 was traced to the use of a single diagnostic kit and to two questionable laboratory practices: having more than six medical technologists perform the test and failure to use controls with the test. Laboratory-based surveillance of rotavirus activity has proven to be useful in identifying and correcting problems in laboratory methods for detecting rotavirus and will be a sensitive means for monitoring coverage of the rotavirus vaccine now being developed.

Child, Preschool↗
PubMed2003

[Surveillance finding on rotavirus in Changchun children's hospital during July 1998-June 2001].

OBJECTIVE: To establish baseline patterns of rotavirus diarrhea and to describe its epidemiologic features in Changchun city, prior to rotavirus vaccine immunization. METHODS: Hospital-based surveillance was conducted among children under 5 years old with acute diarrhea in Changchun Children's Hospital. Fecal samples were determined to identify rotavirus by PAGE and/or ELISA. G serotypes of rotavirus were identified by ELISA and/or nested RT-PCR. P genotyping were carried out by RT-PCR. All data were computerized and analysed by "Generic Manual on Rotavirus Surveillance" set by CDC in the USA. RESULTS: In total, 2 343 diarrhea cases were screened and 1 211 fecal samples were collected. Rotavirus was detected in 31.0% among outpatients and 52.9% in inpatients. During the peak of the season (November through March), 58.6% of diarrhea was caused by rotavirus among inpatients. 95.0% of rotavirus diarrhea cases occurred among children aged < 2 years. The predominant strain was serotype G1 (82.4%), followed by G2 (5.0%), G3 (3.3%), G4 (0.9%). P genotyping showed that P[8] and P[4] were the most common ones. Nine different P-G combinations were identified, four strains (P[8]G1, P[4]G2, P[8]G3, and P[8]G4) commonly seen worldwide accounted for 75.6% of the total. Taken together with uncommon strains, including the novel types P[4]G4 and P[8]G2, it highlights the extraordinary diversity of rotaviruses circulating in China. CONCLUSION: Rotavirus is the major cause of severe child diarrhea in Changchun. Developing a rotavirus vaccine for prevention of severe disease and reduction of treatment costs seemed to be necessary.

Child, Preschool↗
PubMed2004

[Rotavirus surveillance data from Kunming Children's Hospital, 1998 - 2001].

OBJECTIVE: To study the epidemiological status on rotavirus diarrhea in Kunming to improve the rotavirus vaccine immunization program. METHODS: A hospital-based sentinel surveillance program for rotavirus was set up among children less than 5 years old with acute diarrhea in Kunming Children's Hospital. Clinical information and fecal specimens were collected and rotavirus were detected by polyacrylamide gel electrophoresis (PAGE) and/or enzyme linked immunosorbent assay (ELISA). Positive specimens were further serotyped or genotyped by ELISA and/or RT-PCR. RESULTS: During the three years of surveillance, 466 specimens were collected. Rotavirus were detected on 246 (52.8%) specimens. 97% of the rotavirus diarrhea cases occurred among children less than 2 years old. There was a peak of admissions for rotavirus diarrhea cases between October and December which accounted for 48% of all the rotavirus hospitalizations each year. Among 204 specimens with G serotyping, the predominant strain was serotype G1 (47.5%) followed by G2 (17.6%), G3 (15.7%), G9 (4.9%) and G4 (1.0%). Mixed infection (2.5%) were rare and 22 specimens (10.8%) remained non-typeable. P genotyping showed P[4], P[8] and P[6] were the most common strains, accounting for 29.3%, 27.6% and 13.8% respectively. P[4]G2 was the most common strain which accounted for 34.1% (14/41) followed by P[8]G1 (29.3%) and P[6]G9 (12.2%). Another 7 uncommon P-G combinations were also identified. CONCLUSION: Rotavirus was the major cause of acute diarrhea in Kunming. An effective rotavirus vaccine for prevention and control of rotavirus diarrhea should be developed.

Child, Preschool↗
PubMed1998

Rotavirus G and P types in children from Belém, northern Brazil, as determined by RT-PCR: occurrence of mixed P type infections.

Fifty-four group A rotavirus-positive stool samples, obtained from children aged less than three years during a longitudinal (December 1982 to March 1986) study in Belém, Brazil, were re-examined. The samples were tested by reverse-transcription and polymerase chain reaction to determine their G-type and P-type specificity. Only 17 (32%) of these rotavirus strains could be successfully G- and P-genotyped. While 10 (59%) of the 17 strains showed single G- and P-type specificity, the remaining belonged to single G- and mixed P-genotypes. Rotavirus strains P[8], G1 and P[4], G1 predominated, accounting for 29% and 18% of the typed strains respectively. Mixed P-type infections caused by rotaviruses classified as P[8] + P[4], G1 were identified in 23% of cases. All but 3 of the 54 rotavirus strains displayed long genomic profiles, as demonstrated by the analysis of RNA by polyacrylamide gel electrophoresis. Most (70%) rotavirus strains with single G- and P-type specificity were detected during the first year of life, whereas 5 (71%) of the seven mixed P-type infections occurred throughout the second or third year of age. Reinfections were noted in two children, both of them being infected with P[8] + P[4], G1 rotavirus strains when aged 20 months. The high proportion of untypeable rotavirus strains suggests that unusual types may be circulating in Belém. In addition, the occurrence of mixed P-type infections in our region indicates the potential for reassortment between different rotavirus genogroups. Monitoring of these rotavirus strains may have important implication in the context of future strategies of rotavirus vaccination in Brazil.

Child, Preschool↗
PubMed1995

Dansylcadaverine and cytochalasin D enhance rotavirus infection of murine L cells.

Although murine L cells bind and internalize rotavirus as well as permissive cell lines, L cells are essentially nonpermissive for rotaviruses. In nonpermissive cell lines such as L cells, internalized rotavirus fails to uncoat and remains as infectious, double-shelled particles. This block in the infectious cycle can be overcome by direct lipofection of viral particles into the L cell cytoplasm. We hypothesized that the internalized rotavirus particles within L cells are sequestered in the endocytic pathway and are unable to initiate infection. L cells were pretreated with a variety of inhibitors of endocytosis prior to infection with rhesus rotavirus. While agents which inhibit acidification of endosomes had no effect on rotavirus infection, two potential direct inhibitors of vesicular transport, dansylcadaverine and cytochalasin D, enhanced rotavirus infection of L cells 5- to 10-fold. All of the drugs, including both inhibitors of endocytosis and lysosomotrophic agents, significantly reduced infection of L cells by serotype 1 reovirus which is known to infect L cells by the endocytic pathway. Time course studies demonstrated that the drugs were effective in promoting rotavirus infection of L cells in only the early phases of infection. Pretreatment of L cells with dansylcadaverine significantly decreased the number of intact, double-shelled rotavirus particles sequestered within the cells. Inhibition of endocytosis may increase the efficiency of infection of L cells by rotavirus by allowing an increased proportion of attached rotavirus virions to enter cells by a productive route which is probably direct membrane penetration.

Animals↗