A family outbreak of gastroenteritis caused by group C rotavirus

Evidence for zoonotic transmission of group C rotaviruses among children in Belém, Brazil

The prevalence and potential zoonotic transmission of group C rotavirus (RVC) were examined by testing fecal samples collected from children during a longitudinal study that was carried out in the outskirts of Belém, Brazil, from December 1982 to March 1986. The study involved a group of 30 children who were followed from birth to 3 years. Of the 77 samples tested from 29 children, 5 (6.5%) were positive for human and 3 (4%) for porcine RVC by using nested PCR assay with primers specific for VP6 gene of human or porcine RVC and by Southern hybridization using a probe specific for VP6 gene of both human and porcine RVC. In addition, a total of 59 fecal specimens from the 30th child were tested, 1 (1.7%) and 14 (23.7%) were positive for human and porcine RVC, respectively. Partial nucleotide sequences of VP6 gene demonstrated that the six human strains detected in Brazil were homologous with other human RVC, and 14 of the 17 porcine RVC strains examined showed a complete homology among themselves but differed slightly from the porcine Cowden strain, suggesting that a single porcine RVC strain was circulating in Belém. This study is the first to provide evidence for transmission of RVC from swine to human. They also indicate that both human and porcine RVC were endemic in Belém.

Prevalence of group C rotavirus among children in Rhode Island, United States

BACKGROUND

Group C rotavirus causes sporadic cases and outbreaks of acute diarrhea in humans but its burden as a cause of severe gastroenteritis in children remains unclear.

OBJECTIVES

To investigate the epidemiology and burden of group C rotavirus gastroenteritis among children in Rhode Island, United States.

STUDY DESIGN

Diarrhea stool specimens from 124 children < or =10 years of age were collected, screened for group C and A rotavirus by EIA specific for each group, and further examined by nested PCR and Southern hybridization using primers and probes specific to the VP7 gene of human group C rotavirus. Group C rotavirus-positive fecal specimens were also examined by EM.

RESULTS

Rotavirus was detected in 73 (59.0%) of 124 fecal samples. These included 53 (42.7%) positive for group A, 5 (4.0%) for group C and 15 (12.1%) for both group A and C rotaviruses. Examination of group C-positive samples by EM revealed the presence of largely empty or damaged rotavirus-like particles.

CONCLUSION

These findings indicate that group C rotavirus is an important cause or a contributing cause of diarrhea among infants and older children in Rhode Island, United States.

First detection of group C rotavirus in patients with gastroenteritis in Slovenia

Group C rotaviruses are associated with sporadic gastroenteritis and outbreaks of diarrhea in children and adults worldwide. Three cases with group C rotavirus infection are described, and the molecular characterization of the gene for the major capsid protein VP6 is reported. Patients described in this report were 10 years old or more and had mild to moderate clinical symptoms. A high nucleotide (>98%) and amino acid (100%) identity was observed among all three isolated Slovenian group C rotavirus strains. The similar identity is confirmed of Slovenian strains with other human group C rotavirus isolates, which were seen to cluster separately from the animal group C rotavirus isolates by a phylogenetic analysis. This is the first report of group C rotavirus detection in Slovenia.

Seroepidemiology of group C rotavirus infection in England and Wales

A total of 3199 serum samples collected in 1993--1994 from two population cohorts from England and Wales were tested for the prevalence of IgG antibodies specifically directed against group C rotavirus VP6. Seroprevalence was 39% (95% confidence intervals: 37.0-40.4%). Seroprevalence was highest (46.0%) in the oldest age group (61-70 years of age). Infection with group C rotaviruses occurred at an earlier age and with higher incidence in rural than in urban populations. These results may suggest transmission from animals to humans, however further work is required to identify the reservoir of group C rotavirus for human infection.

Production of hybrid double- or triple-layered virus-like particles of group A and C rotaviruses using a baculovirus expression system

Dual infections by group A and group C rotaviruses have been reported, but no reassortants between group A and group C rotaviruses have been described. The VP6 major inner capsid protein of group A and C rotaviruses shares common antigens detected by monoclonal antibodies and also shares 40-43% amino acid identity. Coinfection of Spodoptera frugiperda (Sf9) insect cells with different combinations of the recombinant baculoviruses encoding either group A [RF VP2 (A-VP2), IND VP6 (A-VP6), and VP7 (A-VP7[IND]), 2292B VP7 (A-VP7[2292B])] or C [Shintoku VP6 (C-VP6) and VP7 (C-VP7)] bovine rotavirus proteins produced hybrid group A/C triple-layered VP2/6/7 virus-like particles (TLPs) composed of A-VP2/C-VP6/C-VP7, A-VP2/C-VP6/A-VP7(IND), A-VP2/C-VP6/A-VP7(2292B), and A-VP2/A-VP6/C-VP7. To our knowledge, this is the first report that the inner capsid VP6 of group A or group C rotavirus can support attachment of the heterologous, antigenically distinct group A (G6, IND or G10, 2292B) or group C rotavirus outer capsid VP7 to produce hybrid TLPs in vitro.

Diagnosis of foodborne viral infections in patients

A significant global problem is the microbiological contamination of foods and water. The microorganisms associated with about half of the foodborne disease outbreaks still go unrecognized, primarily as a result of inadequate diagnostic methods and sampling. A significant amount of food- and waterborne diseases are associated with viruses, information that has been obtained only in recent years. Improved diagnostic methods have established that caliciviruses are the most important non-bacterial pathogens associated with food- and waterborne outbreaks, and are the major cause of seafood-associated gastroenteritis.

[Rotavirus infection in Brazil: epidemiology and challenges for its control]

Worldwide, rotaviruses account for 600,000 to 870,000 deaths per year among infants and young children. In Brazil, rotaviruses were first seen in 1976 by scanning electron microscopy of stool samples from diarrheic infants in Belém, Pará. Hospital-based studies have shown that rotaviruses are associated with 12-42% of cases of acute diarrhea. In addition, community-based studies yielded an average of 0.25 rotavirus-related diarrheal episodes per child per year. G types 1 to 4 account for about two-thirds of circulating strains, but the (unusual) P[8],G5 genotype has been claimed to cause over 10% of rotavirus diarrheal episodes. It has been shown that over 70% of children develop rotavirus antibodies by the age of 4-5 years. The tetravalent rhesus-human rotavirus vaccine (RRV-TV) conferred 35% protection according to a two-year follow-up study in Belém, Pará, Brazil, but reached an efficacy of 60% during the first year of life. RRV-TV was also shown to be 75% protective against very severe gastroenteritis in northern Brazil. Vaccination with RRV-TV has been suspended recently in the United States because of the detection of intussusception as a side effect. Therefore, further vaccine trials in Brazil will probably involve rotavirus candidate vaccines other than RRV-TV.

Antibody prevalence and specificity to group C rotavirus in Swedish sera

Of 160 sera collected from different age groups throughout Sweden, 38% were found to be antibody positive for group C rotavirus. The highest antibody prevalence rate was found in individuals aged 11-30 years (45%). An immunoprecipitation assay revealed that the antibodies were directed against VP2, VP4, VP6, VP7, and NSP2, with VP6 being the most immunogenic protein. Neutralising antibodies against a cultivable porcine group C rotavirus (strain AmC-1/Cowden) were detected in 16/19 individuals at titres from 160 to 5,120. The results indicate that group C rotavirus infections are relatively common in older Swedish children and adults but appear to be less common in children younger than 5 years of age. It is concluded that porcine and human group C rotaviruses share epitopes critical for stimulation of neutralising antibodies.

Neutralization assay for human group C rotaviruses using a reverse passive hemagglutination test for endpoint determination

A novel neutralization assay for human group C rotavirus (CHRV) was developed by using a reverse passive hemagglutination (RPHA) test for endpoint determination. In this assay, the neutralization (N)-RPHA test, serial twofold dilutions of sera were mixed with a solution of CHRV that yielded an RPHA test titer of 8 at 3 days after infection. The mixtures were incubated at 37 degrees C for 1 h and were inoculated onto CaCo-2 cell monolayers in a 96-well microplate. Maintenance medium containing 100 microgram of pancreatin per ml was placed in each well. The plate was sealed with sticky plastic film and was incubated at 37 degrees C for 3 days under continuous rotation. Then, the RPHA test titer of each well was determined. The neutralization titer was expressed as the reciprocal of the maximum dilution of the serum that exhibited a fourfold (75%) or greater reduction in the RPHA test titer (8 to 2 or less). Seroconversion of neutralizing antibody was demonstrated by this method in four sets of paired serum specimens from patients with diarrheal disease caused by CHRV. The seroprevalence of CHRV in the general population in Okayama Prefecture was 26.8% by immunofluorescence and 25.5% by the N-RPHA test. The N-RPHA test described here is the first system used to assay for a neutralization antibody against CHRV and is applicable in both clinical and epidemiological settings.

Characterization of group C rotaviruses associated with diarrhea outbreaks in feeder pigs

Feces and serum specimens were collected from three farms in Michigan on which approximately 50-lb (8- to 9-week-old) pigs experienced diarrhea just after placement into all-in-all-out finishing barns. The clinical signs (profuse watery diarrhea lasting about 2 weeks and no vomiting) were similar on all farms, and the morbidity rate was high (ranging from 60 to 80%) but without mortality. Eleven diarrheic fecal samples from the farms were tested for group A and C rotaviruses by immune electron microscopy (IEM) and various assays. IEM indicated that the fecal samples reacted only with antiserum against group C rotaviruses, and polyacrylamide gel electrophoresis indicated that the samples had characteristic genomic electropherotypes for group C rotavirus. Group C rotavirus was detected by cell culture immunofluorescence (CCIF) tests in nine fecal samples, but no group A rotavirus was detected by enzyme-linked immunosorbent assay or CCIF. By reverse transcription (RT)-PCR, all 11 fecal samples were positive for group C rotaviruses, with only 2 samples positive for group A rotaviruses. However, a second amplification of RT-PCR products using nested primers detected group A rotaviruses in all samples. Analysis of nucleotide and deduced amino acid sequences of the RT-PCR product (partial-length VP7) of the group C rotavirus showed 87.2 to 91% nucleotide identity and 92.6 to 95.9% amino acid identity among two strong samples from the different farms and the Cowden strain of porcine group C rotavirus. All nine convalescent-phase serum samples tested had neutralizing antibodies to the Cowden strain, and the majority of them had neutralizing antibody against group A rotaviruses (OSU or/and Gottfried strains) by fluorescent focus neutralization tests. Although group C rotaviruses have been reported as a cause of sporadic diarrhea in suckling or weanling pigs, to our knowledge, this is the first report of epidemic diarrhea outbreaks associated with group C rotavirus in older pigs.

Infection with group C rotavirus in a suburban community in Brazil

Group C rotaviruses are associated with sporadic outbreaks of gastroenteritis worldwide. Age-specific seroprevalence of group C rotavirus antibodies was investigated in sera, randomly collected and representative of a suburban community in Brazil which had previously been screened for group A rotavirus antibodies. Antibody prevalence to group C rotavirus was low in children under 5 years and increased slowly with age to 36% seropositivity in adults, reflecting continuous exposure to primary infection in all age groups. This suggests a higher incidence of infection than disease might predict. Adult antibody prevalence was similar to that in other geographical settings. No obvious patterns of infection with group A and group C rotavirus were found within individuals, which suggests independent transmission. However, further epidemiological studies are required to understand group C rotavirus dynamics and possible interactions with group A rotavirus transmission and immunity.

Rotavirus serotypes and electropherotypes in Finland from 1986 to 1990

Four epidemic seasons of rotaviruses were studied in Helsinki during 1986-1990. This is the first Scandinavian study, where both electropherotypes and serotypes are determined. Out of 5316 fecal specimens 769 (14.5%) rotavirus positive samples were detected by electron microscopy. Of these, 645 isolates (83.9%) gave a clear RNA pattern in gel electrophoresis and they clustered into 87 electropherotypes. An illustrative number of isolates representing each electropherotype (= E-type) was serotyped using VP7 protein-specific monoclonal antibodies for serotypes G1-G4 and without exceptions, within one E-type only a single serotype specificity was found. After establishment of the serotype of each E-type, the distribution of serotypes was scored as 61.2%, 2.0%, 0.5% and 29.8% for G1-G4, respectively; 6.5% remained untypable. Two seasons had one predominant E-type (Season 1, 1986-87, and Season 3, 1988-89, 84.2% and 80.6% of rotavirus positive samples, respectively). Both were followed by a season with no predominant E-type, but several minor E-types. Altogether, 5 short E-types (13/645 samples) with serotype G2 specificity were found, most of them occurring in Season 2. Only 2 E-types (3 samples) belonged to serotype G3. Group C rotavirus was found in 8 specimens. In this study a shift in serotypes, from G1 to G4, was observed in Finland in 1988/89; a similar shift was reported in many European countries at that time.

Biosynthesis and morphogenesis of group C rotavirus in swine testicular cells

Polypeptide synthesis and morphogenesis of a group C rotavirus (AmC-1) adapted to a continuous swine testicular cell line was examined. SDS-PAGE analysis of 35S methionine labeled infected cell lysates revealed 9 viral polypeptides (122, 98, 79, 78, 43, 41, 35, 24, and 20 kD). Viral polypeptide synthesis appeared to be maximal at 7-10h post infection. Purified group C virus grown in the presence of trypsin was found to contain seven structural polypeptides (122, 98, 79, 53, 43, 41, and 30 kD) by protein blotting and five polypeptides (98, 79, 78, 43, and 41 kD) by immunoprecipitation with a hyperimmune rabbit antisera. Tunicamycin treatment, Concanavalin A binding, protein blotting, endo-H treatment and 2,6H-mannose labeling suggested that group C rotavirus contains one structural glycoprotein (41 kD) with a corresponding precursor mol. wt. of 37 kD and one not previously identified nonstructural glycoprotein (24 kD) with a corresponding precursor mol. wt. of < or = 20 kD. Electron microscopy of infected swine testicular cells revealed an assembly process for group C rotavirus similar to group A, with single-shelled particles budding through the rough endoplasmic reticulum with concomitant acquisition of a transient membrane.