Survey on the distribution of the gene 4 alleles of human rotaviruses by polymerase chain reaction

Human transmission and outbreaks of feline-like G6 rotavirus revealed with whole-genome analysis of G6P[9] feline rotavirus

Group A rotaviruses (RVAs) are generally highly species-specific; however, some strains infect across species. Feline RVAs sporadically infect humans, causing gastroenteritis. In 2012 and 2013, rectal swab samples were collected from 61 asymptomatic shelter cats at a public health center in Mie Prefecture, Japan, to investigate the presence of RVA and any association with human infections. The analysis identified G6P[9] strains in three cats and G3P[9] strains in two cats, although no feline RVA sequence data were available for the former. A whole-genome analysis of these G6P[9] strains identified the genotype constellation G6-P[9]-I2-R2-C2-M2-A3-N2-T3-E3-H3. The nucleotide identity among these G6P[9] strains exceeded 99.5% across all 11 gene segments, indicating the circulation of this G6P[9] strain among cats. Notably, strain RVA/Human-wt/JPN/KF17/2010/G6P[9], previously detected in a 3-year-old child with gastroenteritis, shares high nucleotide identity (>98%) with Mie20120017f, the representative G6P[9] strain in this study, across all 11 gene segments, confirming feline RVA infection and symptomatic presentation in this child. The VP7 gene of strain Mie20120017f also shares high nucleotide identity with other sporadically reported G6 RVA strains in humans. This suggests that feline-origin G6 strains as the probable source of these sporadic G6 RVA strains causing gastroenteritis in humans globally. Moreover, a feline-like human G6P[8] strain circulating in Brazil in 2022 was identified, emphasizing the importance of ongoing surveillance to monitor potential global human outbreaks of RVA.

Rotavirus genotypes and clinical outcome of natural infection based on vaccination status in the post-vaccine era

Rotavirus (RV) is a leading cause of gastroenteritis in children. In Japan, Rotarix (RV1; GlaxoSmithKline), which is a monovalent vaccine derived from human RV (G1P[8]), has been introduced since November 2011, and RotaTeq (RV5; MSD) which is an pentavalent, human-bovine mono-reassortant vaccine (G1, G2, G3, G4, and P1A[8]), has been introduced since July 2012. Long-term follow-up on vaccine efficacy and RV genotypical change should be carried out in order to control RV infection. The RV gastroenteritis (RVGE) outbreak occurred during the 2018/2019 season in Aichi prefecture, Japan. Therefore, the molecular epidemiology of RV among three different groups of RVGE, which were outpatients who received RV1, those who received RV5, and those without vaccination, was explored. Clinical features of RVGE patients were compared among the three patient groups. Children less than 15 years of age with gastroenteritis who visited any of seven pediatric practices between January and June 2019 were enrolled in the study. G, P, and E genotypes were determined by direct sequencing of reverse transcription-polymerase chain reaction products amplified from stool samples. Among 110 patients, there were 27, 28, and 55 in the RV1-vaccinated, RV5-vaccinated, and unvaccinated groups, respectively. The most frequent genotype was G8P[8] (92/110 patients, 83.6%). Genotype distributions did not significantly differ among the three patient groups (P = .125). Mean Vesikari score was significantly lower among RV1-vaccinated (7.1) and RV5-vaccinated patients (6.4) than among unvaccinated patients (10.2) (P < .001). Even in RVGE patients treated in an outpatient clinic, RV vaccine reduced the severity of the disease in this cohort.

Outbreak of seafood-related food poisoning from undetectable Vibrio parahaemolyticus-like pathogen, Chiang Mai Province, Thailand, December 2020

OBJECTIVE

On 1 December 2020, the Department of Disease Control of Thailand was notified of a cluster of food poisoning cases among participants at a church festival in Mae Ai district, Chiang Mai province. We conducted an outbreak investigation to confirm diagnosis, describe the epidemiological characteristics of the outbreak, identify possible sources of the outbreak and provide appropriate control measures.

METHODS

We reviewed medical records of the food poisoning cases from the health care centres. Active case finding was conducted among participants who had consumed food and water at the festival. An environmental survey was done in the village where the festival was held. A case-control study was conducted to identify the source of the outbreak. Samples for laboratory analysis included rectal swabs and fresh stool specimens from the cases and food handlers, surface swabs of cooking equipment, food, water and ice samples.

RESULTS

Among 436 participants surveyed, 368 (84.4%) cases of food poisoning were identified. The most common clinical manifestation was abdominal pain (89.7%), followed by watery diarrhoea (45.7%), nausea (43.5%), vomiting (38.9%), fever (18.5%) and bloody diarrhoea (4.6%). None died in this outbreak. The case-control study showed that mixed spicy seafood salad served in the festival was significantly associated with the disease by both univariable and multivariable analyses. However, the causative agent could not be identified. The environmental investigation suggested this seafood might have been undercooked.

CONCLUSION

Clinical manifestations of the cases, incubation period and the suspected seafood salad suggested seafood-related food poisoning. Grimontia hollisae, the organism causing illness similar to Vibrio parahaemolyticus and commonly undetectable in the laboratory with routine testing, might be the pathogen that caused this outbreak. G. hollisae should be in differential diagnosis and identified in seafood-associated outbreaks.

Molecular characterization of rotaviruses obtained from patients with rotavirus-associated encephalitis/encephalopathy

Group A rotavirus (RVA) rarely causes severe complications such as encephalitis/encephalopathy. However, the pathophysiology of this specific complication remains unclear. Next-generation sequence analysis was used to compare the entire genome sequences of RVAs detected in patients with encephalitis/encephalopathy and gastroenteritis. This study enrolled eight patients with RVA encephalitis/encephalopathy and 10 with RVA gastroenteritis who were treated between February 2013 and July 2014. Viral RNAs were extracted from patients' stool, and whole-genome sequencing analysis was carried out to identify the specific gene mutations in RVA obtained from patients with severe neurological complications. Among the eight encephalitis/encephalopathy cases, six strains were DS-1-like G1P[8] and the remaining two were Wa-like G1P[8] (G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1). Meanwhile, eight of the 10 viruses detected in rotavirus gastroenteritis patients were DS-1-like G1P[8], and the remaining two were Wa-like G1P[8]. These strains were further characterized by conducting phylogenetic analysis. No specific clustering was demonstrated in RVAs detected from encephalitis/encephalopathy patients. Although the DS-1-like G1P[8] strain was predominant in both groups, no specific molecular characteristics were detected in RVAs from patients with severe central nervous system complications.

High prevalence of equine-like G3P[8] rotavirus in children and adults with acute gastroenteritis in Thailand

Group A rotavirus (RVA) is a major cause of acute gastroenteritis in infants and young children worldwide. This study aims to clarify the distribution of G/P types and genetic characteristics of RVAs circulating in Thailand. Between January 2014 and September 2016, 1867 stool specimens were collected from children and adults with acute gastroenteritis in six provinces in Thailand. RVAs were detected in 514/1867 (27.5%) stool specimens. G1P[8] (44.7%) was the most predominant genotype, followed by G3P[8] (33.7%), G2P[4] (11.5%), G8P[8] (7.0%), and G9P[8] (1.3%). Unusual G3P[9] (0.8%), G3P[10] (0.4%), G4P[6] (0.4%), and G10P[14] (0.2%) were also detected at low frequencies. The predominant genotype, G1P[8] (64.4%), in 2014 decreased to 6.1% in 2016. In contrast, the frequency of G3P[8] markedly increased from 5.5% in 2014 to 65.3% in 2015 and 89.8% in 2016. On polyacrylamide gel electrophoresis, most (135/140; 96.4%) of the G3P[8] strains exhibited a short RNA profile. Successful determination of the nucleotide sequences of the VP7 genes of 98 G3P[8] strains with a short RNA profile showed that they are all equine-like G3P[8] strains. On phylogenetic analysis of genome segments of two representative Thai equine-like G3P[8] strains, it was noteworthy that they possessed distinct NSP4 genes, one bovine-like and the other human-like. Thus, we found that characteristic equine-like G3P[8] strains with a short RNA electropherotype are becoming highly prevalent in children and adults in Thailand.

Molecular characterization of group A rotaviruses in Mukuru slums Kenya: detection of novel strains circulating in children below 5 years of age

Background

Gastroenteritis is a public health concern due to high morbidity and mortality among children. Rotaviruses are the leading etiological agents of severe gastroenteritis in children and accounts for more than half a million deaths per year in Africa. The study aimed at investigating the rotavirus genotypes that were circulating in children aged 5 years and below in and around Mukuru slums in Nairobi County Kenya.

Methods

A purposive cross sectional sampling method was applied where 166 samples were collected from children below 5 years of age and taken to Kenya Medical Research Institute virology laboratory. Presence of rotaviruses was determined using reverse transcription polymerase chain reaction, while extraction was done using ZR Soil/Fecal RNA MicroPrep™ extraction kit. This was followed by reverse transcription and genotyping using various group A rotavirus primers.

Results

The G type was successfully determined in 37 (92.5%), while the P type was successfully determined in 35 (87.5%) of the 40 (24%) page positive samples. Type G1 was the most predominant of the G types (40.5%), and the incidences of G3 and G9 were 21.6 and 32.4% respectively. Mixed types G3/G9 were detected at 5.4%. Three P types existed in Mukuru slums, P[8] (60%), P[6] (22.9%), P[4] (11.4) and their relative incidence varied over the 15 months of this study.

Conclusions

The G types and P types detected in this study are important causes of acute gastroenteritis in Mukuru slums Nairobi Kenya. An indication that the prevalence of certain genotypes may change over a rotavirus season is significant and mirrors observations from studies in other tropical climates. Thus monitoring of the genotypic changes among circulating viruses should be encouraged over the coming years.

Changes in Rotavirus Genotypes before and after Vaccine Introduction: a Multicenter, Prospective Observational Study in Three Areas of Japan

In Japan, monovalent and pentavalent rotavirus (RV) vaccines were approved in 2011 and 2012, respectively. To monitor changes in the RV genotypes before and after vaccine introduction, we performed a prospective observational study among children (＜ 5 years) with gastroenteritis who tested RV-positive on antigen rapid tests. Stool samples were collected from 3 different sites in Japan: Tsu City, Mie Prefecture; Kurashiki City, Okayama Prefecture; and Isumi City, Chiba Prefecture. RV genotypes were determined using reverse transcription-polymerase chain reaction. In Tsu City, G3P[8] was dominant (61.0-77.1%) before vaccine introduction, but decreased after introduction. Meanwhile, in an inverse proportion to the decrease in G3P[8], G1P[8] increased until the 2013/14 season, when a sudden predominance of G2P[4] (100%) occurred. A similar trend was observed in Kurashiki City in terms of the extent of reduction in G3P[8] and the emergence of G2P[4]. In Isumi City, G1P[8] was dominant (70.3%) before vaccine introduction, and G9P[8] became predominant (83.3%) in the 2013/14 season. To determine whether the genotype changes are attributable to vaccines or natural epidemiological changes, ongoing continuous monitoring of the RV genotypes is required.

Evaluating the first introduction of rotavirus vaccine in Thailand: Moving from evidence to policy

BACKGROUND

We assessed the effectiveness and possible impact of introducing rotavirus vaccine into the routine immunization program.

METHODS

Two provinces were selected for an observational study, one where vaccine was introduced and another where vaccine was not available. In these areas, two sub-studies were linked. The prospective cohort study enrolled children 2month old and followed them to the age of 18months to detect all diarrhea episodes. The hospital surveillance study enrolled all children up to age 5 hospitalized with diarrhea whose fecal samples were tested for rotavirus. Rates of rotavirus hospitalizations in older children who had not been vaccinated in both settings provided data to determine whether immunization had an indirect herd effect. The key endpoints for the study were both vaccine effectiveness (VE) based upon hospitalized rotavirus diarrhea and herd protection.

FINDINGS

From the cohort study, the overall VE for hospitalized rotavirus diarrhea was 88% (95%CI 76-94). Data from hospital surveillance indicated that for 2 consecutive years, the seasonal peak of rotavirus admissions was no longer present in the vaccinated area. Herd protection was observed among older children born before the rotavirus vaccine program was introduced, who experienced a 40-69% reduction in admission for rotavirus.

CONCLUSIONS

Rotavirus vaccine was highly effective in preventing diarrheal hospitalizations and in conferring herd protection among older children who had not been vaccinated.

Rotavirus vaccine and health-care utilization for rotavirus gastroenteritis in Tsu City, Japan

Background

Rotavirus vaccines were introduced in Japan in November 2011. We evaluated the subsequent reduction of the health-care burden of rotavirus gastroenteritis.

Methods

We conducted active surveillance for rotavirus gastroenteritis among children under 5 years old before and after the vaccine introduction. We surveyed hospitalization rates for rotavirus gastroenteritis in children in Tsu City, Mie Prefecture, Japan, from 2007 to 2015 and surveyed the number of outpatient visits at a Tsu City clinic from 2010 to 2015. Stool samples were obtained for rotavirus testing and genotype investigation. We assessed rotavirus vaccine coverage for infants living in Tsu City.

Results

In the pre-vaccine years (2007–2011), hospitalization rates for rotavirus gastroenteritis in children under 5 years old were 5.5, 4.3, 3.1 and 3.9 cases per 1000 person-years, respectively. In the post-vaccine years (2011–2015), the rates were 3.0, 3.5, 0.8 and 0.6 cases per 1000 person-years, respectively. The hospitalization rate decreased significantly in the 2013–2014 and 2014–2015 seasons compared to the average of the seasons before vaccine introduction (P < 0.0001). In one pre-vaccine year (2010–2011), the number of outpatient visits due to the rotavirus infection was 66. In the post-vaccine years (2011–2015), the numbers for each season was 23, 23, 7 and 5, respectively. The most dominant rotavirus genotype shifted from G3P[8] to G1P[8] and to G2P[4]. The coverage of one dose of rotavirus vaccine in Tsu City was 56.5% in 2014.

Conclusion

After the vaccine introduction, the hospitalization rates and outpatient visits for rotavirus gastroenteritis greatly decreased.

Predominant prevalence of human rotaviruses with the G1P[8] and G8P[8] genotypes with a short RNA profile in 2013 and 2014 in Sukhothai and Phetchaboon provinces, Thailand

Of 2,754 stool specimens collected from children with acute gastroenteritis during 2013-2014 in Sukhothai and Phetchaboon provinces, Thailand, 666 (24.2%) were positive for rotavirus A (RVA) in polyacrylamide gel electrophoresis (PAGE). The G and P types of all RVA-positive specimens were determined by semi-nested RT-PCR. G1P[8] (56.5%) was most prevalent, followed by G2P[4] (22.1%). Unusual G8P[8] human RVAs (HuRVAs) were detected at a high frequency (20.0%). Interestingly, 171 of the 376 G1P[8] HuRVAs and all of the 133 G8P[8] HuRVAs showed a short RNA pattern in PAGE. Thus, it was shown that the properties of HuRVAs have been markedly unusual in recent years in Thailand. J. Med. Virol. 89:615-620, 2017. © 2016 Wiley Periodicals, Inc.

Phylogenetic analysis of human group C rotavirus in hospitalized children with gastroenteritis in Belém, Brazil

Group C rotavirus (RVC) is potentially an important pathogen associated with acute gastroenteritis (AG), especially in outbreaks. This study aims to detect and molecularly characterize RVC in hospitalized children with AG in Belém, Brazil. From May 2008 to April 2011, 279 stools were subjected to reverse-transcription polymerase chain reaction targeting VP7, VP6, VP4, and NSP4 genes. RVC positivity rate was 2.1% (6/279) and phylogenetic analysis of positive samples yields genotype G4-P[2]-I2-E2. No evidence of zoonotic transmission and VP7 gene demonstrated close relationship with Asian strains. RVC surveillance is worth to expand information on evolutionary and epidemiological features of this virus.

High Prevalence of G12 Human Rotaviruses in Children with Gastroenteritis in Myanmar

Human rotavirus samples from 54 children with acute gastroenteritis in Myanmar in 2011 were subjected to reverse transcription-PCR to determine their G and P types. On G typing, G2 (24/54; 44.4%) was found to be the most prevalent, followed by G12 (17/54; 31.5%) and G1 (1/54; 1.9%). Mixed cases with G2 and G12 were found in 12 of the 54 (22.2%) samples. On P typing, P[4] was found to be the most predominant (29/54; 53.7%), followed by P[8] (17/54; 31.5%) and P[6] (4/54; 7.4%). Mixed cases with P[4] and P[8] were detected in 4 of 54 (7.4%) samples. Thus, occurrence of G2 and unusual G12 in high proportions was characteristic of human rotaviruses in Myanmar in this study setting.

Three infants with rotavirus gastroenteritis complicated by severe gastrointestinal bleeding

Rotavirus gastroenteritis causes substantial morbidity and mortality worldwide in children. We report three infants with rotavirus gastroenteritis complicated by various severity of gastrointestinal bleeding. Two patients (cases 1 and 2) recovered completely without any specific treatments. One patient (case 3) died despite extensive treatments including a red blood cell transfusion and endoscopic hemostatic therapy. Rotavirus genotypes G1P[8] and G9P[8] were detected in cases 2 and 3, respectively. Rotavirus antigenemia levels were not high at the onset of melena, suggesting that systemic rotaviral infection does not play an important role in causing melena.

Detection of rotavirus and other enteropathogens in children hospitalized with acute gastroenteritis in Havana, Cuba

The aim of the study was to diagnose infections with rotavirus and other enteric pathogens in children under five years old with acute gastroenteritis and to identify the most common epidemiological and clinical characteristics of these pathogens. The study was conducted using 110 stool samples from the same number of children under five years old who were inpatients at three paediatric hospitals in Havana, Cuba, between October and December 2011. The samples were tested for rotavirus and other enteric pathogens using traditional and molecular microbiological methods. Pathogens were detected in 85 (77.3 %) of the children. Rotavirus was the most commonly found, appearing in 54.5 % of the children, followed by bacteria (29 %) and parasites (10.9 %). Other viral pathogens detected included adenovirus (6.4 %) and astrovirus (3.6 %). In rotavirus-positives cases, at least one other pathogen was detected, usually a bacterium (26.6 %). More than three episodes of watery diarrhea in 24 hours were observed in 78.3 % of the cases. Dehydration was found in 30 (50 %) rotavirus-positive children, of whom seven (11.6 %) were transferred to an intensive care unit due to complications of metabolic acidosis. Rotavirus was most commonly observed among children under 12 months old (65 %). The highest incidence of infection occurred in children who were under the care of a relative at home (78.3 %), had not been breastfed (65 %), or had been breastfed for less than six months (28.3 %). The genotype combinations most frequently found were G9P8 (28.3 %) and G1P8 (10 %). This study demonstrates the presence of rotavirus and other enteric pathogens as causes of gastroenteritis in hospitalized infants and young children in Cuba.

Spread and predominance in Japan of novel G1P[8] double-reassortant rotavirus strains possessing a DS-1-like genotype constellation typical of G2P[4] strains

Rotavirus is a major cause of severe gastroenteritis in children <5 years of age worldwide, and two, live attenuated rotavirus vaccines are globally available. As rotavirus vaccines are introduced into national immunization programs, there is an increasing need to monitor circulating wild-type strains. However, few studies have systematically examined their full genotype constellation. This study was therefore undertaken to characterize the whole genotype constellation of circulating rotavirus strains in three widely-separated locations in Japan during the 2012 rotavirus season when rotavirus vaccines became available in the country for the first time. Of 107 rotavirus-positive specimens, 50 (46.7%) strains collected from all three locations possessed an unusual G1-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 constellation in which a typical G2P[4] strain appeared to have acquired its two surface protein genes from the most common G1P[8] strain. These G1P[8] double-reassortant strains were shown to possess the 11 genome segments virtually indistinguishable from each other in their nucleotide sequences and phylogenetic lineages except for two strains that underwent further intra-genotype reassortment. Successful spread to and predominance in broad locations across Japan of novel rotavirus strains possessing a genotype constellation that was previously thought not to be preferred suggests unexpected genomic flexibility of the genotype constellation.

Phylogenetic Analysis of the Rotavirus Genotypes Originated from Children < 5 Years of Age in 16 Cities in South Korea, between 2000 and 2004

Objectives

The purpose of this study was to examine the diversity of the G and P types of human rotavirus strains isolated in South Korea during 2000 to 2004.

Methods

We selected 38 Group A rotavirus isolates among 652 fecal samples, which were collected from infants and children < 5 years of age with acute gastroenteritis or diarrhea admitted in 8 hospitals representative of five provinces of South Korea between 2000 and 2004. Rotavirus P- and G-genotypes were determined by nucleotide sequencing and phylogenetic analysis was performed.

Results

One G1P[4] consisted G1-Id-P[4]-V; one G1P[6] consisted G1-Id-P[6]-Ia; nine G1P[8] consisted G1-Ib-P[8]-Ia (n=3), G1-Ic-P[8]-Ia (n=1), and G1-Id-P[8]-Ia (n=5); 13 G2P[4] consisted G2-V-P[4]-V; two G3P[4] consisted G3-IIId-P[4]-V; five G3P[8] consisted G3-IIId-P[8]-Ia; four G4P[6] consisted G4-Ie-P[6]-Ia; two G4P[8] consisted G4-Ie-P[8]-II; one G9P[6] consisted G9-III-P[6]-Ia.

Conclusions

A considerable amount of rotavirus genotypic diversity was detected in South Korea from 2000 to 2004. These findings are important to develop the effective vaccines and to undertake epidemiologic studies.

Whole genomic analysis of a porcine-like human G5P[6] rotavirus strain isolated from a child with diarrhoea and encephalopathy in Japan

An unusual rotavirus strain, Ryukyu-1120, with G5P[6] genotypes (RVA/Human-wt/JPN/Ryukyu-1120/2011/G5P[6]) was identified in a stool specimen from a hospitalized child aged 4 years who showed diarrhoea and encephalopathy. In this study, we sequenced and characterized the complete genome of strain Ryukyu-1120. On whole genomic analysis, this strain was found to have a unique genotype constellation: G5-P[6]-I5-R1-C1-M1-A8-N1-T1-E1-H1. The VP6 and NSP1 genotypes I5 and A8 are those commonly found in porcine strains. Furthermore, phylogenetic analysis indicated that each of the 11 genes of strain Ryukyu-1120 appeared to be of porcine origin. Thus, strain Ryukyu-1120 was found to have a porcine rotavirus genetic backbone and is likely to be of porcine origin. To our knowledge, this is the first report of whole-genome-based characterization of the emerging G5P[6] strains in Asian countries. Our observations will provide important insights into the origin of G5P[6] strains and the dynamic interactions between human and porcine rotavirus strains.

Evidence for Genetic Reassortment between Human Rotaviruses by Full Genome Sequencing of G3P[4] and G2P[4] Strains Co-circulating in India

Rotavirus A causes severe diarrhoea in infants and young children worldwide. Many unusual combinations of G and P genotypes have been observed in rotaviruses circulating in developing countries. Mixed infection of a single individual with more than one strain is a mechanism by which genetic reassortants are formed with unusual G and P combinations. However, few studies have provided direct evidence for the formation of such unusual strains as a result of co-infection of co-circulating strains. Here, we used full-genome sequencing to re-analyze a G3P[4] strain (107E1B) and a G2P[4] strain (116E3D) detected in India in 1993 and showed that 107E1B had virtually an identical nucleotide sequence with 116E3D, except the VP7 gene. Phylogenetic analysis revealed that the 107E1B VP7 gene was of typical human rotavirus origin, with a 99.3% nucleotide sequence identity with another Indian G3 VP7 gene. Thus, this study provided robust evidence for the formation of the G3P[4] strain through genetic reassortment in which a G2P[4] strain with a typical DS-1 genogroup background acquired the VP7 gene from a co-circulating G3 human rotavirus strain. This study established a basis on which to facilitate full genome sequence analysis of an increasing number of G3P[4] strains in China and elsewhere in the world.

Genotyping of human rotaviruses circulating among children with diarrhea in Valencia, Venezuela

Rotavirus infection is the most common cause of severe gastroenteritis during childhood worldwide, especially in developing countries. Two rotavirus vaccines are available for childhood immunization programs. Evaluation of the vaccine performance will benefit from knowledge of the epidemiological features of rotavirus infection in regional settings. Limited information on the molecular characteristics of the rotavirus types circulating in Venezuela is available. Eighty seven (89.7%) of the 97 ELISA rotavirus positive stool samples collected from children with diarrhea aged <5 years during 2003 in Valencia (Carabobo State), were G-, P- and NSP4-genotyped by RT-PCR and/or automated sequencing. Four common combinations, G3P[8]/NSP4-E1, G2P[4]/NSP4-E2, G9P[8]/NSP4-E1, and G1P[8]/NSP4-E1 were responsible for 50.6%, 35.6%, 5.7%, and 1.1%, respectively of cases of rotavirus diarrhea, most of them (66%) in children ≤12 months. One uncommon G8P[14]/NSP4-E2 strain was also detected. Temporal fluctuation of genotype distribution occurred, but no differences by age, diarrhea severity score, sex, treatment type or patient medical attention were observed, except for the G3P[8]/NSP4-E1, associated with a more severe dehydration than any other type (P < 0.01). The results confirm the broad diversity among rotavirus strains circulating in Venezuela prior to vaccine implementation, showing the predominance of G3, significant proportion of G2 and moderate circulation of G9 strains. Epidemiological surveillance is needed to detect the emergence of new genotypes that could escape protection induced by vaccination.

Emergence of G9 as a predominant genotype of human rotaviruses in Cuba

To study human rotaviruses in Cuban children up to 5 years old with acute diarrhea, a total of 64 faecal samples from two pediatric hospitals between 2006 and 2008 were analyzed. Thirty-nine samples (60.9%) were found positive for rotaviruses by enzyme-linked immunosorbent assay (ELISA) and polyacrylamide gel electrophoresis (PAGE), while four (6.2%) exhibited discordant results (ELISA positives/PAGE negatives). All the positive samples were genotyped by a reverse transcription-polymerase chain reaction (RT-PCR). The most prevalent G and P types were G1 (60.5%) and P[8] (90.6%), respectively. Among the rotaviruses detected, two long RNA patterns were identified by PAGE (L/A and L/B). The predominant genotype in 2006 and 2007 was G1/P[8] with detection rates 71.4% and 80%, respectively. In contrast, G9/P[8] was found at the highest rate (78.5%) in 2008. The phylogenetic analysis of VP7 genes of the ten representative strains indicated that Cuban G1/P[8] rotaviruses were close to those reported in the Americas, and G9/P[8] rotaviruses were located in the lineage of the emerging G9 strains spreading worldwide. This is the first molecular epidemiologic study of rotaviruses in Cuba, highlighting the current increase of the G9 rotavirus which has been recognized globally as an emerging genotype. The study reinforces the need for a systematic surveillance of the molecular epidemiology of rotaviruses.

An outbreak of rotavirus infection among adults in an institution for rehabilitation: long-term residence in a closed community as a risk factor for rotavirus illness

An outbreak of group A rotavirus infection resulted in gastroenteritis among disabled adults in an isolated rehabilitation institution in Kobe, Japan. Of the 95 residents, 16 were diagnosed with rotavirus illness. The causative agent was a single strain of typical human group A rotavirus belonging to VP7 serotype G2, VP4 genotype P[4], and NSP4 genotype A. Mean duration of stay was significantly longer for residents with rotavirus illness (22.1+/-11.8 years) than for residents without the disease (13.5+/-10.6 years; P=0.01). Age, sex, disability and location of resident rooms displayed no significant relationships with illness. These observations suggest that long-term residence in a closed community, which might be related to absence of immuno-stimulation, represents a risk factor for rotavirus illness.

Full genomic analysis of a human group A rotavirus G9P[6] strain from Eastern India provides evidence for porcine-to-human interspecies transmission

Deduced amino acid sequence and phylogenetic analyses of a group A rotavirus G9P[6] strain (designated as mcs/13-07), detected from a 3-year-old child in Eastern India, revealed a VP8* closely related to porcine P[6] strains (P[6] sublineage 1D), and the VP7 clustered with G9 lineage-III strains. To our knowledge, this is the first report of human P[6] strain clustering in sublineage Id. Thus, to further characterize the evolutionary diversity of strain mcs/13-07, all gene segments were analyzed. VP6 and NSP4 exhibited genetic relatedness to Wa-like human subgroup II strains, while VP1-3, NSP1-3 and NSP5 were closely related to porcine strains. Based on the new classification system of rotaviruses, mcs/13-07 revealed a G9-P[6]-I1-R1-C1-M1-A8-N1-T1-E1-H1 genotype with close similarity to human Wa-like and porcine Gottfried strains. Therefore, considering the porcine-like or porcine origin of multiple gene segments, it might be tempting to assume that strain mcs/13-07 represents a rare instance of whole-virus transmission from pig to human, after which the virus evolved with time. Alternatively, it is possible that strain mcs/13-07 resulted from multiple reassortment events involving human subgroup II and porcine P[6] strains. Nevertheless, detection of strain mcs/13-07 provides further evidence for complex interspecies transmission events, which are frequent in developing countries.

Phylogenetic analysis of rotaviruses with predominant G3 and emerging G9 genotypes from adults and children in Wuhan, China

Prevalence and phylogenetic relatedness of rotaviruses causing diarrheal diseases in children and adults were analyzed in Wuhan, China. During a period between June 2006 and February 2008, group A rotavirus was identified in 24.9% (280/1126) and 7.6% (83/1088) of specimens taken from children and adults, respectively. G3P[8] was the most frequent genotype in both children (66.3%) and adults (62.7%), followed by G1P[8] (20.3% and 26.2%, respectively). G9 was detected in specimens from six children (2.0%) and seven adults (5.6%). The VP7 genes of G3P[8] rotaviruses from children and adults showed extremely high sequence identities to each other (98.9-100%) and also to those of G3 viruses isolated in Wuhan in 2003-2004. In the phylogenetic analysis of the VP7 gene, the G3P[8] rotaviruses in Wuhan were clustered into a single lineage with some G3 viruses, which had been referred to as "the new variant G3" rotaviruses, reported recently in East Asia and Southeast Asia. Similar to G3P[8] rotaviruses, extremely high sequence identities between children and adults were observed for VP7 genes of G1 and G9 rotaviruses. The G9 viruses were clustered in the lineage of globally spreading strains, while G1 viruses were genetically close to those reported previously in China and Japan. These findings indicated the persistence of the variant G3 rotaviruses and spread of G9 rotaviruses derived from the global G9 lineage in Wuhan, and suggested that the rotaviruses were circulating among children and adults, irrelevant to the G types.

Detection and characterization of waterborne gastroenteritis viruses in urban sewage and sewage-polluted river waters in Caracas, Venezuela

The detection and molecular characterization of pathogenic human viruses in urban sewage have been used extensively to derive information on circulating viruses in given populations throughout the world. In this study, a similar approach was applied to provide an overview of the epidemiology of waterborne gastroenteritis viruses circulating in urban areas of Caracas, the capital city of Venezuela in South America. Dry season sampling was conducted in sewers and in a major river severely polluted with urban sewage discharges. Nested PCR was used for detection of human adenoviruses (HAds), while reverse transcription plus nested or seminested PCR was used for detection of enteroviruses (HuEVs), rotaviruses (HRVs), noroviruses (HuNoVs), and astroviruses (HAstVs). HRVs were fully characterized with genotype-specific primers for VP4 (genotype P), VP7 (genotype G), and the rotavirus nonstructural protein 4 (NSP4). HuNoVs and HAstVs were characterized by sequencing and phylogenetic analysis. The detection rates of all viruses were >or=50%, and all sampling events were positive for at least one of the pathogenic viruses studied. The predominant HRV types found were G1, P[8], P[4], and NSP4A and -B. Genogroup II of HuNoVs and HAstV type 8 were frequently detected in sewage and sewage-polluted river waters. This study reveals relevant epidemiological data on the distribution and persistence of human pathogenic viruses in sewage-polluted waters and addresses the potential health risks associated with transmission of these viruses through water-related environmental routes.

Human group A rotavirus P[8] Hun9-like and rare OP354-like strains are circulating among diarrhoeic children in Eastern India

During 2004-2006, group A rotavirus P[8] strains were the major VP4 genotype (43.2%, n = 317) among diarrhoeic children in Eastern India. Phylogenetic analysis of VP8* amino acid sequences of 16 of these strains with other P[8] strains revealed four distinct lineages. P[8] strains from Eastern India clustered within rare OP354-like and Hun9-like lineages, pointing towards co-prevalence of divergent P[8] strains. Although it is unclear whether the observed genetic diversity might affect to some extent the efficacy of vaccines, the present study emphasized further efforts to address the much lacking information on diversity of P[8] strains across the Indian subcontinent.

Molecular epidemiologic analysis of group A rotaviruses in adults and children with diarrhea in Wuhan city, China, 2000-2006

To compare epidemiologic features and genetic characteristics of group A rotaviruses causing diarrhea in children and adults, a survey was conducted in Wuhan, China, during the period of Dec. 2000-May 2006. A total of 3839 stool specimens from diarrheal patients from eight hospitals were analyzed. Winter seasonality was observed for rotavirus diarrhea in both adults and children, showing overall rotavirus-positive rates of 9.0 and 23.9%, respectively. Throughout the study period, G3 was the most frequent G serotype in both adults and children (detection rates 86.2 and 87.8%, respectively), and was mostly associated with VP4 genotype P[8], VP 6 genotype II (subgroup II), and NSP4 genotype B. G3 rotaviruses were differentiated into eight electropherotypes, among which seven types were found in specimens from both adults and children. VP7 gene sequences of G3 rotaviruses from adults and children (6 and 4 strains, respectively), detected in different years and different hospitals, showed extremely high sequence identities (99-100%) to each other and to a few G3 rotavirus strains reported in Asia. However, lower sequence identities (82-96%) were observed to most of the human and animal G3 rotaviruses reported so far, including some Chinese strains. These findings indicate that in Wuhan, China, epidemic and genetic features of rotaviruses are similar in adults and children, and it has been suggested that G3 rotaviruses that might have originated from the same rotavirus were circulating among children and adults as prevailing viruses. In this study, two rotavirus strains, G9P[8] strain L169, derived from an adult, and G4P[6] strain R479, derived from a child, were isolated and genetically analyzed. The VP7 gene of L169 belongs to a major lineage of G9 rotaviruses that are globally widespread, but is distinct from G9 rotaviruses reported previously in China. The strain R479 had a VP7 gene which was divergent from most G4 human rotaviruses and showed an unusual dual subgroup specificity, I + II. The R479 VP6 gene does not belong to the main clusters of subgroup I and II rotaviruses phylogenetically, but is related to those of the porcine rotaviruses and some unusual human rotaviruses represented by the RMC321 strain isolated in eastern India.

Genetic distribution of group A human rotavirus types isolated in Gyunggi province of Korea, 1999–2002

BACKGROUND

Human rotavirus genotypes G1-G4 and G9 are the major etiological agents of infantile gastroenteritis. G1 was the most prevalent in Korea during the 10-year period prior to 1997. However, between 1998 and 1999, G4 was the predominant type in Korea, as it was in other Asian countries.

OBJECTIVES

The circulating pattern and genetic variability of group A human rotavirus in Gyunggi, Korea, 1999-2002, were examined in 189 stool specimens.

STUDY DESIGN

Stool samples were collected from children with diarrhea, and group A human rotavirus type was determined using multiplex RT-PCR in those specimens found to be positive for rotavirus by ELISA. Each genotype was sequenced, and phylogenetic analysis was performed on the sequences.

RESULT

We found significant variability from year to year in the prevalence of different G and P types of rotavirus. We also found relatively high prevalence rates for types normally considered to be uncommon. Furthermore, we found that the most prevalent combination of G and P types changed from year to year. Although the combination of G and P types changed every year, the sequence of G genotypes showed a high level of similarity (>97%) compared to those of strains from other Asian countries.

CONCLUSION

We report the types of rotavirus circulating in Gyunggi province, Korea from 1999 to 2002. This information on rotavirus diversity has important implications for rotavirus vaccine efficacy and future vaccine development.

Changing pattern of human group A rotaviruses: Emergence of G12 as an important pathogen among children in eastern India

BACKGROUND

Rotavirus genotypes, G1-G4 and G9 are associated with childhood diarrhoea throughout the world. In our previous study, we detected G1, G2, G4 and three G12 strains from Kolkata, India.

OBJECTIVES

To study the prevalence of G- and P-genotypes of rotaviruses associated with dehydrating diarrhoea in children admitted to two leading hospitals in eastern India.

STUDY DESIGN

An active surveillance was conducted for elucidation of rotavirus infection in two leading hospitals in Kolkata, West Bengal and Berhampur (GM), Orissa, India, separated by 603km from January 2003 to April 2005. The rotaviruses were detected by RNA electrophoresis in polyacrylamide gels. G- and P-typing of the positive samples were accomplished by amplifying VP7 and VP4 genes by RT-PCR and genotyped by seminested multiplex PCR methods. Sequencing, sequence analysis and phylogenetic analysis of VP7 genes of G12 strains were carried out to understand the variations between the strains isolated from different parts of the world.

RESULTS

The genotypic distribution varied remarkably from our earlier study period (1998-2001) with G1 (53.8%) being the most predominant strain followed by G2 (22.5%), G12 (17.1%), G9 (2.1%) and not a single G3 or G4 isolate was detected separately. 35.2% samples exhibited mixed P-types followed by P[4] (31.7%), P[8] (21.8%) and P[6] (9.8%). The phylogenetic analysis of G12 strains revealed that the G12 strains detected from different parts of the world clustered into three different lineages. Though VP7 sequences of G12 strains isolated from Kolkata and Berhampur are conserved, their P-types were different.

CONCLUSION

During this study period we reported emergence of G12 strains as an important pathogen among children in eastern India, thus necessitating its inclusion in future polyvalent vaccine to control rotavirus diarrhoea.

Serotype diversity and reassortment between human and animal rotavirus strains: implications for rotavirus vaccine programs

The development of rotavirus vaccines that are based on heterotypic or serotype-specific immunity has prompted many countries to establish programs to assess the disease burden associated with rotavirus infection and the distribution of rotavirus strains. Strain surveillance helps to determine whether the most prevalent local strains are likely to be covered by the serotype antigens found in current vaccines. After introduction of a vaccine, this surveillance could detect which strains might not be covered by the vaccine. Almost 2 decades ago, studies demonstrated that 4 globally common rotavirus serotypes (G1-G4) represent >90% of the rotavirus strains in circulation. Subsequently, these 4 serotypes were used in the development of reassortant vaccines predicated on serotype-specific immunity. More recently, the application of reverse-transcription polymerase chain reaction genotyping, nucleotide sequencing, and antigenic characterization methods has confirmed the importance of the 4 globally common types, but a much greater strain diversity has also been identified (we now recognize strains with at least 42 P-G combinations). These studies also identified globally (G9) or regionally (G5, G8, and P2A[6]) common serotype antigens not covered by the reassortant vaccines that have undergone efficacy trials. The enormous diversity and capacity of human rotaviruses for change suggest that rotavirus vaccines must provide good heterotypic protection to be optimally effective.

Detection of unusual strains of RV in patients with acute diarrhoea in Mexico

BACKGROUND

Group A rotaviruses are a major cause of acute gastroenteritis in infants. Human strains with a short RNA pattern generally exhibit subgroup I, G2, P1B[4] specificity, those with a long RNA pattern show subgroup II, G1, G3 or G4, P1A[8] specificity. The presence of strains with unusual specificities has been reported worldwide over the last decade.

OBJECTIVE

To determine antigenic diversity among rotaviruses isolated from patients with diarrhoea.

STUDY DESIGN

A laboratory-based survey study was carried out with faecal samples from patients with acute gastroenteritis form January to April 2000. To classify the samples PAGE and ELISA with specific antibodies to serotype G and P and RT-PCR were carried out.

RESULTS

Twenty one specimens from patients with dehydrating diarrhoea had unusual specifies. Nine specimens had unusual combination of long pattern and subgroup I. Twelve specimens with short pattern belong to G1 serotype. As far as the serotypes and genotypes concern 11 samples were P1A, P[4] and one specimen was P1A, P[9].

CONCLUSIONS

These results demonstrated the unexpected presence of unusual strains of rotavirus in Mexico. Detection of strains with both human and animal characteristics may indicate interspecies transmission of RV between humans and animals.

Global distribution of rotavirus serotypes/genotypes and its implication for the development and implementation of an effective rotavirus vaccine

A safe and effective rotavirus vaccine is urgently needed, particularly in developing countries. Critical to vaccine development and implementation is a knowledge base concerning the epidemiology of rotavirus G and P serotypes/genotypes throughout the world. The temporal and geographical distribution of human rotavirus G and P types was reviewed by analysing a total of 45571 strains collected globally from 124 studies reported from 52 countries on five continents published between 1989 and 2004. Four common G types (G1, G2, G3 and G4) in conjunction with P[8] or P[4] represented over 88% of the strains analysed worldwide. In addition, serotype G9 viruses associated with P[8] or P[6] were shown to have emerged as the fourth globally important G type with the relative frequency of 4.1%. When the global G and/or P type distributions were divided into five continents/subcontinents, several characteristic features emerged. For example, the P[8]G1 represented over 70% of rotavirus infections in North America, Europe and Australia, but only about 30% of the infections in South America and Asia, and 23% in Africa. In addition, in Africa (i) the relative frequency of G8 was as high as that of the globally common G3 or G4, (ii) P[6] represented almost one-third of all P types identified and (iii) 27% of the infections were associated with rotavirus strains bearing unusual combinations such as P[6]G8 or P[4]G8. Furthermore, in South America, uncommon G5 virus appeared to increase its epidemiological importance among children with diarrhea. Such findings have (i) confirmed the importance of continued active rotavirus strain surveillance in a variety of geographical settings and (ii) provided important considerations for the development and implementation of an effective rotavirus vaccine (e.g. a geographical P-G type adjustment in the formulation of next generation multivalent vaccines).

Emergence of novel human group A rotavirus G12 strains in India

Three rare human G12 strains were detected from diarrheic clinical samples of children (<8 months of age) in Calcutta during a routine surveillance study of rotaviral diarrhea in India. The VP7 genes of G12 strains and their products showed maximum homology (97 to 99% at the nucleotide level and 98% at the amino acid level, respectively) with those of two recently reported G12 strains (from the United States and Thailand) but lesser homology with those of prototype G12 strain L26.

Detection of a human rotavirus with G12 and P[9] specificity in Thailand

G12 rotavirus has not been detected anywhere in the world since the first detection of a human strain, L26 (G12, P1B[4]), in the Philippines in 1990. In this study, we isolated a human rotavirus (strain T152) with a VP7 of G12 specificity from the stool of an 11-month-old diarrheic patient in Thailand. The strain T152 exhibited a long RNA pattern and subgroup I specificity. In the comparison of the nucleotide and amino acid sequences of the VP7 gene of strain T152 with those of rotaviruses with different G type specificities, strain T152 showed the highest identity, 90.9 and 93.9%, respectively, to G12 prototype strain L26. In contrast, the VP4 gene of strain T152 showed the highest identity with P[9] specificity of human strains K8 and AU-1 and feline strains Cat2 and FRV-1, with homologies of 89.3 to 90.6% at the nucleotide level and 93.9 to 95.6% at the amino acid level. Thus, strain T152 was found to be a natural reassortant strain with G12 and P[9] specificities.

Detection of human group C rotaviruses in Nigeria and sequence analysis of their genes encoding VP4, VP6, and VP7 proteins

In a survey on the etiology of acute gastroenteritis in infants and young children in Nigeria, group C human rotaviruses were detected in two of 112 rotavirus positive stool specimens collected between 1999 and 2000. The VP7, VP6, and VP4 genes of the two Nigerian human group C rotavirus strains (Jajeri and Moduganari) were sequenced in this study. Comparative sequence analysis with other published human group C rotaviruses showed that the genes encoding the three structural proteins were remarkably conserved in primary structure with few mutations. The VP4 and VP7 genes from the two Nigerian strains were related more closely to each other than to those of other published strains, and formed a separate cluster on the phylogenetic tree. In contrast, it was of note that VP6 gene of strain Moduganari was related more closely to the Brazilian strain Belem than to the other Nigerian strain Jajeri. This is the first report of identification of human group C rotavirus in Nigeria and constitutes the first sequence data of human group C rotaviruses in the African continent.

Genomic diversity of group A rotavirus strains infecting humans in eastern India

Between 1998 and 2000, a total of 266 samples were found positive for group A rotaviruses by RNA electrophoresis. Samples were collected from patients admitted to two leading hospitals in Calcutta. Serotyping could be done only with 22% of the positive samples, leaving 78% untypeable. The G (VP7 genotypes) and P (VP4 genotypes) types were determined for 159 samples by reverse transcription and multiplex PCR. The predominant genotype was G1P[8] (20%), followed by G2P[4] (15%) and G4P[8] (6%). A number of uncommon genotypes, G1P[4] (4%), G2P[8] (2.5%), G2P[6] (0.6%), G4P[4] (2.5%), and G4P[6] (1.25%), were also detected during this study period. Twenty two percent of specimens showed mixed infections, 38 (24%) of the total samples remained untypeable for either VP7 or VP4, while only 4 (2.5%) of the samples were untypeable for both genes. Eleven specimens collected from Manipur were also genotyped and revealed a very high degree of genomic reassortment.

Molecular epidemiology of rotaviruses in Nigeria: detection of unusual strains with G2P[6] and G8P[1] specificities

During an epidemiological study on rotaviruses among diarrheic children in the northeastern and middle belt regions of Nigeria, the distribution of G and P types was investigated in 127 stool specimens. By PCR G typing, the G type of rotaviruses in 97 samples was identified. Interestingly, an unusual G8 type, as well as common G1, G2, and G3 types, was detected more frequently (31 of 112; 27.7%). Eleven samples contained multiple G types, and a G9 strain (Bulumkutu) was identified for one of the probable mixed infections. In PCR P typing, P[6] was detected most frequently, P[8] being the second most common type, while the P type of 73 samples could not be identified. One rotavirus strain with a G8 type specificity could be cultivated in cell culture, and the P type of this strain was found to be P[1], which is usually carried by bovine strains. When the combinations of G and P types were examined, the unusual strains G2P[6] and G8P[1] were often identified. Sequence analysis was performed for the VP7 gene of the G9 strain Bulumkutu and the VP4 and VP7 genes of G8P[1] strain HMG035. The VP7 sequence of the Nigerian serotype G9 was more closely related to that of a Brazilian strain than to those of other African strains. The VP7 and VP4 genes of G8P[1] strain HMG035 were found to be very similar to that of a Thai bovine strain A5, suggesting that bovine strains may have been transmitted directly to humans. These results highlight an unexpected diversity among rotavirus strains in Nigeria and emphasize the need for further serological and genetic surveys on more rotavirus strains in African countries, including Nigeria.

Rotavirus strains bearing genotype G9 or P[9] recovered from Brazilian children with diarrhea from 1997 to 1999

Human rotavirus strains belonging to genotype G9 or P[9] were detected in a collection of stool specimens from children with diarrhea in two cities of the state of Rio de Janeiro, Brazil, between March 1997 and December 1999. G9 strains were first detected in April 1997 and remained prevalent until the end of the study, at a frequency of 15.9% (n = 157). A high percentage of VP7 nucleotide (99.0 to 99.5%) and deduced amino acid identity (98.6 to 99.1%) was found between three randomly selected Brazilian G9 strains and the American G9 strain US1205. A novel G9:P[4] genotype combination was detected in addition to G9:P[8] and G9:P[6], demonstrating that this G genotype may undergo constant genetic reassortment in nature. The P[9] rotavirus strains constituted 10.2%, the majority of which were detected between April and July 1997. The RNA electrophoretic migration pattern of the G3:P[9] strains resembled that of AU-1 virus (G3:P3[9]), suggesting a genetic similarity between the Brazilian G3:P[9] strains and the Japanese virus, which is similar to a feline rotavirus genetically.

Distribution of rotavirus VP7 serotypes and VP4 genotypes circulating in Sousse, Tunisia, from 1995 to 1999: emergence of natural human reassortants

Rotavirus strains circulating in Sousse, Tunisia, between 1995 and 1999 were characterized antigenically by monoclonal antibodies to the VP6 subgroup and the VP7 serotype. The VP4 genotype was determined by reverse transcription-PCR, as were the strains with untyped VP7. Only 17% of 375 children were shedding rotavirus as determined by latex agglutination assay. Most rotavirus strains were G1P[8] (50%), followed by G4P[8] and G4P[6]. Reassortant G1P[4] strains emerged in Sousse during the 1998-1999 season.

Identification of human rotavirus strains with the P[14] genotype by PCR

A seminested PCR typing assay has been extended to identify rotavirus strains with the P[14] genotype. The specificity of the method was confirmed by Southern hybridization and by restriction analysis with the enzyme AluI. One out of four human rotavirus (HRV) strains with unusual subgroup-electropherotype linkage but none out of 50 HRV strains with usual linkage was typed as P[14].

Epidemiological study of the G serotype distribution of group A rotaviruses in Kenya from 1991 to 1994

An epidemiological study on the G serotype distribution of group A rotaviruses (GARV) isolated in Kenya was carried out in one urban hospital in Nairobi and in two rural hospitals in Nanyuki and Kitui to clarify the prevalent G serotypes before future introduction of the ready licensed rotavirus vaccine in Kenya. A total of 1,431 stool specimens were collected from children, who were mainly outpatients, aged from 0 to 6 years old with acute gastroenteritis from August 1991 to July 1994. Samples positive for GARV by conventional ELISA were then analyzed by subgrouping and serotyping ELISA and by PAGE. To ascertain the G serotypes of viruses in samples that were unable to be typed by serotyping ELISA, polymerase chain reaction was also attempted. The prevalence of GARV was 28.4% in the urban hospital, 22.5% in Nanyuki, and 13.7% in Kitui. Among rotavirus-positive samples, subgroup II rotaviruses were detected in 63.1%, and subgroup I rotaviruses were 25.9%. Serotype G4 was most prevalent, accounting for 41.6% followed by 23.3% of serotype G1, 17.0% of serotype G2, and serotype G3 was rarely isolated. Seven strains of serotype G8/P1B rotavirus was detected for the first time in Kenya by RT-PCR. Eleven specimens with an unusual composition of subgroup, serotype, and electropherotype were atypical GARV in which the P-serotype was P1A, P1B, or P2. Although uncommon GARV serotype G8/P1B and atypical GARV were detected, the four major GARV serotypes, G1 through G4, should be targeted at this moment for vaccination to control this diarrheal disease in Kenya. Continuous monitoring of the G- and P-serotype distribution of GARV should provide important information about the impact of rotavirus vaccination in Kenya.

VP4 and VP7 genotyping of rotavirus samples recovered from infected children in Ireland over a 3-year period

Between September 1995 and August 1998, the incidence and diversity of the main human rotavirus genotypes (G1, G2, G3, and G4 and P[8], P[4], P[6], and P[9]) among Irish children were determined by using established and adapted reverse transcriptase PCR-based genotyping methods. From a total of 193 rotavirus-positive specimens collected from nine hospitals we successfully identified the P type in 182 (94%) of the samples and the G type in 165 (85.5%) of the samples. Only four samples could not be assigned a G or P type. Two P types existed in Ireland, P[8] (78%) and P[4] (16%), and their relative incidence varied over the 3 years of this study. No P[6] or P[9] types were detected. G1 was the most predominant G type (55%), and the incidences of G2, G3, and G4 isolates were 15.5, 1, and 11%, respectively. Three percent of the samples tested had a mixed G type. A P and G type was assigned to 158 (81.8%) of samples. Of the typeable samples, G1 P[8] was the most prevalent (65%), whereas G2 P[4] (17%), G3 P[8] (1%), G4 P[8] (12%), and mixed types (all G1/ G4 P[8]) (4%) were detected less frequently. In the third year a significant genotypic shift from G1 P[8] to G2 P[4] and G4 P[8] was observed. During the study, we noticed that the inclusion of random primers during cDNA synthesis greatly increased the specificity of the PCR typing assays. No correlation was seen between the contributing hospitals and a specific genotype. In conclusion, the coverage of infection given by the recently licensed tetravalent vaccine would be significantly high in Ireland, although future monitoring of genotypic changes among Irish isolates should be encouraged.

Characterization of rotavirus P genotypes circulating among paediatric inpatients in northern brazil

Between November 1992 and August 1993, twenty-eight rotavirus-positive stool samples obtained from paediatric inpatients in Belem, Brazil, aged less than four years, were tested by RT-PCR to determine the P genotype specificities. With the exception of 7 non-diarrhoeic children, all patients were either diarrhoeic at admission or developed diarrhoea while in hospital. Rotavirus strains with the gene 4 alleles corresponding to P1B[4] and P1A[8] types (both of which bearing G2 specificity) predominated, accounting for 78.6% of the strains. While only one P2A[6] type strain - with (mixed) G1 and 4 type specificities - was detected, the gene 4 allele could not be identified in 4 (14.3%) of the strains. Most (81%) of the specimens were obtained from children during their first 18 months of life. Rotavirus strains bearing single P1B[4] type-specificity were identified in both diarrhoeic (either nosocomial, 28.6% or community-acquired diarrhoea, 28.6%) and non-diarrhoeic (42.8%) children. P1A[8] gene 4 allele, on the other hand, was detected only among diarrhoeic children, at rates of 57.1% and 42.9% for nosocomial- and- community acquired diarrhoea, respectively. Mixed P1A[8],1B[4] type infection was identified in only one case of community-acquired diarrhoea.

Development of a rapid and sensitive quantitative assay for rotavirus based on flow cytometry

A very sensitive and accurate flow cytometry (FC) based method have developed to quantitate rotavirus infection in MA104 cells. Confluent cell monolayers were infected with serial dilutions of rotavirus SA11. After infection, the cells were recovered with the aid of trypsin and then reacted with monoclonal antibody M60 (specific for the rotavirus outer capsid protein, VP7), followed by a second antibody (anti-mouse IgG-FITC). A FACScan FC was used to estimate the number of infected cells, as well as the level of infection. Viral infection was optimised by varying the concentration of trypsin used in the maintenance medium. The FC method enables many cells to be screened quickly for infectivity, and can detect low levels of virus. This method can be adapted to monitor the presence of other viruses in clinical and environmental samples without the need for prolonged periods of adaptation to growth in tissue culture.