Genetic characterization of rotavirus in children in South Korea from 2007 to 2009

Rotavirus is the most important etiological agent in children with acute gastroenteritis (AGE). The recent implementation of a rotavirus vaccine in Korea requires the monitoring of prevailing rotavirus strains in order to control the infection. One hundred thirty-nine rotavirus strains were detected in children hospitalized with AGE in Seoul, Korea from 2007 to 2009. The most frequent combination of genotypes was G9P[8] (32.1%), followed by G1P[8] (20.7%) and G3P[8] (11.7%). Mixed G-types were detected in 14 samples (10.0%), and mixed P-types were found in six samples (4.3%). G9 genotypes were predominant from 2007 to 2008, whereas G1 and G3 genotypes were predominant from 2008 to 2009. G1 strains clustered mostly in the Id lineage, and some clustered in the Ic, IId, and Ia lineages. G2 strains clustered in the IV and V lineages. G3 and G9 strains clustered in the IIId and Id lineages, respectively. This study shows a rapid change of the prevalent genotype from G9 to G1 and G3 genotypes, suggesting that continuous surveillance of rotavirus strains is important for rotavirus vaccination.     

Changing pattern of rotavirus G genotype distribution in Chiang Mai, Thailand from 2002 to 2004: decline of G9 and reemergence of G1 and G2

Group A rotaviruses are the most common cause of acute viral diarrhea in humans and animals throughout the world. Previous surveillance studies of group A rotaviruses in Thailand indicated that the dominant types of rotaviruses were changing from time to time. During 2000 and 2001, the G9 rotavirus emerged as the most prevalent genotype, with an exceptionally high frequency (91.6%) in Chiang Mai, Thailand. In the year 2002-2004, group A rotavirus was detected in 98 out of 263 (37.3%) fecal specimens collected from children hospitalized with diarrhea. Of these, 40 (40.8%) were G9P[8], 33 (33.7%) were G1P[8], 23 (23.5%) were G2P[4], and 2 (2.0%) were G3P[9]. The G9P[8] was found to be the most predominant strain in 2002, but the prevalence rate abruptly decreased during the period 2003-2004. In addition, G2P[4] reemerged in the epidemic season of 2003, whereas G1P[8] became the most predominant strain in the following year (2004). Phylogenetic analysis of the VP7 genes revealed that G1, G2, and G9 rotavirus strains clustered together with recently circulating strains, which were isolated from different regional settings in Thailand. In conclusion, the study demonstrated a decrease of incidence of G9P[8] and reemergence of G1P[8] and G2P[4] rotaviruses in Chiang Mai, Thailand during the period 2002-2004. These data imply that the distribution of group A rotavirus genotypes circulating in Chiang Mai, Thailand, changes over time.     

Genotypic distribution of rotavirus strains causing severe gastroenteritis in Gyeonggi province,South Korea,from 2003 to 2005

Rotavirus was present in 1,367 of 7,060 stool samples (19.4%) collected in Gyeonggi province of South Korea from 2003 through 2005. The predominant genotypes were confirmed as G4/P2A[6] (19.0%) followed by G3/P1A[8] (15.6%), G2/P1B[4] (9.3%), and G1/P1A[8] (6.5%). The predominant types of rotavirus by year were G3/P[8] in 2003, G4/P[6] in 2004, and G1/P[8] in 2005. The prevalent rotavirus genotypes changed constantly from 2003 to 2005. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Surveillance for rotavirus in Argentina

Group A rotaviruses are the major cause of severe gastroenteritis in young children worldwide. Because rotavirus vaccination appeared imminent, a nationwide surveillance program was organized between October 1996 and October 1998 in the largest Argentine cities. Surveillance for disease burden, rotavirus detection, and rotavirus typing was undertaken at nine locations. Results showed rotavirus to be associated with 42% of diarrhea admissions. Although the prevalent G types changed from year to year, common G types were found in 96% of the cases and were usually associated with common P types. Uncommon G types, G9 and G5, were found at low prevalence and uncommon G/P combinations occurred at almost every study site. These data suggest that a rotavirus vaccine could substantially decrease the rotavirus disease burden in Argentina, but that introduction of a vaccine should be accompanied by a concurrent surveillance system.     

G and P genotyping of human rotavirus isolated in a university hospital in Korea: implications for nosocomial infections

To characterize rotavirus G and P genotypes circulating among infants and young children hospitalized with severe diarrhea in a university hospital in Gyeonggi province, Korea, and to examine any association of the genotypes and nosocomial infections, we genotyped 103 isolates of rotavirus by multiplex RT-PCR. In July 2001-June 2002, we found that globally common strains constituted 64.2% (G2P[4] 28.3%, G3P[8] 28.3%, G4P[8] 5.7%, and G1P[8] 1.9%), and the uncommon strain, G4P[6], constituted 26.4%. During July 2002-June 2003, the percentage of common strains decreased to 44.0% (G3P[8] 18.0%, G2P[4] 16.8%, and G1P[8] 10.0%), but G4P[6] increased to 36.0%. G9P[8] was identified in 10.0% of cases, and thus can be considered an emerging strain in Korea. Eight-eight percent of G4P[6] was isolated from newborn babies. Among the 103 patients, there was an evidence of nosocomial rotavirus infection in 23 children (22.3%). Of these, 19 (82.6%) were newborns infected with G4P[6] strains of rotavirus. Most of the children who acquired rotavirus infection nosocomially showed symptoms of diarrhea, vomiting, fever, poor sucking, or dehydration, regardless of the genotype. This study revealed that G4P[6] has been the major genotype causing nosocomial rotavirus infection in our hospital.     

Diversity of group A rotavirus strains circulating in Paraguay from 2002 to 2005: detection of an atypical G1 in South America.

BACKGROUND: Group A rotaviruses are the main cause of severe gastroenteritis in children worldwide. OBJECTIVES: To survey human rotavirus strains circulating in Paraguay. STUDY DESIGN: One hundred ninety-six rotavirus-positive fecal samples collected from children up to 5 years old, from 2002 to 2005, were characterized. RESULTS: The most common G genotype detected was G9 (36.2%), followed by G1 (34.2%), G2 (11.7%) and G4 (8.7%). Changes in the G genotype frequency were observed from year to year. The G4 genotype was predominant in 2002; G1 in 2003; and G9 from 2004 to 2005. Sequence and phylogenetic analysis of the VP7 gene from Paraguayan G1 strains suggested that the high frequency of G1 in 2003 could be due to the introduction of an atypical sub-lineage. In addition, there were amino acid changes in the variable/antigenic regions of the VP7 gene from G4 and G9 strains detected in different years. CONCLUSIONS: This study further indicates that antigenic pressure can drive the evolution of rotaviruses, and also suggests that a vaccine that protects against the most prevalent strains and its variants, will be necessary to elicit a protective immune response against the range of rotavirus types currently circulating in Paraguay.     

Genotypes of rotavirus strains circulating in Amman, Jordan, in 2006/07 and their significance for the potential effectiveness of future rotavirus vaccination

The prevalence, seasonality and genotypes of rotavirus circulating in Jordan were determined to provide data useful for the implementation of a rotavirus vaccine in the national childhood vaccination program. During 2006/07, rotavirus was detected in 35% of hospitalized children, and 88% of the cases occurred in children aged between 6 and 23 months. Rotavirus infection persisted throughout the year and peaked in winter. Seven genotypes were identified by RT-PCR and sequencing: G1P[8], G9P[8], G2P[4], G1P[4], G3P[8], G4P[8] and G9P[6], which represented 69%, 8.8%, 2.4%, 2.0%, 1.2%, 0.4% and 0.4% of the rotavirus strains, respectively. Thirteen percent and 2.8% of the total strains were partially typed or untypeable, respectively. Eighty-eight percent and 12% of the rotavirus strains possessed a long and short electropherotype, respectively. As more than 90% of the rotavirus strains circulating in Jordan possessed the G1 or P[8]-genotype, it is concluded that the implementation of the rotavirus vaccine in the framework of the national childhood vaccination program of Jordan would most likely be very effective. Continuous monitoring of the currently circulating genotypes in Jordan should be encouraged.     

Epidemiological features of rotavirus infection among hospitalized children with gastroenteristis in Ho Chi Minh City,Vietnam

An epidemiological study of the G serotype and P genotype distribution of group A rotaviruses by using ELISA and/or RT-PCR was conducted in children (aged 1 month to 15 years) with diarrhea that were admitted to the General Children's Hospital No. 1, Ho Chi Minh City, Vietnam from December 1999 to November 2000. The results showed that rotavirus is associated with 65.6% (889/1355) of diarrheal admissions. Rotavirus infection mostly affected children under 2 years of age with a peak incidence in children 1 to 2 years of age (75.7%) and it occurs year round with a slight seasonal pattern; 99.5% of the specimens could be G-typed: G1 was predominant (68.7%), followed by G4 (15.4%), G2 (12.3%), G3 (0.6%), and G9 (0.5%). High identities of VP7 nucleotide (96.3 to 96.9%) and deduced amino acid (98.1 to 98.4%) were found between two Vietnamese G9 strains and also the recent emergence of G9 strains US 1205, Brazilian R143, and Malawian MW69. Mixed infections were identified in 17 (2.0%), and 5 strains (0.5%) remained untypable. The four most common worldwide strains, G1P[8], G2P[4], G3P[8], and G4P[8], constituted 81.1% of all rotaviruses typed with G1P[8] being the most prevalent type (58.2%). Unusual G/P combinations (11 strains) were detected in 11.7% of all strains, of which, G1P[4] was the most prevalent, accounting for 5.6% of the total. Several combinations of G and P types were observed in this study, suggesting a complex rotavirus infection pattern in Vietnam. This study has provided for the first time clear indication on the circulating G and P genotypes among hospitalized children in Ho Chi Minh City, Vietnam. The results suggest that these viral infections are prevalent among hospitalized children and that the four most common worldwide G types as well as the four most common G-P combinations were also infecting children in Ho Chi Minh City, Vietnam. This result could have important implications for rotavirus vaccine programs and for understanding the epidemiological characteristics of human rotavirus in Ho Chi Minh City, Vietnam.     

A first report on the characterization of rotavirus strains in Sierra Leone

In an effort to reduce the high mortalities associated with rotavirus infections, a number of African countries are considering introducing human rotavirus vaccines. The demonstrated safety and efficacy of the live‐attenuate human rotavirus vaccines in several clinical trials worldwide has accelerated such initiatives. Although the percentage‐mortality rates for Sierra Leone are top of the list for rotavirus‐associated deaths in Africa, no study has reported the prevalent strains circulating within this country. In this study, stool specimens were collected from 128 Sierra Leonean children presenting with diarrhea in 2005. Almost 37.5% (48/128) were rotavirus positive by EIA, of which 89.6% (43/48) revealed a short electropherotype, and a further 6.98% (3/48) could not be assigned a PAGE pattern. Genotyping analysis revealed G2P[4] (30.23%), G2P[6] (13.95%), G8P[6] (11.63%), G2P[8] (4.65%), G8P[4] (4.65%), and G8P[8] (2%) strains. About 11% were only assigned VP7 genotypes (G2), while 20.9% had mixed G and P types. The frequent detection of G2 rotaviruses could be of concern considering data generated from some studies that suggests lower efficacy of Rotarix® vaccine against G2 rotaviruses. This underscores the need for extensive and continuous regional strain surveillance to support rotavirus vaccines introduction and guide future vaccine development efforts. Such information will be useful before considering administration of specific rotavirus vaccine candidates in countries like Sierra Leone where little is known about circulating rotavirus strains. J. Med. Virol. 83:540–550, 2011. © 2011 Wiley‐Liss, Inc.     

Higher proportion of G2P[4] rotaviruses in vaccinated hospitalized cases compared with unvaccinated hospitalized cases,despite high vaccine effectiveness against heterotypic G2P[4] rotaviruses

The overall vaccine effectiveness of the monovalent rotavirus vaccine in an observational, prospective, multicentre, hospital-based case-control study in Belgium (RotaBel) was 90%. However, rotavirus genotype and co-infecting pathogens are important parameters to take into account when assessing vaccine effectiveness. In this study we specifically investigated the effect of rotavirus genotypes and co-infecting pathogens on vaccine effectiveness of the monovalent vaccine. In addition, we also investigated the effect of co-infecting pathogens on disease severity. From February 2008 to June 2010 stool samples of rotavirus gastroenteritis cases of a random sample of 39 Belgian hospitals were collected and subsequently genotyped. Fisher’s exact tests were performed to investigate the relationships between rotavirus genotype, co-infecting pathogens and disease severity. The vaccine effectiveness of a full series of the monovalent rotavirus vaccine against hospitalized rotavirus gastroenteritis caused by GIP[8] rotavirus strains was 95% (95% CI 77.5-98.7). Against G2P[4], the vaccine effectiveness was 85% (95% CI: 63.7-93.8). G4P[8]- and G3P[8]-specific vaccine effectiveness was 90% (95% CI 19.2-98.7) and 87% (95% CI -5.2 to 98.4), respectively. A post-hoc analysis showed that the genotype distribution was significantly related to the vaccination status (p <0.001), whereby G2P[4] strains were proportionally more prevalent in vaccinated cases than in unvaccinated cases. No statistical associations were found between co-infection status and vaccination status, Vesikari severity score or rotavirus genotype. The high vaccine effectiveness against the individual genotypes implies robust protection of the monovalent rotavirus vaccine against hospitalized rotavirus gastroenteritis caused by the major human rotavirus genotypes. The prevalence of G2P[4] requires continued monitoring.     

Molecular characterization of rotavirus diarrhea among children in South Korea: detection of an unusual G11 strain

Among 312 rotavirus-positive samples collected from eight hospitals across South Korea during 2008 and 2009, the most prevalent circulating G genotype was G1 (35.9%), followed by G3 (24.7%), G2 (17.0%), G4 (7.7%), and G9 (2.6%). Notably, one unusual G11 lineage III strain-the first hypoendemic infection case in the world-was found. Of the P genotypes, P[8] (43.9%) was the most common, followed by P[6] (29.5%), P[4] (9.3%) and P[9] (0.6%). Determining G- and P-type combinations showed that G1P[8] was the most prevalent (20.5%), followed by G2P[6] (12.8%) and G3P[8] (12.8%). These findings provide new information concerning the current prevalence and spread of the rare G11 rotavirus.     

Genomic diversity of group A rotavirus strains in patients aged 1–36 months admitted for acute watery diarrhoea in northern India: a hospital-based study

The diversity and capacity of human rotaviruses for rapid evolution and genetic reassortment suggests that rotavirus vaccine should be designed to provide heterotypic protection. The objective of the present study was to provide information on the circulating genotypes of rotavirus and allied baseline epidemiology in Lucknow, India. In a cross-sectional study, the prevalence of rotavirus G-P types was studied in patients aged 1–36 months with acute watery diarrhoea. Various sociodemographic, environmental and clinical factors were assessed as potential predictors of rotavirus infection; 412 patients with acute watery diarrhoea were recruited into the study from September 2004 to April 2008 and rotavirus was identified in 19.2% (79/412) cases using ELISA and PAGE. The genotypes identified were G1 (38.0%), G2 (15.2%), G3 (16.5%), G9 (10.9%), G4 (5.1%) and mixed G types (10.1%). The most common G-P combinations were G1P[8], G3P[6], G1P[6] and G2P[8]. Rotavirus diarrhoea was found to occur throughout the year with a single peak in winter months (November–January). Rotavirus diarrhoea was found to be associated with children not currently breast fed (adjusted OR 2.2, 95% CI 1.3–3.7, p 0.004), children ≤7 months of age (adjusted OR 1.1, 95% CI 1.0–1.1, p 0.002) and children with severe dehydration (adjusted OR 1.8, 95% CI 1.1–3.0, p 0.03) using multivariate logistic regression. A high degree of strain diversity of rotavirus G and P types was detected. Rotavirus was found to be associated with dehydrating diarrhoea, particularly in children aged 0–7 months, placing them at increased risk of mortality.     

G[P] type profiles of group A human rotavirus and their distribution in Nizhni Novgorod and Dzerzhinsk in 1997-2005

RT-PCR was used to determine G (VP7) and P (VP4) genotypes of group A rotavirus found in 2454 children with diarrhea in 1997-2005. Eight G[P] combinations, including G1-4 serotypes and P[4, 6, 8, 9] genotypes, were identified. The P[8] genotype was presented by the subtypes P[8]-1 and P[8]-2. In 1997-2005, the spectrum and distribution of G[P] types were as follows: G1P[8]-1 (10%), G1P[8]-2 (67%), G1P[6] (3%), G2P[4] (9%), G3P[8]-2 (5%), G3P[6] (1%), G3P[9] (1%), G4P[8]-2 (3%), G9 (0%), G?P[?] (1%). Five G[P] types of rotavirus were identified in the 2004-2005 season. The G2P[4] type was prevalent (37%), the GI P[8]-2 type was detected in 25% of cases; G3P[8]-2 in 22%; G4P[8]-2 in 12%; G3P in 2%), G[?]P[?] in 2%. The P[8]-1 subgemotype was not found. The spectrum of the G1P[8] types of rotavirus and their distribution should be taken into account while developing a vaccine prophylaxis program against rotavirus gastroenteritis in Russia.     

Detection of G3P[3] and G3P[9] rotavirus strains in American Indian children with evidence of gene reassortment between human and animal rotaviruses

The distribution and evolution of human rotavirus strains is important for vaccine development and effectiveness. In settings where rotavirus vaccine coverage is high, vaccine pressure could select for replacement of common strains (similar to those included in rotavirus vaccines) with uncommon strains, some of which could be generated by reassortment between human and animal rotaviruses. Between 2002 and 2004, a phase-III rotavirus vaccine clinical trial was conducted among American Indian children of the Navajo and White Mountain Apache tribes, which are known to be at high risk for rotavirus diarrhea. We evaluated the rotavirus strains collected from study participants who received placebo during the trial to determine the distribution of rotavirus genotypes and to detect emerging strains that contribute to disease and could influence rotavirus vaccine effectiveness. Three uncommon strains of human rotavirus, two G3P[3] and one G3P[9] strains were detected in stools of children aged 3 to 6 months of age. Segments of all 11 rotavirus genes were sequenced and genotyped by comparison of cognate gene fragments with reference strains. The G3P[3] strains had similar genotypes to each other and to reference dog and cat strains. The G3P[9] strain had similar genotypes to cow, cat and dog reference strains. Genetic analyses of these three strains support the known diversity generating mechanisms of rotavirus.     

Rotavirus genotypes circulating in Brazil before national rotavirus vaccination: A review.

BACKGROUND: Rotavirus vaccine was recently introduced in Brazil, which has the potential to greatly reduce childhood deaths from diarrhoea. To provide baseline data to assess the effect of mass rotavirus vaccination on the ecology of circulating rotavirus strains, we systematically analysed published studies in the pre-vaccine era. AIMS: To describe the distribution of rotavirus genotypes in Brazil prior to vaccine introduction. METHODS: Systematic literature searches in health-related databases from 1986 to 2006. Information extracted and analysed by time and region. RESULTS: 117 studies with 48,401 participants were included. Of these, 3036 were infected with rotavirus. More than 51 genotype combinations were reported, the distribution of which changed over time. P[8]G1 (43%) was the most frequent genotype throughout, followed by P[8]G9 (22%) and P[4]G2 (7%). The detection rate of P[8]G9 increased, while P[4]G2 decreased during the study period. There was a high frequency of G/P combinations between 1995 and 2000 and a low frequency before and after these years. CONCLUSIONS: While considerable diversity of rotavirus strains was recognized during the pre-vaccine era, three strains comprised 72% of the total analysed. These data provide a baseline against which any changes in circulating rotavirus strains post-vaccine introduction can be measured.