Distribution Of Rotavirus Strains Research Articles

Rotavirus Strain Distribution before and after Introducing Rotavirus Vaccine in India.

In April 2016, an indigenous monovalent rotavirus vaccine (Rotavac) was introduced to the National Immunization Program in India. Hospital-based surveillance for acute gastroenteritis was conducted in five sentinel sites from 2012 to 2020 to monitor the vaccine impact on various genotypes and the reduction in rotavirus positivity at each site. Stool samples collected from children under 5 years of age hospitalized with diarrhea were tested for group A rotavirus using a commercial enzyme immunoassay, and rotavirus strains were characterized by RT-PCR. The proportion of diarrhea hospitalizations attributable to rotavirus at the five sites declined from a range of 56–29.4% in pre-vaccine years to 34–12% in post-vaccine years. G1P[8] was the predominant strain in the pre-vaccination period, and G3P[8] was the most common in the post-vaccination period. Circulating patterns varied throughout the study period, and increased proportions of mixed genotypes were detected in the post-vaccination phase. Continuous long-term surveillance is essential to understand the diversity and immuno-epidemiological effects of rotavirus vaccination.

Emergence of G8P[6] rotavirus strains in Korean neonates

BackgroundRotaviruses are the major causes of pediatric gastroenteritis worldwide. The genotypic distribution of rotavirus strains shows temporal and geographical fluctuations, and knowledge of the molecular epidemiology of rotaviruses is important for the development of vaccines and diagnostic reagents. We investigated VP4 and VP7 capsid genotypes of rotaviruses isolated from 211 stool specimens collected from Korean neonates in a neonatal intensive care unit from September 2017 to March 2018.ResultsOf 211 stool specimens, 15 specimens (7.1%) were rotavirus-positive. Eleven specimens (73.3%) were G8P[6] type and 4 (26.7%) were G4P[6] type. Sequence analysis revealed that all G8 sequences in this study showed the highest nucleotide identity to G8 sequences of G8P[8] rotavirus strains isolated in Vietnam in 2014, and P[6] gene sequences showed the highest nucleotide identity to P[6] sequences of G4P[6] strains detected in Korea in 2012. Only one amino acid difference in VP7 was found in 3 of the 11 G8P[6] strains in this study, but multiple amino acid substitutions in VP7 were detected between these G8P[6] strains and the commonly used vaccine strains.ConclusionsThis study showed that rotavirus G8P[6] strains were firstly detected at high frequency in Korean neonates from September 2017 to March 2018. These new rotavirus G8P[6] strains were estimated to be derived from reassortment events between the G8 of G8P[8] strains in Asian region and the P[6] of G4[6] in Korea. Whether the emergence of this unusual G8P[6] strain reflects continuous prevalence or transient occurrence will require continuous monitoring of rotavirus epidemiology.

Burden of rotavirus gastroenteritis and distribution of rotavirus strains in India: A systematic review and meta-analysis

Background: Rotavirus is the leading cause of severe diarrhea and diarrhea associated morbidity in Indian children. Vaccination is one of the most effective approaches to reduce the morbidity. Vaccine composition depends on the prevalence of most common strains. Therefore, it is important to understand the burden of rotavirus gastroenteritis (RVGE) and prevalence of different strains. This systematic review was aimed to estimate the burden of rotavirus gastroenteritis (RVGE) and distribution of rotavirus strains in India. Methods & Materials: A systemic search of published literature was carried out using PubMed, Elsevier ScienceDirect, Cochrane library databases and Google scholar (from 1990 to April 2015) by two independent reviewers. Reference list of the related articles was also screened to find out the relevant studies. Newcastle Ottawa scale was used to assess the study quality. Publication bias was assessed by using funnel plot. Cochrane Q-statistics test and I2 statistics were used to assess the heterogeneity. Random effect model was used. Comprehensive Meta-Analysis software (Version 2.2, Biostat, Englewood NJ) was used. Results: A total of 44 studies, covering a total of 33313 hospitalized children suffering from diarrhea. Maximum number of studies belongs to north followed by studies from south, east and west part of country (15, 10, 7 and 5 studies, respectively). Seven studies were Multi-centric. The number of participants varied from 106 to 6765. The proportion of gastroenteritis cases due to rotavirus was 23.9% (95% confidence interval [CI], 21.1-26.9). Among G type, G1 was found most commonly prevalent followed by G2 and G9 (27.7%, 25.8% and 13%, respectively). The most common P type were P8, P4 and P6 (31.9%, 24.9%, and 11.1%, respectively). G2P[4] was found most prevalent in GP combinations, followed by G1P8 and G9P8 (16.5%, 16.1%, and 6.0%, respectively). The most prevalent GP combinations were G3P[8] (32.1%), G1P[8] (23.0%), and G2P[4] (7.9%). Conclusion: Rotavirus gastroenteritis (RVGE) is an important cause of diarrheal disease in Indian children. G1 and P8 were found most prevalent strains in G and P type, respectively. Vaccination programme with broad serotype vaccine may help in decreasing the RVGE burden in India.

Hospital based surveillance of rotavirus gastroenteritis in children

Background: Rotavirus (RV) is the single most common cause of severe gastroenteritis (GE) in children aged <5 years worldwide. Data on the burden and epidemiology of RV disease in Lebanon is limited. Therefore, this study aimed to determine the attributable fraction (AF) of RV as the etiologic agent of GE, RV strain distribution and seasonality of RVGE in children aged <5 years in Lebanon. Methods: This multicenter, hospital-based surveillance conducted between May 2007 and May 2008, enrolled children <5 years hospitalized with GE episodes. Stool samples were tested for the presence of RV by enzyme immuno assay (EIA). RV positive samples were genotyped by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). Seasonality of RVGE cases was recorded during the study period. Severity of the RVGE episodes was measured using the Vesikari scale, where a score of ≥11 was considered severe. Results: Of the 534 children enrolled in this study, 491 (91.9%) were included in the final analysis in the according-to-protocol cohort; 27.7% (136/491) of subjects were RV positive, 71.5% (351/491) were RV negative and 0.8% (4/491) had unknown RV status. Of the RV positive subjects, 75% (102/136) of cases were seen in children <2 years of age. Although RVGE cases occurred throughout the year, the peak season was observed between December 2007 and March 2008 (65.4%; 89/136). Severe GE cases observed before hospitalization was 79.4% (108/136) in RV positive and 76.1% (267/351) in RV negative subjects (p = 0.44). G4 (36.9%) and P[8]WT (77.7%) were the most common RV types detected among RV positive samples that were genotyped (N = 130). Conclusion: The data generated from this first burden of disease study in Lebanon showed that the AF of Rotavirus in children <5 years of age corresponded to 27.7% of hospitalized GE. Most of the RV cases (75%) were in children aged <2 years. These baseline epidemiology data might guide policy makers in initiating nationwide public health strategies, including vaccination to reduce the RV disease burden in Lebanese children <5 years of age.

Burden of rotavirus gastroenteritis and distribution of rotavirus strains in Asia: A systematic review

Rotavirus is the leading cause of severe diarrhea in children worldwide. We systematically reviewed the burden of rotavirus gastroenteritis (RVGE) and distribution of rotavirus strains in Asia. We searched MEDLINE, EMBASE and the World Health Organization (WHO) website for the term "rotavirus" and the name of each country. We included studies that were conducted in children between 2000 and 2011 and that examined the epidemiology, health and/or economic burden of RVGE, and G and P-type distribution in Eastern, South East, Southern and Central Asia. Random effects models were used to pool the proportions of RVGE. We also estimated child mortality due to RVGE using the updated WHO and United Nations Children's Fund's mortality estimates in 2008. The search identified 113 eligible articles. The incidence rates of rotavirus-related hospitalizations in children under 5 years of age ranged from 2.1 to 20.0 cases per 1000 children per year with the highest rates reported in Bangladesh, South Korea, Taiwan, Thailand, and Vietnam. Rotavirus accounted for 37.5% of year-round hospitalized gastroenteritis cases, with higher proportions reported in South East Asia. Rotavirus was associated with approximately 145,000 deaths every year in Asia, with the greatest numbers occurring in India, Pakistan, and Indonesia. The highest annual societal costs of treating RVGE were reported in China (US$365 million), followed by Japan (US$254 million) and India (US$41-72 million). A diversity of rotavirus G and P-types was observed across Asia and the distribution of strains differed by country and year. The most common strains were G1P[8] (23.6%), G2P[4] (11.8%), G3P[8] (18.9%), and G9P[8] (7.4%). Rotavirus is associated with substantial hospitalizations and deaths among children and causes large healthcare expenditures throughout Asia. Safe and effective rotavirus vaccines could substantially reduce the burden of disease.

Epidemiology of Rotavirus Diarrhea in Mongolia and Sri Lanka, March 2005–February 2007

Rotavirus is the most common cause of severe gastroenteritis among children. We conducted hospital-based surveillance to estimate the burden of hospitalizations for rotavirus among children aged <5 years and to describe strain distribution patterns during the 2-year study period. Children aged <5 years with diarrhea were prospectively enrolled and evaluated by trained pediatricians at representative hospitals in Mongolia and Sri Lanka. Fecal specimens were tested by rotavirus antigen detection enzyme immunoassay. Specimens that tested positive for rotavirus were further characterized to determine the genotype of strains by reverse-transcriptase polymerase chain reaction. From 1 March 2005 through 28 February 2007, a total of 1277 hospitalized children with diarrhea were enrolled in Mongolia, and 1916 were enrolled in Sri Lanka. Of the 1152 children in Mongolia who had samples tested, 458 (40%) had results positive for rotavirus, and in Sri Lanka, 428 (24%) of 1806 children with samples tested had positive results. G3P[8] was the most common genotype among rotavirus strains in Mongolia (68%) and Sri Lanka (15%). Rotavirus causes 40% and 24% of hospitalizations for diarrhea among children in Mongolia and Sri Lanka, respectively. Each study site will continue surveillance of rotavirus, and additional laboratory testing will be performed to provide additional information on the distribution of rotavirus strains by G and P genotype.

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.