Rotavirus Genotypes Research Articles

Epidemiological and clinical significance of rotavirus infection during the vaccination period

Rotavirus infection is one of the leading causes of severe diarrhea in children under five years of age worldwide and contributes significantly to child mortality. The introduction of rotavirus vaccination for epidemic indications into the Russian National Immunization Schedule has not impacted the epidemiological situation due to low vaccination coverage. This article provides a review of studies evaluating the clinical significance of rotavirus infection in the context of mass vaccination, as well as its impact on the circulation of rotavirus genotypes. We have analyzed data on the prevalence of rotavirus, the severity of clinical cases, and changes in the genetic diversity of the virus. It has been noted that vaccination reduces the severity of gastroenteritis; however, over time, changes in circulating viral strains have been observed. Despite the positive effects of vaccination, some countries have reported an increase in the prevalence of other pathogens, such as norovirus and Campylobacter. These findings emphasize the need to continue vaccination efforts and monitor changes in the structure of pathogens responsible for acute intestinal infections to improve preventive measures and control the epidemiological situation.

Study of rotavirus genotypes G and P in one Egyptian center-cross-sectional study.

Rotavirus-associated gastroenteritis is a common health problem in children, different variations of rotavirus genotypes differ according to geographic locations and the practice of wide-scale vaccination. Therefore, the present study aimed to detect both the G and P genotypes of rotavirus in children ≤ 5 years old in one center in Egypt as a cross-sectional study, to correlate the genotypes with various demographic and clinical data in infected children and to evaluate the common mixed genotypes G and P in infected children. The cross-sectional study included children with acute gastroenteritis ≤ 5 years old from January 2023 till March 2024 recruited from Mansoura University Children's Hospital, Egypt based upon laboratory diagnosis by exclusion of bacterial and protozoa pathogens. The stool samples were obtained from each child and subjected to detection of rotavirus antigen by enzyme-linked immunosorbent assay (ELISA) followed by genotypes identification of G and P genotypes by nested polymerase chain reaction (PCR). A nested PCR study for rotavirus genotypes revealed that G1 was the most common genotype (24.7%) followed by G2 (21.1%), G3 (20%), G9 (20%), and G4 (14.1%). The genotyping of the P genotype revealed that P9 was the commonest genotype (24.7%), followed by P4 (21.2%), P10 (20%), P8 (17.6%) and P6 (16.5%). The commonest combined genotypes of G and P were G1P4 (85.7%), G3P8(88.2%), followed by G2P6 (77.8%) and G9P9(76.5%) and G4P9 (66.7%) followed by G4P10 (33.3%), G9P10(23.5%), G2P10(22.2%), G1P10 (14.3%), G3P10(11.8%). The distribution was significant (P = 0.001). The positive rotavirus antigen was more frequently detected in females (55.3%) than males (44.7%, Odd ratio 0.2, 95% CI 0.22-0.71, P = 0.001). There was a significant association between the summer season and positive rotavirus antigen (P = 0.001) and rural residence of the patients (Odd ratio 6,9 95%CI 3,5-13.5, P = 0.001). The significant associated clinical sign with positive rotavirus antigen was fever (Odd ratio 3,3, 95%CI 1,8-6.05, P = 0.001). The genotypes G and P were significantly associated with positive rotavirus antigen as all cases positive by antigen had been detected by nested PCR with the commonest genotypes G4 (24.7%, P = 0.001) and genotype P9 (24.7%, P = 0.001). The present study highlights the common genotypes of rotavirus at one center in Egypt, G1, G2, and G3 were the commonest G genotypes. As regard genotype P the commonest genotypes were P9, P4, and P10. The commonest combined genotypes were G1P4, G3P8, G2P6. There was no effect of the practice of rotavirus vaccination at limited rates at private health sections as the rotavirus is still a major pathogen of acute gastroenteritis in children. There is a need for the inclusion of rotavirus vaccination in the national program of children vaccination in Egypt.

VP8 Mosaic Nanoparticles Elicit Cross-Neutralizing Immune Responses and Provide Protection Against Heterotypic Rotavirus Challenge in Mice.

Group A rotaviruses (RVA) remain one of the dominant pathogens causing diarrhea in children under 5 years of age worldwide, despite a sharp decrease of RVA-associated diarrhea and mortality since the introduction of rotavirus vaccines. The decreased effectiveness of live attenuated rotavirus vaccines, coupled with the emergence of new rotavirus genotypes and the risk of cross-species virus transmission, underscores the necessity to develop more effective and broad-spectrum rotavirus vaccines. In this study, we utilized nanoparticles coupled with the SpyCatcher-SpyTag system to effectively display the truncated VP8-1 protein. The modular display of the monovalent VP8-1 proteins markedly increased the immunogenicity of VP8-1. Furthermore, the bivalent display of VP8-1 proteins from simian rotavirus SA11 and lamb rotavirus LLR on the same particle not only increased immunogenicity against homotypic antigens but also elicited robust heterotypic immune responses and conferred effective protection against a distant heterotypic rotavirus with sequence identities of only 62%-66% in an adult mouse model. Therefore, mosaic VP8 nanoparticles could be considered as a viable strategy for the development of the next-generation broad-spectrum rotavirus vaccine.

Rapid production of recombinant rotaviruses by overexpression of NSP2 and NSP5 genes with modified nucleotide sequences.

Reverse genetics systems for rotaviruses (RV) facilitate the generation of genetically engineered RVs by transfection of 11 plasmids encoding 11 genomic viral RNA segments. In addition to viral genome expression, overexpression of NSP2 and NSP5 has been used to increase the rescue efficiency of recombinant RVs. Here, we showed that the overexpression of nucleotide sequence-modified NSP2 and NSP5 enabled the rapid and efficient production of recombinant RVs. Using improved reverse genetics, we established a reverse genetics system for human and bovine RV clinical isolates, as well as laboratory strains of bovine RV (NCDV and UK) and porcine RV (Gottfried). In addition, we rescued low-replicating recombinant RVs carrying a mutant NSP4 lacking the double-layered particle-binding domain, which was deficient in the efficient production of mature virions. These advancements in reverse genetics enabled the generation of molecular clones of RV clinical isolates and recombinant RVs harboring critical amino acid mutations, offering a versatile platform for investigating RV biology and pathogenesis.IMPORTANCERecombinant rotavirus (RV) synthesis via reverse genetics relies on both the viral propagation capacity and the efficiency of the experimental system. Since the establishment of our reverse genetics system, several enhancements have been implemented to augment the rescue efficiency. Nevertheless, challenges persist in generating RV clinical strains and recombinant viruses with low replication capacities. Notably, this improved reverse genetics system successfully facilitated the establishment of molecular clones of human and bovine RV clinical isolates. Fecal samples from patients with RV typically harbor quasi-species or, occasionally, multiple genotypes of RV. In the present study, we performed the genetic sequencing of clinical viral strains during the early propagation stages in cultured cells. Subsequently, infectious viruses were synthesized, allowing the characterization of circulating viruses in nature. This approach provides valuable insights into the genetic diversity and dynamics of RV populations and contributes to a more comprehensive understanding of viral pathogenesis and evolution.

New Genotype G3 P[8] of Rotavirus Identified in a Mexican Gastroenteric Rabbit

Rotavirus species A (RVA) is a major cause of acute viral gastroenteritis in young humans and diverse animal species. The study of the genetic characteristics of RVAs that infect rabbits (Oryctolagus cuniculus) (lapine strain [LRV]) has been limited, and, to date, the most common and epidemiologically important combinations of G/P genotypes in rabbits have been reported to be G3 P[14] and G3 P[22]. In this study, a rotavirus species A detected from an outbreak of enteritis in a Mexican commercial rabbitry was genotypically characterized. Based on sequence and phylogenetic analysis of the VP7 and VP4 genes, the strain identified in this study (C-3/15) demonstrated a G3 P[8] genotype of rotavirus, which had not previously been reported in rabbits. Moreover, both genes were closely related to human, not lapine, rotaviruses. The G3 genotype has been reported in a wide variety of hosts, including humans and rabbits, whereas the P[8] genotype has only been reported in humans. Because this combination of genotypes has never been identified in rabbits, it is proposed that the finding presented here is possibly the result of an interspecies transmission event. This is the first work to study the molecular characteristics of rotaviruses in rabbits in Mexico, as well as the identification of human G3 and P[8] genotypes in a rabbit with enteric disease.

Identification of Rotavirus Genotypes in Children under Five Years in the United Arab Emirates Using Nanopore Sequencing Technology.

Group A rotaviruses (RVA) remain a principal cause of childhood diarrhea in the UAE, despite universal vaccine use. Monitoring genetic diversity is important for identifying prevalent genotypes and escape mutants. Although real-time polymerase chain reaction (RT-PCR) is widely used for RVA genotyping, it may not detect some new strains. This study evaluates nanopore sequencing and RT-PCR for RVA genotyping. Thirty-three RVA strains from children under 5 years presenting with diarrhea were genotyped using both methods. Thirteen strains were genotyped by RT-PCR and confirmed by nanopore sequencing. Fifteen strains were genotyped by nanopore method alone. Most PCR-genotyped strains (56%) had the VP7 G9 genotype, with G3 in five strains and G12 in two. For VP4, P8 (n = 8) and P4 (n = 7) were dominant. The most frequent combinations were G9P[8] (31%) and G9P[4] (25%). Nanopore sequencing of 28 strains revealed G3P[8] (29%) as the most prevalent, followed by G8P[8] (18%). G9P[8] and G2P[4] were present in 14% of samples with G12P[6] being the rarest (7%). Other combinations were detected in 4% the specimens with one nontypeable. Nanopore sequencing was superior to PCR in identifying diverse and emerging genotypes like G8P[8]. This method may enhance surveillance studies and guide preventive measures for RVA gastroenteritis.

Comparison of Rotavirus Genotypes Before and After the COVID-19 Pandemic

Comparison of Rotavirus Genotypes Before and After the COVID-19 Pandemic

Shigella and Enterotoxigenic Escherichia coli Have Replaced Rotavirus as Main Causes of Childhood Diarrhea in Rwanda After 10 Years of Rotavirus Vaccination.

The causes of diarrhea after 10 years of rotavirus vaccination in Rwanda were investigated with real-time polymerase chain reaction in 496 children with diarrhea and 298 without. Rotavirus was detected in 11% of children with diarrhea (odds ratio, 2.48; P = .002). Comparison of population attributable fractions (PAFs) shows that Shigella (PAF, 11%) and enterotoxigenic Escherichia coli producing labile toxin (PAF, 12%) have replaced rotavirus as the main causative agents. The PAF for rotavirus had declined from 41% prevaccination to 6.5% postvaccination, indicating that rotavirus has become one among several similarly important causes of childhood diarrhea in Rwanda. A rotavirus genotype shift to G3P[8] points at the importance of continued genotype surveillance.

The Frequency of Rotavirus Gastroenteritis in Children from West of Iran and Genotyping of Rotavirus Isolates: A Suggestion for Further Changes in Childhood Immunization Program.

Rotavirus is the most common cause of gastroenteritis among children. Currently, four oral live-attenuated vaccines are available to prevent rotavirus infection. The World Health Organization (WHO) has recommended including rotavirus vaccination in national immunization programs; however, it has not been introduced to the Iranian national immunization program. The study aimed to assess the frequency of rotavirus gastroenteritis in the west of Iran and investigate the necessity of rotavirus vaccination. Study Design: A case series study. In this case series study, 284 cases under six years of age who presented with acute gastroenteritis from March 2021 to 2022 to a referral hospital in the west of Iran were evaluated. Data on baseline characteristics, clinical manifestations, results of stool test, ELISA for rotavirus detection, and polymerase chain reaction (PCR) test for genotyping of rotavirus-positive samples were recorded. Results showed that the prevalence of rotavirus infection was 36.6%. The highest frequency was observed among children aged 6-12 months and during the autumn. According to the PCR results, G1P[8], G9P[8], G9P[4], and G1P [4] were the dominant genotypes, and 33.75% of samples were infected with multiple rotavirus genotypes. The study highlights the considerable prevalence of rotavirus infection among cases of acute gastroenteritis in children under six years of age who were referred to a referral hospital in the west of Iran and the high diversity of rotavirus genotypes in the targeted community. Consequently, physicians and health policymakers should prioritize strategies for the prevention and control of this infection, particularly by considering the rotavirus vaccine as a priority for the Iranian national immunization program.

Complete genome constellation of a dominant Bovine rotavirus genotype circulating in Bangladesh reveals NSP4 intragenic recombination with human strains

Rotavirus A is a leading cause of non-bacterial gastroenteritis in humans and domesticated animals. Despite the vast diversity of bovine Rotavirus A strains documented in South Asian countries, there are very few whole genomes available for phylogenetic study. A cross-sectional study identified a high prevalence of the G6P[11] genotype of bovine Rotavirus A circulating in the commercial cattle population in Bangladesh. Next-generation sequencing and downstream phylogenetic analysis unveiled all 11 complete gene segments of this strain (BD_ROTA_CVASU), classifying it under the genomic constellation G6P[11]-I2-R2-C2-M2-A13-N2-T6-E2-H3, which belongs to a classical DS-1-like genomic backbone. We found strong evidence of intragenic recombination between human and bovine strains in the Non-structural protein 4 (NSP4) gene, which encodes a multifunctional enterotoxin. Our analyses highlight frequent zoonotic transmissions of rotaviruses in diverse human-animal interfaces, which might have contributed to the evolution and pathogenesis of this dominant genotype circulating in the commercial cattle population in Bangladesh.

Immunogenicity of a Rotavirus VP8* Multivalent Subunit Vaccine in Mice.

Rotavirus remains a significant public health threat, especially in low-income countries, where it is the leading cause of severe acute childhood gastroenteritis, contributing to over 128,500 deaths annually. Although the introduction of the Rotarix and RotaTeq vaccines in 2006 marked a milestone in reducing mortality rates, approximately 83,158 preventable deaths persisted, showing ongoing challenges in vaccine accessibility and effectiveness. To address these issues, a novel subcutaneous vaccine formulation targeting multiple rotavirus genotypes has been developed. This vaccine consists of nine VP8* proteins from nine distinct rotavirus genotypes and sub-genotypes (P[4], P[6], P[8]LI, P[8]LIII, P[8]LIV, P[9], P[11], P[14], and P[25]) expressed in E. coli. Two groups of mice were immunized either with a single immunogen, the VP8* from the rotavirus Wa strain (P[8]LI), or with the nonavalent formulation. Preliminary results from mouse immunization studies showed promising outcomes, eliciting antibody responses against six of the nine immunogens. Notably, significantly higher antibody titers against VP8* P[8]LI were observed in the group immunized with the nonavalent vaccine compared to mice specifically immunized against this genotype alone. Overall, the development of parenteral vaccines targeting multiple rotavirus genotypes represents a promising strategy in mitigating the global burden of rotavirus-related morbidity and mortality, offering new avenues for disease prevention and control.

Determining genetic diversity of prevalent G and P genotype of Bovine Rotavirus A from neonatal calves of Gujarat, India.

Neonatal calf diarrhea is a major cause of mortality in newborn calves worldwide, posing a significant challenge in bovine herds. Group A Bovine Rotaviruses (BRVA) are the primary contributors to severe gastroenteritis in calves under two months old. This study examined the prevalence and molecular characterization of BRVA in neonatal calves in Gujarat, India. Sixty-nine diarrheic fecal samples were collected and subjected to various molecular methods of BRVA detection, isolation, and characterization. The latex agglutination test (LAT), electropherotyping (RNA-PAGE), and reverse transcription polymerase chain reaction revealed positivity rates of 39.13%, 20.30%, and 37.70%, respectively. RNA-PAGE identified 11 bands with a 4:2:3:2 migration pattern, indicative of the segmented genome of BRVA. BRVA was successfully isolated from LAT-positive samples, with 26 samples exhibiting clear cytopathic effects upon passage in MA-104 cell lines. Genotyping identified G10 as the predominant G genotype, with P[11] genotypes comprising 76.92% of the isolates. The most common G/P combination was G10P[11], highlighting its zoonotic potential. These findings underscore the importance of molecular detection and genotyping for effective vaccine development. This study provides crucial insights into the prevalent G and P genotypes of BRVA in Gujarat, India, aiding in the development of targeted control measures.

Australian Rotavirus Surveillance Program Annual Report, 2022.

This report from the Australian Rotavirus Surveillance Program describes the circulating rotavirus genotypes identified in children and adults during the period 1 January to 31 December 2022. After two years of a lower number of stool samples received as a result of the coronavirus disease 2019 (COVID-19) pandemic, this reporting period saw the highest number of samples received since the 2017 surveillance period, with samples received from all states and territories. During this period, 1,379 faecal specimens had been referred for rotavirus G- and P- genotype analysis, of which 1,276 were confirmed as rotavirus positive. In total, 1,119/1,276 were identified as wildtype rotavirus, 155/1,276 identified as the Rotarix vaccine strain and 2/1,276 that could not be confirmed as vaccine or wildtype due to sequencing failure. Whilst G12P[8] was the dominant genotype nationally among wildtype samples (28.2%; 315/1,119), multiple genotypes were identified at similar frequencies including G9P[4] (22.3%; 249/1,119) and G2P[4] (20.3%; 227/1,119). Geographical differences in genotype distribution were observed, largely driven by outbreaks reported in some jurisdictions. Outbreaks and increased reports of rotavirus disease were reported in the Northern Territory, Queensland, and New South Wales. A small number of unusual genotypes, potentially zoonotic in nature, were identified, including: G8P[14]; G10[14]; caninelike G3P[3]; G6P[9]; and G11P[25]. Ongoing rotavirus surveillance is crucial to identify changes in genotypic patterns and to provide diagnostic laboratories with quality assurance by reporting incidences of wildtype, vaccine-like, or false positive rotavirus results.

Rotavirus genotype dynamics in Pakistan: G9 and G12 emerging as dominant strains in vaccinated children (2019)

Rotavirus A (RVA) is a leading cause of severe gastroenteritis in children worldwide, and vaccination has become a pivotal strategy to reduce the associated morbidity and mortality. This study presents a molecular characterization of RVA genotypes circulating among vaccinated children in Pakistan during the year 2019. A total of 510 stool samples were collected from children of up to five years of age presenting with acute gastroenteritis symptoms in Rawalpindi, Islamabad regions of Pakistan. The RVA antigen was detected using ELISA on these samples. RVA G/P genotyping was performed on ELISA positive samples using Multiplex semi-nested reverse transcriptase PCR. RVA was found in 130 fecal samples, with an overall prevalence of 25.4 %. G9P[8] (20 %) is the most prevalent genotype, followed by G12P[6] (17 %), G3P[8] (14 %), G1P[8] (12 %), G2P[4] (10 %), G12P[8] (7 %), G9P[6] (7 %), G3P[6] (6 %), G3P[4] (4 %) and G1P[6] (3 %) respectively. There is a statistically significant difference (p < 0.05) found in the group age (in months) of RVA gastroenteritis cases as detected by RT-PCR. The highest number of positive cases was found in the age range from 0 to 6 months, followed by 7–12 months, 13–24 months, and 25–60 months, respectively. Dehydration is statistically significantly associated (p˂ 0.05) in RVA gastroenteritis cases compared to those who tested negative. This study emphasizes the significance of maintaining a continuous surveillance system and conducting genomic analysis of RVA genotypes in children upto the age of 5 years. This is essential for tracking the circulation of RVA genotypes. The results from this research enhance our comprehension of how RVA genotypes are changing over time in Pakistan, underscoring the ongoing necessity for improving vaccine coverage and effectiveness. This, in turn, can help reduce the impact of RVA-related illnesses in children.

Human Rotaviruses of Multiple Genotypes Acquire Conserved VP4 Mutations during Serial Passage.

Human rotaviruses exhibit limited tropism and replicate poorly in most cell lines. Attachment protein VP4 is a key rotavirus tropism determinant. Previous studies in which human rotaviruses were adapted to cultured cells identified mutations in VP4. However, most such studies were conducted using only a single human rotavirus genotype. In the current study, we serially passaged 50 human rotavirus clinical specimens representing five of the genotypes most frequently associated with severe human disease, each in triplicate, three to five times in primary monkey kidney cells then ten times in the MA104 monkey kidney cell line. From 13 of the 50 specimens, we obtained 25 rotavirus antigen-positive lineages representing all five genotypes, which tended to replicate more efficiently in MA104 cells at late versus early passage. We used Illumina next-generation sequencing and analysis to identify variants that arose during passage. In VP4, variants encoded 28 mutations that were conserved for all P[8] rotaviruses and 12 mutations that were conserved for all five genotypes. These findings suggest there may be a conserved mechanism of human rotavirus adaptation to MA104 cells. In the future, such a conserved adaptation mechanism could be exploited to study human rotavirus biology or efficiently manufacture vaccines.

Epidemiology of rotavirus infection: the evolution of the pathogen and the success of vaccination

The review presents data on the spread of various rotavirus genotypes and its variability in the world and in Russia, which occur both due to natural causes and under the influence of vaccination against rotavirus infection, as well as on the transformation of clinical and epidemiological features of the course of this disease in children as a result of the pathogen mutations.

Prevalence and genetic diversity of rotavirus among children under 5 years of age in China: a meta-analysis.

This meta-analysis was performed to assess the prevalence and circulating strains of rotavirus (RV) among Chinese children under 5 years of age after the implantation of the RV vaccine. Studies published between 2019 and 2023, focused on RV-based diarrhea among children less than 5 years were systematically reviewed using PubMed, Embase, Web of Science, CNKI, Wanfang and SinoMed Data. We synthesized their findings to examine prevalence and genetic diversity of RV after the RV vaccine implementation using a fixed-effects or random-effects model. Seventeen studies met the inclusion criteria for this meta-analysis. The overall prevalence of RV was found to be 19.00%. The highest infection rate was noted in children aged 12-23months (25.79%), followed by those aged 24-35 months (23.91%), and 6-11 months (22.08%). The serotype G9 emerged as the most predominant RV genotype, accounting for 85.48% of infections, followed by G2 (7.70%), G8 (5.74%), G1 (4.86%), and G3 (3.21%). The most common P type was P[8], representing 64.02% of RV cases. Among G-P combinations, G9P[8] was the most frequent, responsible for 78.46% of RV infections, succeeded by G8P[8] (31.22%) and G3P[8] (8.11%). Despite the variation of serotypes observed in China, the G1, G2, G3, G8 and G9 serotypes accounted for most RV strains. The genetic diversity analysis highlights the dynamic nature of RV genotypes, necessitating ongoing surveillance to monitor changes in strain distribution and inform future vaccine strategies.

Rotavirus in developing countries: molecular diversity, epidemiological insights, and strategies for effective vaccination.

Rotavirus (RV) causes the loss of numerous children's lives worldwide each year, and this burden is particularly heavy in low- and lower-middle-income countries where access to healthcare is limited. RV epidemiology exhibits a diverse range of genotypes, which can vary in prevalence and impact across different regions. The human genotypes that are most commonly recognized are G1P[8], G2P[4], G3P[8], G4P[8], G8P[8], G9P[8], and G12P[8]. The diversity of rotavirus genotypes presents a challenge in understanding its global distribution and developing effective vaccines. Oral, live-attenuated rotavirus vaccines have undergone evaluation in various contexts, encompassing both low-income and high-income populations, demonstrating their safety and effectiveness. Rotavirus vaccines have been introduced and implemented in over 120 countries, offering an opportunity to assess their effectiveness in diverse settings. However, these vaccines were less effective in areas with more rotavirus-related deaths and lower economic status compared to wealthier regions with fewer rotavirus-related deaths. Despite their lower efficacy, rotavirus vaccines significantly decrease the occurrence of diarrheal diseases and related mortality. They also prove to be cost-effective in regions with a high burden of such diseases. Regularly evaluating the impact, influence, and cost-effectiveness of rotavirus vaccines, especially the newly approved ones for worldwide use, is essential for deciding if these vaccines should be introduced in countries. This is especially important in places with limited resources to determine if a switch to a different vaccine is necessary. Future research in rotavirus epidemiology should focus on a comprehensive understanding of genotype diversity and its implications for vaccine effectiveness. It is crucial to monitor shifts in genotype prevalence and their association with disease severity, especially in high-risk populations. Policymakers should invest in robust surveillance systems to monitor rotavirus genotypes. This data can guide vaccine development and public health interventions. International collaboration and data sharing are vital to understand genotype diversity on a global scale and facilitate the development of more effective vaccines.

Genetic characterization of group A rotavirus in children with acute gastroenteritis in Kericho County Referral Hospital, Kenya.

approximately over 80% of mortalities due to rotavirus occur in countries that have limited resources, especially in sub-Saharan Africa and South Asia. The study was intended to determine the genetic characteristics of rotavirus A in children exhibiting gastroenteritis at Kericho County Referral Hospital. the study design was cross-sectional. Consecutive sampling was engaged obtaining a sample size of 200 stool samples. Genetic characterization of group A rotavirus strains was done using Enzyme-Linked Immunosorbent Assay. Positive samples underwent Sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Afterwards viewing of the RNA double strands of the rotavirus genome in gels was done using Silver Nitrate. The positive samples underwent RT-PCR amplification followed by sequencing on the pieces of the VP7 or VP4 gene obtained. one hundred and six (53%) samples from males and 94 (47%) from females. Twenty-three samples were positive hence a prevalence of 11.5%. The most affected demographics were children of guardians with secondary school education (51%). The most affected social economic status was housewives (46.5%). The most affected age was 21-30 months at 26.5%. Long electropherotypes were in 22 samples (96%). The G3 genotype of rotavirus A was prevalent 16/23 (69.57%). rotavirus prevalence was 11.5%. The G3 genotype was the most prevalent in circulation. The occurrence of non-typable strains indicated that the strains may be diversified emphasizing the need to include emerging strains within the vaccines in use. Hence the need to continuously monitor the effects in older children.

Rotavirus genotype diversity in Tanzania during Rotavirus vaccine implementation between 2013 and 2018

The study aims to determine Rotavirus genotypes between 2013 and 2018 during implementation of ROTARIX vaccine in Tanzania. The analysis of surveillance data obtained between 2013 and 2018 was done to determine circulating genotypes after introduction of Rotarix vaccine. From 2013 to 2018, a total of 10,557 samples were collected and screened for Rotavirus using an enzyme immunoassay. A significant decrease in Rotavirus positivity (29.3% to 17.8%) from 2013 to 2018 (OR 0.830, 95% CI 0.803–0.857, P < 0.001) was observed. A total of 766 randomly selected Rotavirus positive samples were genotyped. Between 2013 and 2018, a total of 18 Rotavirus genotypes were detected with G1P [8] being the most prevalent. The G1P [8] strain was found to decrease from 72.3% in 2015 to 13.5% in 2018 while the G9P [4] strain increased from 1 to 67.7% in the same years. G2P [4] was found to decrease from 59.7% in 2013 to 6.8% in 2018 while G3P [6] decreased from 11.2% in 2014 to 4.1% in 2018. The data has clearly demonstrated that ROTARIX vaccine has provided protection to varieties of the wild-type Rotavirus strains. Continuous surveillance is needed to monitor the circulation of Rotavirus strains during this era of vaccine implementation.