Rotavirus-associated Diarrhea Research Articles

Estimation of Rotavirus Associated Diarrheal Disease Burden Amongst Primary School Children of Sindh

Introduction: Human Rotavirus Virus (HRV) is amongst the common enteric viral diarrheal diseases that indirectly or directly influence school-going children in low-income countries. Inadequate information exists on the presence of rotavirus, with reference to drinking water supplies of primary schools in Sindh, Pakistan. Aims & Objectives: We estimated the risk of rotavirus-associated diarrhea through drinking water. The study further compared the HRV-associated risk of diarrheal disease by a type of water source. Place and Duration of Study: A cross-sectional survey was conducted in ten representative districts of Sindh from February 2022 to December 2022. The samples for drinking water were collected from primary schools of ten representative districts of Sindh. This study was a part of the WASH Project funded by USAID (USPCASW Seed Grant P-II) Material & Methods: We selected 425 samples of drinking water from primary schools based on pre-defined selection criteria. We used a Quantitative Microbial Risk Analysis using indicator organisms, i.e., E. coli, to predict the possible health risks of rotavirus. Data was entered and analyzed on SPSS version 26. The graphs were developed using Arc GIS version 3. Morbidity and mortality were predicted using the Quantitative Microbial Risk Assessment (QAMRA) model. Results: Our data revealed that the highest daily risk of HRV-associated diarrhea amongst school children was 11 per 10,000 schoolchildren, resulting in 8.4% annual risk, and the minimum risk was estimated to be 1 in 10,000 children. The burden of diseases for rotavirus using the QAMRA model revealed the severity of the diarrhea. Majority of the children presented with mild diarrhea (86%) followed by severe, and the probability of death was less than <1%. The daily risk of HRV infection was highest (estimated to be 7 and 11%) in pupils of Southern Sindh, with an annual risk of 17.4% to 40%. Conclusion: Our study concluded that the children in the primary schools of Sindh were exposed to poor drinking water quality. The surface water source poses the highest risk of HRV-related diarrhea to school children. Thus, it is highly recommended that point-of-use drinking water treatment systems be adopted. The water sanitation and hygiene (WASH) resources are interlinked, so each resource impacts the other; hence, schools urgently need to invest in providing adequate WASH facilities to stop enteric virus transmission through drinking water sources.

Adenovirus and rotavirus-associated diarrhea among children under five years of age in Offa, Kwara State, North Central Nigeria

Adenovirus and rotavirus-associated diarrhea among children under five years of age in Offa, Kwara State, North Central Nigeria

Maternal and Infant Histo-Blood Group Antigen (HBGA) Profiles and Their Influence on Oral Rotavirus Vaccine (RotarixTM) Immunogenicity among Infants in Zambia.

Live-attenuated, oral rotavirus vaccines have significantly reduced rotavirus-associated diarrhoea morbidity and infant mortality. However, vaccine immunogenicity is diminished in low-income countries. We investigated whether maternal and infant intrinsic susceptibility to rotavirus infection via histo-blood group antigen (HBGA) profiles influenced rotavirus (ROTARIX®) vaccine-induced responses in Zambia. We studied 135 mother-infant pairs under a rotavirus vaccine clinical trial, with infants aged 6 to 12 weeks at pre-vaccination up to 12 months old. We determined maternal and infant ABO/H, Lewis, and secretor HBGA phenotypes, and infant FUT2 HBGA genotypes. Vaccine immunogenicity was measured as anti-rotavirus IgA antibody titres. Overall, 34 (31.3%) children were seroconverted at 14 weeks, and no statistically significant difference in seroconversion was observed across the various HBGA profiles in early infant life. We also observed a statistically significant difference in rotavirus-IgA titres across infant HBGA profiles at 12 months, though no statistically significant difference was observed between the study arms. There was no association between maternal HBGA profiles and infant vaccine immunogenicity. Overall, infant HBGAs were associated with RV vaccine immunogenicity at 12 months as opposed to in early infant life. Further investigation into the low efficacy of ROTARIX® and appropriate intervention is key to unlocking the full vaccine benefits for U5 children.

Genomic characterization of the rotavirus G3P[8] strain in vaccinated children, reveals possible reassortment events between human and animal strains in Manhiça District, Mozambique.

Mozambique introduced the rotavirus vaccine (Rotarix®; GlaxoSmithKline Biologicals, Rixensart, Belgium) in 2015, and since then, the Centro de Investigação em Saúde de Manhiça has been monitoring its impact on rotavirus-associated diarrhea and the trend of circulating strains, where G3P[8] was reported as the predominant strain after the vaccine introduction. Genotype G3 is among the most commonly detected Rotavirus strains in humans and animals, and herein, we report on the whole genome constellation of G3P[8] detected in two children (aged 18 months old) hospitalized with moderate-to-severe diarrhea at the Manhiça District Hospital. The two strains had a typical Wa-like genome constellation (I1-R1-C1-M1-A1-N1-T1-E1-H1) and shared 100% nucleotide (nt) and amino acid (aa) identities in 10 gene segments, except for VP6. Phylogenetic analysis demonstrated that genome segments encoding VP7, VP6, VP1, NSP3, and NSP4 of the two strains clustered most closely with porcine, bovine, and equine strains with identities ranging from 86.9-99.9% nt and 97.2-100% aa. Moreover, they consistently formed distinct clusters with some G1P[8], G3P[8], G9P[8], G12P[6], and G12P[8] strains circulating from 2012 to 2019 in Africa (Mozambique, Kenya, Rwanda, and Malawi) and Asia (Japan, China, and India) in genome segments encoding six proteins (VP2, VP3, NSP1-NSP2, NSP5/6). The identification of segments exhibiting the closest relationships with animal strains shows significant diversity of rotavirus and suggests the possible occurrence of reassortment events between human and animal strains. This demonstrates the importance of applying next-generation sequencing to monitor and understand the evolutionary changes of strains and evaluate the impact of vaccines on strain diversity.

Impact of rotavirus vaccination on diarrheal hospitalizations in children younger than 5 years of age in a rural southern Mozambique

BackgroundRotavirus vaccine(Rotarix®) was introduced in Mozambique through its Expanded Program of Immunization in September 2015. We assessed the impact of rotavirus vaccination on childhood gastroenteritis-associated hospitalizations post-vaccine introduction in a high HIV prevalence rural setting of southern Mozambique. MethodsWe reviewed and compared the trend of hospitalizations (prevalence) and incidence rates of acute gastroenteritis (AGE), and rotavirus associated-diarrhea (laboratory confirmed rotavirus) in pre- (January 2008–August 2015) and post-rotavirus vaccine introduction periods (September 2015–December 2020), among children <5 years of age admitted to Manhiça District Hospital. ResultsFrom January 2008 to December 2020, rotavirus vaccination was found to contribute to the decline of the prevalence of AGE from 19% (95% CI: 18.14–20.44) prior to the vaccine introduction to 10% (95% CI: 8.89–11.48) in the post-introduction period, preventing 40% (95 % IE: 38–42) and 84% (95 % IE: 80–87) of the expected AGE and laboratory confirmed rotavirus cases, respectively, among infants. Similarly, the overall incidence of rotavirus was 11.8-fold lower in the post-vaccine introduction period (0.4/1000 child-years-at-risk [CYAR]; 95% CI: 0.3–0.6) compared with the pre-vaccination period (4.7/1000 CYAR; 95% CI: 4.2–5.1) with the highest reduction being observed among infants (16.8-fold lower from the 15.1/1000 CYAR in the pre-vaccine to 0.9/1000 CYAR in the post-vaccine eras). ConclusionsWe documented a significant reduction in all-cause diarrhea hospitalizations and rotavirus positivity after vaccine introduction demonstrating the beneficial impact of rotavirus vaccination in a highly vulnerable population.

Prevalence and characteristics of rotavirus acute gastroenteritis among under-five children in ahmadu bello university teaching hospital, Zaria, Nigeria.

Rotavirus infection is a significant cause of gastroenteritis in developing countries and, in severe cases even leads to death. The impact of rotavirus vaccine introduction in reducing the rotavirus disease burden in children was well known. The study was aimed to determine the prevalence and clinical characteristics of rotavirus gastroenteritis before the introduction of rotavirus vaccine into Nigeria's routine immunization program. We conducted a cross-sectional hospital-based study involving 735 children aged 0-59 months with acute gastroenteritis hospitalized at the Ahmadu Bello University Teaching Hospital Zaria from September 2017 to August 2020. Relevant sociodemographic and clinical data were obtained and entered into the World Health Organization standardized case investigation forms. Stool specimens were tested for rotavirus Group A antigen using the ProSpecT™ Rotavirus Microplate Assay by Thermoscientific Oxoid Microbiology UK. One hundred and fifty-three stool samples tested positive for rotavirus giving a prevalence of 20.8%. One hundred and two (66.7%) children with rotavirus gastroenteritis were infants. There were 87 males and 66 females with M: F ratio of 1.3:1. Only 30 (19.6%) children with rotavirus-associated diarrhea presented with severe dehydration. The presence of vomiting was significantly associated with rotavirus diarrhea (P = 0.001). More cases of rotavirus diarrhea occurred in September through February. None of the studied children were vaccinated against rotavirus. The prevalence of rotavirus diarrhea remains high in this study. Infants were recognized as a high-risk group, and none of them were vaccinated against rotavirus and this underscores the urgent need for implementing the rotavirus vaccine in the national vaccination program to reduce the disease burden in the country.

One Health approaches to improve refugee health

One Health approaches to improve refugee health

Prevalence, Pattern and Genetic Diversity of Rotaviruses among Children under 5 Years of Age with Acute Gastroenteritis in South Africa: A Systematic Review and Meta-Analysis.

Rotavirus is the most significant cause of severe acute gastroenteritis among children under 5 years of age, worldwide. Sub-Saharan Africa particularly bears the brunt of the diarrheal deaths. A meta-analysis was conducted on 43 eligible studies published between 1982 and 2020 to estimate the pooled prevalence of rotavirus infection and changes in the main rotavirus strains circulating before and after vaccine introduction among under-five children in South Africa. The pooled national prevalence of rotavirus infection was estimated at 24% (95% CI: 21–27%) for the pre-vaccination period and decreased to 23% (95% CI: 21–25%) in the post-vaccination period. However, an increased number of cases was observed in the KwaZulu-Natal (21–28%) and Western Cape (18–24%) regions post-vaccination. The most dominant genotype combinations in the pre-vaccine era was G1P[8], followed by G2P[4], G3P[8], and G1P[6]. After vaccine introduction, a greater genotype diversity was observed, with G9P[8] emerging as the predominant genotype combination, followed by G2P[4], G12P[8], and G1P[8]. The introduction of the rotavirus vaccine was associated with a reduction in the burden of rotavirus-associated diarrhea in South Africa, although not without regional fluctuation. The observed changing patterns of genotype distribution highlights the need for ongoing surveillance to monitor the disease trend and to identify any potential effects associated with the dynamics of genotype changes on vaccine pressure/failure.

Rotavirus gastroenteritis in children hospitalized in northeastern Poland in 2006–2020: Severity, seasonal trends, and impact of immunization

ObjectivesThe introduction of the rotavirus vaccine in 2006 significantly reduced childhood incidence of acute gastroenteritis (AGE) worldwide. The rotavirus vaccine was included in Poland’s national immunization program in 2021. Our study aimed to summarize the epidemiology of AGE in northeastern Poland prior to 2021 and to evaluate the effectiveness of voluntary, out-of-pocket rotavirus childhood vaccination on the incidence of rotavirus AGE. MethodsA review of patients aged 0–17 years with gastroenteritis hospitalized between 2006 and 2020 in northeastern Poland in the context of rotavirus vaccine coverage in the region. ResultsRotavirus was the most common agent of gastroenteritis in hospitalized patients. The seasonality of rotavirus gastroenteritis peaked between February and May in each year of study, except for 2020, when the COVID-19 pandemic skewed any viable comparison of seasonality. Rotavirus vaccine coverage in northeastern Poland did not exceed 25% during the study period and had no impact on hospitalization numbers. ConclusionsRotavirus was the primary causative agent of AGE in children hospitalized in northeastern Poland during the study period. Voluntary vaccinations did not affect the number of hospitalizations due to rotavirus AGE. Our data suggest that universal immunization is key to achieving a significant reduction of rotavirus-associated diarrhea.

Rotavirus Diarrhoea among Children Aged

Diarrhoea remains among the highest causes of death in children under 5 years of age in developing countries. Before the introduction of rotavirus vaccine in Tanzania, rotavirus infection was the leading cause of severe diarrhoea in children below the age of 5 years but there is a paucity of studies reporting the severity of this infection after the introduction of rotavirus vaccine. This hospital-based study reports the proportion of children with rotavirus-associated diarrhoea in Dar es Salaam, its severity and associated factors. A hospital-based cross-sectional study was conducted at the inpatient and outpatient paediatrics departments of the selected health facilities from September 2018 to February 2019. A total of 314 children meeting inclusion criteria were enrolled into the study. A structured questionnaire was used to collect demographic and medical history, anthropometric measurements were taken and a stool sample was collected from each patient for rotavirus antigen detection using CTK Biotech Onsite rotavirus antigen rapid test. A total of 314 children were included in the study with age range between 2 and 59 months. The median age was 12 months with an interquartile range of 8-19 months. Symptoms of rotavirus diarrhoea were vomiting (p-value = 0.018) and severe dehydration (p-value = 0.000). Independent associated factors of rotavirus diarrhoea included: age of mother between 35 and 49 years (AoR 4.1, 95% CI 1.0-17.1, p-value = 0.05), geographical distribution (Ilala District, AoR 4.0, 95% CI 1.1-10.4, p-value = 0.039), poor hand hygiene (AoR 8.5, 95% CI 2.6-28.1, p-value = 0.000) and drinking bottled/home-treated water (AoR 5.4, 95% CI 1.3-22.7, p-value = 0.02). Rotavirus infection is still prevalent and severe among children with diarrhoea. The difference in prevalence among the districts is also of concern and hence larger community-based cohort studies are needed to assess the association of rotavirus diarrhoea with the geographical variation across districts and regions. Improving sanitation and hygiene through health education amongst households is crucial for disease prevention.

Rotavirus disease burden pre-vaccine introduction in young children in Rural Southern Mozambique, an area of high HIV prevalence.

BackgroundRotavirus vaccines have been adopted in African countries since 2009, including Mozambique (2015). Disease burden data are needed to evaluate the impact of rotavirus vaccine. We report the burden of rotavirus-associated diarrhea in Mozambique from the Global Enteric Multicenter Study (GEMS) before vaccine introduction.MethodsA case-control study (GEMS), was conducted in Manhiça district, recruiting children aged 0–59 months with moderate-to-severe diarrhea (MSD) and less-severe-diarrhea (LSD) between December 2007 and November 2012; including 1–3 matched (age, sex and neighborhood) healthy community controls. Clinical and epidemiological data and stool samples (for laboratory investigation) were collected. Association of rotavirus with MSD or LSD was determined by conditional logistic regression and adjusted attributable fractions (AF) calculated, and risk factors for rotavirus diarrhea assessed.ResultsOverall 915 cases and 1,977 controls for MSD, and 431 cases and 430 controls for LSD were enrolled. Rotavirus positivity was 44% (217/495) for cases and 15% (160/1046) of controls, with AF = 34.9% (95% CI: 32.85–37.06) and adjusted Odds Ratio (aOR) of 6.4 p< 0.0001 in infants with MSD compared to 30% (46/155) in cases and 14% (22/154) in controls yielding AF = 18.7%, (95% CI: 12.02–25.39) and aOR = 2.8, p = 0.0011 in infants with LSD. The proportion of children with rotavirus was 32% (21/66) among HIV-positive children and 23% (128/566) among HIV-negative ones for MSD. Presence of animals in the compound (OR = 1.9; p = 0.0151) and giving stored water to the child (OR = 2.0, p = 0.0483) were risk factors for MSD; while animals in the compound (OR = 2.37, p = 0.007); not having routine access to water on a daily basis (OR = 1.53, p = 0.015) and washing hands before cooking (OR = 1.76, p = 0.0197) were risk factors for LSD.ConclusionThe implementation of vaccination against rotavirus may likely result in a significant reduction of rotavirus-associated diarrhea, suggesting the need for monitoring of vaccine impact.

Evidence of rotavirus vaccine impact in sub-Saharan Africa: Systematic review and meta-analysis.

BackgroundOver 34 countries in Africa have introduced rotavirus vaccine to their national immunization programs: monovalent (Rotarix®, RV1) and pentavalent (RotaTeq®, RV5) after South Africa introduced it in 2009. Since then several studies assessing the impact of the vaccine have been conducted. The principal aim of this study was to evaluate the impact of rotavirus vaccine in sub-Saharan Africa.MethodsA Literature search was performed using Mendeley, PubMed, ScienceDirect, grey literature and Web of Science databases of published studies from January 1, 2017, as years of recent publications on rotavirus vaccine impact in sub-Saharan Africa. A meta-analysis was conducted for rotavirus infection in children under 5 years using proportions of pre and post-vaccine introduction in these populations. Random-effect estimates were considered since the samples were from universal populations.ResultsOut of the 935 articles identified, 17 studies met the inclusion for systematic review and meta-analysis. The pooled proportion for pre-vaccination period was 42%, 95% (CI: 38–46%), and reduced to 21%, 95% (CI: 17–25%) during post-vaccination period. Rotavirus diarrhea significantly reduced in children < 12 months as compared to children 12–24 months old. Seasonal peaks of rotavirus diarrhea were between June–September. However, data is limited to one year of post-vaccine introduction, and bias may present due to early vaccine impact.ConclusionWe observed that the introduction of the rotavirus vaccine was partly responsible for the significant reduction in the burden of rotavirus-associated diarrhea in sub-Saharan Africa. Therefore, there is a need to encourage the remaining countries to introduce the vaccine to their routine national immunization programs.

Rotavirus-associated acute diarrhea outbreak in West Shewa Zone of Oromia Regional State, Ethiopia, 2017.

IntroductionRotavirus causes severe-diarrheal diseases in infants. An estimation of 138 million rotavirus-associated diarrheal cases and 215,000 deaths occur every year globally. In December 2016, West-Shewa zone in Ethiopia reported unidentified gastrointestinal diarrhea outbreak. We investigated to identify the causative agent of the outbreak to support response operations.MethodsMedical records were reviewed, and the daily line list was collected from health facilities. Descriptive data analysis was done by time, person and place. Stool specimens were first tested by antigen capture enzyme immunoassay (EIA) technique and further confirmed by reverse-transcription polymerase chain reaction (RT-PCR) as a gold standard. The product of RT-PCR was genotyped for each gene using G1-G4, G8-G9 and G12 primers for VP7 gene and P(4), P(6), P(8) and P(14) primers for VP4 gene.ResultsA total of 1,987 diarrheal cases (5.7 per 1000) and five deaths (case-fatality rate 0.25%) were identified and epidemiologically-linked to confirmed rotavirus from December 2016 to February 2017. Among the cases, 1,946 (98%) were < 5 children. Fourteen (74%) of the 19 tested stool specimens were positive for rotavirus by EIA and RT-PCR. Majority of strains detected were G12P(6) (25%) and G-negative P(8) (25%) followed by G9P(8) (19%), G1P(8) (13%) and G3/G2 P(8), G12P(8), and G-negative P(6) (6% each).ConclusionDiarrheal outbreak which occurred in West-Shewa zone of Ethiopia was associated with rotavirus and relatively more affected districts with low vaccination coverage. Routine rotavirus vaccination quality and coverage should be evaluated and the surveillance system needs to be strengthened to detect, prevent and control a similar outbreak.

Hospital-based surveillance for rotavirus diarrhea in Ulaanbaatar, Mongolia, April 2009 through March 2016

BackgroundDiarrheal disease is one of the leading causes of illness and death in young children in the world, especially the developing countries. Diarrheal disease results in about half a million childhood death per year, ranking second among all causes worldwide. Diarrheal disease due to rotavirus infection is currently the most common cause of severe diarrhea in infants and young children worldwide. Rotavirus immunization of infants is a safe and effective public health intervention for rotavirus infection control and expected to lead to a reduction of childhood morbidity and mortality. MethodsWe conducted hospital-based surveillance at two representative hospitals in Mongolia to estimate the burden of hospitalizations for rotavirus diarrhea among children aged <5 years and to describe strain distribution patterns during 6-year study period. Fecal specimens were tested by rotavirus antigen detection enzyme immunoassay (EIA). Specimens that tested positive for rotavirus were further characterized to determine the genotype of strains by reverse-transcriptase polymerase chain reaction. ResultsBetween April 2009 and March 2016, among 7076 eligible children with diarrhea 6078 patients were enrolled nationally. Forty-six percent (2794/6078) of EIA a specimens were positive for rotavirus. Ninety-three percent (5649/6078) of hospitalizations for diarrhea involved children less than 2 years. No deaths were recorded due to rotavirus diarrhea.The most common genotype was G3P [8] (47.7%) followed by G9P [6] (14.4%), G2P [4] (12%), and G9P [8] (7.1%). ConclusionsThis study found a relatively high prevalence of severe rotavirus-associated diarrhea disease in Mongolia and infants were the most affected. It highlights the urgent need for introduction of rotavirus vaccine into the national immunization program. Continued surveillance is crucial and pre-vaccine introduction rotavirus genotype patterns in Mongolia are valuable and can be followed post-introduction to assess vaccine impact.

Rotavirus Vaccines: Why Continued Investment in Research Is Necessary

Rotavirus vaccines were first introduced more than a decade ago and have had a tremendous impact on reducing the number of hospitalizations and deaths due to rotavirus-associated diarrhea. This review will discuss current rotavirus vaccines, post-licensure surveillance, progress in non-replicating vaccine development, and why continued research is important for understanding a virus that remains a globally leading cause of death due to diarrhea. Research advances have enhanced our understanding of how vaccines induce protection against subsequent severe disease, how the virus replicates and spreads in the face of the host immune system, and basic mechanisms governing the viral life cycle. Much remains to be learned about how to improve vaccine success, what are the molecular determinants of host range and virulence, and what are the interactions of the virus with the host that drive its replicative success, among many other important questions.

Point-of-care diagnosis and risk factors of infantile, rotavirus-associated diarrhoea in Calabar, Nigeria.

BackgroundRotaviruses are the primary cause of acute gastroenteritis in young children worldwide and a significant proportion of these infections occur in Africa.ObjectivesIn the present study, we determined the prevalence and risk factors of rotavirus infection among children younger than age 5 years with or without diarrhoea in Calabar, Nigeria, using a rapid point-of-care test.MethodsTwo hundred infants younger than age 5 years presenting with acute gastroenteritis and a control group of 200 infants without diarrhoea were tested for rotavirus. Each stool sample was homogenised in an extraction buffer and the supernatant added into the sample well of the Rida Quick rotavirus test cassette and allowed to run for 5 minutes at room temperature. When both the control band and test band were visible on the test cassette a positive result was recorded, whereas when only the control band was visible a negative results was recorded.ResultsRotavirus was detected in 25 (12.5%) of children with diarrhoea and in no children without diarrhoea. Our results demonstrated that children who were exclusively breast-fed by their mothers were not infected with rotavirus and that 92% of the infants infected with rotavirus experienced vomiting.ConclusionThese data demonstrate that asymptomatic rotavirus infection is rare and that rotavirus is commonly detected in stool samples of children suffering from diarrhoea with concomitant vomiting. Use of point-of-care rotavirus tests will enhance early diagnosis of rotavirus-associated diarrhoea and reduce irrational use of antibiotics.

Human rotavirus strains circulating in Venezuela after vaccine introduction: predominance of G2P[4] and reemergence of G1P[8

BackgroundRotavirus (RV) is the most common cause of severe childhood diarrhea worldwide. Despite Venezuela was among the first developing countries to introduce RV vaccines into their national immunization schedules, RV is still contributing to the burden of diarrhea. Concerns exist about the selective pressure that RV vaccines could exert on the predominant types and/or emergence of new strains.ResultsTo assess the impact of RV vaccines on the genotype distribution 1 year after the vaccination was implemented, a total of 912 fecal specimens, collected from children with acute gastroenteritis in Caracas from February 2007 to April 2008, were screened, of which 169 (18.5%) were confirmed to be RV positive by PAGE. Rotavirus-associated diarrhea occurred all year-round, although prevailed during the coolest and driest months among unvaccinated children under 24 months old. Of 165 RV strains genotyped for G (VP7) and P (VP4) by seminested multiplex RT-PCR, 77 (46.7%) were G2P[4] and 63 (38.2%) G1P[8]. G9P[8], G3P[8] and G2P[6] were found in a lower proportion (7.3%). Remarkable was also the detection of <5% of uncommon combinations (G8P[14], G8P[4], G1P[4] and G4P[4]) and 3.6% of mixed infections. A changing pattern of G/P-type distribution was observed during the season studied, with complete predominance of G2P[4] from February to June 2007 followed by its gradual decline and the reemergence of G1P[8], predominant since January 2008. Phylogenetic analysis of VP7 and VP4 genes revealed a high similarity among G2P[4] and global strains belonging to G2-II and P[4]-V lineages. The amino acid substitution 96D → N, related with reemergence of the G2 genotype elsewhere, was observed. The G1P[8] strains from Caracas were grouped into the lineages G1-I and P[8]-III, along with geographically remote G1P[8] rotaviruses, but they were rather distant from Rotarix® vaccine and pre-vaccine strains. Unique amino acid substitutions observed on neutralization domains of the VP7 sequence from Venezuelan post-vaccine G1P[8] could have conditioned their re-emergence and a more efficient dissemination into susceptible population.ConclusionsThe results suggest that natural fluctuations of genotypes in combination with forces driving the genetic evolution could determine the spread of novel strains, whose long-term effect on the efficacy of available vaccines should be determined.

Prevalence and genetic diversity of rotavirus infection in children with acute gastroenteritis in a hospital setting, Nairobi Kenya in post vaccination era: a cross-sectional study.

IntroductionRotavirus is the leading cause of severe diarrhoea among infants and young children. Each year more than 611 000 children die from rotavirus gastroenteritis, and two million are hospitalized, worldwide. In Kenya, the impact of recent rotavirus vaccinations on morbidities has not been estimated. The study aimed at determining the prevalence and identity of rotavirus strains isolated from rotavirus-associated diarrhoea in vaccinated children presenting with acute gastroenteritis.MethodsTwo hundred and ninety eight specimen from children presented at Gertrude Childrens’ Hospital from January to June 2012 were tested by EIA (Enzyme-linked Immunosorbent Assay) for rotavirus antigens. Molecular characterization was conducted on rotavirus-positive specimens. Extracted viral RNA was separated by polyacrylamide gel electrophoresis (PAGE) and the specific rotavirus VP4 (P-types) and VP7 (G-types) determined.ResultsThe prevalence rate of rotavirus was 31.5% (94/298). Of the rotavirus dsRNA, 57 (60.1%) gave visible RNA profiles, 38 (40.4%) assigned long electropherotypes while 19 (20.2%) were short electropherotypes. The strains among the vaccinated were G3P [4], G12P [6], G3P [6], G9P [4], G mixed G9/3P [4] and G1/3P [4]. Specifically, the G genotypes were G9/3 (5.3%), G9 (4.3%), G3 (4.3%), G12 (2.1%) and mixed G1/3 (1.1%). The P genotypes detected were P [4] (5.3%) and P [6] (5.3%).ConclusionThe present study demonstrates diversity in circulating genotypes with emergence of genotypes G3, G9, G12 and mixed genotypes G9/3 and recommends that vaccines should be formulated with a broad range of strains to include G9 and G12.

Lactobacillus rhamnosus GG increases Toll-like receptor 3 gene expression in murine small intestine ex vivo and in vivo.

Administration of Lactobacillus rhamnosus GG (LGG) has been reported to be therapeutically effective against acute secretory diarrhoea resulting from the structural and functional intestinal mucosal lesions induced by rotavirus infection; however, the underlying mechanisms remain to be completely elucidated. Because Toll-like receptor 3 (TLR3) plays a key role in the innate immune responses following the recognition of rotavirus, the present study examined whether LGG influences TLR3 gene expression in murine small intestine ex vivo and in vivo. We employed cultured intestinal organoids derived from small intestinal crypts as an ex vivo tissue model. LGG supplementation increased TLR3 mRNA levels in the intestinal organoids, as estimated by quantitative real-time polymerase chain reaction. Likewise, single and 7-day consecutive daily administrations of LGG increased TLR3 mRNA levels in the small intestine of C57BL/6N mice. The mRNA levels of other TLRs were not substantially altered both ex vivo and in vivo. In addition, LGG supplementation increased the mRNA levels of an antiviral type 1 interferon, interferon-α (IFN-α), and a neutrophil chemokine, CXCL1, upon stimulation with a synthetic TLR3 ligand, poly(I:C) in the intestinal organoids. LGG administration did not alter IFN-α and CXCL1 mRNA levels in the small intestine in vivo. Supplementation of other bacterial strains, Bifidobacterium bifidum and Lactobacillus paracasei, failed to increase TLR3 and poly(I:C)-stimulated CXCL1 mRNA levels ex vivo. We propose that upregulation of TLR3 gene expression may play a pivotal role in the therapeutic efficacy of LGG against rotavirus-associated diarrhoea. In addition, we demonstrated that intestinal organoids may be a promising ex vivo tissue model for investigating host-pathogen interactions and the antiviral action of probiotics in the intestinal epithelium.

Controlling Rotavirus-associated diarrhea: Could single-domain antibody fragments make the difference?

Group A Rotavirus (RVA) remains a leading cause of severe diarrhea and child mortality. The variable domain of camelid heavy chain antibodies (VHH) display potent antigen-binding capacity, have low production costs and are suitable for oral therapies. Two sets of anti-RVA VHHs have been developed: ARP1-ARP3; 2KD1-3B2. Here, we explore the potential of both sets as a prevention strategy complementary to vaccination and a treatment option against RVA-associated diarrhea in endangered populations. Both sets have been expressed in multiple production systems, showing extensive neutralizing capacity against strains of RVA in vitro. They were also tested in the neonatal mouse model with various degrees of success in preventing or treating RVA-induced diarrhea. Interestingly, mitigation of the symptoms was also achieved with freeze-dried ARP1, so that it could be applied in areas where cold chains are difficult to maintain. 3B2 was tested in a pre-clinical trial involving gnotobiotic piglets where it conferred complete protection against RVA-induced diarrhea. ARP1 was used in the first clinical trial for anti-RVA VHHs, successfully reducing stool output in infants with RVA diarrhea, with no detected side effects.