Epidemiology and phylogenetic analysis of VP7 and VP4 genes of rotaviruses circulating in Rawalpindi, Pakistan during 2010

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.

Molecular characterization of rotavirus indicates predominance of G9P[4] genotype among children with acute gastroenteritis: First report after vaccine introduction in Pakistan

Globally, Group A rotavirus (RVA) is the leading cause of acute gastroenteritis in children under 5 years old, with Pakistan having the highest rates of RVA-related morbidity and mortality. The current study aims to determine the genetic diversity of rotavirus and evaluate the impact of Rotarix-vaccine introduction on disease epidemiology in Pakistan. A total of 4749 children, hospitalized with acute gastroenteritis between 2018 and 2020, were tested at four hospitals in Lahore and Karachi. Of the total, 19.3% (918/4749) cases were tested positive for RVA antigen, with the positivity rate varying annually (2018 = 22.7%, 2019 = 14.4%, 2020 = 20.9%). Among RVA-positive children, 66.3% were under 1 year of age. Genotyping of 662 enzyme-linked immuno sorbent assay-positive samples revealed the predominant genotype as G9P[4] (21.4%), followed by G1P[8] (18.9%), G3P[8] (11.4%), G12P[6] (8.7%), G2P[4] (5.7%), G2P[6] (4.8%), and 10.8% had mixed genotypes. Among vaccinated children, genotypes G9P[4] and G12P[6] were more frequently detected, whereas a decline in G2P[4] was observed. Phylogenetic analysis confirmed the continued circulation of indigenous genotypes detected earlier in the country except G9 and P[6] strains. Our findings highlight the predominance of G9P[4] genotype after the vaccine introduction thus emphasizing continual surveillance to monitor the disease burden, viral diversity, and their impact on control of rotavirus gastroenteritis in children.

First report of coinfection and whole-genome sequencing of norovirus and sapovirus in an acute gastroenteritis patient from Pakistan

Acute gastroenteritis is one of the most common diseases in infants and children in developing countries including Pakistan. In Pakistan, rotavirus (RVA) is known to contribute significantly to pediatric diarrheal illness, but the contribution of other viruses is still unclear. In the current study we have identified a case of mixed infection of norovirus (NoV) and sapovirus (SaV) in a 2-year-old child with acute gastroenteritis. The sample was initially processed for the detection of group A RVA through ELISA followed by NoV using RT-PCR assay. The sample tested positive for NoV RNA and was later subjected to whole-genome sequencing using meta-genome approach on Miseq (Illumina) platform. Sequencing results revealed GII.15 genotype of NoV that clustered with viruses from China and USA from 2017 to 2021. We also retrieved the complete genome of SaV (GI.1 genotype) from the same sample and phylogenetic analysis showed clustering with strains reported from Japan, South Korea, US, and Taiwan during 2012-2016. This is the first report from Pakistan that confirms coinfection of NoV and SaV and elucidates their whole genomes. We recommend initiation of NoV and SaV surveillance program to ascertain disease burden and explore genetic diversity, especially as RVA vaccines have been included in national immunization program.

Diversity of Rotavirus Strains among Children with Acute Diarrhea in Karachi, Pakistan

One of the common viral pathogens in infectious diarrhea is Rotavirus; in developing countries, it is a primary cause of deaths in children less than five years of age. This study was planned to find out the etiologic agents of acute watery diarrhea. In this study, 1465 stool samples were analyzed with the symptoms of acute diarrhea. Demographic data analysis showed no. of episodes of diarrhea, vomiting, and fever. All samples were checked by ELISA technique for the presence of Rotavirus circulating strains. More than 6% patients were found to be positive with Rotavirus. Common Rotavirus genotypes, including G2P4, G2P6, G3P4, G8P4, G8P6, G9P4, and G10P4, were detected in patients through RT-PCR. This study concluded that detection of rotavirus strain diversity and management of diarrheal patients may identify assortment of emerging strains and reduce emergence of antimicrobial resistance and repeated episodes of diarrhea, which may also help to avoid and manage the essential nutrients lost leading to malnutrition and stunted growth, as well as to reduce high mortality rate in young children less than five years.

Characterization of rotavirus strains isolated from children with acute gastroenteritis in Rawalpindi, Pakistan

Diarrhea is the leading cause of childhood morbidity and mortality particularly in developing countries and rotavirus has been identified as the major pathogen associated with diarrheal infections. The present study was conducted to detect genotypic distribution of predominant rotavirus strains circulating in children suffering from acute gastroenteritis in Rawalpindi, Pakistan. Stool specimens were collected from children ≤ 5 years of age, visiting Military Hospital, Rawalpindi, with signs and symptoms of acute gastroenteritis. 284 specimens were collected during the period from April 2017 to March 2018. Enzyme immunoassay was performed for detection of rotavirus and reverse transcription-PCR (RT-PCR) was carried out for amplification of VP7 and VP4 gene segments followed by multiplex PCR using genotype specific primers. Out of 284 children, 71 were found rotavirus positive and among them 54 % were females and 46 % males. Our findings showed 92% of infection among children ≤ 2 years of age, while, the peak age of rotavirus incidence was found to be6 to 12 months. Although, rotavirus infection was observed throughout the year but frequency increased in winter. Subtype G1P[8] was more prevalent followed by G2P[4], G3P[8] and G4P[6] subtypes. The results of the present study provide insight into the disease burden as well as information on rotavirus diversity which will be useful to develop future strategies to control and prevent diarrheal infections among children. This article is protected by copyright. All rights reserved.

Emergence of equine-like G3 strains as the dominant rotavirus among children under five with diarrhea in Sabah, Malaysia during 2018-2019

Rotavirus infection is a dilemma for developing countries, including Malaysia. Although commercial rotavirus vaccines are available, these are not included in Malaysia's national immunization program. A scarcity of data about rotavirus genotype distribution could be partially to blame for this policy decision, because there are no data for rotavirus genotype distribution in Malaysia over the past 20 years. From January 2018 to March 2019, we conducted a study to elucidate the rotavirus burden and genotype distribution in the Kota Kinabalu and Kunak districts of the state of Sabah. Stool specimens were collected from children under 5 years of age, and rotavirus antigen in these samples was detected using commercially available kit. Electropherotypes were determined by polyacrylamide gel electrophoresis of genomic RNA. G and P genotypes were determined by RT-PCR using type specific primers. The nucleotide sequence of the amplicons was determined by Sanger sequencing and phylogenetic analysis was performed by neighbor-joining method. Rotavirus was identified in 43 (15.1%) children with watery diarrhea. The male:female ratio (1.9:1) of the rotavirus-infected children clearly showed that it affected predominantly boys, and children 12-23 months of age. The genotypes identified were G3P[8] (74% n = 31), followed by G1P[8] (14% n = 6), G12P[6](7% n = 3), G8P[8](3% n = 1), and GxP[8] (3% n = 1). The predominant rotavirus circulating among the children was the equine-like G3P[8] (59.5% n = 25) with a short electropherotype. Eleven electropherotypes were identified among 34 strains, indicating substantial diversity among the circulating strains. The circulating genotypes were also phylogenetically diverse and related to strains from several different countries. The antigenic epitopes present on VP7 and VP4 of Sabahan G3 and equine-like G3 differed considerably from that of the RotaTeq vaccine strain. Our results also indicate that considerable genetic exchange is occurring in Sabahan strains. Sabah is home to a number of different ethnic groups, some of which culturally are in close contact with animals, which might contribute to the evolution of diverse rotavirus strains. Sabah is also a popular tourist destination, and a large number of tourists from different countries possibly contributes to the diversity of circulating rotavirus genotypes. Considering all these factors which are contributing rotavirus genotype diversity, continuous surveillance of rotavirus strains is of utmost importance to monitor the pre- and post-vaccination efficacy of rotavirus vaccines in Sabah.

Epidemiological studies on gastroenteritis in children in the Bannu district, Khyber Pakhtunkhwa, Pakistan

Aims

Gastroenteritis is a digestive disorder among children with symptoms of abdominal cramps, diarrhoea, and vomiting. This study aimed to determine the prevalence of gastroenteritis in children in the Bannu district in 2019, and also contributed for adopting preventive measures to reduce mortality in children.

Subject and methods

A retrospective study was conducted to determine the prevalence of gastroenteritis in children in Bannu. The data were collected from official registers of admission maintained in the children wards in the Women and Children Hospital, Bannu. Patients with symptoms of gastroenteritis at the outpatient department were admitted to one of the children wards.

Results

Overall, 1456 children—897 (61.4%) males and 559 (38.6%) females—suffered from gastroenteritis during the study period. The age group ≤6 months demonstrated the highest share (37.8%), followed by >6 m ≤ 1y (35.5%), >1y ≤ 2y (15.8%), >2y ≤ 5y (7.3%), >5 ≤ 10y (3.2%), and > 10y ≤ 15y (0.4%). Overall, 89.1% of cases were from children ≤2 years old and 96.4% of cases were attributed to children ≤ 5 years of age. April demonstrated the highest percentage of prevalence of 17.7, followed by May (13.5%), November (13%), June (11.7%), September (10.4%), October (9.8%), July (9.5%), August (8.4%), March (3.4%), and February (2.6%). The age group ≤6 m was the dominant group during February through May and was replaced by the age group >6 m ≤ 1y during August through November.

Conclusion

Gastroenteritis showed a reduced prevalence when shifted from lower to higher age groups. Being male and age group ≤6 m showed the highest prevalence of gastroenteritis with the peak of disease in April. Further research is needed to determine the cause-based prevalence of different gastroenteritis cases in the study area.

Rotavirus gastroenteritis in Pakistan, 2018: updated disease burden

Objective

Rotavirus A (RVA) is a significant cause of severe diarrheal illness and one of the common causes of death in children under the age of five. This study was aimed at detecting the prevalence of RVA in Pakistan after rotavirus vaccines were introduced. Fecal samples were obtained from 813 children from different hospitals in Rawalpindi and Islamabad, Pakistan, from January 2018 to December 2018. To obtain additional information from the parents / guardians of the children, a standard questionnaire was used.

Results

Using an enzyme-linked immunosorbent assay kit (ELISA), rotavirus antigen was detected and ELISA positive samples were subjected to reverse transcription PCR (RT-PCR). The findings showed 22% prevalence of RVA in children with acute gastroenteritis (AGE) via ELISA and 21% prevalence via RT-PCR in children with AGE. There was no statistically significant difference between gender, age and RVA infections. The winter, spring and fall/autumn seasons were statistically significant for RVA prevalence.

Conclusion

The present study will provide post vaccine prevalence data for the health policy makers. The implementation of rotavirus vaccines, along with adequate nutrition for babies, clean water supply and maternal hygienic activities during infant feeding, is recommended. Furthermore, continuous surveillance is mandatory in the whole country to calculate the disease burden caused by RVA.

Whole genome analysis of Aichivirus A, isolated from a child, suffering from gastroenteritis, in Pakistan

Viruses are the primary cause of acute gastroenteritis in children all over the world. Understanding the emergence and genetic variation of these viruses may help to prevent infections. Aichivirus (AiV) is a member of the Kobuvirus genus, which currently contains six officially recognized species: Aichivirus A-F. The species AiV A contains six types including Aichivirus 1 (AiV 1) and eventually, three genotypes have been identified in the human AiV 1 (named A to C). The present study describes the identification and sequencing of the polyprotein gene of a human AiV 1 strain PAK419 via NGS in Pakistani children with acute gastroenteritis. Our study strain PAK419 was classified as AiV 1 genotype A, most commonly found in Japan and Europe, and closely related to non-Japanese and European strains on the phylogenetic tree. PAK419 showed 95-98 % nucleotide sequence identity with strains isolated from Ethiopia (ETH/2016/P4), Australia (FSS693) and China (Chshc7). On phylogenetic observation PAK419 formed a distinct cluster in the AiV 1 genotype A with the above mentioned and other human AiV strains detected around the world (Germany, Brazil, Japan, Thailand, Korea and Vietnam). The data clearly showed that Pakistani AiV strains and human strains identified from all over the world are distinct from Aichivirus strains found in bovine, swine, canine, feline, caprine, ferret, bat, and environmental samples. The distinguishing characteristics of the AiV genome showed a lower probability of inter-genotypic recombination events, which may support the lack of AiV serotypes. PAK419 also had a high content of C nucleotide (37.4 %), as found in previous studies, which could also restrict the possible genetic variation of AiV. This study demonstrate the power of NGS in uncovering unknown gastroenteric etiological agents circulating in the population.

Phylogenetic analysis of open reading frame of 11 gene segments of novel human-bovine reassortant RVA G6P[1] strain in Pakistan

Multiple Rotavirus A (RVA) strains are linked with gastrointestinal infections in children that fall in age bracket of 0 to 60 months. However, the problem is augmented with emergence of unique strains that reassort with RVA strains of animal origin. The study describes the sequence analysis of a rare G6P[1] rotavirus strain isolated from a less than 1 year old child, during rotavirus surveillance in Rawalpindi district, Pakistan in 2010. Extracted RNA from fecal specimen was subjected to high throughput RT-PCR for structural and nonstructural gene segments. The complete rotavirus genome of one isolate RVA/Human-wt/PAK/PAK99/2010/G6P[1] was sequenced for phylogenetic analysis to elucidate the evolutionary linkages and origin. Full genome examination of novel strain RVA/Human-wt/PAK/PAK99/2010/G6P[1] revealed the unique genotype assemblage: G6-P[1]-I2-R2-C2-M2-A3-N2-T6-E2-H1. The evolutionary analyses of VP7, VP4, NSP1 and NSP3 gene segments revealed that PAK99 clustered with bovine, or cattle-like rotavirus strains from other closely related species, in the genotypes G6, P[1], A3 and T6 respectively. Gene segments VP6, VP1, VP2, VP3, NSP2 and NSP4 all possessed the DS-1-like bovine genotype 2 and bovine (-like) RVA strains instead of RVA strains having human origin. However, the NSP5 gene was found to cluster closely with contemporary human Wa-like rotavirus strains of H1 genotype. This is the first report on bovine-human (Wa-like reassortant) genotype constellation of G6P[1] strain from a human case in Pakistan (and the second description worldwide). Our results emphasize the significance of incessant monitoring of circulating RVA strains in humans and animals for better understanding of RV evolution.

Comparative Analysis of G1P[8] Rotaviruses Identified Prior to Vaccine Implementation in Pakistan With Rotarix™ and RotaTeq™ Vaccine Strains

Group A rotavirus (RVA) is the leading cause of severe childhood diarrhea globally, even with all effective interventions, particularly in developing countries. Among the diverse genotypes of RVA, G1P[8] is a common genotype that has continued to pervade around the world, including Pakistan. Two universally accepted rotavirus vaccines-Rotarix™ and RotaTeq™ contain the genotype G1P[8]. The current work was aimed at identifying differences between antigenic epitopes of Pakistan’s G1P[8] strains and those of the two licensed vaccines. We sequenced 6 G1P[8] rotavirus strains previously reported in Rawalpindi, Islamabad, Pakistan in 2015 and 2016 for their outer capsid genes (VP7 and VP4). Phylogenetic analysis was then conducted in order to classify their specific lineages and to detect their association with strains isolated throughout world. Compared with the Rotarix™ and RotaTeq™ vaccine strains (G1-lineage II, P[8]-lineage III), our study G1-lineage I, P[8]-lineage IV strains showed 3 and 5 variations in the VP7 epitopes, respectively, and 13 and 11 variations in the VP4 epitopes, respectively. The G1 lineage II strains showed no single amino acid change compared to Rotarix™ (lineage II), but exhibited changes at 2 positions compared to RotaTeq™ (lineage III). So, this has been proposed that these G1 strains exist in our natural setting, or that they may have been introduced in Pakistan from other countries of the world. The distinct P[8]-lineage IV (OP354-like) strains showed twelve and thirteen amino acid variations, with Rotarix™ and RotaTeq™ (lineages II and III) strains, respectively. Such findings have shown that the VP4-P[8] component of the G1P[8] strains circulating in Pakistan differs considerably from that of the vaccine viruses compared to that of the VP7-G1. To monitor the long-term effects of vaccines on the emergence of G1P[8] strains with different lineages, routine and successful monitoring of these strains will be crucial.

Molecular characterization of the complete genome sequence of human Parechovirus 1 in Pakistan

Human parechoviruses (HPeVs) are highly common pathogens in children under 2 years of age. Of the 19 distinct HPeV genotypes identified worldwide, HPeV1 is still the most prevalent type associated with respiratory and gastrointestinal symptoms in infants and young children. Pakistan's previous studies have focused only on the detection and partial sequencing of HPeV genotypes. In the present study, we have obtained the complete genomes of 2 HPeV1 strains (PAK419 and PAK663) from children using NGS method on Illumina Hiseq Platform. These samples were collected from children suffering from acute gastroenteritis in Rawalpindi, Pakistan during 2016. The near complete genome sequences obtained for two HPeV1 strains (PAK419 and PAK663) consist of total 6877 nucleotides with a single, large open reading frame (ORF) encoding a polyprotein gene. Phylogenetic analysis showed that both HPeV1 strains exhibited maximum amino acid similarity (97 %) to HPeV1 strains from The Nederlands (2007-863, GQ183034) and clustered closely with this and with other HPeV1 strains isolated from other countries in the world (Ethiopia, Taiwan, Russia and Brazil). A motif of arginine-glycine-aspartic acid (RGD) in the VP1 (Outer capsid protein) C-terminus region that is suggested to help virus entry into the host cell also identified in PAK419 and PAK663. SimPlot analysis revealed that intergenotypic recombination events may have take place in the non-structural region between both HPeV1 strains (PAK419, PAK663), two major strains of HPeV1 (GQ183034 and MG873157) and four minor strains of HPeV4 (AM235750), HPeV7 (EU556224), HPeV15 (MN265386) and HPeV18 (KT879915). The full genome of HPeV1 strains characterized in the current study will provide complete information on these newly isolated strains for further preventive or treatment measures.

G3 and G9 Rotavirus genotypes in waste water circulation from two major metropolitan cities of Pakistan

Rotavirus A (RVA) is a diarrheal pathogen affecting children under age five, particularly in developing and underdeveloped regions of the world due to malnutrition, poor healthcare and hygienic conditions. Water and food contamination are found to be major sources of diarrheal outbreaks. Pakistan is one of the countries with high RVA related diarrhea burden but with insufficient surveillance system. The aim of this study was to gauge the RVA contamination of major open sewerage collecting streams and household water supplies in two major metropolitan cities of Pakistan. Three concentration methods were compared using RNA purity and concentration as parameters, and detection efficiency of the selected method was estimated. Water samples were collected from 21 sites in Islamabad and Rawalpindi in two phases during the year 2014-2015. Meteorological conditions were recorded for each sampling day and site from Pakistan Meteorological Department (PMD). Nested PCR was used to detect the presence of RVA in samples targeting the VP7 gene. Logistic regression was applied to assess the association of weather conditions with RVA persistence in water bodies. Statistical analysis hinted at a temporal and seasonal pattern of RVA detection in water. Phylogenetic analysis of selected isolates showed a close association of environmental strains with clinical RVA isolates from hospitalized children with acute diarrhea during the same period. This is the first scientific report cataloging the circulating RVA strains in environmental samples from the region. The study highlights the hazards of releasing untreated sewerage containing potentially infectious viral particles into collecting streams, which could become a reservoir of multiple pathogens and a risk to exposed communities. Moreover, routine testing of these water bodies can present an effective surveillance system of circulating viral strains in the population.

Magnitude of Rotavirus A and Campylobacter jejuni infections in children with diarrhea in Twin cities of Rawalpindi and Islamabad, Pakistan

Background

Acute diarrhea is a leading cause of morbidity and mortality in children particularly in developing countries of Asia and Africa. The present study was conducted to detect the two most important pathogens, rotavirus and Campylobacter Jejuni in children suffering with diarrhea in Rawalpindi and Islamabad, Pakistan in 2014. The clinical and epidemiological aspects of the disease were also investigated.

Methods

A total of 500 stool samples were collected from children presented with clinical signs and symptoms of acute diarrhea. The samples were initially screened for the presence of rotavirus A (RVA) via ELISA (Enzyme-linked immunosorbent assay) and RT-PCR (Reverse Transcriptase PCR) and then were analysed for C. jejuni by using species specific PCR assay.

Results

The detection rate of RVA was 26.4% (132/500) while, Campylobacter was detected in 52% (260/500) of samples with C. jejuni accounted for 48.2% (241/500) of all study cases. Co-infection of C. jejuni with RVA was identified in 21.8% of all cases. Children with RVA and C. jejuni co-infection showed a higher probability (p = 0.01) to be dehydrated. A significant association (p = 0.02) was found between C. jejuni positive status and fever in children. The median age of children with both RVA and C. jejuni infection was 6–11 months. The RVA detection rate was high in winter months of the year while, C. jejuni infections were documented high in summer over 1 year study period.

Conclusions

The overall results have demonstrated the high prevalence of C. jejuni in Rawalpindi, Islamabad, Pakistan in 2014. The results of present study will not only help to calculate disease burden caused by C. jejuni and rotavirus but also will provide critical information to health authorities in planning public health care strategies against these pathogens.

Molecular characterization of human group A rotavirus genotypes circulating in Rawalpindi, Islamabad, Pakistan during 2015-2016

Group A rotaviruses (RVA) are one of the major causes of acute gastroenteritis (AGE) in young children worldwide. Owing to lack of proper surveillance programs and health facilities, developing countries of Asia and Africa carry a disproportionately heavy share of the RVA disease burden. The aim of this hospital-based study was to investigate the circulation of RVA genotypes in Rawalpindi and Islamabad, Pakistan in 2015 and 2016, prior to the implementation of RVA vaccine. 639 faecal samples collected from children under 10 years of age hospitalized with AGE were tested for RVA antigen by ELISA. Among 171 ELISA positive samples, 143 were successfully screened for RT-PCR and sequencing. The prevalence of RVA was found to be 26.8% with the highest frequency (34.9%) found among children of age group 6-11 months. The most predominant circulating genotypes were G3P[8] (22.4%) followed by G12P[6] (20.3%), G2P[4] (12.6%), G1P[8] (11.9%), G9P[6] (11.9%), G3P[4] (9.1%), G1P[6] (4.2%), G9P[8] (4.2%), and G3P[6] (0.7%). A single mixed genotype G1G3P[8] was also detected. The findings of this study provide baseline data, that will help to assess if future vaccination campaigns using currently available RVA vaccine will reduce RVA disease burden and instigate evolutionary changes in the overall RVA biology. The high prevalence of RVA infections in Pakistan require to improve and strengthen the surveillance and monitoring system for RVA. This will provide useful information for health authorities in planning public health care strategies to mitigate the disease burden caused by RVA.

Systematic review of the rotavirus infection burden in the WHO-EMRO region

Rotavirus gastroenteritis imposes a heavy burden on low- and middle-income countries. The World Health Organization defines the Eastern Mediterranean region (WHO-EMRO) as a diverse area in terms of socioeconomic status and health indicators. Rotavirus vaccination has been introduced, at least partially, in 19 out of the 22 EM countries; however, vaccine coverage remains low, and data on rotavirus disease burden is scarce.Available data on rotavirus prevalence, seasonality, vaccination status, and genotype evolution was systematically compiled following a literature review that identified 165 relevant WHO-EMRO epidemiology studies published between 1990 and 2017.Although the infectious agents responsible for acute gastroenteritis vary over time, rotavirus remained the leading cause of acute gastroenteritis in children, as seen in 76.3% of reviewed publications. Younger children (<2 years old) were at higher risk and thus increased vaccination coverage and surveillance systems are required to reduce the rotavirus gastroenteritis burden in WHO-EMRO countries.

Evidence of zoonotic transmission of VP6 and NSP4 genes into human species A rotaviruses isolated in Pakistan in 2010

Introduction of animal group A rotavirus (RVA) gene segments into the human RVA population is a major factor shaping the genetic landscape of human RVA strains. The VP6 and NSP4 genes of 74 G/P-genotyped RVA isolates collected in Rawalpindi during 2010 were analyzed, revealing the presence of VP6 genotypes I1 (60.8%) and I2 (39.2%) and NSP4 genotypes E1 (60.8%), E2 (28.3%) and E-untypable (10.8%) among the circulating human RVA strains. The typical human RVA combinations I1E1 and I2E2 were found in 59.4% and 24.3% of the cases, respectively, whereas 5.4% of the RVA strains were reassortants, i.e., either I1E2 or I2E1. The phylogeny of the NSP4 gene showed that one G2P[4] and two G1P[6] RVA strains clustered with porcine E1 RVA strains or RVA strains that were considered to be (partially) of porcine origin. In addition, the NSP4 gene segment of the unusual human G6P[1] RVA strains clustered closely with bovine E2 RVA strains, further strengthening the hypothesis of an interspecies transmission event. The study further demonstrates the role of genomic re-assortment and the involvement of interspecies transmission in the evolution of human RVA strains. The VP6 and NSP4 nucleotide sequences analyzed in the study received the GenBank accession numbers KC846908- KC846971 and KC846972-KC847037, respectively.

Circulating rotavirus G and P strains post rotavirus vaccination in Eastern Mediterranean Region

OBJECTIVE

To detect changes in circulating strains of rotavirus in the Eastern Mediterranean Region post rotavirus immunization drive.

METHODS

We searched MEDLINE, PubMed, ScienceDirect, and the Cochrane Library and specific database website (Nutrition and Food Sciences) for relevant articles. Our search included websites of a number of relevant organizations in addition to gray literature search. Of the 2198 articles found, we included only 35 studies after excluding irrelevant, ineligible, duplicated, and very low-quality papers.

RESULTS

Thirty pre-vaccination studies reported frequent rotavirus strains among children below 5 years of age. G1P[8] has been identified as the most dominant type prior to vaccination in Eastern Mediterranean Region (EMR) countries. Five post-vaccination studies conducted in 3 countries (Saudi Arabia, Morocco, and Yemen) illustrated that G1P[8] is the most prevalent strain in Saudi Arabia, and the incidence of G2P[4] has increased from 21.6% to 33.3%. In Yemen, G1P[4] is the most prevalent strain (87.5%), followed by G9P[8] (57%) and G1P[8] (18.5%). Furthermore, in Yemen, G9P[8] were the most prevalent strains accounting to 57% and 14% in G9P[4], post vaccination. Finally, in Morocco, G1P[8] was not reported 3 years post vaccination; however, incidence of G9P[8] was reported at 67% and G2P[4] at 33%.

CONCLUSIONS

Rotavirus circulating strain prevalence in EMR countries has changed post vaccination, and G9P[8], G2P[4], and G9P[4] have become more dominant. Proportion of rotavirus strains in these countries after vaccination has significantly reduced. There is an increase in circulating strain G2P[4] in the post-vaccination period, which needs further monitoring.

Rotavirus: Genetics, pathogenesis and vaccine advances

Since its discovery 40 years ago, rotavirus (RV) is considered to be a major cause of infant and childhood morbidity and mortality particularly in developing countries. Nearly every child in the world under 5 years of age is at the risk of RV infection. It is estimated that 90% of RV-associated mortalities occur in developing countries of Africa and Asia. Two live oral vaccines, RotaTeq (RV5, Merck) and Rotarix (RV1, GlaxoSmithKline) have been successfully deployed to scale down the disease burden in Europe and America, but they are less effective in Africa and Asia. In April 2009, the World Health Organization recommended the inclusion of RV vaccination in national immunization programs of all countries with great emphasis in developing countries. To date, 86 countries have included RV vaccines into their national immunization programs including 41 Global Alliance for Vaccines and Immunization eligible countries. The predominant RV genotypes circulating all over the world are G1P[8], G2P[4], G3P[8], G4P[8], and G9P[8], while G12[P6] and G12[P8] are emerging genotypes. On account of the segmented genome, RV shows an enormous genetic diversity that leads to the evolution of new genotypes that can influence the efficacy of current vaccines. The current need is for a global RV surveillance program to monitor the prevalence and antigenic variability of new genotypes to formulate future vaccine development planning. In this review, we will summarize the previous and recent insights into RV structure, classification, and epidemiology and current status of RV vaccination around the globe and will also cover the status of RV research and vaccine policy in Pakistan.

High prevalence of G3 rotavirus in hospitalized children in Rawalpindi, Pakistan during 2014

Rotavirus A species (RVA) is the leading cause of severe diarrhea among children in both developed and developing countries. Among different RVA G types, humans are most commonly infected with G1, G2, G3, G4 and G9. During 2003-2004, G3 rotavirus termed as "new variant G3" emerged in Japan that later disseminated to multiple countries across the world. Although G3 rotaviruses are now commonly detected globally, they have been rarely reported from Pakistan. We investigated the genetic diversity of G3 strains responsible RVA gastroenteritis in children hospitalized in Rawalpindi, Pakistan during 2014. G3P[8] (18.3%; n = 24) was detected as the most common genotype causing majority of infections in children less than 06 months. Phylogenetic analysis of Pakistani G3 strains showed high amino acid similarity to "new variant G3" and G3 strains reported from China, Russia, USA, Japan, Belgium and Hungary during 2007-2012. Pakistani G3 strains belonged to lineage 3 within sub-lineage 3d, containing an extra N-linked glycosylation site compared to the G3 strain of RotaTeqTM. To our knowledge, this is the first report on the molecular epidemiology of G3 rotavirus strains from Pakistan and calls for immediate response measures to introduce RV vaccine in the routine immunization program of the country on priority.

Rotavirus surveillance in Pakistan during 2015-2016 reveals high prevalence of G12P[6]

The G12 rotavirus genotype has emerged globally since their first detection in 1987 from the Philippines; however it remains a rare cause of gastroenteritis in Pakistan. Rotavirus surveillance conducted during 2015-2016, assessed 3446 children <5 years hospitalized for gastroenteritis and found 802 (23.2%) positive on ELISA. Genotyping of a subset of positive samples (n = 319) revealed G12P[6] (11.28%) as the third most common G/P combination following G3P[8] (28.5%) and G1P[8] (12.5%); G2P[4] (10.65%) and G3P[6] (8.15%) were other frequently detected strains. Phylogenetic analysis of G12 strains from Pakistan revealed high genetic similarity to G12 strains from Italy, Thailand, Korea, and Great Britain as well as local strains within G12 lineage III. In conclusion, G12P[6] was a major contributor of RVA gastroenteritis in Pakistani children. Robust surveillance after the introduction of rotavirus vaccines will help determine the evolution of G12 and other circulating genotypes in the country.

Whole Genomic Analysis of Human G12P[6] and G12P[8] Rotavirus Strains that Have Emerged in Myanmar

G12 rotaviruses are emerging rotavirus strains causing severe diarrhea in infants and young children worldwide. However, the whole genomes of only a few G12 strains have been fully sequenced and analyzed. In this study, we sequenced and characterized the complete genomes of six G12 strains (RVA/Human-tc/MMR/A14/2011/G12P[8], RVA/Human-tc/MMR/A23/2011/G12P[6], RVA/Human-tc/MMR/A25/2011/G12P[8], RVA/Human-tc/MMR/P02/2011/G12P[8], RVA/Human-tc/MMR/P39/2011/G12P[8], and RVA/Human-tc/MMR/P43/2011/G12P[8]) detected in six stool samples from children with acute gastroenteritis in Myanmar. On whole genomic analysis, all six Myanmarese G12 strains were found to have a Wa-like genetic backbone: G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 for strains A14, A25, P02, P39, and P43, and G12-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1 for strain A23. Phylogenetic analysis showed that most genes of the six strains examined in this study were genetically related to globally circulating human G1, G3, G9, and G12 strains. Of note is that the NSP4 gene of strain A23 exhibited the closest relationship with the cognate genes of human-like bovine strains as well as human strains, suggesting the occurrence of reassortment between human and bovine strains. Furthermore, strains A14, A25, P02, P39, and P43 were very closely related to one another in all the 11 gene segments, indicating derivation of the five strains from a common origin. On the other hand, strain A23 consistently formed distinct clusters as to all the 11 gene segments, indicating a distinct origin of strain A23 from that of strains A14, A25, P02, P39, and P43. To our knowledge, this is the first report on whole genome-based characterization of G12 strains that have emerged in Myanmar. Our observations will provide important insights into the evolutionary dynamics of spreading G12 rotaviruses in Asia.

Viral etiologies of acute dehydrating gastroenteritis in pakistani children: confounding role of parechoviruses

Despite substantial interventions in the understanding and case management of acute gastroenteritis, diarrheal diseases are still responsible for a notable amount of childhood deaths. Although the rotavirus is known to cause a considerable burden of pediatric diarrheal cases, the roles of other viruses remain undefined for the Pakistani population. This study was based on tertiary care hospital surveillance, from January 2009 to December 2010, including the detection of rotavirus, norovirus, astrovirus, and human parechovirus in children under the age of five using serological or molecular assays. Rotavirus, human parechovirus, norovirus, and astrovirus were detected in 66%, 21%, 19.5%, and 8.5% subjects, respectively. Human parechovirus genotypes, determined through analysis of VP1 gene sequences, showed a great diversity among co-circulating strains. Eighty percent of hospitalized children had dual or multiple viral infections, while 98% parechovirus positive cases were co-infected with rotavirus. The remarkable diversity of viruses associated with the childhood diarrhea in Pakistan calls for large-scale epidemiological surveys, coupled with case control studies, to ascertain their role in clinical manifestations. In addition, these findings also highlight the need for the implementation of up-to-date health interventions, such as the inclusion of a rotavirus vaccine in routine immunization programs for the improvement of quality in child health care.

Review of global rotavirus strain prevalence data from six years post vaccine licensure surveillance: is there evidence of strain selection from vaccine pressure?

Comprehensive reviews of pre licensure rotavirus strain prevalence data indicated the global importance of six rotavirus genotypes, G1P[8], G2P[4], G3P[8], G4P[8], G9P[8] and G12P[8]. Since 2006, two vaccines, the monovalent Rotarix (RV1) and the pentavalent RotaTeq (RV5) have been available in over 100 countries worldwide. Of these, 60 countries have already introduced either RV1 or RV5 in their national immunization programs. Post licensure vaccine effectiveness is closely monitored worldwide. This review aimed at describing the global changes in rotavirus strain prevalence over time. The genotype distribution of the nearly 47,000 strains that were characterized during 2007-2012 showed similar picture to that seen in the preceding period. An intriguing finding was the transient predominance of heterotypic strains, mainly in countries using RV1. Unusual and novel antigen combinations continue to emerge, including some causing local outbreaks, even in vaccinated populations. In addition, vaccine strains have been found in both vaccinated infants and their contacts and there is evidence for genetic interaction between vaccine and wild-type strains. In conclusion, the post-vaccine introduction strain prevalence data do not show any consistent pattern indicative of selection pressure resulting from vaccine use, although the increased detection rate of heterotypic G2P[4] strains in some countries following RV1 vaccination is unusual and this issue requires further monitoring.

Molecular epidemiology of contemporary G2P[4] human rotaviruses cocirculating in a single U.S. community: footprints of a globally transitioning genotype

Group A rotaviruses (RVs) remain a leading cause of childhood gastroenteritis worldwide. Although the G/P types of locally circulating RVs can vary from year to year and differ depending upon geographical location, those with G1P[8], G2P[4], G3P[8], G4P[8], G9P[8], and G12P[8] specificities typically dominate. Little is known about the evolution and diversity of G2P[4] RVs and the possible role that widespread vaccine use has had on their increased frequency of detection. To address these issues, we analyzed the 12 G2P[4] RV isolates associated with a rise in RV gastroenteritis cases at Vanderbilt University Medical Center (VUMC) during the 2010-2011 winter season. Full-genome sequencing revealed that the isolates had genotype 2 constellations typical of DS-1-like viruses (G2P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2). Phylogenetic analyses showed that the genome segments of the isolates were comprised of two or three different subgenotype alleles; this enabled recognition of three distinct clades of G2P[4] viruses that caused disease at VUMC in the 2010-2011 season. Although the three clades cocirculated in the same community, there was no evidence of interclade reassortment. Bayesian analysis of 328 VP7 genes of G2 viruses isolated in the last 39 years indicate that existing G2 VP7 gene lineages continue to evolve and that novel lineages, as represented by the VUMC isolates, are constantly being formed. Moreover, G2 lineages are characteristically shaped by lineage turnover events that introduce new globally dominant strains every 7 years, on average. The ongoing evolution of G2 VP7 lineages may give rise to antigenic changes that undermine vaccine effectiveness in the long term.

IMPORTANCE

Little is known about the diversity of cocirculating G2 rotaviruses and how their evolution may undermine the effectiveness of rotavirus vaccines. To expand our understanding of the potential genetic range exhibited by rotaviruses circulating in postvaccine communities, we analyzed part of a collection of rotaviruses recovered from pediatric patients in the United States from 2010 to 2011. Examining the genetic makeup of these viruses revealed they represented three segregated groups that did not exchange genetic material. The distinction between these three groups may be explained by three separate introductions. By comparing a specific gene, namely, VP7, of the recent rotavirus isolates to those from a collection recovered from U.S. children between 1974 and 1991 and other globally circulating rotaviruses, we were able to reconstruct the timing of events that shaped their ancestry. This analysis indicates that G2 rotaviruses are continuously evolving, accumulating changes in their genetic material as they infect new patients.

Human parechovirus genotypes -10, -13 and -15 in Pakistani children with acute dehydrating gastroenteritis

Human parechoviruses are known to cause asymptomatic to severe clinical illness predominantly respiratory and gastroenetric infections. Despite their global prevalence, epidemiological studies have not been performed in Pakistan. In this study, we retrospectively analyzed 110 fecal specimen and found 26 (24%) positive for viral RNA with HPeV-10 (n = 3, 23%), HPeV-13 (n = 4, 31%) and HPeV-15 (n = 6, 46%) genotypes. Clinical features of patients with different HPeV genotypes were compared. All HPeV positive children were aged ≤4 years (mean 13.92 months). The male-to-female ratio was 1: 1.17 (46.2 vs 53.8%) with significant association (p = .031) to HPeV infectivity. HPeV-10 and -13 were found during summer while HPeV-15 was only detected during late winter season. Disease symptoms were more severe in children infected with HPeV-10 and -13 as compared to HPeV-15. Fever and vomiting were observed in 100% cases of HPeV-10 and -13 while only 17% patients of HPeV-15 had these complaints. Phylogenetic analyses showed that HPeV-10, -13 and -15 strains found in this study have 9-13%, 16.8% and 21.8% nucleotide divergence respectively from the prototype strains and were clustered to distinct genetic lineages. This is the first report of HPeV-15 infection in humans although first identified in rhesus macaques. The arginine-glycine-aspartic acid (RGD) motif present at the C-terminal of VP1 responsible for the viral attachment to cellular integrins was not found in all of these strains. In conclusion, these findings enhance our knowledge related to the epidemiology and genetic diversity of the HPeV in Pakistan and support the need for continued laboratory based surveillance programs especially in infants and neonatal clinical settings. Further, the parechovirus pathogenesis, cross-species transmission and disease reservoirs must be ascertained to adopt better prevention measures.