Rotavirus infections with multiple emerging genotypes in Sri Lanka

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.

Hygiene risk of waterborne pathogenic viruses in rural communities using onsite sanitation systems and shallow dug wells

We evaluated the hygienic influence of onsite sanitation systems (OSSs) on drinking water wells in rural Sri Lanka by determining the safe setback distance between wells and the management of OSSs. Although previous studies have used bacterial indicators such as E. coli to evaluate the OSS impact, these parameters cannot assess the hygiene risk for waterborne pathogenic viruses (e.g. rotaviruses). Therefore, pepper mild mottle virus was selected as an indicator of human-specific faecal virus contamination. From a viral perspective, not only can the horizontal distance between a well and the nearest OSS reasonably represent hygiene safety, but the OSS sludge management can mitigate the contamination of wells even at short distances from the OSSs. Quantitative microbial risk assessment suggests that the infection risk of rotavirus was extremely high compared to the international standard. As proper management of OSSs would be key to reducing viral risk, it is necessary to reach out to the residents who are unaware of the importance and necessity of such management.

Diversity of rotavirus genotypes circulating in children < 5 years of age hospitalized for acute gastroenteritis in India from 2005 to 2016: analysis of temporal and regional genotype variation

Background

From 2016, the Government of India introduced the oral rotavirus vaccine into the national immunization schedule. Currently, two indigenously developed vaccines (ROTAVAC, Bharat Biotech; ROTASIIL, Serum Institute of India) are included in the Indian immunization program. We report the rotavirus disease burden and the diversity of rotavirus genotypes from 2005 to 2016 in a multi-centric surveillance study before the introduction of vaccines.

Methods

A total of 29,561 stool samples collected from 2005 to 2016 (7 sites during 2005–2009, 3 sites from 2009 to 2012, and 28 sites during 2012–2016) were included in the analysis. Stools were tested for rotavirus antigen using enzyme immunoassay (EIA). Genotyping was performed on 65.8% of the EIA positive samples using reverse transcription- polymerase chain reaction (RT-PCR) to identify the G (VP7) and P (VP4) types. Multinomial logistic regression was used to quantify the odds of detecting genotypes across the surveillance period and in particular age groups.

Results

Of the 29,561 samples tested, 10,959 (37.1%) were positive for rotavirus. There was a peak in rotavirus positivity during December to February across all sites. Of the 7215 genotyped samples, G1P[8] (38.7%) was the most common, followed by G2P[4] (12.3%), G9P[4] (5.8%), G12P[6] (4.2%), G9P[8] (4%), and G12P[8] (2.4%). Globally, G9P[4] and G12P[6] are less common genotypes, although these genotypes have been reported from India and few other countries. There was a variation in the geographic and temporal distribution of genotypes, and the emergence or re-emergence of new genotypes such as G3P[8] was seen. Over the surveillance period, there was a decline in the proportion of G2P[4], and an increase in the proportion of G9P[4]. A higher proportion of mixed and partially typed/untyped samples was also seen more in the age group 0–11 months.

Conclusions

This 11 years surveillance highlights the high burden of severe rotavirus gastroenteritis in Indian children < 5 years of age before inclusion of rotavirus vaccines in the national programme. Regional variations in rotavirus epidemiology were seen, including the emergence of G3P[8] in the latter part of the surveillance. Having pre-introduction data is important to track changing epidemiology of rotaviruses, particularly following vaccine introduction.

Human-porcine reassortant rotavirus generated by multiple reassortment events in a Sri Lankan child with diarrhea

A human-porcine reassortant rotavirus, strain R1207, was identified from 74 group A rotaviruses detected in 197 (37.6%) stool samples collected from patients who attended a tertiary care hospital in Ragama, Sri Lanka. This is the first report of a human-porcine reassortant rotavirus in Sri Lanka. The patient was a 12-month-old boy who had been hospitalized with fever and acute diarrhea with a duration of 6 days. The family had pigs at home before the birth of this boy. However, the neighbors still practice pig farming. The genotype constellation of R1207 was G4-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1. This is based on the assignment of all the eleven gene segments a full genome-based genotyping system. R1207 showed a 4-2-3-2 genomic electrophoretic migration pattern, which is characteristic of group A rotaviruses. Our analyses revealed that five (NSP2, NSP4, VP1, VP2, and VP7) of the 11 genes were closely related to the respective genes of porcine strains. Although the remaining six genes (NSP1, NSP3, NSP5, VP3, VP4, and VP6) were related to human strains, with the exception of the gene sequence of NSP1, all of these human strains were human-porcine reassortants. With a genogroup 1 genetic backbone, this strain was possibly formed via multiple genetic reassortments. We do not know whether this strain is circulating in pigs, as no data are available on porcine rotaviruses in Sri Lanka. Surveillance should be strengthened to determine the epidemiology of this genotype of rotavirus in Sri Lanka and to assess whether the infection was limited or sustained by ongoing human-to-human transmission.

Molecular epidemiology of rotaviruses in the south-east Asian region from 2009 to 2015

BACKGROUND

In Asia, rotavirus accounts for approximately 45% of admissions due to acute gastroenteritis in children <5 years, and causes about 145,000 deaths every year. We studied the distribution of rotavirus strains from Myanmar, Sri Lanka, and Nepal during 2009-2015.

METHODS

Stool samples collected from children <5 years of age hospitalized with acute diarrhea in the three sites and positive for rotavirus antigen by enzyme immunoassay (EIA) were sent to the Christian Medical College, Vellore from 2009 to 2015. G and P typing of rotavirus strains were performed using reverse-transcription polymerase chain reaction (RT-PCR).

RESULT

Of the 2354 EIA positive samples tested, G12P[8] (36.8%), G1P[8] (30.1%), and G12P[6] (41.3%) were the most common strains isolated from Myanmar, Sri Lanka, and Nepal respectively.

CONCLUSION

There was substantial diversity of rotavirus genotypes, and continued surveillance in developing countries of Asia will help in understanding the epidemiology of rotavirus before and after introduction of vaccines.

Emergence of Rotavirus G12P[8] in St. Louis During the 2012-2013 Rotavirus Season

BACKGROUND

We observed an increase in the number of rotavirus cases in the St. Louis area during the 2012-2013 rotavirus season compared with recent seasons. We aimed to determine whether the rotavirus cases during the 2012-2013 rotavirus season were of types not included in licensed vaccines.

METHODS

Microbiology laboratories of 3 children's hospitals in St. Louis provided samples that were positive using rapid antigen tests from 2010 to 2013. The majority of samples were from St. Louis Children's Hospital. We determined rotavirus genotypes by polymerase chain reaction tests and further characterized a subset of viruses by genome sequencing and comparative sequence analysis.

RESULTS

Eighty-six percent (24 of 28) of typed viruses analyzed from the 2012-2013 rotavirus season were G12. We performed whole genome sequencing on 8 G12 viruses, all of which were VP4 type P[8]. The sequenced viruses showed differences from vaccine strains in major antigenic epitopes on the VP7 protein, but most epitopes on VP4 were conserved. Rotavirus vaccine histories were available for 11 G12 cases, of whom 10 had not been vaccinated.

CONCLUSIONS

G12 was a dominant community-wide genotype in 2013. Most of the G12 cases for whom vaccine histories were available had not received rotavirus vaccine. The experience demonstrates the potential for rapid shifts in rotavirus genotype distribution and underscores the need for vigilant surveillance to detect unusual genotypes that might escape from vaccine protection.

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.

A Prospective Hospital-based Surveillance to Estimate Rotavirus Disease Burden in Bhutanese Children under 5 Years of Age

As part of efforts to develop an informed policy for rotavirus vaccination, this prospective study was conducted to estimate the burden of rotavirus diarrhea among children less than 5 years old attended to the Department of Pediatrics, Jigme Dorji Wangchuk National Referral Hospital (JDWNRH), Thimphu, Bhutan. The duration of the study was three years, extending from February 2010 through December 2012. We estimated the frequency of hospitalization in the pediatric ward and dehydration treatment unit (DTU) for diarrhea and the number of events attributable to rotavirus infection among children under 5 years of age. During the study period, a total of 284 children (1 in 45) were hospitalized in the pediatric ward, and 2,220 (1 in 6) in the DTU with diarrhea among children residing in the Thimphu district. Group A rotavirus was detected in 32.5% and 18.8% of the stool samples from children hospitalized in the pediatric ward, respectively. Overall, 22.3% of the stool samples were rotavirus-positive, and the majority (90.8%) of them was detected in children under 2 years of age. From this study, we estimated that the annual incidence of hospitalization in the pediatric ward and DTU due to rotavirus diarrhea was 2.4/1000 (95% CI 1.7–3.4) and 10.8/1000 (95% CI 9.1–12.7) children, respectively. This study revealed that rotavirus is a major cause of diarrhea in Bhutanese children in Thimphu district and since no study has been performed previously, represents an important finding for policy discussions regarding the adoption of a rotavirus vaccine in Bhutan.

Dominance of emerging G9 and G12 genotypes and polymorphism of VP7 and VP4 of rotaviruses from Bhutanese children with severe diarrhea prior to the introduction of vaccine

A prospective study was performed to determine the molecular characteristics of rotaviruses circulating among children aged <5 years in Bhutan. Stool samples were collected from February 2010 through January 2011 from children who attended two tertiary care hospitals in the capital Thimphu and the eastern regional headquarters, Mongar. The samples positive for rotavirus was mainly comprised genotype G1, followed by G12 and G9. The VP7 and VP4 genes of all genotypes clustered mainly with those of neighboring countries, thereby indicating that they shared common ancestral strains. The VP7 gene of Bhutanese G1 strains belonged to lineage 1c, which differed from the lineages of vaccine strains. Mutations were also identified in the VP7 gene of G1 strains, which may be responsible for neutralization escape strains. Furthermore, we found that lineage 4 of P[8] genotype differed antigenically from the vaccine strains, and mutations were identified in Bhutanese strains of lineage 3. The distribution of rotavirus genotypes varies among years, therefore further research is required to determine the distribution of rotavirus strain genotypes in Bhutan.

Whole genomic analysis of human G12P[6] and G12P[8] rotavirus strains that have emerged in Kenya: identification of porcine-like NSP4 genes

G12 rotaviruses are globally emerging rotavirus strains causing severe childhood diarrhea. However, the whole genomes of only a few G12 strains have been fully sequenced and analyzed, of which only one G12P[4] and one G12P[6] are from Africa. In this study, we sequenced and characterized the complete genomes of three G12 strains (RVA/Human-tc/KEN/KDH633/2010/G12P[6], RVA/Human-tc/KEN/KDH651/2010/G12P[8], and RVA/Human-tc/KEN/KDH684/2010/G12P[6]) identified in three stool specimens from children with acute diarrhea in Kenya, Africa. On whole genomic analysis, all three Kenyan G12 strains were found to have a Wa-like genetic backbone: G12-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1 (strains KDH633 and KDH684) and G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 (strain KDH651). Phylogenetic analysis showed that most genes of the three strains examined in this study were genetically related to globally circulating human G1, G9, and G12 strains. Of note is that the NSP4 genes of strains KDH633 and KDH684 appeared to be of porcine origin, suggesting the occurrence of reassortment between human and porcine strains. Furthermore, strains KDH633 and KDH684 were very closely related to each other in all the 11 gene segments, indicating derivation of the two strains from a common origin. On the other hand, strain KDH651 consistently formed distinct clusters of 10 of the 11 gene segments (VP1-2, VP4, VP6-7, and NSP1-5), indicating a distinct origin of strain KDH651 from that of strains KDH633 and KDH684. To our knowledge, this is the first report on whole genome-based characterization of G12 strains that have emerged in Kenya. Our observations will provide important insights into the evolutionary dynamics of emerging G12 rotaviruses in Africa.

Molecular epidemiology and genetic evolution of the whole genome of G3P[8] human rotavirus in Wuhan, China, from 2000 through 2013

BACKGROUND

Rotaviruses are a major etiologic agent of gastroenteritis in infants and young children worldwide. Since the latter of the 1990s, G3 human rotaviruses referred to as "new variant G3" have emerged and spread in China, being a dominant genotype until 2010, although their genomic evolution has not yet been well investigated.

METHODS

The complete genomes of 33 G3P[8] human rotavirus strains detected in Wuhan, China, from 2000 through 2013 were analyzed. Phylogenetic trees of concatenated sequences of all the RNA segments and individual genes were constructed together with published rotavirus sequences.

RESULTS

Genotypes of 11 gene segments of all the 33 strains were assigned to G3-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1, belonging to Wa genogroup. Phylogenetic analysis of the concatenated full genome sequences indicated that all the modern G3P[8] strains were assigned to Cluster 2 containing only one clade of G3P[8] strains in the US detected in the 1970s, which was distinct from Cluster 1 comprising most of old G3P[8] strains. While main lineages of all the 11 gene segments persisted during the study period, different lineages appeared occasionally in RNA segments encoding VP1, VP4, VP6, and NSP1-NSP5, exhibiting various allele constellations. In contrast, only a single lineage was detected for VP7, VP2, and VP3 genes. Remarkable lineage shift was observed for NSP1 gene; lineage A1-2 emerged in 2007 and became dominant in 2008-2009 epidemic season, while lineage A1-1 persisted throughout the study period.

CONCLUSION

Chinese G3P[8] rotavirus strains have evolved since 2000 by intra-genogroup reassortment with co-circulating strains, accumulating more reassorted genes over the years. This is the first large-scale whole genome-based study to assess the long-term evolution of common human rotaviruses (G3P[8]) in an Asian country.

Rotavirus genotype distribution in Kyrgyzstan and Kazakhstan, 2007-2009

This is the first study to present rotavirus genotype distribution in children admitted to a hospital with acute gastroenteritis in Kyrgyzstan and Kazakhstan from January 2007 through December 2009. In total, 858 rotavirus ELISA-positive samples were characterized by RT-PCR, with a considerable geographical and seasonal variation in genotype distribution observed during the study. The globally common genotypes (G1P[8], G2P[4], G3P[8], G4P[8], G9P[8], G12P[8] and G12P[6]) accounted for 81.5-88.2% of the infections in Kyrgyzstan and 72.3-79.3% of the infections in Kazakhstan. The predominant genotypes were G1P[8], G2P[4] and G3P[8]. G1P[8] was the dominating genotype in Kyrgyzstan, detected in 51-64.7% of the samples. A similar predominance was not seen for G1P[8] in Kazakhstan, with a shift to G2P[4] predominance being seen in 2008. G9P[8] was a rare genotype in both countries, whereas G12 was detected in between 2.2% and 7.6% of the samples. The surveillance period was characterized by many co-circulating genotypes, and eight unusual combinations (G1P[4], G2P[8], G2P[6], G3P[4], G9P[4], G12P[4], G9P[9] and G10P[4]) were detected. This study provides important baseline data on rotavirus genotypes in Kyrgyzstan and Kazakhstan in the pre-vaccine era, and the results may indicate that the two licensed vaccines can be expected to prevent rotavirus disease in these countries.

Inaccurate identification of rotavirus genotype G9 as genotype G3 strains due to primer mismatch

Reverse transcription (RT)-PCR is now the standard method for typing group A rotaviruses (RVA) to monitor the circulating genotypes in a population. Selection of primers that can accurately type the circulating genotypes is crucial in the context of vaccine introduction and correctly interpreting the impact of vaccination on strain distribution. To our knowledge this study is the first report from Asia of misidentification of genotype G9 as G3 due to a primer-template mismatch. We tested two published G-genotype specific primers sets, designed by Gouvea and colleagues (Set A) and Iturriza‐Gomara and colleagues (Set B) on RVA from Hong Kong and Sri Lanka. Among 52 rotaviruses typed as G3 by set A primers, 36 (69.2%) were identified as G9 by nucleotide sequencing and set B primers. Moreover, of 300 rotaviruses tested, 28.3% were untypable by set A primers whereas only 12.3% were untypable by set B primers. Our findings reinforce the need to periodically monitor the primers used for RVA genotyping.

Seasonality of rotavirus in South Asia: a meta-analysis approach assessing associations with temperature, precipitation, and vegetation index

BACKGROUND

Rotavirus infection causes a significant proportion of diarrhea in infants and young children worldwide leading to dehydration, hospitalization, and in some cases death. Rotavirus infection represents a significant burden of disease in developing countries, such as those in South Asia.

METHODS

We conducted a meta-analysis to examine how patterns of rotavirus infection relate to temperature and precipitation in South Asia. Monthly rotavirus data were abstracted from 39 published epidemiological studies and related to monthly aggregated ambient temperature and cumulative precipitation for each study location using linear mixed-effects models. We also considered associations with vegetation index, gathered from remote sensing data. Finally, we assessed whether the relationship varied in tropical climates and humid mid-latitude climates.

RESULTS

Overall, as well as in tropical and humid mid-latitude climates, low temperature and precipitation levels are significant predictors of an increased rate of rotaviral diarrhea. A 1°C decrease in monthly ambient temperature and a decrease of 10 mm in precipitation are associated with 1.3% and 0.3% increase above the annual level in rotavirus infections, respectively. When assessing lagged relationships, temperature and precipitation in the previous month remained significant predictors and the association with temperature was stronger in the tropical climate. The same association was seen for vegetation index; a seasonal decline of 0.1 units results in a 3.8% increase in rate of rotavirus.

CONCLUSIONS

In South Asia the highest rate of rotavirus was seen in the colder, drier months. Meteorological characteristics can be used to better focus and target public health prevention programs.

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

BACKGROUND

Rotavirus is the leading cause of severe diarrhea in children worldwide. We systematically reviewed the burden of rotavirus gastroenteritis (RVGE) and distribution of rotavirus strains in Asia.

METHODS

We searched MEDLINE, EMBASE and the World Health Organization (WHO) website for the term "rotavirus" and the name of each country. We included studies that were conducted in children between 2000 and 2011 and that examined the epidemiology, health and/or economic burden of RVGE, and G and P-type distribution in Eastern, South East, Southern and Central Asia. Random effects models were used to pool the proportions of RVGE. We also estimated child mortality due to RVGE using the updated WHO and United Nations Children's Fund's mortality estimates in 2008.

RESULTS

The search identified 113 eligible articles. The incidence rates of rotavirus-related hospitalizations in children under 5 years of age ranged from 2.1 to 20.0 cases per 1000 children per year with the highest rates reported in Bangladesh, South Korea, Taiwan, Thailand, and Vietnam. Rotavirus accounted for 37.5% of year-round hospitalized gastroenteritis cases, with higher proportions reported in South East Asia. Rotavirus was associated with approximately 145,000 deaths every year in Asia, with the greatest numbers occurring in India, Pakistan, and Indonesia. The highest annual societal costs of treating RVGE were reported in China (US$365 million), followed by Japan (US$254 million) and India (US$41-72 million). A diversity of rotavirus G and P-types was observed across Asia and the distribution of strains differed by country and year. The most common strains were G1P[8] (23.6%), G2P[4] (11.8%), G3P[8] (18.9%), and G9P[8] (7.4%).

CONCLUSIONS

Rotavirus is associated with substantial hospitalizations and deaths among children and causes large healthcare expenditures throughout Asia. Safe and effective rotavirus vaccines could substantially reduce the burden of disease.

The molecular epidemiology of circulating rotaviruses: three-year surveillance in the region of Monastir, Tunisia

BACKGROUND

Rotavirus infection is the most common cause of severe, dehydrating, gastroenteritis among children worldwide. In developing countries, approximately 1440 children die from rotavirus infections each day, with an estimated 527,000 annually. In infants, rotavirus is estimated to cause more than 2 million hospitalizations every year depending on the income level of the country. The purpose of this study was to estimate the proportion of rotavirus gastroenteritis and identify the distribution of circulating G and P genotype rotavirus strains among children consulting several dispensaries in the region of Monastir (outpatients departments) or admitted to Monastir University Hospital (inpatients department) with acute gastroenteritis.

METHODS

This study was undertaken during a 3-year period from April 2007 to April 2010 in Tunisian children under 13 suffering from acute gastroenteritis. Group A rotaviruses were detected in stools by ELISA and genotyped using multiplex reverse transcription PCRs with type-specific primers on the basis of their outer capsid proteins. Statistical analyses were performed with SPSS software, version 19.

RESULTS

Of the 435 stool samples from children with acute gastroenteritis, 27.6% were positive for rotavirus A. The predominant G type was G1 (37.5%), followed by G3 (25%), G2 (17.5%), G4 (12.5%), G9 (2.5%) and three mixed-G infections G3G4 (2.5%) were identified. Only P[8] (80.8%), P[4] (16.7%) and P[9] (0.8%) genotypes were found. The predominant single G/P combination was G1P[8] (37.5%), followed by G3P[8] (25%), G2P[4] (16.7%), G4P[8] (12.5%), G9P[8] (1.7%) and one case of the unusual combination G9P[9] (0.8%). The G-mixed types G3G4 combined with P[8] (2.5%). Infants less than 3 months of age were most frequently affected. The prevalence of rotavirus infection peaked in the winter season, when temperatures were low, and decreased in summer.

CONCLUSIONS

Rotavirus gastroenteritis is a common disease associated with significant morbidity, mortality, and economic burden. Epidemiological knowledge of rotavirus is critical for the development of effective preventive measures, including vaccines. These data will help to make informed decisions as to whether rotavirus vaccine should be considered for inclusion in Tunisia's National Immunisation Programme.

Co-dominance of G1 and emerging G3 rotaviruses in Hong Kong: a three-year surveillance in three major hospitals

BACKGROUND

The World Health Organization recommends rotavirus vaccines be included in all national immunization programs as part of a strategy to control diarrhoeal diseases. Sentinel surveillance is advised to monitor impact post-vaccine introduction and to document changes in genotype distribution.

OBJECTIVES

To determine the molecular epidemiology of circulating rotaviruses in Hong Kong prior to implementation of universal rotavirus vaccination.

STUDY DESIGN

From December 2004 through December 2007, 830 rotavirus-positive stool samples from subjects admitted for acute diarrhea to three major hospitals in Hong Kong were examined. The electropherotypes, and the G and P genotypes of these rotaviruses were determined. Phylogenetic analysis of the VP7 gene was performed.

RESULTS

G3P[8] was the dominant genotype (46.1%), followed by G1P[8] (36.5%) and G9P[8] (9.2%). A total of 35 electropherotypes were identified. The G3 and G1 strains had high sequence similarities among themselves and were clustered with strains from Asia particularly mainland China. The G9 strains were clustered with the globally spreading strains. G12 and G4 were not found. The prevalence of rotavirus infection peaked in winter season when temperature was low, atmospheric pressure was high, relative humidity was low and rainfall was negligible.

CONCLUSIONS

Genotype G3 and G1 were the dominant rotaviruses circulating in Hong Kong between 2004 and 2007. Strains were mainly related with those from mainland China. Ongoing surveillance of circulating genotypes should continue in anticipation of universal rotavirus vaccine introduction.

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

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

Human parechovirus infection in children hospitalized with acute gastroenteritis in Sri Lanka

Of 362 fecal specimens collected from infants and children hospitalized with acute gastroenteritis in Sri Lanka from September 2005 to August 2006, 30 (8.3%) were positive for human parechovirus (HPeV). Six different HPeV genotypes, including HPeV1, -3, -4, -5, -10, and -11, were identified, of these, HPeV11 was reported for the first time.