Neonatal rotavirus infection in Belém, northern Brazil: nosocomial transmission of a P[6] G2 strain

Incidence, Clinical Characteristics, and Genotype Distribution of Rotavirus in a Neonatal Intensive Care Unit 5 Years After Introducing Rotavirus Vaccine

BACKGROUND

Rotavirus (RV) is a common cause of viral gastroenteritis in children worldwide. We aimed to investigate the incidence, symptoms, and genotype of RV infection in a neonatal intensive care unit (NICU) in South Korea 5 years after the introduction of RV vaccination to evaluate its effect on newborn infants.

METHODS

A total of 431 fecal specimens were collected from patients admitted to NICU between April 20, 2012 and September 10, 2013. Enzyme-linked immunoassays were used to detect RV antigen. Nested multiplex polymerase chain reaction was used for genotyping.

RESULTS

The overall incidence of RV infection was 43.9% and was significantly higher in preterm infants, infants born in the study hospital, low birth weight infants, and cesarean births (P < 0.05). Symptoms of diarrhea, poor feeding, abdominal distension, and apnea were significantly higher in infants with RV infection than those without infection. RV infection gradually increased depending on infant care at home, postpartum clinic, or hospital (26.0, 45.1, and 60.2%, respectively; P = 0.000). The dominant RV genotype in the NICU was G4P[6] at 95.4%.

CONCLUSION

Current RV vaccines did not affect the incidence of RV infection in newborn and preterm infants in the NICU. Most RV-positive patients in the NICU had symptoms, and the incidence of RV infection was relatively higher in hospitals and postpartum clinics with group life than home. The dominant RV genotype was G4P[6] across study groups.

Complete genomic analysis of uncommon G12P[11] rotavirus causing a nosocomial outbreak of acute diarrhea in the newborns in New Delhi, India

Rotaviruses (RVs) are the major causative agents of acute gastroenteritis in children, but in neonates, RV infections are generally nosocomial in origin and mostly asymptomatic. However, there have been infrequent reports of nosocomial outbreaks of clinical disease in this population. In this study, we describe uncommon RV genotype; G12P[11] associated with an outbreak of acute gastroenteritis in the neonatal ward and neonatal intensive care unit (NICU) in New Delhi, North India. Full-genome analyses of the pathogenic G12P[11] strain was carried out to map the genotype constellation and further to explore the variations in the antigenic epitopes on the immunodominant VP7 and VP4 proteins, the amino acid sequences were compared with neonatal strains; ROTAVAC® (G9P[11]) and asymptomatic G12P[11] and also other G/P-type matched strains. The study revealed G12-P[11]-I1-R1-C1-M1-A1-N1-T1-E1-H1 human Wa-like genotype constellation and highlights evidence of gene reassortment. No significant differences were observed in the sequences of structural (except VP3) and nonstructural encoding genes of G12P[11] strains recovered from symptomatic and asymptomatic neonates. Presence of additional N-linked glycosylation site was noted in the G12 strains, as a consequence of a change from Asp→Asn at amino acid position 238. Interestingly, only two and four amino acids substitution within the 7-1a and 8-1 antigenic epitope were observed, respectively, compared with asymptomatic G12P[11] strain. The study emphasizes the importance of close monitoring of RV outbreaks in neonates for early alarming of novel strain.

Glycan recognition in globally dominant human rotaviruses

Rotaviruses (RVs) cause life-threatening diarrhea in infants and children worldwide. Recent biochemical and epidemiological studies underscore the importance of histo-blood group antigens (HBGA) as both cell attachment and susceptibility factors for the globally dominant P[4], P[6], and P[8] genotypes of human RVs. How these genotypes interact with HBGA is not known. Here, our crystal structures of P[4] and a neonate-specific P[6] VP8*s alone and in complex with H-type I HBGA reveal a unique glycan binding site that is conserved in the globally dominant genotypes and allows for the binding of ABH HBGAs, consistent with their prevalence. Remarkably, the VP8* of P[6] RVs isolated from neonates displays subtle structural changes in this binding site that may restrict its ability to bind branched glycans. This provides a structural basis for the age-restricted tropism of some P[6] RVs as developmentally regulated unbranched glycans are more abundant in the neonatal gut.

Human rotaviruses (RV) bind to histo-blood group antigens (HBGA) for attachment, but how different viral genotypes interact with HBGA isn’t known. Here, Hu et al. report crystal structures of a prevalent and a neonate-specific RV in complex with HBGA and provide insights into glycan recognition and age-restricted tropism of RVs.

The Lewis A phenotype is a restriction factor for Rotateq and Rotarix vaccine-take in Nicaraguan children

Histo-blood group antigens (HBGAs) and the Lewis and secretor antigens are associated with susceptibility to rotavirus infection in a genotype-dependent manner. Nicaraguan children were prospectively enrolled in two cohorts vaccinated with either RotaTeq RV5 (n = 68) or Rotarix RV1 (n = 168). Lewis and secretor antigens were determined by saliva phenotyping and genotyping. Seroconversion was defined as a 4-fold increase in plasma IgA antibody titer 1 month after administration of the first dose of the vaccine. Regardless of the vaccine administered, significantly fewer of the children with Lewis A phenotype (0/14) seroconverted after receiving the first vaccine dose compared to 26% (45/175) of those with the Lewis B phenotype and 32% (15/47) of the Lewis negative individuals (P < 0.01). Furthermore, following administration of the RV1 vaccine, secretor-positive ABO blood group B children seroconverted to a significantly lesser extent (5%) compared to secretor-positive children with ABO blood groups A (26%) and O (27%) (P < 0.05). Other factors such as pre-vaccination titers, sex, breastfeeding, and calprotectin levels did not influence vaccine-take. Differences in HBGA expression appear to be a contributing factor in the discrepancy in vaccine-take and thus, in vaccine efficacy in different ethnic populations.

Rotavirus Gastroenteritis in a Neonatal Unit of a Greek Tertiary Hospital: Clinical Characteristics and Genotypes

INTRODUCTION

Rotavirus (RV) infection in neonatal age can be mild or even asymptomatic. Several studies have reported that RV is responsible for 31%-87% of pediatric nosocomial diarrhea and causes gastroenteritis outbreaks in pediatric and neonatal units.

OBJECTIVES

Study clinical characteristics, genotypes and risk factors of RV infection in neonatal age.

METHODS

A prospective study was conducted from April 2009 till April 2013 in the neonatal special care unit of the largest tertiary pediatric hospital of Greece. Fecal samples and epidemiological data were collected from each neonate with gastrointestinal symptoms. RV antigen was detected with a rapid immunochromatography test. RV positive samples were further genotyped with RT PCR and sequencing using specific VP7 and VP4 primers.

RESULTS

Positive for RV were 126/415 samples (30.4%). Mean age of onset was 18 days. Seventy four cases (58%) were hospital acquired. Seasonality of RV infection did not differ significantly throughout the year with the exception of 4 outbreaks. Genotypes found during the study period were G4P[8] (58.7%), G1P[8] (14.7%), G12P[8] (9.3%), G3P[8] (9.3%), G12P[6] (5.3%), G9P[8] (1.3%) and G2P[4] (1.3%). RV cases presented with: diarrhea (81%), vomiting (26.2%), fever (34.9%), dehydration (28.6%), feeding intolerance (39.7%), weight loss (54%), whilst 19% of cases were asymptomatic. Comparing community with hospital acquired cases differences in clinical manifestations were found.

CONCLUSIONS

Significant incidence of nosocomially transmitted RV infection in neonatal age including asymptomatic illness exists. Genotypes causing nosocomial outbreaks are not different from community strains. Circulating vaccines can be effective in prevention of nosocomial RV infection through herd immunity.

Phylogenetic analysis of probable non-human genes of group A rotaviruses isolated from children with acute gastroenteritis in Belém, Brazil

Rotaviruses (RVs) are the main cause of acute viral gastroenteritis in both humans and young animals of various species such as calves, horses, pigs, dogs, cats, and birds. The genetic diversity of RVs is related to a variety of evolutionary mechanisms, including point mutation, and genome reassortment. The objective of this study was to characterize molecularly genes that encode structural and nonstructural proteins in unusual RV strains. The clinical specimens selected for this study were obtained from children and newborn with RV gastroenteritis, who participated in research projects on viral gastroenteritis conducted at the Evandro Chagas Institute. Structural (VP1-VP4, VP6, and VP7) and nonstructural (NSP1-NSP6) genes were amplified from stool samples by the polymerase chain reaction and subsequently sequenced. Eight unusual RV strains isolated from children and newborn with gastroenteritis were studied. Reassortment between genes of animal origin were observed in 5/8 (62.5%) strains analyzed. These results demonstrate that, although rare, interspecies (animal-human) transmission of RVs occurs in nature, as observed in the present study in strains NB150, HSP034, HSP180, HST327, and RV10109. This study is the first to be conducted in the Amazon region and supports previous data showing a close relationship between genes of human and animal origin, representing a challenge to the large-scale introduction of RV vaccines in national immunization programs.

Phylogenetic analysis of G1P[6] group A rotavirus strains detected in Northeast Brazilian children fully vaccinated with Rotarix™

In 2009 the World Health Organization recommended the use of group A rotavirus (RVA) vaccines in all national immunization programs (NIPs) in order to control severe RVA gastroenteritis disease. In Brazil, Rotarix™ was introduced in the NIP in March 2006, and a significant reduction in mortality rates among children ≤ 5 years old was observed, especially in the Northern and Northeastern Brazil. In the current study the 11 gene segments of six Brazilian G1P[6] RVA strains, isolated in 2009 and 2010 from vaccinated children, were analyzed in order to investigate if the genetic composition of these strains might help to elucidate why they were able to cause acute gastroenteritis in vaccinated children. All six Brazilian RVA strains revealed a complete Wa-like genotype constellation: G1-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1. Phylogenetic analysis showed that all six strains were nearly identical and showed a close genetic relationship with contemporary typical human Wa-like RVA strains. These results suggests that the fact that these strains were able to cause acute gastroenteritis in vaccinated children is likely not due to the genetic background of the strains, but rather to other factors such as host relating factors, co-infecting pathogens or vaccine efficacy. P[6] RVA strains are detected rather occasionally in humans in most regions of the world, except for South Asia and Sub-Saharan Africa. However, recently two studies conducted in Brazil showed the circulation of G12P[6] and G2P[6]. This is the first report on the detection and complete genome analyses of G1P[6] RVA strains in Brazil. Surveillance studies will be crucial to further investigate the prevalence of this genotype in the Brazilian population, and the efficacy of current licensed vaccines, which do not contain the P[6] genotype.

Spike protein VP8* of human rotavirus recognizes histo-blood group antigens in a type-specific manner

Rotaviruses (RVs), an important cause of severe diarrhea in children, have been found to recognize sialic acid as receptors for host cell attachment. While a few animal RVs (of P[1], P[2], P[3], and P[7]) are sialidase sensitive, human RVs and the majority of animal RVs are sialidase insensitive. In this study, we demonstrated that the surface spike protein VP8* of the major P genotypes of human RVs interacts with the secretor histo-blood group antigens (HBGAs). Strains of the P[4] and P[8] genotypes shared reactivity with the common antigens of Lewis b (Le(b)) and H type 1, while strains of the P[6] genotype bound the H type 1 antigen only. The bindings between recombinant VP8* and human saliva, milk, or synthetic HBGA oligosaccharides were demonstrated, which was confirmed by blockade of the bindings by monoclonal antibodies (MAbs) specific to Le(b) and/or H type 1. In addition, specific binding activities were observed when triple-layered particles of a P[8] (Wa) RV were tested. Our results suggest that the spike protein VP8* of RVs is involved in the recognition of human HBGAs that may function as ligands or receptors for RV attachment to host cells.

Genotyping of human rotaviruses circulating among children with diarrhea in Valencia, Venezuela

Rotavirus infection is the most common cause of severe gastroenteritis during childhood worldwide, especially in developing countries. Two rotavirus vaccines are available for childhood immunization programs. Evaluation of the vaccine performance will benefit from knowledge of the epidemiological features of rotavirus infection in regional settings. Limited information on the molecular characteristics of the rotavirus types circulating in Venezuela is available. Eighty seven (89.7%) of the 97 ELISA rotavirus positive stool samples collected from children with diarrhea aged <5 years during 2003 in Valencia (Carabobo State), were G-, P- and NSP4-genotyped by RT-PCR and/or automated sequencing. Four common combinations, G3P[8]/NSP4-E1, G2P[4]/NSP4-E2, G9P[8]/NSP4-E1, and G1P[8]/NSP4-E1 were responsible for 50.6%, 35.6%, 5.7%, and 1.1%, respectively of cases of rotavirus diarrhea, most of them (66%) in children ≤12 months. One uncommon G8P[14]/NSP4-E2 strain was also detected. Temporal fluctuation of genotype distribution occurred, but no differences by age, diarrhea severity score, sex, treatment type or patient medical attention were observed, except for the G3P[8]/NSP4-E1, associated with a more severe dehydration than any other type (P < 0.01). The results confirm the broad diversity among rotavirus strains circulating in Venezuela prior to vaccine implementation, showing the predominance of G3, significant proportion of G2 and moderate circulation of G9 strains. Epidemiological surveillance is needed to detect the emergence of new genotypes that could escape protection induced by vaccination.

Genetic variation of G4P[6] rotaviruses: evidence for novel strains circulating between the hospital and community

One hundred forty-six fecal specimens collected between 2007 and 2008 from infants with acute gastroenteritis were screened for rotavirus by ELISA with VP6-specific antibody. One hundred twenty-three of the samples (84.2%) were confirmed to be positive for group A rotavirus (community-acquired, n = 90 [73.2%] and nosocomial, n = 33 [26.8%]), and were typed subsequently using RT-PCR and sequence analysis methods. Determination of G- and P-type combinations showed that G4P[6] (78.9%) was the most common strain, followed by G3P[8] (7.3%), G1P[8] (6.5%), G2P[4] (0.8%), G2P[6] (0.8%), G1P[6] (0.8%), and G9P[8] (0.8%) strains. Of the 97 G4P[6] strains, 62 (63.8%) were responsible for community-acquired cases and 35 (36.1%) were hospital-acquired cases. Phylogenetic analysis of the VP7 gene from the G4P[6] strains revealed that both the community-acquired and nosocomial strains were segregated to the human rotaviruses circulating world-wide, including the prototype vaccinal strain, ST3, which constituted a novel sublineage in lineage 1. Owing to the recent emergence of G4P[6] rotaviruses within the hospital, as well as in the community, the findings from this study are important since they provide new information concerning the community and nosocomial spread of rotaviruses.

Viral agents associated with acute gastroenteritis in children hospitalized with diarrhea in Lanzhou, China

BACKGROUND

Gastroenteritis is a major cause of childhood morbidity and mortality worldwide. Rotavirus, human caliciviruses (HucV), adenovirus, and astrovirus are recognized as common etiologies of acute gastroenteritis.

OBJECTIVES

To use antigen detection and molecular methods to determine the viral etiology of childhood diarrhea in Lanzhou, China, 2005-2007.

STUDY DESIGN

544 stool specimens were collected from children hospitalized with diarrhea. ELISA, RT-PCR, or PCR were used to detect viruses commonly causing diarrhea.

RESULTS

Group A rotavirus, norovirus, sapovirus, astrovirus, and adenovirus, were detected in 54.0%, 9.2%, 1.1%, 3.3%, and 4.4%, respectively. No group B or group C rotaviruses were detected. The relative contribution of these viruses changed greatly over 2 years. The percentage of rotavirus and adenovirus dropped from 61.2% and 5.4% to 47.6% and 1.4%, whereas HucV increased from 5.0% to 15.0%. G1 and P[8] were the predominant rotavirus strains, and P[6] was detected for the first time in this area. The predominant norovirus strain changed from GII3 to GII4, and the subtypes of GII4 changed from the Hunter strain to the variant 2006b strain.

CONCLUSIONS

The distribution of viruses and genotypes of individual viruses causing gastroenteritis in Lanzhou, China changed greatly during 2005-2007.

Identification of risk factors associated with nosocomial infection by rotavirus P4G2, in a neonatal unit of a tertiary-care hospital

A rotavirus outbreak in newborns admitted to the 'La Paz' University Hospital, Madrid was detected, followed up and controlled. Uninfected children were selected as control subjects. Samples of faeces were taken once or twice weekly from all the newborns, including those who were asymptomatic and who were admitted to the neonatal unit for early detection of rotavirus and the positive were separated from the rest of the neonates. Contact-related precautions were taken for all patients, and alcohol solutions were used for hand washing. During the months of the outbreak, 1773 children were admitted to the hospital, 131 of whom were affected by the rotavirus infection (7.4%). Of these, 72 (55%) had symptomatic infections. In the first month of the outbreak, nine cases of necrotizing enterocolitis were diagnosed (one patient developed massive intestinal necrosis). The infections (symptomatic and asymptomatic) presented a bimodal distribution caused by a new outbreak of rotavirus type P4G2 after two patients who had acquired the infection outside the hospital were admitted when the first outbreak was subsiding. The characteristics of cases and controls were analysed using bivariate and multivariate methods (non-conditional multivariate logistic regression) to identify four risk factors strongly associated with rotavirus infection: premature birth, infections other than rotavirus, malformation, and changes in glycaemia and/or presence of jaundice.

Group A rotavirus strains circulating in the eastern center of Tunisia during a ten-year period (1995-2004)

An epidemiological survey investigating rotavirus infections in children was undertaken in the Eastern Center of Tunisia between January 1995 and December 2004. A total of 982 faecal specimens collected from children less than 5 years in age were screened by enzyme-linked immunosorbent assay (ELISA) or latex agglutination assay for the presence of group A rotavirus antigen. Rotavirus-positive samples were used for G and P typing by multiplex semi-nested reverse transcription-PCR. Rotaviruses were detected in 22% (n = 220) of stools. Of these, 164 were typed for VP7: G genotypes found were G1 (59%), G2 (2%), G3 (9%), G4 (10%), G8 (1%), and G9 (1%). Sixteen specimens (9%) showed mixed G profiles. A total of 119 specimens were typed for VP4. P genotypes detected were P[8] (32%), P[6] (15%), and P[4] (13%). Mixed P profiles were also detected (6%). Although the distribution of the detected genotypes appeared to change annually, G1P[8] rotavirus strains always predominated during the 10-year period of study. This is the first report of rotaviruses in Tunisia with unconventional VP7 serotypes such as G8 and G9, highlighting the need for continual surveillance of emerging strains in Northern Africa. Indeed, the new commercial vaccines only contain the VP7 genes that dictate G1 or G1 to G4 specificities. These vaccines may protect less well against unusual strains circulating in countries planning to implement a rotavirus vaccine strategy.

Rotavírus A em crianças de até três anos de idade, hospitalizadas com gastroenterite aguda em Campo Grande, Estado do Mato Grosso do Sul

Através da eletroforese em gel de poliacrilamida e do ensaio imunenzimático combinado para rotavírus e adenovirus, foram analisadas 380 amostras fecais de crianças com até 3 anos, hospitalizadas com diarréia aguda, entre maio de 2000 e janeiro de 2004, em Campo Grande, MS. Do total de amostras, 88 (23,2%) foram positivas para Rotavirus A. Dentre essas, 81 (92%) tiveram padrão eletroferotípico definido, sendo 77 (87,5%) de padrão longo e quatro (4,5%) de padrão curto. A caracterização genotípica G e P foi feita por RT-Nested-PCR para 85 amostras, sendo 56 (65,9%) genotipáveis para genótipo G. Dentre essas, 49 (87,5%) foram G1, cinco (8,9%) G4, uma (1,8%) G3 e uma (1,8%) G9. Considerando a genotipagem P, 37 (43,5%) foram genotipáveis e todas eram P[8]. A associação G e P mais observada foi G1P[8], 33 (89,2%) amostras; seguida de G4P[8], duas (5,4%) amostras; G3P[8], uma (2,7%) amostra; e G9P[8], uma (2,7%) amostra.

Detection of a neonatal human rotavirus strain with VP4 and NSP4 genes of porcine origin

A human rotavirus strain (NB-150) was detected in stool samples from a neonate hospitalized for mild/moderate community-acquired diarrhoea. This baby lived in the outskirts of Belém, Brazil, under poor sanitation conditions. The NB-150 strain displayed a typical long electrophoretic pattern with 11 gene segments. It had two VP7 alleles, G1 and G4, and belonged to VP6 subgroup II. A close relatedness with human rotaviruses was shown for VP7 alleles: G1 (96.9–100 % similarity at the amino acid level) and G4 (97.1–100 % similarity at the amino acid level). As for VP6, 95.1–97.5 % similarity at the amino acid level was noted. VP8* and NSP4 genes showed a close relatedness with those of porcine rotavirus strains, as follows: VP8* (95.0 % similarity at the amino acid level) and NSP4 (93.7–96.0 % similarity at the amino acid level). This is believed to be the first report in Brazil of a rotavirus infection involving a strain with G1 and G4 alleles, with VP8* and NSP4 genes of porcine origin. These findings strongly suggest the occurrence of interspecies transmission.

Molecular characterization of VP4 and NSP4 genes from rotavirus strains infecting neonates and young children in Belém, Brazil

Several reports have identified P[6] specificities in humans and in animals in different countries of the world, but few sequence data are available in public databases. In this work we have characterized the VP4 strains bearing P[6] specificity and NSP4 genotypes among diarrheic young children and diarrheic and non-diarrheic neonates from three studies previously conducted in Belém, Northern region of Brazil. As the to VP8* fragment, we observed a close relationship to both human prototypes of lineage P[6]-Ia (bootstrap of 99%) and porcine sublineages Ib and Ic (89.2-98.1% aa similarity and mean of 95%). With regards to the NSP4, the samples clustered into genotypes A and B. Of note, of the 27 P[6] strains analyzed in the present study and classified as genotype B, 8 (29.6%) were more similar to porcine prototypes when VP8* and NSP4 genes are compared, and were recovered, one from a neonate and seven from diarrheic children. These preliminary findings reinforce that further investigations are needed to assess the relative frequencies of P[6] strains in our region, as well as to investigate the potential for interspecies transmission involving humans and animals, particularly pigs.

Healthcare-associated infections in neonatal units: lessons from contrasting worlds

Neonatal intensive care units are vulnerable to outbreaks and sporadic incidents of healthcare-associated infections (HAIs). The incidence and outcome of these infections are determined by the degree of immaturity of the neonatal immune system, invasive procedures involved, the aetiological agent and its antimicrobial susceptibility pattern and, above all, infection control policies practised by the unit. It is important to raise awareness of infection control practices in resource-limited settings, since overdependence upon antimicrobial agents and co-existing lack of awareness of infection control is encouraging the emergence of multi-drug-resistant nosocomial pathogens. We reviewed 125 articles regarding HAIs from both advanced and resource-limited neonatal units in order to study risk factors, aetiological agents, antimicrobial susceptibility patterns and reported successes in infection control interventions. The articles include surveillance studies, outbreaks and sporadic incidents. Gram-positive cocci, viruses and fungi predominate in reports from the advanced units, while Gram-negative enteric rods, non-fermenters and fungi are commonly reported from resource-limited settings. Antimicrobial susceptibility patterns from surveillance studies determined the empirical therapy used in each neonatal unit. Most outbreaks, irrespective of the technical facilities available, were traced to specific lack of infection control practices. We discuss infection control interventions, with special emphasis on their applicability in resource-limited settings. Cost-effective measures for implementing these interventions, with particular reference to the recognition of the role of the microbiologist, the infection control team and antibiotic policies are presented.

Genetic distribution of group A human rotavirus types isolated in Gyunggi province of Korea, 1999–2002

BACKGROUND

Human rotavirus genotypes G1-G4 and G9 are the major etiological agents of infantile gastroenteritis. G1 was the most prevalent in Korea during the 10-year period prior to 1997. However, between 1998 and 1999, G4 was the predominant type in Korea, as it was in other Asian countries.

OBJECTIVES

The circulating pattern and genetic variability of group A human rotavirus in Gyunggi, Korea, 1999-2002, were examined in 189 stool specimens.

STUDY DESIGN

Stool samples were collected from children with diarrhea, and group A human rotavirus type was determined using multiplex RT-PCR in those specimens found to be positive for rotavirus by ELISA. Each genotype was sequenced, and phylogenetic analysis was performed on the sequences.

RESULT

We found significant variability from year to year in the prevalence of different G and P types of rotavirus. We also found relatively high prevalence rates for types normally considered to be uncommon. Furthermore, we found that the most prevalent combination of G and P types changed from year to year. Although the combination of G and P types changed every year, the sequence of G genotypes showed a high level of similarity (>97%) compared to those of strains from other Asian countries.

CONCLUSION

We report the types of rotavirus circulating in Gyunggi province, Korea from 1999 to 2002. This information on rotavirus diversity has important implications for rotavirus vaccine efficacy and future vaccine development.

Changing pattern of rotavirus G genotype distribution in Chiang Mai, Thailand from 2002 to 2004: Decline of G9 and reemergence of G1 and G2

Group A rotaviruses are the most common cause of acute viral diarrhea in humans and animals throughout the world. Previous surveillance studies of group A rotaviruses in Thailand indicated that the dominant types of rotaviruses were changing from time to time. During 2000 and 2001, the G9 rotavirus emerged as the most prevalent genotype, with an exceptionally high frequency (91.6%) in Chiang Mai, Thailand. In the year 2002-2004, group A rotavirus was detected in 98 out of 263 (37.3%) fecal specimens collected from children hospitalized with diarrhea. Of these, 40 (40.8%) were G9P[8], 33 (33.7%) were G1P[8], 23 (23.5%) were G2P[4], and 2 (2.0%) were G3P[9]. The G9P[8] was found to be the most predominant strain in 2002, but the prevalence rate abruptly decreased during the period 2003-2004. In addition, G2P[4] reemerged in the epidemic season of 2003, whereas G1P[8] became the most predominant strain in the following year (2004). Phylogenetic analysis of the VP7 genes revealed that G1, G2, and G9 rotavirus strains clustered together with recently circulating strains, which were isolated from different regional settings in Thailand. In conclusion, the study demonstrated a decrease of incidence of G9P[8] and reemergence of G1P[8] and G2P[4] rotaviruses in Chiang Mai, Thailand during the period 2002-2004. These data imply that the distribution of group A rotavirus genotypes circulating in Chiang Mai, Thailand, changes over time.

G and P genotyping of human rotavirus isolated in a university hospital in Korea: implications for nosocomial infections

To characterize rotavirus G and P genotypes circulating among infants and young children hospitalized with severe diarrhea in a university hospital in Gyeonggi province, Korea, and to examine any association of the genotypes and nosocomial infections, we genotyped 103 isolates of rotavirus by multiplex RT-PCR. In July 2001-June 2002, we found that globally common strains constituted 64.2% (G2P[4] 28.3%, G3P[8] 28.3%, G4P[8] 5.7%, and G1P[8] 1.9%), and the uncommon strain, G4P[6], constituted 26.4%. During July 2002-June 2003, the percentage of common strains decreased to 44.0% (G3P[8] 18.0%, G2P[4] 16.8%, and G1P[8] 10.0%), but G4P[6] increased to 36.0%. G9P[8] was identified in 10.0% of cases, and thus can be considered an emerging strain in Korea. Eight-eight percent of G4P[6] was isolated from newborn babies. Among the 103 patients, there was an evidence of nosocomial rotavirus infection in 23 children (22.3%). Of these, 19 (82.6%) were newborns infected with G4P[6] strains of rotavirus. Most of the children who acquired rotavirus infection nosocomially showed symptoms of diarrhea, vomiting, fever, poor sucking, or dehydration, regardless of the genotype. This study revealed that G4P[6] has been the major genotype causing nosocomial rotavirus infection in our hospital.

G8 rotavirus strains isolated in the Democratic Republic of Congo belong to the DS-1-like genogroup

Several G8P[6] and G8P[8] rotavirus strains were isolated from hospitalized patients in the Democratic Republic of Congo in 2003. To investigate their overall genomic relatedness and to determine to which genogroup they belonged, the complete genomes of strains DRC88 (G8P[8]) and DRC86 (G8P[6]) were determined. Genomic comparison of these two African G8 strains revealed that 10 out of their 11 gene segments, except for VP4, were nearly identical (>98.9% identical at the nucleotide level), suggesting that this rare G8P[8] rotavirus strain originated recently from a reassortment between a common G8P[6] strain and a strain with a P[8] specificity. A very close evolutionary relationship between 9 out of the 11 gene segments of DRC88 and DRC86 and rotavirus strains belonging to the DS-1-like (G2P[4]) "genogroup" was found, and several possible reassortment events preceding the occurrence of G8P[8] and G8P[6] human rotaviruses were hypothesized. Since the genes of G2P[4] rotavirus strains are very well adapted to infect humans, the acquirement of a new VP7 (G8) gene, and especially the replacement of P[6] (believed to be of animal origin) by P[8] (most common in human rotaviruses), might make DRC88-like rotaviruses very well equipped to become a predominant human rotavirus strain and an important pathogen on the African continent and the rest of the world. These findings have important implications for rotavirus vaccine development and highlight that typing of new rotavirus strains by merely sequencing their VP7 and VP4 genes provides us with only the tip of the iceberg regarding rotavirus diversity.

Etiology of diarrheal infections in children of Porto Velho (Rondonia, Western Amazon region, Brazil)

In the present study, 470 children less than 72 months of age and presenting acute diarrhea were examined to identify associated enteropathogenic agents. Viruses were the pathogens most frequently found in stools of infants with diarrhea, including 111 cases of rotavirus (23.6% of the total diarrhea cases) and 30 cases of adenovirus (6.3%). The second group was diarrheogenic Escherichia coli (86 cases, 18.2%), followed by Salmonella sp (44 cases, 9.3%) and Shigella sp (24 cases, 5.1%). Using the PCR technique to differentiate the pathogenic categories of E. coli, it was possible to identify 29 cases (6.1%) of enteropathogenic E. coli (EPEC). Of these, 10 (2.1%) were typical EPEC and 19 (4.0%) atypical EPEC. In addition, there were 26 cases (5.5%) of enteroaggregative E. coli, 21 cases (4.4%) of enterotoxigenic E. coli, 7 cases (1.4%) of enteroinvasive E. coli (EIEC), and 3 cases (0.6%) of enterohemorrhagic E. coli. When comparing the frequencies of diarrheogenic E. coli, EPEC was the only category for which significant differences were found between diarrhea and control groups. A low frequency of EIEC was found, thus EIEC cannot be considered to be a potential etiology agent of diarrhea. Simultaneous infections with two pathogens were found in 39 diarrhea cases but not in controls, suggesting associations among potential enteropathogens in the etiology of diarrhea. The frequent association of diarrheogenic E. coli strains was significantly higher than the probability of their random association, suggesting the presence of facilitating factor(s).

Molecular analysis of VP4, VP7, and NSP4 genes of P[6]G2 rotavirus genotype strains recovered from neonates admitted to hospital in Belém, Brazil

This investigation describes the molecular characterization of P[6]G2 rotavirus strains from hospitalized neonates with community-acquired diarrhea (CAD), nosocomial diarrhea (ND), and asymptomatic nosocomial infection (ANI) in Belém, Brazil. Twenty-six rotavirus strains with P[6]G2 genotype were sequenced to genes coding for VP4, VP7, and NSP4 proteins. Phylogenetic analysis of the VP4 gene, including prototype strains RV3, ST3, M37, and U1205, showed that local P[6]G2 strains clustered forming a distinct lineage (bootstrap of 99%). Brazilian P[6]G2 strains had the highest homology (ranging from 96.0%-98.3%) with the African strain GR1107, G4P[6]. Phylogenetic tree for VP7 gene was constructed including old and new G2 African strains SA3958GR/97, SA356PT/96, SA514GR/87, SA4476PT/97, BF3676/99, GH1803/99, and representative strains of G1, G3, G4, G5, G8, and G9 genotypes. The Brazilian P[6]G2 samples fell into a distinct group (bootstrap value of 97%) and showed homology rates ranging from 92.1% to 93.5% with P[6]G2 African strains BF3676/99, GH1803/99, and SA3958GR/97. Nucleotide sequence analysis of the NSP4 gene, including human prototype strains S2, KUN, DS-1, RV5, RV3 and ST3, and animal prototype OSU, showed that all neonatal isolates fell into genotype A and clustered with a bootstrap value of 100%, with in-group similarities ranging from 99.3% to 100%. In this study no significant differences in nucleotide sequences of the VP4, VP7, and NSP4 genes could be observed when comparing diarrheic (CAD and ND) and non-diarrheic (ANI) babies. Monitoring of rotavirus strains in hospital environments is of particular importance, since it is claimed currently that an efficacious rotavirus vaccine, when available for routine use, will determine an impact on hospital-acquired rotavirus disease.

Molecular Epidemiological Profile of Rotavirus in South Korea, July 2002 through June 2003: Emergence of G4P[6] and G9P[8] Strains

To determine the distribution of rotavirus strain genotypes in South Korea, rotavirus-positive stool specimens were collected from July 2002 through June 2003 at 8 hospitals in the Korean Rotavirus Strain Surveillance Network, and they were genotyped by means of reverse-transcription polymerase chain reaction. The globally uncommon G4P[6] type was the most prevalent type identified among strains (27% of strains), the newly emerging G9P[8] strain accounted for 11% of strains, and the globally common genotypes (i.e., G1P[8], G2P[4], G3P[8], and G4P[8]) constituted 55% of the strains characterized. Ninety percent of G4P[6] strains were detected in specimens obtained from neonates. Common genotypes were responsible for the rotavirus epidemic that began in January 2003 and ended in May 2003; however, an early peak in infections with the G4P[6] strain occurred from August through October 2002, and infections with this strain were detected throughout the remaining study period. G4P[6] strains were most commonly identified at 6 urban health care centers, but they were absent from 2 rural health care centers. The newly emerging strain G9P[8] represented a relatively greater proportion of strains identified at a hospital in the central region of Korea and at 2 hospitals in the southern region. The identification of novel rotavirus genotypes in this laboratory-based surveillance study underscores the importance to public health of continued strain surveillance among children for whom prevention of rotavirus infection by vaccination might be considered.

Global distribution of rotavirus serotypes/genotypes and its implication for the development and implementation of an effective rotavirus vaccine

A safe and effective rotavirus vaccine is urgently needed, particularly in developing countries. Critical to vaccine development and implementation is a knowledge base concerning the epidemiology of rotavirus G and P serotypes/genotypes throughout the world. The temporal and geographical distribution of human rotavirus G and P types was reviewed by analysing a total of 45571 strains collected globally from 124 studies reported from 52 countries on five continents published between 1989 and 2004. Four common G types (G1, G2, G3 and G4) in conjunction with P[8] or P[4] represented over 88% of the strains analysed worldwide. In addition, serotype G9 viruses associated with P[8] or P[6] were shown to have emerged as the fourth globally important G type with the relative frequency of 4.1%. When the global G and/or P type distributions were divided into five continents/subcontinents, several characteristic features emerged. For example, the P[8]G1 represented over 70% of rotavirus infections in North America, Europe and Australia, but only about 30% of the infections in South America and Asia, and 23% in Africa. In addition, in Africa (i) the relative frequency of G8 was as high as that of the globally common G3 or G4, (ii) P[6] represented almost one-third of all P types identified and (iii) 27% of the infections were associated with rotavirus strains bearing unusual combinations such as P[6]G8 or P[4]G8. Furthermore, in South America, uncommon G5 virus appeared to increase its epidemiological importance among children with diarrhea. Such findings have (i) confirmed the importance of continued active rotavirus strain surveillance in a variety of geographical settings and (ii) provided important considerations for the development and implementation of an effective rotavirus vaccine (e.g. a geographical P-G type adjustment in the formulation of next generation multivalent vaccines).

Rotavirus surveillance in the city of Rio de Janeiro-Brazil during 2000-2004: Detection of unusual strains with G8P[4] or G10P[9] specificities

Rotavirus diarrhea is a potentially life-threatening disease that affects millions of children annually around the world. Because protection against rotavirus disease is thought to be type specific, continuous rotavirus surveillance before and after implementation of a vaccine is still of essential importance. Rotavirus surveillance has been conducted in the city of Rio de Janeiro, Brazil since 1982. In the present study, we report rotavirus surveillance data in Rio de Janeiro city from 2000 to 2004. One hundred twenty nine of 1,568 (8.2%) stool samples, collected from children with acute diarrhea between January 2000 and July 2004 were rotavirus-positive. One hundred twenty eight of the 129 (99.2%) rotavirus-positive samples were genotyped for G and/or P specificity. G1 was the predominant strain (49.6%, 64/129) followed by G9 (30.2%, 39/129), and G4 (17.8%, 23/129); G2 and G3 viruses were not detected. One sample (0.8%) was non-typeable. P genotypes were determined for 124 of the 129 (96%) samples, and P[8] was the predominant genotype (90.6%, 117/129). Genotypes P[4] and P[9] were detected in two (1.6%) samples each; one (0.8%) sample presented P[6] genotype; and five (3.8%) samples were non-typeable. Two samples (1.6%) presented mixed P genotypes (P[6] + P[8]). Two unusual strains were isolated: a G8P[4] strain isolated from a non-hospitalized child with diarrhea and a G10P[9] strain isolated from a hospitalized child with diarrhea.

Human rotavirus strains bearing VP4 gene P[6] allele recovered from asymptomatic or symptomatic infections share similar, if not identical, VP4 neutralization specificities

A rotavirus VP4 gene P[6] allele has been documented in a number of countries to be characteristically associated with an endemic predominantly asymptomatic infection in neonates in maternity hospital nurseries. The mechanisms underlying the endemicity and asymptomatic nature of such neonatal infections remain unknown. Rotavirus strains sharing this same P genotype, however, have more recently been recovered from an increasing number of symptomatic diarrheal episodes in infants and young children in various parts of the world. Previously, we have shown that an asymptomatic P[6] rotavirus neonatal infection is not associated with a unique VP7 (G) serotype but may occur in conjunction with various G types. Although amino acid sequence comparisons of the VP4 gene between selected "asymptomatic" and "symptomatic" P[6] rotavirus strains have been reported and yielded information concerning their VP4 genotypes, serotypic comparisons of the outer capsid spike protein VP4 of such viruses have not been studied systematically by two-way cross-neutralizations. We determined the VP4 neutralization specificities of four asymptomatic and four symptomatic P[6] strains: two each of asymptomatic and symptomatic strains by two-way tests, and two each of additional asymptomatic and symptomatic strains by one-way tests. Both asymptomatic and symptomatic P[6] strains were shown to bear similar, if not identical, VP4 neutralization specificities. Thus, P[6] rotavirus strains causing asymptomatic or symptomatic infections did not appear to belong to unique P (VP4) serotypes. In addition, a close VP4 serotypic relationship between human P[6] rotavirus strains and the porcine P[6] rotavirus Gottfried strain was confirmed.

Surveillance of rotavirus strains in Rio de Janeiro, Brazil, from 1997 to 1999

One hundred fifty-seven (23%; n = 678) rotavirus-positive stool samples were collected between March 1997 and December 1999 in the cites of Rio de Janeiro and Niterói. Rotaviruses in 143 (91%) samples were genotyped by reverse transcription-PCR for G and/or P specificity. Rotaviruses in the majority of G-P-typeable samples (73.3%; 74 of 101) were identified as having globally common genotypes G1P[8], G2P[4], G3P[8], and G4P[8]. Unusual strains such as G1P[9], G2[P8], G3P[9], and G9P[4] strains were detected in 8.9% (9 of 101) of the samples. Genotypes G9P[8], G9P[6], and a mixture of G9 and other G or P types represented 15.9% (25 of 157) of the isolates. Mixed infections were detected in 25 (15.9%) samples, and rotaviruses in 15 samples (9.6%) were not typed.