Rotavirus serotype G5 associated with diarrhea in Brazilian children

Detection of a porcine-like rotavirus in a child with enteritis in Italy

During a 1-year rotavirus surveillance of children hospitalized with acute gastroenteritis in Brescia Hospital, Italy, a chimerical rotavirus strain, G3P[6], was detected, displaying the VP7 and VP4 genes of porcine origin and the NSP4 and VP6 genes of human origin. The reassortant nature of the virus rules out a direct zoonotic event.

New oligonucleotide primers for P-typing of rotavirus strains: Strategies for typing previously untypeable strains

BACKGROUND

The use of molecular methods for rotavirus characterisation provides increased sensitivity for typing, and allows the identification of putative reassortant strains. However, due to the constant accumulation of point mutations through genetic drift; and to the emergence of novel genotypes; and possibly zoonotic transmission and subsequent reassortment, the reagents and methods used for genotyping require close monitoring and updating.

OBJECTIVES

To design and evaluate a new VP4 consensus oligonucleotide primer pair that provides increased sensitivity and allows typing of strains that were untypeable using available methods.

STUDY DESIGN

A total of 489 rotavirus-positive faecal specimens from studies conducted between 1996 and 2006 were used for the evaluation of the new VP4 primers which was performed in the WHO Rotavirus Collaborating and Reference centres in the US, Australia, South Africa and the UK.

RESULTS

The new primer pair allowed P-typing of rotavirus strains and provided increased sensitivity, allowing typing of a significant number of strains that previously could not be P-typed.

CONCLUSIONS

This study highlights the importance of a constant reconsideration of primer sequences employed for the molecular typing of rotaviruses.

Changing profile of rotavirus in Ireland: predominance of P[8] and emergence of P[6] and P[9] in mixed infections

Six hundred and thirty three fecal specimens were collected from patients under 6 years, suffering from non-bacterial, putative viral gastroenteritis in the south of Ireland, between 2003 and 2006. Following laboratory identification of rotavirus as the aetiological agent in 558 specimens, reverse transcriptase polymerase chain reaction was employed to amplify the VP7 and VP4 gene segments of 249 and 245 samples, respectively. G and P typing was subsequently carried out on these amplicons. G1 (65.1%), and G3 (16.1%) were found to be the most prevalent circulating G types over the course of the study. Both G2 (1.2%) and G9 (3.6%), were also found to be circulating, however, these types were less frequently detected. Mixed G type infections were found to account for 41 samples (14%). P typing was carried out on 245 samples. P[8] was the most commonly detected P type over the course of the study (93.5%). Both P[6] and P[9], which had not previously been detected in the Irish population, were detected during this investigation. P[6] was detected in both single and mixed P type infections, while P[9] was detected as part of mixed infections only. The key findings of this study were the emergence of P[6] and P[9] as epidemiologically important rotavirus strains in the Irish population. The profile of rotavirus is changing continuously in Ireland, and continued surveillance of the circulating strains is needed to detect the appearance of new strains, or new variants which could escape immune protection induced by an outdated vaccine.

Emergence of G12 rotavirus strains in Delhi, India, in 2000 to 2007

The prospect that rotavirus diarrhea in children may soon be prevented by vaccines has placed a new priority on understanding the diversity of rotavirus strains and the mechanism by which these strains evolve over time. We have characterized a total of 465 rotavirus strains collected in North India from 2000 to 2007 for G and P types by reverse transcription-PCR and sequencing. The novel G12 rotavirus strains recently detected in other countries were first detected in India in 2001 and have emerged as the predominant strains in Delhi, India, during 2005 to 2007. While the VP7 sequence was highly homologous among G12 strains isolated in Delhi, suggesting recent emergence from a common ancestor, the strains had a diverse constellation of other gene segments, demonstrating substantial reassortment. For the entire period, the common rotavirus G types G1 (26%), G2 (25%), and G9 (14%) comprised 65% of the strains, and common P types, P[4] (19%), P[6] (22%), and P[8] (35%), comprised 76% of the total P types. Of note, we detected a high percentage of unusual (17%) strains and fecal specimens with mixed (12% G and 15% P) rotavirus infections having a variety of genomic constellations. For the first time, we identified two novel rotavirus strains with unusual G/P combinations, G2P[11] and G3P[11], in patients with diarrhea. The study highlights the great diversity among rotaviruses isolated from Indian children, the opportunity for genetic reassortment between strains, and the emergence of a novel G12 strain in our country. Due to the demonstrated effect of antigenic diversity on rotavirus vaccines, it will be important to continue careful monitoring of these strains as rotavirus vaccine programs are implemented in India.

Molecular epidemiology of rotavirus diarrhea among children in Saudi Arabia: first detection of G9 and G12 strains

In anticipation of rotavirus vaccine introduction in Saudi Arabia, this study was undertaken to determine the distribution of the G and P genotypes of rotaviruses in order to examine whether there was any emerging serotype or unusual strain circulating in children in Saudi Arabia. Of 984 stool specimens collected between 17 April 2004 and 16 April 2005, rotavirus was detected by an enzyme-linked immunosorbent assay in 187 (19%) diarrheal children less than 5 years of age. Of these, 160 (86%) were classified into G and P genotypes as follows: G1P[8] (44%), G2P[4] (20%), G9P[8] (11%), G12P[8] (4%), and G3P[8] (4%). RNA polyacrylamide gel electrophoresis identified 94 (50%) specimens as long RNA patterns, 30 (16%) specimens as short RNA patterns, and 1 mixed infection. Only a single long RNA electropherotype was identified for seven specimens containing G12P[8] rotavirus. RNA-RNA hybridization demonstrated that the G12P[8] strains were similar in their genomic constellation to locally cocirculating strains and to a Nepalese G12P[8] strain. The Saudi Arabian G12 VP7 gene had a 99% nucleotide sequence identity with Nepalese and Indian G12 VP7 genes and belonged to the third lineage. This study is the first to describe the distribution of rotavirus G and P types and also the first to identify G9P[8] and G12P[8] strains in the country.

Rotavirus G5P[6] in child with diarrhea, Vietnam

We detected rotavirus G5P[6] with a long RNA pattern in a Vietnamese child with diarrhea. Viral outer capsid protein VP7 and VP4 genes suggest that it likely originated from porcine rotavirus either by genetic reassortment or as whole virions. To our knowledge, this is the first report of human rotavirus G5 in Asia.

G and P rotavirus genotypes in stool samples from children in Teresina, State of Piauí

A total of 123 stool specimens collected in Teresina, Piauí between 1994 and 1996, from 0 to 2-year-old children with diarrhea, were used for this study. Molecular characterization of the G and P rotavirus genotypes was performed using the reverse transcriptase polymerase chain reaction. The following results were obtained for the P genotypes: P[8] (17. 1%), P[1] (4. 9%), P[4] (3. 3%), P[6, M37] (2. 4%) and mixtures (27. 6%). The P[1]+P[8] mixture was found in 19. 5% of the samples. For the G genotypes, the results were: G1 (25. 2%), G5 (13. 8%), G2 (2. 5%), G4 (2. 5%), G9 (0. 8%) and mixtures (41. 5%). G1+G5 was the mixture most frequently found (12. 1%). Our results showed unusual combinations such as P[1]G5 and P[1]+P[8]G5. The high percentage of mixtures and unusual combinations containing mixtures of human and animal rotavirus genotypes strongly suggests the possibility of gene reassortment and interspecies transmission.

Molecular epidemiology of rotavirus in Central and Southeastern Europe

A surveillance network was implemented by the Istituto Superiore di Sanità of Rome in collaboration with laboratories of virology in Czech Republic, Slovenia, Croatia, Albania, and Bulgaria. About 1,500 rotavirus-positive stool samples were collected from children with severe gastroenteritis admitted to hospitals or outpatient wards between 2004 and 2006. The G and P genotypes were determined by reverse transcription-nested PCR. Significant differences were found in the geographical distributions of rotavirus genotypes between countries participating in the study. The prevalence of "common" G/P combinations, G1P[8], G3P[8], G4P[8], and G2P[4], ranged between 50 and 85%. The G9 genotype, which is emerging worldwide, was identified in 2 to 35% of all samples depending on the country. Unusual combinations, such as G1 or G4 associated with P[4] or G2 with P[8], which may have arisen by reassortment between human strains, were found in samples from 3 to 20% of patients. The uncommon genotypes G8P[8] and G10P[6], which may have an animal origin, were also identified. Double infections with two rotavirus strains were observed in between 1.7 and 14% of cases studied. Our findings might implicate challenges for rotavirus vaccine implementation in a wide geographic area of the Balkans and Central-Eastern Europe and underscore the importance of extensive strain surveillance for success in vaccine development.

Human rotavirus G9 and G3 as major cause of diarrhea in hospitalized children, Spain

In Spain, diarrhea remains a major cause of illness among infants and young children. To determine the prevalence of rotavirus genotypes and temporal and geographic differences in strain distribution, a structured surveillance study of hospitalized children <5 years of age with diarrhea was initiated in different regions of Spain during 2005. Rotavirus was detected alone in samples from 362 (55.2%) samples and as a coinfection with other viruses in 41 samples (6.3%). Enteropathogenic bacterial agents were detected in 4.9% of samples; astrovirus and norovirus RNA was detected in 3.2% and 12.0% samples, respectively; and adenovirus antigen was detected in 1.8% samples. Including mixed infections, the most predominant G type was G9 (50.6%), followed by G3 (33.0%) and G1 (20.2%). Infection with multiple rotavirus strains was detected in >11.4% of the samples studied during 2005.

Novel human rotavirus of genotype G5P[6] identified in a stool specimen from a Chinese girl with diarrhea

During a rotavirus surveillance conducted in Lulong County, Hebei Province, China, a total of 331 stool specimens collected in 2003 from children under 5 years old with diarrhea were screened. We identified a novel group A human rotavirus of genotype G5P[6]. Phylogenetic analysis confirmed that the VP7 protein of this newly identified strain, LL36755, was closely related to those of the G5 strains. As such, it has 95.4% homology with its counterparts in the porcine G5 strains C134 and CC117 at the amino acid sequence level. On the other hand, the VP4 protein of the LL36755 strain was 94.5% homologous to those of the porcine P[6] strains 134/04-10, 134/04-11, 221/04-7, and 221/04-13. Our findings indicate a dynamic interaction between human and porcine rotaviruses.

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.

Brazilian P[8],G1, P[8],G5, P[8],G9, and P[4],G2 rotavirus strains: Nucleotide sequence and phylogenetic analysis

Rotavirus epidemiological surveys with molecular analysis of strains are required for gastroenteritis control and prevention. Twenty-nine human rotavirus strains detected in Rio de Janeiro, Brazil, from 1986 to 2004 were characterized as P[8],G1, P[8],G5, P[8],G9, and P[4],G2 genotypes. The VP7 genes were sequenced and phylogenetic analysis was performed. Strains of genotype G1 revealed two distinct lineages, G1-3 and G1-4; strains of genotype G2 grouped in lineage G2-1; G5 strains clustered with other Brazilians G5 strains and G9 strains were closely related to each other in lineage G9-3, distinct from the original G9 strains detected in 1980s. The VP4 genes were analyzed and P[8] strains fell into two major genetic lineages, P[8]-2 and P[8]-3. Our findings document an intragenotype diversity represented by lineages and sublineages within rotavirus circulating in Rio de Janeiro from 1986 to 2004, before application of a vaccine (Rotarix) in Brazil. This report emphasizes the importance of continuing monitor genotypes to verify if uncommon strains or newly strains are emerging to be specifically addressed in future vaccine trials.

Identification of group A porcine rotavirus strains bearing a novel VP4 (P) Genotype in Italian swine herds

The VP4 gene of a G5 Italian porcine rotavirus strain, 344/04-1, was nontypeable by PCR genotyping. The amino acid sequence of the full-length VP4 protein had low identity (<or=76.6%) with the homologous sequences of representative strains of the remaining P genotypes, providing evidence for a novel P genotype.

Shifts of rotavirus g and p types in Nicaragua--2001-2003

The present study reports the diversity of rotavirus strains circulating in León, Nicaragua during three years. There was a shift of G and P genotypes with increment of one specific genotype during the second most important peak of diarrhea occurring in the beginning of every year.

Molecular characterization of novel G5 bovine rotavirus strains

Group A rotaviruses are a major cause of acute gastroenteritis in young children as well as many domestic animals. The rotavirus genome is composed of 11 segments of double-stranded RNA and can undergo genetic reassortment during mixed infections, leading to progeny viruses with novel or atypical phenotypes. The aim of this study was to determine if the bovine group A rotavirus strains KJ44 and KJ75, isolated from clinically infected calves, share genetic features with viruses obtained from heterologous species. All 11 genes sequences of the KJ44 and KJ75 strains were sequenced and analyzed. The KJ44 VP4 had 91.7% to 96.3% deduced amino acid identity to the bovine related P[1] strain, whereas the KJ75 strain was most closely related to the bovine related P[5] strain (91.9% to 96.9% amino acid identity). Both KJ44 and KJ75 strains also contained the bovine related VP3 gene. The remaining 9 segments were closely related to porcine group A rotaviruses. The KJ44 and KJ75 strains showed high amino acid identity to the G5 rotaviruses, sharing 90.4% to 99.0% identity. In addition, these strains belonged to the NSP4 genotype B, which is typical of porcine rotaviruses and subgroup I, with the closest relationship to the porcine JL-94 strain. These results strongly suggest that bovine rotavirus strains with the G5 genotype occur in nature as a novel G genotype in cattle as a result of a natural reassortment between bovine and porcine strains.

Molecular epidemiology of group A rotavirus diarrhea among children in Buenos Aires, Argentina, from 1999 to 2003 and emergence of the infrequent genotype G12

To examine the epidemiology of rotaviruses in Buenos Aires, Argentina, we screened 1,212 stool samples from children with diarrhea in the southern district of Buenos Aires from 1999 to 2003. We identified 187 samples (15.4%) that were positive for group A rotavirus by use of antigen enzyme-linked immunosorbent assay. Among these specimens, 112 were available for typing: 93 (83.0%) were single-type infections, 9 (8.0%) were mixed-type infections with more than one G or P type, and 10 (8.9%) were G and/or P nontypeable. In contrast to the findings in our last study, from 1996 to 1998, genotype P[4], G2 strains were almost completely absent and P[8], G1 and P[8], G4 strains were dominant, representing more than 80% of the G and P types found. Genotypes G2 and G9 were detected in few samples, and type G3 was completely absent. We identified several uncommon genotype G12 strains, representing the first detections outside of Asia and the United States, by sequencing. Using a genotype G12-specific reverse transcription-PCR, we identified eight (6.7%) positive samples for the 1999 to 2003 period. The high degree of sequence identity between recent G12 isolates from Argentina, the United States, and Asian countries suggests a relatively recent introduction(s) of these strains into humans from a common progenitor. The Argentinean G12 strains belonged to genotype P[9], similar to most of the recently described Asian G12 strains. The finding of G12 strains in several other regions of the world raises the possibility that G12 may be emerging globally and suggests that surveillance for this strain should be conducted routinely.

Human rotavirus serotype G9, São Paulo, Brazil, 1996-2003

Diverse rotavirus strains are present, and frequency of G9 is high.

A total of 3,101 fecal specimens were collected during an 8-year survey for rotavirus infection in São Paulo, Brazil. Group A rotavirus was detected in 774 (25.0%) specimens. Of these, 431 strains (55.7%) were analyzed for G and P types by reverse transcription–polymerase chain reaction; G1 was the predominant serotype (68.2%), followed by G9 (17.2%), G4 (6.3%), G2 (1.2%), G3 (0.7%), mixed infection (1.8%), and untypeable (4.6%). Both rotavirus G and P types could be established in 332 strains (77.0%). We identified the 4 most common strains worldwide: P[8]G1 (66.6%), P[4]G2 (1.0%), P[8]G3 (0.6%), and P[8]G4 (7.2%). Among the single G9 strains detected, VP4 genotyping showed that P[8]G9 was the most prevalent, followed by P[4]G9 and P[6]G9. The emergence and high frequency of rotavirus G9 in São Paulo, Brazil, and other parts of the world will affect the development and evaluation of future vaccines.

Characterization of VP1, VP2 and VP3 Gene Segments of A Human Rotavirus Closely Related to Porcine Strains

Long RNA electropherotype rotavirus strains with subgroup I specificity predominated the infantile gastroenteritis outbreak in Manipur, India, in 1987-88. One such strain (RMC321) was found to possess porcine characteristics in 7 out of 8 genes sequenced. Partial characterization of its remaining VP1, VP2 and VP3 genes along with a porcine rotavirus strain (HP140) uncovered their close genetic relation to porcine strains. VP7 was the only gene segment of this strain with significant genetic identity to human strains. This indicates that a rotavirus reassortant strain with most of its genetic material derived from a porcine strain may cause symptomatic infection in a human host.

Full genomic analysis of human rotavirus strain B4106 and lapine rotavirus strain 30/96 provides evidence for interspecies transmission

The Belgian rotavirus strain B4106, isolated from a child with gastroenteritis, was previously found to have VP7 (G3), VP4 (P[14]), and NSP4 (A genotype) genes closely related to those of lapine rotaviruses, suggesting a possible lapine origin or natural reassortment of strain B4106. To investigate the origin of this unusual strain, the gene sequences encoding VP1, VP2, VP3, VP6, NSP1, NSP2, NSP3, and NSP5/6 were also determined. To allow comparison to a lapine strain, the 11 double-stranded RNA segments of a European G3P[14] rabbit rotavirus strain 30/96 were also determined. The complete genome similarity between strains B4106 and 30/96 was 93.4% at the nucleotide level and 96.9% at the amino acid level. All 11 genome segments of strain B4106 were closely related to those of lapine rotaviruses and clustered with the lapine strains in phylogenetic analyses. In addition, sequence analyses of the NSP5 gene of strain B4106 revealed that the altered electrophoretic mobility of NSP5, resulting in a super-short pattern, was due to a gene rearrangement (head-to-tail partial duplication, combined with two short insertions and a deletion). Altogether, these findings confirm that a rotavirus strain with an entirely lapine genome complement was able to infect and cause severe disease in a human child.

Identification of a novel VP4 genotype carried by a serotype G5 porcine rotavirus strain

Rotavirus genome segment 4, encoding the spike outer capsid VP4 protein, of a porcine rotavirus (PoRV) strain, 134/04-15, identified in Italy was sequenced, and the predicted amino acid (aa) sequence was compared to those of all known VP4 (P) genotypes. The aa sequence of the full-length VP4 protein of the PoRV strain 134/04-15 showed aa identity values ranging from 59.7% (bovine strain KK3, P8[11]) to 86.09% (porcine strain A46, P[13]) with those of the remaining 25 P genotypes. Moreover, aa sequence analysis of the corresponding VP8* trypsin cleavage fragment revealed that the PoRV strain 134/04-15 shared low identity, ranging from 37.52% (bovine strain 993/83, P[17]) to 73.6% (porcine strain MDR-13, P[13]), with those of the remaining 25 P genotypes. Phylogenetic relationships showed that the VP4 of the PoRV strain 134/04-15 shares a common evolutionary origin with porcine P[13] and lapine P[22] rotavirus strains. Additional sequence analyses of the VP7, VP6, and NSP4 genes of the PoRV strain 134/04-15 revealed the highest VP7 aa identity (95.9%) to G5 porcine strains, a porcine-like VP6 within VP6 genogroup I, and a Wa-like (genotype B) NSP4, respectively. Altogether, these results indicate that the PoRV strain 134/04-15 should be considered as prototype of a new VP4 genotype, P[26], and provide further evidence for the vast genetic and antigenic diversity of group A rotaviruses.

Isolation and molecular characterization of a naturally occurring non-structural protein 5 (NSP5) gene reassortant of group A rotavirus of serotype G2P[4] with a long RNA pattern

We report here two unusual strains of group A rotavirus, AU85 and AU102, isolated from children with diarrhea. These strains showed an unusual combination of serotype G2 and a long RNA pattern. RNA-RNA hybridization assays showed that these strains are reassortants in which a single genome segment 11 (the NSP5 gene) was derived from a Wa genogroup strain, while other 10 genome segments from a DS-1 genogroup strain. Phylogenetic analysis showed that the NSP5 gene of strain AU85 did not form cluster with Wa strain, while it belonged to the cluster of YM and other porcine strains. Phylogenetic analysis also showed that NSP5 and VP7 genes of AU85 were derived from the rotavirus circulating in the area. Both co-electrophoresis and RNA-RNA hybridization showed that AU85 and AU102 are identical strains. Moreover, the nucleotide sequence comparison between these two strains revealed that they had 100% identical NSP4, NSP5, and VP7 genes. These results suggest that AU85 was a reassortant formed relatively recently between rotaviruses belonging to the Wa and the DS-1 genogroup.

Serotype diversity and reassortment between human and animal rotavirus strains: implications for rotavirus vaccine programs

The development of rotavirus vaccines that are based on heterotypic or serotype-specific immunity has prompted many countries to establish programs to assess the disease burden associated with rotavirus infection and the distribution of rotavirus strains. Strain surveillance helps to determine whether the most prevalent local strains are likely to be covered by the serotype antigens found in current vaccines. After introduction of a vaccine, this surveillance could detect which strains might not be covered by the vaccine. Almost 2 decades ago, studies demonstrated that 4 globally common rotavirus serotypes (G1-G4) represent >90% of the rotavirus strains in circulation. Subsequently, these 4 serotypes were used in the development of reassortant vaccines predicated on serotype-specific immunity. More recently, the application of reverse-transcription polymerase chain reaction genotyping, nucleotide sequencing, and antigenic characterization methods has confirmed the importance of the 4 globally common types, but a much greater strain diversity has also been identified (we now recognize strains with at least 42 P-G combinations). These studies also identified globally (G9) or regionally (G5, G8, and P2A[6]) common serotype antigens not covered by the reassortant vaccines that have undergone efficacy trials. The enormous diversity and capacity of human rotaviruses for change suggest that rotavirus vaccines must provide good heterotypic protection to be optimally effective.

Sequence analysis of the VP7 and VP4 genes identifies a novel VP7 gene allele of porcine rotaviruses, sharing a common evolutionary origin with human G2 rotaviruses

During an epidemiological survey encompassing several porcine herds in Saragoza, Spain, the VP7 and VP4 of a rotavirus-positive sample, 34461-4, could not be predicted by using multiple sets of G- and P-type-specific primers. Sequence analysis of the VP7 gene revealed a low amino acid (aa) identity with those of well-established G serotypes, ranging between 58.33% and 88.88%, with the highest identity being to human G2 rotaviruses. Analysis of the VP4 gene revealed a P[23] VP4 specificity, as its VP8* aa sequence was 95.9% identical to that of the P14[23],G5 porcine strain A34, while analysis of the VP6 indicated a genogroup I, that is predictive of subgroup I specificity. Analysis of the 10th and 11th RNA segments revealed close identity to strains of porcine and human origin, respectively. The relatively low overall aa sequence conservation (<89% aa) to G2 human rotaviruses, the lack of N-glycosylation sites that are usually highly conserved in G2 rotaviruses, and the presence of several amino acid substitutions in the major antigenic hypervariable regions hampered an unambiguous classification of the porcine strain 34461-4 as G2 serotype on the basis of sequence analysis alone. The identification of a borderline, G2-like, VP7 gene allele in pigs, while reinforcing the hypotheses of a tight relationship in the evolution of human and animal rotaviruses, provides additional evidence for the wide genetic/antigenic diversity of group A rotaviruses.

Phylogenetic analyses of human rotavirus in central Taiwan in 1996, 2001 and 2002

BACKGROUND

Rotavirus epidemiology information is required for gastroenteritis disease control and prevention. Information gathered about the serotype distribution of rotaviruses isolated in Taiwan is of crucial significance, before a licensed rotavirus vaccine is introduced.

OBJECTIVES

The purpose of the present study is to investigate the epidemiological diversity of rotaviruses in Taiwan.

STUDY DESIGN

A total of 51 stool samples taken from cases of acute gastroenteritis were collected from three teaching hospitals in central Taiwan in 1996, 2001 and 2002. The samples were subjected to RT-PCR tests of VP7 gene of the human rotavirus group A, B, C.

RESULTS

A total of 16 stool samples were detected positive by RT-PCR and 10 were sequence analyzed and classified into G1, G3, and G9 types. Compared with other HRV strains: the sequences of CS96-40 of G1 are similar to MVD9816 (identity rate 97.15% and 96.09%, respectively, from Uruguay); the sequences of CS02-01 of G3 are similar to 98-B31 (identity rate 98.93% and 98.72%, respectively, from Japan); the sequences of CS01-05, CS01-06, CS01-07, CS01-09, CS01-13, CS02-02, CS02-03, CS02-04 are very similar to other established G9 rotaviruses sequences (identity rate 96.85-99.88%), especially between CS02-04 and SP2737 (from Japan) with an identity rate of 99.88% and 100% nucleotide and amino acid, respectively. Except for CS01-06 strain, it is VR3, but not VR5, VR7 or VR8, that found to be the most frequent mutated amino acid regions of VP7 in these strains.

CONCLUSIONS

Our findings are the first to document the high prevalence of G9 HRV strains in Taiwan, and suggest the re-emergence of G3 strains in central Taiwan since 1991. Epidemiological surveys carried out in this study suggest genotype shifts from type G1 before 1996, to G9 in 2001 and 2002 and the re-emergence of G3 type in 2002.

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 genotyping: keeping up with an evolving population of human rotaviruses

The use of molecular methods for rotavirus characterisation provides not only increased sensitivity for typing, but also allows accurate and more complete characterisation of strains, and the identification of putative reassortant strains. However, due to the constant accumulation of point mutations through genetic drift, and to the emergence of novel genotypes, possibly zoonotic transmission and subsequent reassortment, the reagents and methods used require close monitoring and updating. Methods and oligonucleotide primers are described to overcome failures to type G9, G10 and P[11] rotavirus strains, and cross-reactivity identified between G10 and G3 rotaviruses.

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.

Dominating prevalence of P[8],G1 and P[8],G9 rotavirus strains among children admitted to hospital between 2000 and 2003 in Budapest, Hungary

Group A rotaviruses are the main cause of acute dehydrating diarrhea in children, responsible for high mortality in developing countries and a significant socio-economic burden associated with treating the disease in developed countries. Two rotavirus vaccine candidates predicated on either homotypic or heterotypic protection have undergone clinical trials recently and await licensure for routine use. In anticipation of a future vaccination campaign in Hungary, the diversity of rotaviruses collected from Budapest between 2000 and 2003 were analyzed by polyacrylamide gel electrophoresis (PAGE) of the viral genome and by serotyping and genotyping of the outer capsid genes, VP7 and VP4. Among 2,763 rotavirus positive specimens available for analysis, we were able to determine the electropherotype of 2,227, and, of these, 1,517 (68.1%) were subjected to G typing and 1,173 (52.7%) were subjected to P typing. We successfully G typed 1,481 (97.6%) and P typed 1,130 (96.3%) strains, respectively. A total of six G types (G1, 50.2%; G2, 2.2%; G3, 1.7%; G4, 5.8%; G6, 0.6%; and G9, 34.4%) and four P types (P[4], 3.0%; P[6], 0.7%; P[8], 89.9%; and P[9], 1.7%) were identified in nine individual combinations (P[8],G1; P[4],G2; P[8],G3; P[8],G4; P[8],G9; P[6],G4; P[4],G1; P[9],G3; and P[9],G6). The prevalence of VP7 and VP4 specificities varied from year to year. In this regard, a shift in serotype predominance from G1 in 2000-2001 (61.8%) and 2001-2002 (69.7%) to G9 in 2002-2003 (51.3%) was an intriguing observation that has been reported recently in some other countries, as well. The emergence of serotype G9 rotaviruses in Hungary and other parts of the world may have implications for future vaccine development and use, particularly, if current vaccine candidates cannot confer adequate homotypic or heterotypic protection against these strains.

Molecular characterization and genetic variation of theVP7 gene of human rotaviruses isolated in Paraguay

Rotavirus is the main cause of acute diarrhea in infants and young children worldwide. In Paraguay, acute diarrhea ranks fourth among the causes of mortality in children under 4 years of age. Rotavirus was detected in 93 out of 410 patients admitted to three main hospitals in Asunción, Paraguay from August 1998 to August 2000. Samples from 64 patients were analyzed by RT-PCR for G and P typing. G4P[8] (46.9%; 30/64) was the most common strain detected, followed by G9P[8] (17.2%; 11/64) and G1P[8] (10,9%; 7/64). Since G4 was predominant during the epidemiological peaks of 1998 and 1999, four samples were sequenced and all grouped into sublineage Ic. This sublineage was reported for the first time in 1998 in Argentina, southern border of Paraguay, and it was shown to be responsible for the increased prevalence of G4 during the epidemiological season of 1998 in that country. In addition, Paraguayan G1 strains grouped in different lineages (I and II). However, G9 was predominant during the rotavirus epidemiological peak of 2000, and phylogenetic analysis of five samples grouped into a common emergent/reemergent lineage that circulates worldwide. Since vaccination could reduce the severity and the number of cases of rotavirus disease, this study suggests that a vaccine containing recently isolated variants of the most prevalent types (G1-G4) together with the emerging G9 type, might be sufficient to elicit a protective immune response against the rotavirus types circulating currently in Paraguay.

Culture adaptation of serotype G6 human rotavirus strains from hospitalized diarrhea patients in India

During serotyping of fecal specimens positive for rotavirus from hospitalized diarrhea patients in Pune, India, about 10% showed multireactivity in enzyme immunoassay with monoclonal antibodies specific for serotypes G1-4, 6, 8, and 10. In order to characterize some of these, three fecal specimens from children and one from adult were culture adapted. All the isolates showed long RNA pattern, but three out of four isolates belonged to subgroup I and II and one, to subgroup I. The isolates were confirmed as G6 by neutralization assay and polymerase chain reaction. Nucleotide sequences of cDNA derived from the gene encoding the outer capsid protein, VP7 of two strains indicated >94% identity with G6, the serotype, generally associated with cattle. The isolates were more close to G6 RF strain, which is a bovine rotavirus, reported from France. This is a first report of isolation of bovine serotype, G6 from children as well as adults from India.

Rotavirus strain surveillance in Latin America: a review of the last nine years

BACKGROUND

Latin America will likely be the first area in the developing world where rotavirus vaccine will be introduced into the routine childhood immunization schedule. In anticipation of that goal, we reviewed the distribution of group A rotavirus genotypes in Latin America to understand the diversity of strains to be targeted by vaccines and to identify novel strains that may pose challenges for vaccines.

METHODS

We reviewed studies characterizing rotavirus strains in Latin America (published in English since 1995) that used molecular methods to type genes encoding the G and P outer capsid proteins, VP7 and VP4, and that reported data on >50 specimens.

RESULTS

Fifteen studies from 5 countries met our criteria. In total, 1989 samples were characterized; 12% (233) were mixed rotavirus infections with more than 1 strain, and 20% (402) were not fully typable. Of the remaining 1354 samples that were fully typed, 83% represented the 4 common strains: P[8],G1 (40%); P[4],G2 (30%); P[8],G3 (6%); P[8],G4 (7%). The unusual strains provide interesting insights into virus evolution: some strains (G5) were regionally common; the emerging G9 strains were widely distributed; many animal-human reassortants were present; and some common serotypes (G3 and G4) were of animal origin. Also an unusual G12 serotype was recently detected in Argentina.

CONCLUSIONS

The common rotavirus serotypes should remain the prime targets for vaccine development. However, the changing profile of rare strains, animal-human reassortants and nontypable strains suggest that rotavirus is constantly evolving. Laboratory surveillance is needed to monitor rotavirus strains now in circulation and to detect those that might escape the immunity induced by vaccines or represent vaccine strains entering the environment.

Epidemiology of rotavirus diarrhoea in Iranian children

Human rotavirus is the most important cause of severe diarrhoea in infants and young children worldwide. We describe the aetiology of viral diarrhoea and the characteristics of rotavirus infection in Shahrekord, Iran. Two hundred and fifty nine children <5 years old admitted to Hajar Hospital, 245 children with acute diarrhoea attending primary health centres in Shahrekord, and 114 children hospitalised for elective surgery were selected from October 2001 to August 2002. Stool samples were screened for enteric viruses using EM. Rotaviruses were characterised using ELISA, reverse transcription‐polymerase chain reaction (RT‐PCR), and electropherotyping. One hundred and eighty six viruses were identified, of which 146 (78%) were rotavirus. The second most frequent virus was coronavirus, followed by calicivirus. Rotaviruses exhibited a marked seasonal variation, being most frequently isolated from November to February (50% of rotavirus recovered) and affected mostly children <2 years old. The RT‐PCR successfully typed 139 of the 146 (95%) rotavirus G types and 124 (85%) P types. The most frequent P type was, P[8] in 108 (74%), P[4] in 16 (11%), and was P non‐typeable in 22 (15%). Among the G types, G1 was identified in 120 (82%), G2 in 19 (13%), and was G‐non‐typeable in 7 (5%). Our results are the first report of rotavirus genotypes affecting Iranian children. The most frequent G and P types (G1, G2, P[8], and P[4]) are similar to those reported from around the world and will be covered by existing rotavirus vaccines targeting G types G1–G4. J. Med. Virol. 73:309–312, 2004. © 2004 Wiley‐Liss, Inc.

Diversity of group A human rotavirus types circulating over a 4-year period in Madrid, Spain

The incidence and distribution of human rotavirus G types among children under 5 years old with acute gastroenteritis were determined over a 4-year period (1998 to 2002) by using monoclonal antibodies and reverse transcription-PCR methods. Rotavirus was detected in 1,155 (31%) of 3,760 specimens tested. Rotavirus was studied in every month of the 48-month survey period. Rotavirus activity occurred mainly (51%) in the typically cooler months in Spain (November to February). The age distribution of rotavirus-positive cases showed that 90% of patients (1,038 of 1,155) were under 2 years old. Rotavirus types were determined for 576 of 1,155 patients (50%). G1 was the main genotype detected (53%), and the second most common was G4 (24%). The G2, G9, and G3 rotavirus types were detected in 14, 6, and 2% of the cases, respectively. Dual infections were detected in only 0.6%. The seasonal distribution of genotypes showed a significant genotypic shift: whereas G4 strains predominated (57%) during the 1998 to 2000 seasons, the G1 gradually increased to account for 75% in the 2000 to 2002 seasons. In addition, the present study reports the first detection of the G9 genotype in human fecal samples in Spain. Therefore, additional types may be required for vaccine development strategies that currently target only types G1 to G4.

Chromatography paper strip method for collection, transportation, and storage of rotavirus RNA in stool samples

We developed a novel method that uses sodium dodecyl sulfate-EDTA-treated chromatography paper strips to collect unconcentrated fresh stool samples. After the paper strips were stored for 4 months at room temperature, rotavirus RNA could be successfully amplified by using reverse transcriptase PCR. The use of filter paper strips as a specimen support allows (self-)collection of stool samples by untrained persons. Diarrheal stool samples from remote areas can be stored and transported to a central diagnostic laboratory without the need for freezers or special shipping conditions. This convenient and inexpensive rotavirus sample collection system can be of use in epidemiological surveillance studies and vaccine trials.

Characterization of rotavirus strains from hospitalized and outpatient children with acute diarrhoea in São Paulo, Brazil

From August 1994 to July 1995, 234 faecal samples from children with or without acute diarrhoea were collected and tested. The group of children with acute diarrhoea (A) was subdivided into two subgroups: subgroup A(1) was made up of children with severe diarrhoea, dehydrated and who needed hospitalization and subgroup A(2) was composed of children who only needed outpatient care. Group B was composed of children without acute diarrhoea (controls). Rotavirus was detected in 36.7% (18/49), 22.0% (15/68) and 1.7% (2/117) patients in groups A(1), A(2) and B, respectively. Of the 35 positive samples in which rotaviruses were detected the VP7 genotypes G1, G2, G3, G5 and the mixture (G2 + G5) were found in 40.0, 11.4, 11.4, 22.9 and 2.9% of the samples, respectively. Also, the VP4 genotypes P[8], P[4] and P[6] were detected in 57.1, 31.4 and 5.7%, respectively. Rotavirus VP6 subgroups I and II were detected at a frequency of 22.4 and 54.3%, respectively. Rotavirus RNA segments had short and long electrophoresis profiles in 20.0 and 51.4% of the cases, respectively. The severity of the disease was not related to a specific G and P types, subgroup or electropherotype.

Rotavirus typing methods and algorithms

Vaccination is the current strategy for control and prevention of severe rotavirus infections, a major cause of acute, dehydrating diarrhoea in young children worldwide. Public health interventions aimed at improving water, food and sanitation are unlikely adequately to control the disease. The development of vaccines against severe rotavirus diarrhoea is based upon homotypic or heterotypic protection provided against either a single common G serotype (monovalent vaccines) or against multiple serotypes (multivalent vaccines). Rotavirus strain surveillance has a high priority in disease control programmes worldwide. The continued identification of the most common G and P serotypes for inclusion in vaccines is an important priority. And subsequent to the introduction of a vaccine candidate, not only monitoring of circulating strains is recommended, but also surveillance of potential reassortment of animal rotavirus genes from the vaccine into human rotavirus strains is critical. Conventional methods used in the characterisation of rotavirus strains, such as enzyme immunoassay serotyping and reverse‐transcription PCR‐based genotyping often fail to identify uncommon and newly appearing strains. The application of newer molecular approaches, including sequencing and oligonucleotide microarray hybridisation, may be required to characterise such strains. The present paper presents a brief overview of the variety of standard methods available, followed by suggestions for a systematic approach for routine rotavirus strain surveillance as well as for characterisation of incompletely typed rotavirus strains. Improved detection and characterisation of incompletely typed strains will help to develop a comprehensive strain surveillance that may be required for tailoring effective rotavirus vaccines. Published in 2004 by John Wiley & Sons, Ltd.

Prevalence of neutralizing antibodies against different rotavirus serotypes in children with severe rotavirus-induced diarrhea and their mothers

Neutralizing antibody (NAb) responses to different rotavirus serotypes were compared in 64 convalescent-phase serum samples from hospitalized rotavirus-positive children less than 2 years of age and their mothers. Compared to the child patients, the mothers showed significantly higher NAb positivity to animal rotavirus serotypes G3 simian (96.88%), G6 bovine (85.94%), and G10 bovine (25.0%) and to human rotavirus serotypes G8 (79.69%) and G3 (57.81%) (P < 0.01 for each) but not to human serotypes G1, G2, G4, and G9 (P > 0.05). The overall prevalence of NAb among the child patients was low for human rotavirus serotypes G1 (20.31%) and G3 (21.8%). The comparative NAb response in individual mother-child paired serum samples was analyzed against each rotavirus serotype. A substantial number of child patients showed higher NAb titers than their mothers to serotypes G1, G2, G4, and G9, indicating that these serotypes are the major serotypes causing rotavirus diarrhea among the children of Pune, India. In these cases, the mothers were either negative or had lower titers of NAbs than their children. Correlation was observed between the infecting serotype and child patient serum that showed a homologous NAb response at a higher level than that of the mother. It appears that when the level of NAb to a particular serotype is higher among child patients than among their mothers, that serotype is the infecting serotype, and that low titers of NAb among the mothers predispose the children to infection with that serotype, if the serotype is in circulation.

Detection of an unusual human rotavirus strain with G5P[8] specificity in a Cameroonian child with diarrhea

Rotavirus strains detected as part of ongoing strain surveillance in Cameroon, and whose first-round reverse transcription-PCR product could not be genotyped by using conventional genotyping primers, were subjected to sequence analysis for strain characterization. We detected for the first time in Africa a human rotavirus with G5 specificity. The Cameroonian G5 strain had a short electrophoretic pattern and was of VP6 subgroup I specificity and a VP4 P[8] type. The VP7 gene shared a higher nucleic acid and amino acid homology with the porcine G5 strain CC117 (90 and 96%, respectively) than with human G5 strain IAL-28 (86 and 92%, respectively). Phylogenetic analysis showed Cameroonian strain MRC3105 clustered together in the same lineage as two other reported porcine G5 strains. The Cameroonian G5 strain, the first to be reported in humans outside of Latin America, may be a natural reassortant between animal and human rotavirus strains.

Nucleotide variation in the VP7 gene affects PCR genotyping of G9 rotaviruses identified in Italy

A modified (aFT9m) and a degenerate (aFT9d) version of the rotavirus G9-specific primer (aFT9) allowed strains that were previously untypable, because of point mutations accumulating at the primer binding site, to be G typed by reverse transcription-polymerase chain reaction. The strains were collected during 2001-2002 in Italy in hospitals of the Apulia region, from children affected by severe rotavirus-associated enteritis. Using a wide selection of G9 rotaviruses detected worldwide, sequencing of the G9 untypable strains, sequence comparison, and phylogenetic analysis showed that the Italian strains have strong genetic similarity (< or =99.4%) to G9 rotaviruses identified recently in many parts of the world and different from the old G9 strains identified during the 1980s (less than 90%). Genetic variation of G9 rotaviruses explains the constraints encountered in the typing assays and presumably accounts, together with genetic reassortment events, for the emergence on a global scale of the G9 serotype.

Genetic variability among serotype G6 human rotaviruses: identification of a novel lineage isolated in Hungary

Rotavirus serotype G6 has been demonstrated to be a rare cause of gastroenteritis in man. To date, only a few well characterized strains have been described from Italy, Australia, and the United States. Nucleotide sequencing of G6 VP7 genes shows that these strains belong to two distinct G6 lineages, one for strains of serotype P11[14],G6 (PA169-like strains) and one for strains of serotype P3[9],G6 (PA151-like strains). In this study, we sequenced the VP7 genes and VP8* gene fragments of human rotavirus G6 strains detected in Hungary. Phylogenetic analysis demonstrated that the VP7 genes of Hungarian G6 strains fell into three lineages, represented by a single PA169-like strain, three PA151-like strains, and two novel G6 strains, respectively. The amino acid sequence identity of VP7 was 97.2-100% within each lineage and 92-93.9% between any two lineages. The sequence analysis of VP8* revealed that the single PA169-like Hungarian G6 strain belonged to genotype P[14] and was phylogenetically closely related to P11[14],G6 strains characterized previously. In contrast, the VP8* of PA151-like Hungarian G6 strains clustered in accordance with their VP7 genes representing genetically distinguishable variants of genotype P[9]. This finding raises the possibility that Hungarian genotype P[9],G6 strains might have been generated through independent reassortment events. Serotype G6-specific primers for each human G6 lineage were also developed. The use of these primers in reverse-transcription polymerase chain reaction genotyping may help determine the epidemiological role of G6 strains in humans.

Genetic analysis of Group A rotaviruses: evidence for interspecies transmission of rotavirus genes

Rotaviruses are the major cause of severe gastroenteritis in young children and animals. The rotavirus genome is composed of eleven segments of double-stranded RNA and can undergo genetic reassortment during mixed infections, leading to progeny viruses with novel or atypical phenotypes. There are numerous descriptions of rotavirus strains isolated from human and animals that share genetic and antigenic features of viruses from heterologous species. In many cases, genetic analysis by hybridization has clearly demonstrated the genetic relatedness of gene segments to those from viruses isolated from different species. Together with the observation that some virus strains appear to have been transmitted to a different species as a whole genome constellation, these data suggest that interspecies transmission occurs naturally, albeit at low frequencies. Although interspecies transmission has not been documented directly, there is an increasing number of reports of atypical rotaviruses that are apparently derived from transmission between: humans, cats and dogs; humans and cattle; humans and pigs; pigs and cattle; and pigs and horses. Interspecies evolutionary relationships are supported by phylogenetic analysis of rotavirus genes from different species. The emergence of novel strains derived from interspecies transmission has implications for the design and implementation of successful human rotavirus vaccine strategies.

Group A rotavirus in sewage samples from Barcelona and Cairo: emergence of unusual genotypes

The presence of rotavirus strains in sewage samples from Cairo, Egypt (November 1998 to October 1999), and Barcelona, Spain (November 1998 to December 2002), was investigated by using a generic molecular detection method based on amplification of a VP6 gene fragment. Overall, 85.7 and 66.9% of the sewage samples from Cairo and Barcelona, respectively, were positive. Positive samples were characterized further, and VP7 and VP4 genotypes were determined. Although 30% of the positive samples from Cairo were G untypeable, the distribution of G types in the positive samples was 69.6% G1, 13% G3, 8.7% G4, and 8.7% G9. The percentage of untypeable samples was much higher for the Barcelona samples (56.5%), and the distribution in the positive samples was 56.4% G1, 31.5% G3, 6% G9, 4% G2, and 2% G5. When the P types were examined, 26.7% of the positive samples from Cairo were untypeable, and the distribution of types in the positive samples was 53.3% P[8], 30% P[6], and 16.6% P[4]. In Barcelona, 27.2% of the samples were P untypeable, and the frequencies of the types detected were 49.7% P[8], 37.2% P[4], 8.8% P[6], and 4.2% P[9]. The distribution for strains from Cairo was 38.5% P[8]G1, 27% P[6]G1, 11.5% P[4]G1, 11.5% P[8]G3, 7.7% P[6]G4, and 3.8% P[8]G9. Strikingly, equivalent frequencies of common and uncommon strains were observed for Barcelona samples, and the distribution was 38.8% P[8]G1, 30.6% P[4]G1, 11.6% P[8]G3, 6.6% P[4]G3, 5.8% P[6]G1, 1.6% P[6]G3, 1.6% P[9]G1, 0.8% P[4]G2, 0.8% P[6]G9, 0.8% P[8]G9, and 0.8% P[8]G5. Additionally, two P[-]G5 strains were isolated in Barcelona, and the porcine or human origin of these strains was unclear. Rotavirus variability exhibited not only a geographic pattern but also a temporal pattern.

Rotavirus diarrhea severity is related to the VP4 type in Mexican children

This report is of a community-based case control study to assess whether the severity of acute diarrhea by rotavirus (RV) in young children is associated with a particular VP7 (G) or VP4 (P) RV serotype. Five hundred twenty children younger than 2 years of age with diarrhea lasting less than 3 days were age and gender matched with 520 children with no diarrhea. The G and P serotypes were determined with specific monoclonal antibodies, and the VP4 serotype specificity in a subgroup was confirmed by genotyping. Infection with a G3 serotype led to a higher risk of diarrhea than infection with a G1 serotype. Infection with a G3-nontypeable-P serotype was associated with more severe gastroenteritis than infection with a G3 (or G1) P1A[8] serotype. A child with diarrhea-associated dehydration was almost five times more likely to be infected with a G3-nontypeable-P serotype than a child without dehydration (P < 0.001). Moreover, the two predominant monotypes within serotype P1A[8] had significantly different clinical manifestations. In this study, the severity of RV-associated diarrhea was related to different P serotypes rather than to G serotypes. The relationship between serotype and clinical outcomes seems to be complex and to vary among different geographic areas.