VP4 and VP7 genotyping of rotavirus samples recovered from infected children in Ireland over a 3-year period

Group A Rotavirus Detection and Genotype Distribution before and after Introduction of a National Immunisation Programme in Ireland: 2015-2019

Immunisation against rotavirus infection was introduced into Ireland in December 2016. We report on the viruses causing gastroenteritis before (2015–2016) and after (2017–2019) implementation of the Rotarix vaccine, as well as changes in the diversity of circulating rotavirus genotypes. Samples from patients aged ≤ 5 years (n = 11,800) were received at the National Virus Reference Laboratory, Dublin, and tested by real-time RT-PCR for rotavirus, Rotarix, norovirus, sapovirus, astrovirus, and enteric adenovirus. Rotavirus genotyping was performed either by multiplex or hemi-nested RT-PCR, and a subset was characterised by sequence analysis. Rotavirus detection decreased by 91% in children aged 0–12 months between 2015/16 and 2018/19. Rotarix was detected in 10% of those eligible for the vaccine and was not found in those aged >7 months. Rotavirus typically peaks in March–May, but following vaccination, the seasonality became less defined. In 2015–16, G1P[8] was the most common genotype circulating; however, in 2019 G2P[4] was detected more often. Following the introduction of Rotarix, a reduction in numbers of rotavirus infections occurred, coinciding with an increase in genotype diversity, along with the first recorded detection of an equine-like G3 strain in Ireland.

Sequence analysis of human rotavirus strains: comparison of clinical isolates from Northern and Southern Italy

The surveillance and monitoring of rotavirus (RV)-related diseases, preferably through the establishment of sentinel surveillance sites, are essential for assessing the need for vaccination and the projected results of the vaccine in terms of reducing the burden of disease. The objective of the present study was to compare RV strains isolated in Northern (Ferrara) and Southern (Galatina-LE) Italy. During 2007-2008, 115 RV-positive stool samples were collected from children with diarrhea admitted to the hospitals of Ferrara and Galatina. The specimens were genotyped for VP7 (G-type) and VP4 (P-type) gene by reverse transcription (RT) and multiplex polymerase chain reaction (PCR). A subset of 21 RV strains was randomly selected and characterized by sequence analysis of the VP7 genes. In total, seven G/P combinations (G1P[8], G2P[4], G4P[8], G9P[8], G2P[8], G1P[9], and G2P[10]) were identified. Phylogenetic comparison of the VP7 encoding gene of selected strains showed that there was similarity among RV strains circulating in Northern and Southern Italy. The observation of nucleotide sequence diversity contributes to a better understanding of RV spreading and helps to characterize the various antigenic shifts that could have an impact on vaccine effectiveness.

Incidence of rotavirus infection in children with gastroenteritis attending Jos university teaching hospital, Nigeria

This study was conducted to determine the incidence of rotavirus infection in children with gastroenteritis attending Jos university teaching hospital, Plateau State. A total of 160 children with acute diarrhea were selected by random sampling. Stool samples were obtained and assayed for rotavirus antigens by enzyme linked immunosorbent assay technique using standard diagnostic BIOLINE Rotavirus kit. Demographic data of parents were also recorded. Rotavirus were detected in faeces of 22(13.8%) children with acute diarrhea, 90.9% of positive cases of rotavirus gastroenteritis were under 2 years of age with highest prevalence in children 7-12 months of age. Males excreted rotavirus at a significant higher rate than females (P < 0.05). Rotavirus excretion was highest when all three symptoms (diarrhea, fever and vomiting) occurred in the same child (7.5%) and lower when 2 symptoms occurred together (diarrhea and vomiting) with 3.8%, diarrhea and fever with 1.3% and lowest when diarrhea occurred alone with 1.3%. Playing with toys, attending day care, distance of source of water from toilet, eating of food not requiring cooking and playing with other children may serve as predisposing factors of rotavirus disease in these children.

[Evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007)]

BACKGROUND

Rotaviruses are the most frequent agents associated with diarrhoea in children worldwide. Analysis of mobility of the 11 segments of genomic RNA by polyacrylamide gel electrophoresis (PAGE) yields a pattern which is characteristic for a particular rotavirus isolate. The group A rotaviruses can be further characterized by analysis of VP7 and VP4 genes specificities, responsible for rotavirus classification into G and P genotypes, respectively. The aim of the present study was to determine the evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007).

MATERIAL AND METHODS

A total of 1503 stool samples collected from children less than five years old, consulting or hospitalised in Tunisia for diarrhoea between 2005 and 2007, were screened for the presence of group A Rotaviruses. Rotavirus-positive specimens were further analyzed by PAGE and G/P-genotyped by multiplex semi-nested RT-PCR.

RESULTS

Rotaviruses were detected in 323 stool samples over 1503 (21 %). Long electropherotypes predominated in Tunisia during the whole period of study (N=158 vs N=82 short electropherotypes). VP7 genotyping showed the cocirculation of five different genotypes: G1, G2, G3, G4 and G9. VP4 typing detected four different P-genotypes: P[8], P[4], P[6] and P[11]. Rotavirus strains with G3P[8] specificity were predominating in Tunisia in 2005 and 2006, replaced by G2P[4] strains in 2007.

Rotavirus infections among HIV-infected children in Nairobi, Kenya

Human rotaviruses have emerged as a leading cause of acute diarrhea in children <5 years of age worldwide. Although there are previous reports relating to various aspects of rotaviruses, there is limited data on the involvement of rotavirus infection in HIV-infected children. We therefore evaluated the importance of rotavirus infections in HIV-related diarrhea in Kenyan children. Fecal samples were collected from a total of 207 children during the period February 1999 to June 2000 and screened for HRV antigen by enzyme-linked immunosorbent assay (ELISA). Positive samples were analyzed by VP6 subgroup specificity assay, by polyacrylamide gel electrophoresis (PAGE) and reverse transcriptase/polymerase chain reaction (RT-PCR). Fourteen percent (29/207) of the samples were positive. HIV-seropositive children with diarrhea were more likely than their counterparts without diarrhea to have rotaviruses [23.3% (10/43) versus 2.9% (2/70); p = 0.0001]. Rotavirus strain G3P[6] was predominant. These results indicate that rotavirus is an important viral etiological agent causing diarrhea in HIV-seropositive children.

Gastroenteritis by rotavirus in Spanish children. Analysis of the disease burden

Rotavirus is one of the most common causes of gastroenteritis worldwide. With the commercialisation of effective rotavirus vaccines in Europe in sight, it is necessary to provide studies which evaluate the disease burden. The aim of this study is two-fold, on one hand, to determine the burden of the rotavirus disease in Spanish children under the age of five, and on the other, to estimate the economic cost of these hospitalizations. The study was undertaken during a 5 year period (2000-2004). The rotavirus hospitalization rate was determined using the Minimum Basic Data Set of the national hospital discharge register. The observed data were compared with those expected by applying a model developed by the Centers for Disease Control and Prevention (CDC) adapted for European Countries. The financial expense of these hospitalizations was estimated. Of all admissions coded as gastroenteritis, 31.6% were due to rotavirus. The hospitalization rate by rotavirus was 480 cases per 100,000 children under five. These data are within the confidence range proposed by the adapted CDC model. The financial expense due to hospitalizations reaches 123,262 euros yearly in a Spanish University Hospital. In conclusion, rotavirus contributes significantly to the hospitalization of acute gastroenteritis. The rate of hospitalization by rotavirus is higher compared to other studies carried out in Spain. In view of future commercialisation of rotavirus vaccines, more in-depth analysis considering direct and indirect costs are necessary.

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.

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.

Mutated G4P[8] rotavirus associated with a nationwide outbreak of gastroenteritis in Nicaragua in 2005

During February and March 2005, one of the largest national recorded outbreaks of severe acute gastroenteritis occurred in Nicaragua, affecting >or=64,000 individuals and causing >or=56 deaths, predominantly in children under 5 years of age. Through a nationwide laboratory-based study, stool samples were collected and investigated for rotavirus. Of 108 stool samples examined, 72 (67%) were positive for rotavirus. While 69% (50/72) of the positive samples were found in children less than 2 years of age, 50% (6/12) of the adult samples were positive. A mutated G4P[8] strain was the most commonly recognized strain (85%), followed by mixed G strains (8%) and G9P[8] (7%) strains. Phylogenetic analysis of the VP7 gene revealed that the G4 strains belonged to the emerging lineage Ic and was distantly related to the ST3 and VA70 G4 strains. Secondary structure predictions of the VP7 G4 protein revealed an insert of an asparagine residue in position 76, which, combined with additional mutations, surprisingly modified two downstream beta-sheets at amino acid positions 80 to 85 and 115 to 119. The 2005 G4P[8] strain compared to a G4P[8] strain from 2002 had a substitution of an asparagine residue for threonine (Asn-->Thr) at position 96 within antigenic region A, thus eliminating a potential glycosylation site. The mutated G4 virus was introduced in Nicaragua after 2002 and probably emerged from Brazil, Argentina, or Uruguay.

Real-time reverse transcription-PCR for detection of rotavirus and adenovirus as causative agents of acute viral gastroenteritis in children

Viral pathogens are the most common cause of gastroenteritis in developed countries. Human rotavirus and adenovirus infections are major causes of acute outbreaks and sporadic cases of gastroenteritis, occurring primarily among children less than 2 years of age. Patient hospitalization is often required, with enormous infection control implications. This work describes the development of real-time PCR assays for the detection of group F adenovirus, rotavirus A, and rotavirus C from stool specimens. Two hundred twenty stool samples from pediatric patients exhibiting symptoms of diarrhea and/or vomiting were examined. PCR results were compared with those of virus detection by electron microscopy and latex agglutination antigen detection. The incorporation of an internal-control RNA that was spiked into individual stool extracts functioned as an internal validation for the reporting of PCR-negative results. Rotavirus C was not detected by real-time PCR in the patient stool samples examined. Real-time reverse transcription-PCR resulted in 175% and 111% increases in the rates of detection of adenovirus F and rotavirus A, respectively, compared with latex agglutination testing. Molecular detection increased the number of stool specimens in which causative agents of gastroenteritis were identified by 155% compared to electron microscopy. Genotyping of a proportion of the rotavirus and adenovirus strains identified only genotype G1 rotavirus and both adenovirus genotypes 40 and 41 in circulation within the patient cohort examined. The results highlight the significance of rapid molecular methods for the routine screening of stool samples in hospital laboratories to provide rapid definitive diagnoses.

Analysis of human rotavirus G1P[8] strains by RFLP reveals higher genetic drift in the VP7 than the VP4 gene during a 4-year period in Mexico

Several studies have demonstrated that rotaviruses of the G1P[8] genotype are among the most important worldwide. Sequence analysis of G1P[8] strains has revealed high genetic variability of VP4 and VP7 genes. The aim of this study was to investigate by restriction fragment length polymorphism (RFLP) analysis the genetic variability of the VP7 and VP4 genes within rotaviruses of the G1P[8] genotype. A total of 60 rotavirus-positive fecal samples genotyped as G1P[8], were collected from children with acute diarrhea under 5 years of age, between October 1995 and October 1998. The VP7 and VP4 genes were amplified by RT/PCR, using the Beg9/End9 primer pair and the Con3 and Con2 primers, respectively. VP7 amplicons were digested with three restriction enzymes Hae III, Taq I and Rsa I in separate reactions and VP4 amplicons were digested similarly with endonucleases Hinf I, Sau96 I and Rsa I. Analysis of the digested VP7 and VP4 amplicons showed a higher genetic drift for the VP7 gene (18 RFLPs) compared to the VP4 gene (9 RFLPs). The combination of profiles for both VP7 and VP4 amplicons, showed 27 different patterns, none of them similar to the Wa-1 strain. Furthermore, RFLP analysis of these G1P[8] strains, clearly differentiated the viruses into two main clusters, both of them sharing the same restriction pattern for the VP4 gene, and a different one for the VP7 gene.

Molecular characterisation and analysis of bovine rotavirus strains circulating in Ireland 2002–2004

One hundred and two faecal samples were collected from calves diagnosed with rotavirus infection, in the southern region of Ireland, from 2002 to 2004. Ninety one percent (n=93) were confirmed positive for rotavirus, using latex agglutination and enzyme linked immunosorbent assay (ELISA) methods. Determination of the G- and P-types was carried out using nested reverse transcriptase polymerase chain reaction (nRT-PCR). G6 was the most prevalent genotype, accounting for 80.6% (75/93), G10 accounted for 6.5% (6/93) and G6G10 mixed types accounted for 9.7% (9/93) of the collection. Rotavirus in three of the samples (3.2%) could not be characterised with any of the five G-specific primers used in this study. A subset of the positive samples (n=54) was examined for their P-type specificities, P[5] and P[11] accounted for 77.8% (42/54), and 9.3% (5/54), respectively. One P[1] genotype (1.9%) was found in the collection. P[5] and P[11] mixed genotypes accounted for 11% (6/54) of the study. The genotypes corresponded to the UK-like strain (G6P[5]) 57.4%, KN4-like strain (G6[P11]) 7.4%, B223-like strain (G10P[11]) and NCDV-like strain (G6P[1]) 1.9% each. The unusual combination of G10P[5] accounted for 7.4%, with mixed infections G6+G10P[5] and G6P[5]+P[11] representing 13% and 11%, respectively. This is the first time that the G- and P-types of bovine rotaviruses (BRVs) have been determined in Ireland, and this study contributes to a better understanding of the epidemiology of such viruses circulating in Ireland.

G-serotypes of group A rotaviruses in Pilsen region (Czechia)

A total of 260 feces samples from children with confirmed rotavirus infection collected during 1999-2002 were serotyped, using enzymoimmunoassay with VP7 specific monoclonal antibodies for G1-G4 serotypes. The serotypes were identified in 185 feces, i.e. 71.2 %. Individual serotypes occurred in 43, 2, 16 and 2 %; 8 % samples reacted with 2 type-specific monoclonal antibodies. The G1 serotype was prevalent over the whole period. The G3 type occurred with a statistically higher significance in children of up to 36 months (chi2 = 4.6, p = 0.028). In 4 children a different serotype was demonstrated in the first and second, or in the second and third stools, respectively. No dominant serotype was found in children with nosocomial infection.

Rotavirus types in Europe and their significance for vaccination

The degree of diversity of cocirculating human rotavirus wild-type strains is high. This article reviews the occurrence and frequency of rotavirus types in European children younger than 5 years of age during the past 10-15 years. To enable greater understanding of the overall epidemiologic situation, rotavirus types found in animals in Europe are described. In addition, rotavirus types occurring in children outside Europe are considered. Taken together, these data provide an essential background to the development of rotavirus vaccines. The different concepts of immunization with the 2 main rotavirus candidate vaccines are briefly discussed, and their potential impact on the epidemiology of cocirculating rotavirus wild-type viruses is considered. A case is made for comprehensive surveillance of cocirculating human rotavirus types in Europe after the implementation of rotavirus vaccination.

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.

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).

Emergence of G3 and G9 rotavirus and increased incidence of mixed infections in the southern region of Ireland 2001-2004

Two hundred and thirty fecal specimens were collected from children (up to 5 years of age) admitted with suspected rotaviral gastroenteritis at four Irish hospitals (Cork University Hospital, Mercy Hospital, Cork, Waterford Regional Hospital, and Kerry General Hospital) in the southern region of Ireland, between 2001 and 2004. Following laboratory confirmation of the aetiological agent, the rotavirus G-type was determined in all positive samples by reverse transcriptase-polymerase chain reaction (RT-PCR). The distribution of the G-types (n=230) over the 3 year period was G1 (31%), G9 (21.8%), G3 (8.7%), G4 (6.5%), and G2 (3.5%). There were many mixed infections which accounted for 28.5% of the collection. G9 emerged as the most prevalent G type (30.1%) in 2001-2002, whilst G3 first emerged in 2002-2003 and accounted for 15.8% of the collection. Notably, G2 strains were present at a very low frequency (3.5%) during 2001-2004, compared to an earlier study (1997-1999), where they accounted for 28.5% of the specimens. A smaller subset of the study collection was similarly P-typed (n=139). P[8]-type was identified as the most prevalent P-type, accounting for 97.4% (n=186), while P[4] accounted for just 2.6% (n=5) of the collection. The low frequency of P[4] coincided with the decrease in G2 strains in circulation. The key finding in this study was the emergence of G3- and G9-serotypes as epidemiologically important rotavirus strains since 1999, and the low prevalence of the previously common G2 strains in Ireland. The profile of rotavirus is changing continuously in Ireland and the implications for a successful vaccination program are discussed.

Surveillance study (2000 to 2001) of G- and P-type human rotaviruses circulating in South Korea

Human rotavirus VP4 and VP7 gene sequences were amplified by reverse transcription-PCR from 53% (322 of 607) of fecal specimens collected from children with severe diarrhea who visited hospitals in six urban areas of South Korea in 2000 and 2001. G2 was the most frequently found G type (constituted 50.6%), followed by G1 (30.1%) and G4 (13.0%). Although the P types of high incidence were P[4] (53.1%) and P[8] (21.4%), a significant incidence of P[6] (20.2%) was also noticeable. The commonest G- and P-type combination found in this study was G2P[4], rather than G1P[8], the most prevalent type known worldwide.

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.

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.

Use of internal standard RNA molecules for the RT-PCR amplification of the faeces-borne RNA viruses

The diagnostic system based on reverse transcription (RT)-PCR has been used widely for the detection of viral genomes of faecal-borne RNA viruses. However, faecal specimens often produce both false positive and false negative results. Therefore, there is a need for a diagnosis procedure that can control for 'false-results'. In this study, an internal standard RNA that can serve as a non-competitive positive template was developed and used directly to detect faecal-borne RNA viruses without noticeable competitive inhibition of the target viral genome. These results suggest that the internal standard RNA is a useful standard molecule when undertaking diagnostic qualitative RT-PCR procedures for enteroviruses and related faecal-borne RNA viruses.

Changes in the prevalence of rotavirus G and P types in diarrheic calves from the Kagoshima prefecture in Japan

G8 bovine group A rotavirus was the most predominant serotype in calf diarrheal fecal specimens examined between 1995 and 1996 in Japan [Vet. Microbiol. 66 (1999) 301]. To date, no evidence that G8 was the most predominant in the typeable specimens has been observed outside Japan. To investigate whether G8 continues to be as common as G6 and G10, the incidence of the main serotypes was determined in the same area (Kagoshima prefecture) between 1997 and 1998 by reverse transcription-polymerase chain reaction. From a total of 104 rotavirus-positive specimens, we successfully identified G type in 79 (76.0%) and P type in 71 (68.3%). The combination of G and P types varied periodically; in 1995, G10P[11] was most common. The most predominant types changed drastically in 1996, and G8 and mixed P types were the most predominant. A dramatic shift of the most predominant type occurred again in 1997 when G6P[5] was most common. This frequency of G6P[5] also continued in 1998. These results suggest that the serotypes prevailing in certain areas change periodically.

Application of restriction fragment length polymorphism analysis of VP7-encoding genes: fine comparison of Irish and global rotavirus isolates

A restriction fragment length polymorphism (RFLP) detection assay was developed to examine the genetic relationship(s) among VP7-encoding genes from 100 Irish rotavirus isolates and 30 randomly selected global rotavirus isolates (from the current databases). RFLP analysis of the VP7 gene segments was performed independently with three enzymes (RsaI, AluI, and EcoRV) in separate reactions by direct digestion of the DNA product amplified by reverse transcriptase (RT)-mediated PCR (RT-PCR) or by using computational methods. Thirty-six RFLP patterns were identified for all 130 strains, and of these, only nine patterns were associated with the Irish isolates. A correlation between the G type of the Irish isolates and certain single or combined enzyme profiles was apparent. These data suggested that the Irish wild-type rotavirus population was homogeneous and could be distinguished by RFLP analysis from global isolates of the same serotype(s). The deduced amino acid sequences of the VP7 RT-PCR products from six Irish isolates known to be of the G serotype revealed significant amino acid substitutions within major antigenic regions. In addition, these data identified the existence of at least two genetic lineages within serotype G1 strains which were distinguishable by RFLP analysis.

Genomic diversity of group A rotavirus strains infecting humans in eastern India

Between 1998 and 2000, a total of 266 samples were found positive for group A rotaviruses by RNA electrophoresis. Samples were collected from patients admitted to two leading hospitals in Calcutta. Serotyping could be done only with 22% of the positive samples, leaving 78% untypeable. The G (VP7 genotypes) and P (VP4 genotypes) types were determined for 159 samples by reverse transcription and multiplex PCR. The predominant genotype was G1P[8] (20%), followed by G2P[4] (15%) and G4P[8] (6%). A number of uncommon genotypes, G1P[4] (4%), G2P[8] (2.5%), G2P[6] (0.6%), G4P[4] (2.5%), and G4P[6] (1.25%), were also detected during this study period. Twenty two percent of specimens showed mixed infections, 38 (24%) of the total samples remained untypeable for either VP7 or VP4, while only 4 (2.5%) of the samples were untypeable for both genes. Eleven specimens collected from Manipur were also genotyped and revealed a very high degree of genomic reassortment.

Epidemiological patterns of rotaviruses causing severe gastroenteritis in young children throughout Australia from 1993 to 1996

Rotavirus strains that caused severe diarrhea in 4,634 (2,533 male) children aged less than 5 years and admitted to major hospitals in eight centers throughout Australia from 1993 to 1996 were subject to antigenic and genetic analyses. The G serotypes of rotaviruses were identified in 81.9% (3,793 of 4,634) children. They included 67.8% (from 3,143 children) serotype G1 isolates (containing 46 electropherotypes), 11.5% (from 531 children) serotype G2 isolates (27 electropherotypes), 0.8% (from 39 children) serotype G3 isolates (8 electropherotypes), and 1.6% (from 76 children) serotype G4 isolates (9 electropherotypes). G6 (two strains) and G8 (two strains) isolates were identified during the same period. G1 serotypes were predominant in all centers, with intermittent epidemics of G2 serotypes and sporadic detection of G3 and G4 strains. With the exception of two strains (typed as G1P2A[6] and G2P2A[6]) all serotype G1, G3, and G4 strains were P1A[8] and all serotype G2 strains were P1B[4]. Two contrasting epidemiological patterns were identified. In all temperate climates rotavirus incidence peaked during the colder months. The genetic complexity of strains (as judged by electropherotype) was greatest in centers with large populations. Identical electropherotypes appeared each winter in more than one center, apparently indicating the spread of some strains both from west to east and from east to west. Centers caring for children in small aboriginal communities showed unpredictable rotavirus peaks unrelated to climate, with widespread dissemination of a few rotavirus strains over distances of more than 1,000 km. Data from continued comprehensive etiological studies of genetic and antigenic variations in rotaviruses that cause severe disease in young children will serve as baseline data for the study of the effect of vaccination on the incidence of severe rotavirus disease and on the emergence of new strains.

The relative frequencies of G serotypes of rotaviruses recovered from hospitalized children with diarrhea: A 10-year survey (1987-1996) in Japan with a review of globally collected data

Since rotavirus vaccines aim to protect children from severe diarrhea, knowledge of the prevailing G serotypes among rotaviruses from hospitalized children is essential. Thus, we determined the G serotypes of rotaviruses collected from children with acute diarrhea in a local referral hospital in Akita, Japan, over the 10-year period between January 1987 and December 1996. Based on the assumption that rotaviruses with an identical electropherotype possess the same G serotype, the G serotypes of 488 rotavirus-positive specimens that were classified into 63 electropherotypes were determined by enzyme-linked immunosorbent assay with a supplementary use of G typing by reverse transcription-PCR. The relative frequencies over the 10-year period were 77.0 (G1), 14.5 (G2), 2.7 (G3) and 5.3% (G4), leaving the possibility that only 0.4% had G serotypes uncommon to human rotaviruses. Of 24,050 rotaviruses extracted by reviewing 63 serotyping studies in literature, the relative frequencies of the four major G serotypes were 50.6 (G1), 9.3 (G2), 7.2 (G3) and 11.6% (G4). As to uncommon G serotypes, only 0.9% were described as serotypes other than G1-4, and our estimate for potential uncommon serotypes were at most 8.1%. Thus, both this long-term study focusing on the rotaviruses only from severe cases in a single hospital in Japan and the global review of G serotypes published to date indicate that the primary target of any rotavirus vaccines should be rotaviruses possessing serotypes G1-4.

Molecular characterization of rotavirus in Ireland: detection of novel strains circulating in the population

A collection of three hundred thirty rotavirus-positive stool samples from children with diarrhea in the southern and eastern regions of Ireland between 1997 and 1999 were submitted to the Molecular Diagnostics Unit of the Cork Institute of Technology, Cork, Ireland, for investigation. These strains were characterized by several methods, including polyacrylamide gel electropherotyping and G and P genotyping. A subset of the G types was confirmed by nucleic acid sequencing. The most prevalent types found in this collection included G1P[8] (n = 106; 32.1%), G2P[4] (n = 94; 28.5%), and G4P[8] (n = 37; 11.2%). Novel strains were also detected, including G1P[4] (n = 19; 5.8%), and G4P[4] (n = 2; 0.6%). Interestingly, mixed infections accounted for 18.8% (n = 62) of the total collection, with only 3% (n = 10) which were not G and/or P typeable. Significantly, six G8 and five G9 strains were identified as part of mixed infections. These strains have not previously been identified in Irish children, suggesting a greater diversity in rotavirus strains currently circulating in Ireland.

VP7 and VP4 genotypes among rotavirus strains recovered from children with gastroenteritis over a 3-year period in Valencia, Spain

Between September 1996 and May 1999, the incidence and distribution of the main human rotavirus G genotypes (VP7 associated: G1-G4) and P genotypes (VP4 associated: P[8], P[4], P[6] and P[9]) among children with rotavirus gastroenteritis were determined using reverse transcription and polymerase chain reaction (RT-PCR)-based genotyping methods. From a total of 145 rotavirus strains examined, we identified the G type in 131 (90.3%) and the P type in 127 (87.5%) of the samples. An overall predominance of genotypes P[8] G1 (42.7%) and P[8] G4 (32.4%) was found during the period of study, with much lower incidence of genotypes P[4] G2 (5.5%) and P[8] G3 (2%). P[6] and P[9] types were not detected, neither were unusual combinations of P and G types. A significant genotypic shift was observed: whereas P[8] G4 was the most prevalent genotype during the first year of the study (60%), the genotype P[8] G1 gradually increased to account for 62.3% of the strains analysed in the following winter season. Mixed G types revealing dual infections G1/G4 and G3/G4 were found at low frequency (2%).

G and P genotyping of rotavirus strains circulating in france over a three-year period: detection of G9 and P[6] strains at low frequencies. The AZAY Group

Rotavirus G and P types from 716 children with acute diarrhea in Dijon from 1995 to 1998 and throughout France during the winter of 1997-1998 were analyzed by reverse transcription-PCR. P[8],G1 predominated, followed by P[8],G4, which emerged during the last winter. G9 and P[6] strains were detected at low frequencies.

Viral gastroenteritis

A large number of viruses can be found in the human intestine. Some (bacteriophages) infect the bacteria present as normal flora and others use the gut as a portal of entry. This review examines the virology, pathogenesis, immunology, epidemiology, clinical features, treatment and prevention of the viral enteropathogens. Rotavirus is undoubtedly the most important, causing an estimated 800,000 deaths each year, especially in developing countries. Recently, an oral live quadrivalent rhesus rotavirus vaccine has been licensed for use in the USA. It has great potential but there are a number of hurdles to be overcome before it can be given to infants in developing countries. Molecular techniques are revolutionizing our understanding of rotavirus pathogenesis, and the tremendous diversity of Caliciviridae and Astroviridae, as well as producing new diagnostic techniques and vaccines.