Brigitta László

Systematic review of regional and temporal trends in global rotavirus strain diversity in the pre rotavirus vaccine era: insights for understanding the impact of rotavirus vaccination programs.

Recently, two rotavirus vaccines have been recommended for routine immunization of infants worldwide. These vaccines proved efficacious during clinical trials and field use in both developing and developed countries, and appear to provide good protection against a range of rotavirus genotypes, including some that are not included in the vaccines. However, since conclusive data that the vaccines will protect against a wide variety of rotavirus strains are still lacking and since vaccines may exert some selection pressure, a detailed picture of global strain prevalence from the pre-rotavirus vaccine era is important to evaluate any potential changes in circulating strains observed after widespread introduction of rotavirus vaccines. Thus, we systematically reviewed rotavirus genotyping studies spanning a 12-year period from 1996 to 2007. In total, ~110,000 strains were genotyped from 100 reporting countries. Five genotypes (G1-G4, and G9) accounted for 88% of all strains, although extensive geographic and temporal differences were observed. For example, the prevalence of G1 strains declined from 2000 onward, while G3 strains re-emerged, and G9 and G12 strains emerged during the same period. When crude strain prevalence data were weighted by region based on the regions contribution to global rotavirus mortality, the importance of genotypes G1 and G9 strains that were more prevalent in regions with low mortality was reduced and conversely the importance of G8 strains that were more prevalent in African settings with greater contribution to global rotavirus mortality was increased. This study provides the most comprehensive, up-to-date information on rotavirus strain surveillance in the pre-rotavirus vaccine era and will provide useful background to examine the impact of rotavirus vaccine introduction on future strain prevalence.

Rotavirus genotypes co-circulating in Europe between 2006 and 2009 as determined by EuroRotaNet, a pan-European collaborative strain surveillance network

EuroRotaNet, a laboratory network, was established in order to determine the diversity of co-circulating rotavirus strains in Europe over three or more rotavirus seasons from 2006/2007 and currently includes 16 countries. This report highlights the tremendous diversity of rotavirus strains co-circulating in the European population during three years of surveillance since 2006/2007 and points to the possible origins of these strains including genetic reassortment and interspecies transmission. Furthermore, the ability of the network to identify strains circulating with an incidence of ≥1% allowed the identification of possible emerging strains such as G8 and G12 since the beginning of the study; analysis of recent data indicates their increased incidence. The introduction of universal rotavirus vaccination in at least two of the participating countries, and partial vaccine coverage in some others may provide data on diversity driven by vaccine introduction and possible strain replacement in Europe.

Review of group A rotavirus strains reported in swine and cattle

Abstract Group A rotavirus (RVA) infections cause severe economic losses in intensively reared livestock animals, particularly in herds of swine and cattle. RVA strains are antigenically heterogeneous, and are classified in multiple G and P types defined by the two outer capsid proteins, VP7 and VP4, respectively. This study summarizes published literature on the genetic and antigenic diversity of porcine and bovine RVA strains published over the last 3 decades. The single most prevalent genotype combination among porcine RVA strains was G5P[7], whereas the predominant genotype combination among bovine RVA strains was G6P[5], although spatiotemporal differences in RVA strain distribution were observed. These data provide important baseline data on epidemiologically important RVA strains in swine and cattle and may guide the development of more effective vaccines for veterinary use.

Rotavirus Surveillance in Europe, 2005–2008: Web-Enabled Reporting and Real-Time Analysis of Genotyping and Epidemiological Data

BACKGROUND The first European rotavirus surveillance network, EuroRotaNet, comprising 16 laboratories in 15 European countries, has been established. METHODS Fecal samples from gastroenteritis cases positive for group A rotavirus antigen were collected from multiple European countries from 2005 to mid-2008 and were subjected to G and P genotyping. Epidemiological data collected included age, sex, geographical location, setting, dates of onset and sample collection, and clinical symptoms. RESULTS A total of 8879 rotavirus-positive samples were characterized: 2129 cases were from the 2005-2006 season, 4030 from the 2006-2007 season, and 2720 from the ongoing 2007-2008 season. A total of 30 different G and P type combinations of strains circulated in the region from 2005 through 2008. Of these strains, 90% had genotypes commonly associated with human infections-G1P[8], G2P[4], G3P[8], G4P[8], and G9P[8]-and 1.37% represented potential zoonotic introductions. G1P[8] remained the most prevalent genotype in Europe as a whole, but the incidence of infection with G1P[8] rotavirus strains was <50% overall, and all 3 seasons were characterized by a significant diversity of cocirculating strains. The peak incidence of rotavirus infection occurred from January through May, and 81% of case patients were aged <2.5 years. Conclusions. Data gathered through EuroRotaNet will provide valuable background information on the rotavirus strain diversity in Europe before the introduction of rotavirus vaccines, and the network will provide a robust method for surveillance during vaccine implementation.

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

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

One Year Survey of Human Rotavirus Strains Suggests the Emergence of Genotype G12 in Cameroon

In this study the emergence of rotavirus A genotype G12 in children <5 years of age is reported from Cameroon during 2010/2011. A total of 135 human stool samples were P and G genotyped by reverse transcriptase PCR. Six different rotavirus VP7 genotypes were detected, including G1, G2, G3, G8, G9, and G12 in combinations with P[4], P[6] and P[8] VP4 genotypes. Genotype G12 predominated in combination with P[8] (54.1%) and P[6] (10.4%) genotypes followed by G1P[6] (8.2%), G3P[6] (6.7%), G2P[4] (5.9%), G8P[6] (3.7%), G2P[6] (0.7%), G3P[8] (0.7%), and G9P[8] (0.7%). Genotype P[6] strains in combination with various G‐types represented a substantial proportion (N = 44, 32.6%) of the genotyped strains. Partially typed strains included G12P[NT] (2.2%); G3P[NT] (0.7%); G(NT)P[6] (1.5%); and G(NT)P[8] (0.7%). Mixed infections were found in five specimens (3.7%) in several combinations including G1 + G12P[6], G2 + G3P[6] + P[8], G3 + G8P[6], G3 + G12P[6] + P[8], and G12P[6] + P[8]. The approximately 10% relative frequency of G12P[6] strains detected in this study suggests that this strain is emerging in Cameroon and should be monitored carefully as rotavirus vaccine is implemented in this country, as it shares neither G‐ nor P‐type specificity with strains in the RotaTeq® and Rotarix® vaccines. These findings are consistent with other recent reports of the global spread and increasing epidemiologic importance of G12 and P[6] strains. J. Med. Virol. 85:1485–1490, 2013.

Large-scale whole genome sequencing identifies country-wide spread of an emerging G9P[8] rotavirus strain in Hungary, 2012

With the availability of rotavirus vaccines routine strain surveillance has been launched or continued in many countries worldwide. In this study relevant information is provided from Hungary in order to extend knowledge about circulating rotavirus strains. Direct sequencing of the RT-PCR products obtained by VP7 and VP4 genes specific primer sets was utilized as routine laboratory method. In addition we explored the advantage of random primed RT-PCR and semiconductor sequencing of the whole genome of selected strains. During the study year, 2012, we identified an increase in the prevalence of G9P[8] strains across the country. This genotype combination predominated in seven out of nine study sites (detection rates, 45-83%). In addition to G9P[8]s, epidemiologically major strains included genotypes G1P[8] (34.2%), G2P[4] (13.5%), and G4P[8] (7.4%), whereas unusual and rare strains were G3P[8] (1%), G2P[8] (0.5%), G1P[4] (0.2%), G3P[4] (0.2%), and G3P[9] (0.2%). Whole genome analysis of 125 Hungarian human rotaviruses identified nine major genotype constellations and uncovered both intra- and intergenogroup reassortment events in circulating strains. Intergenogroup reassortment resulted in several unusual genotype constellations, including mono-reassortant G1P[8] and G9P[8] strains whose genotype 1 (Wa-like) backbone gene constellations contained DS1-like NSP2 and VP3 genes, respectively, as well as, a putative bovine-feline G3P[9] reassortant strain. The conserved genomic constellations of epidemiologically major genotypes suggested the clonal spread of the re-emerging G9P[8] genotype and several co-circulating strains (e.g., G1P[8] and G2P[4]) in many study sites during 2012. Of interest, medically important G2P[4] strains carried bovine-like VP1 and VP6 genes in their genotype constellation. No evidence for vaccine associated selection, or, interaction between wild-type and vaccine strains was obtained. In conclusion, this study reports the reemergence of G9P[8] strains across the country and indicates the robustness of whole genome sequencing in routine rotavirus strain surveillance.

Surveillance of human rotaviruses in 2007–2011, Hungary: Exploring the genetic relatedness between vaccine and field strains

BACKGROUND The availability of rotavirus vaccines has resulted in an intensification of post vaccine strain surveillance efforts worldwide to gain information on the impact of vaccines on prevalence of circulating rotavirus strains. OBJECTIVES In this study, the distribution of human rotavirus G and P types in Hungary is reported. In addition, the VP4 and VP7 genes of G1P[8] strains were sequenced to monitor if vaccine-derived strains were introduced and/or some strains/lineages were selected against. STUDY DESIGN The study was conducted in 8 geographic areas of Hungary between 2007 and 2011. Rotavirus positive stool samples were collected from diarrheic patients mostly <5 years of age. Viral RNA was amplified by multiplex genotyping RT-PCR assay, targeting the medically most important G and P types. When needed, sequencing of the VP7 and VP4 genes was performed. RESULTS In total, 2380 strains were genotyped. During the 5-year surveillance we observed the dominating prevalence of genotype G1P[8] (44.87%) strains, followed by G4P[8] (23.4%), G2P[4] (14.75%) and G9P[8] (6.81%) genotypes. Uncommon strains were identified in a low percentage of samples (4.12%). Phylogenetic analysis of 318 G1P[8] strains identified 55 strains similar to the Rotarix strain (nt sequence identities; VP7, up to 97.9%; VP4, up to 98.5%) although their vaccine origin was unlikely. CONCLUSIONS Current vaccines would have protected against the majority of identified rotavirus genotypes. A better understanding of the potential long-term effect of vaccine use on epidemiology and evolutionary dynamics of co-circulating wild type strains requires continuous strain surveillance.

Lineage-specific silencing of human IL-10 gene expression by promoter methylation in cervical cancer cells

Epigenetic analysis was performed to demonstrate that the normal and neoplastic epithelial cells do not serve as the source of the locally elevated IL-10 production during cervical carcinogenesis. Bisulfite sequencing was used to correlate promoter CpG methylation with the transcription of the gene. Lack of IL-10 transcription in HeLa, SiHa, Caski, HT-3, C33-A, HaCaT cell lines and in primary human keratinocytes correlated consistently with the methylated state of the proximal CpG residues, particularly with the two most proximal CpGs at positions -185 and -110. These two sites were also highly methylated in normal and malignant cervical cells directly isolated from patient material. On the other hand, IL-10 producing peripheral blood mononuclear cells had unmethylated CpG residues in the proximal promoter associated with acetylated H3 and H4 histones as determined by chromatin immunoprecipitation. In HeLa carrying epigenetically silenced endogeneous IL-10 promoter, the transfected non-CpG methylated 1 kb and 0.6 kb proximal promoter fragments could drive reporter gene expression, which was reversed by cassette methylation of these promoter fragments. In conclusion, the CpG methylation pattern of the proximal promoter is implicated as a major determinant of transcriptional silencing of human IL-10 expression in cells of cervical epithelial origin.

First Detection of P[6],G9 Rotaviruses in Hungary—An Imported Strain From India?

EuroRotaNet was launched to monitor rotavirus strain prevalence during and after introduction of rotavirus vaccines in Europe. In early 2007, we detected P[6],G9 rotaviruses to appear in Hungary, representing the first documented occurrence of this strain in our surveillance area. Epidemiologic data suggested that this strain was introduced from India.