ABSTRACT
In the present study, epidemiological survey and molecular characterization of hepatitis A virus during an outbreak in five Tunisian childcare centers in El-Mahres during October and November 2006 were carried out. Five well-water and five drinking water samples were included in the present study. Serological investigation and molecular characterization were carried out. All patients were IgM seropositive and the viral genome was detected in all clinical and well-water samples whereas it was not detected in drinking water from the five childcare centers. Sequence analysis showed that all Tunisian strains belong to sub-genotype IA. The genetic profile of the VP1/2A junction showed that the outbreak isolates underwent an amino acid substitution which was absent in virus's strains detected previously in Tunisia. Further studies need to be conducted to evaluate the emergence of the virus's strains in clinical and water samples and more epidemiological data need to be collected about the risk factors which may contribute to acute hepatitis.
Subject(s)
Humans , Disease Outbreaks , Immunoglobulin M , Sequence Analysis, DNA , Sequence Analysis, Protein , Hepatitis Viruses/genetics , Diagnostic Techniques and Procedures , Methods , Patients , Water SamplesABSTRACT
In the present study, epidemiological survey and molecular characterization of hepatitis A virus during an outbreak in five Tunisian childcare centers in El-Mahres during October and November 2006 were carried out. Five well-water and five drinking water samples were included in the present study. Serological investigation and molecular characterization were carried out. All patients were IgM seropositive and the viral genome was detected in all clinical and well-water samples whereas it was not detected in drinking water from the five childcare centers. Sequence analysis showed that all Tunisian strains belong to sub-genotype IA. The genetic profile of the VP1/2A junction showed that the outbreak isolates underwent an amino acid substitution which was absent in virus's strains detected previously in Tunisia. Further studies need to be conducted to evaluate the emergence of the virus's strains in clinical and water samples and more epidemiological data need to be collected about the risk factors which may contribute to acute hepatitis.
ABSTRACT
In the present study, epidemiological survey and molecular characterization of hepatitis A virus during an outbreak in five Tunisian childcare centers in El-Mahres during October and November 2006 were carried out. Five well-water and five drinking water samples were included in the present study. Serological investigation and molecular characterization were carried out. All patients were IgM seropositive and the viral genome was detected in all clinical and well-water samples whereas it was not detected in drinking water from the five childcare centers. Sequence analysis showed that all Tunisian strains belong to sub-genotype IA. The genetic profile of the VP1/2A junction showed that the outbreak isolates underwent an amino acid substitution which was absent in virus's strains detected previously in Tunisia. Further studies need to be conducted to evaluate the emergence of the virus's strains in clinical and water samples and more epidemiological data need to be collected about the risk factors which may contribute to acute hepatitis.
ABSTRACT
Knowledge of the molecular biology of hepatitis A virus (HAV) has increased exponentially since its identification. HAV exploits all known mechanisms of genetic variation to ensure survival, including mutation and genetic recombination. HAV has been characterized by the emergence of different genotypes, three human antigenic variants and only one major serotype. This paper reviews the genetic variability and molecular epidemiology of HAV. Its evolutionary mechanisms are described with particular emphasis on genetic recombination and HAV mutation rate. Genotypic classification methods are also discussed.
Subject(s)
Genetic Variation , Hepatitis A Virus, Human/genetics , Amino Acid Sequence , Antigenic Variation , Biological Evolution , Canada/epidemiology , Europe/epidemiology , Genotype , Hepatitis A/epidemiology , Hepatitis A Antigens/genetics , Hepatitis A Virus, Human/classification , Humans , Incidence , Molecular Epidemiology , Molecular Sequence Data , Mutation , RNA, Viral/genetics , Recombination, Genetic , Sequence Alignment , South America/epidemiologyABSTRACT
Hepatitis A virus (HAV) is a positive-stranded RNA virus in the genus Hepatovirus in the family Picornaviridae So far, analysis of the genetic variability of HAV has been based on two discrete regions, the VP1/2A junction and the VP1 N terminus. In this report, we determined the nucleotide and deduced amino acid sequences of the complete VP1 gene of 81 strains from France, Kosovo, Mexico, Argentina, Chile, and Uruguay and compared them with the sequences of seven strains of HAV isolated elsewhere. Overall strain variation in the complete VP1 gene was found to be as high as 23.7% at the nucleotide level and 10.5% at the amino acid level. Different phylogenetic methods revealed that HAV sequences form five distinct and well-supported genetic lineages. Within these lineages, HAV sequences clustered by geographical origin only for European strains. The analysis of the complete VP1 gene allowed insight into the mode of evolution of HAV and revealed the emergence of a novel variant with a 15-amino-acid deletion located on the VP1 region where neutralization escape mutations were found. This could be the first antigenic variant of HAV so far identified.
Subject(s)
Disease Outbreaks , Evolution, Molecular , Hepatitis A virus/classification , Hepatitis A virus/genetics , Hepatitis A/epidemiology , Viral Structural Proteins/genetics , Amino Acid Sequence , France/epidemiology , Genetic Variation , Hepatitis A/virology , Humans , Mexico/epidemiology , Molecular Sequence Data , Phylogeny , Picornaviridae/genetics , Sequence Analysis, DNA , South America/epidemiology , Yugoslavia/epidemiologyABSTRACT
Genetic analysis of selected genome regions of hepatitis A virus (HAV) suggested that distinct genotypes of HAV could be found in different geographical regions. In order to gain insight into the genetic variability and mode of evolution of HAV in South America, an analysis was performed of sequence data obtained from the VP1 amino terminus and the VP1/2A region of HAV strains isolated over a short period of time in Uruguay, Argentina and Chile. Sequences obtained from 22 distinct HAV isolates were compared with published sequences from 21 different strains isolated all over the world. Phylogenetic analysis revealed that all strains isolated belong to a unique sub-genotype (IA). Strains isolated during an outbreak period showed a higher degree of heterogeneity than anticipated previously and the co-circulation of different isolates. The genetic variability among strains isolated in this region seems to be higher in comparison with strains isolated in other regions of the world.