RESUMO
Hepatitis A virus (HAV) infection is a communicable disease, typically transmitted by faecal-oral contamination. HAV outbreaks usually occur in endemic areas. We report an outbreak of HAV from June to July, 2008 among Thai navy recruits who had received training at the Sattahip Navy Base, Chonburi province, Thailand. Upon conclusion of the training, the recruits were deployed to serve at several navy bases across the country. Secondary cases of HAV infection were reported among military personnel from these navy bases. To elucidate origin and distribution of these outbreaks, we characterized the genome and genotype of HAV isolated from the different navy bases. Sera and stool from the subjects were tested for antiHAV IgM, antiHAV IgG and HAV RNA. Subsequently, molecular characterization of HAV was performed by nucleotide sequencing of the VP1-P2A region, BLAST/FASTA and phylogenetic analysis. HAV RNA was detected in specimens obtained from different areas. All isolated strains clustered in the same lineage and belonged to genotype 1A. They shared nearly 100% genome homology indicating a single point source of this outbreak. This study provides essential baseline data as a reference for genetic analysis of HAV strains causing future outbreaks. Early detection of HAV infection and identification of the source by using molecular characterization and prompt preventive measures will hopefully prevent further outbreaks.
Assuntos
Surtos de Doenças , Vírus da Hepatite A Humana , Hepatite A/epidemiologia , Hepatite A/virologia , Militares , Adulto , Sequência de Bases , Fezes , Genótipo , Hepatite A/diagnóstico , Hepatite A/transmissão , Anticorpos Anti-Hepatite A/sangue , Vírus da Hepatite A Humana/classificação , Vírus da Hepatite A Humana/genética , Vírus da Hepatite A Humana/imunologia , Vírus da Hepatite A Humana/isolamento & purificação , Humanos , Técnicas de Diagnóstico Molecular , Epidemiologia Molecular , Filogenia , RNA Viral/sangue , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de RNA , Tailândia/epidemiologia , Proteínas Estruturais Virais/genéticaRESUMO
In a recent study of hepatitis A virus (HAV) in Thailand, viral isolates recovered during several outbreaks of infection that occurred between 2001 and 2005 were genotyped and subjected to phylogenetic analysis. Anti-HAV IgM was detected, by ELISA, in many of the 283 serum samples that were collected from the provinces of Suphanburi, Songkhla, Chiangrai and Lampang: 40 (48.2% of those investigated), 38 (47.5%), 25 (41.0%) and 32 (54.2%), respectively. The HAV RNA in the positive samples was reverse transcribed and amplified, using a nested PCR focussed on the VP1-2A region, before the nucleotides of the VP1-2A region of each HAV-RNA-positive sample were sequenced. All the isolates investigated clustered in subgenotype IA and, hence, are closely related to the strains previously investigated in Thailand. When the genome of one sample from an outbreak in Lampang (LP014) was fully sequenced, the results of genome comparison and phylogenetic analysis again indicated subgenotype 1A, which appears to be the predominant form of HAV circulating throughout Thailand.