Comparative Genotype Analysis of Hepatitis A Virus: Two One-Year Studies in South Korea in 2002 and 2011

Hepatitis A virus (HAV) positive stool samples were collected from acute hepatitis A patients during the two study periods of 2002 and 2011 in Seoul, South Korea, and their genetic variability was determined. From a total of 79 specimens, the nucleotide sequences of the VP1 and 2A junction were successfully amplified in 27 (34.2%) samples and subjected to sequence analysis. Genetically, there was a dramatic change in HAV subgenotypes from IA to IIIA during the past ten years. Sequence analysis identified that most strains belonged to genotype I, which is the main genotype globally. The subgenotype IA (93.3%, n=13/14) was the major subgenotype in 2002, whereas the subgenotype IIIA (69.2%, n=9/13) was predominant in 2011. Interestingly, a IIIA strain was identified from a patient who had a history of travel to India in 2002. The finding presented provides new insight into the genetic shift of circulating HAVs in South Korea.

A Metaviromic Analysis of Viral Communities in the Feces of Unexplained Acute Gastroenteritis

Although viruses are the most common cause of acute gastroenteritis (AGE) in humans, details about the causative viruses in AGE are largely unknown because many causative viruses are unable to be cultured by current culture techniques. In our study, fecal samples from 10 children under five years of age with unexplained AGE and 10 healthy children were investigated for RNA viruses using random priming (RP)-mediated sequence-independent single primer amplification (SISPA). The causative viruses in cases of cryptogenic diarrhea were then assessed for their potential diagnostic value. Of the 1,129 viral clones identified, rotavirus was most commonly associated with AGE (125 sequences, 22.4%). In contrast, bacteriophage was most common (43 sequences, 13.6%) in healthy children. The remaining 515 viral clones were unidentifiable. These findings suggest that investigation of cases or outbreaks of unexplained diarrhea using a metaviromic strategy is a new avenue for diagnosis.