Genetic analysis of hepatitis A virus isolates from Brazil

Abstract

A limited number of hepatitis A virus (HAV) isolates from South America have been characterised at the genomic level. IgM anti-HAV positive serum samples collected from patients with hepatitis A living in the five geographical regions of Brazil (North, Northeast, Central, South, and Southeast) were used to obtain HAV isolates and determine their genetic relatedness. Of the 232 case isolates, sequence data were obtained from the VP1/2A junction region of the HAV genome. All isolates were classified in genotype I; 231 belonged to subgenotype IA, and one to subgenotype IB. HAV isolates from four States formed distinct clusters of highly related sequences. However, isolates from other states did not cluster and the sequences from those states were intermingled with sequences found in the other states. The amino acid sequences of all but two isolates showed a Leu --> Ile substitution at position 42 in the 2A protein. This substitution appeared to be a characteristic geographic fingerprint of HAV sequences within Brazil.

Co-circulation of genotypes IA and IB of hepatitis A virus in Northeast Brazil

“…Phylogenetic analysis of the nucleotide sequence of the VP1/2A region of the HAV genome classified all isolates as genotype I, confirming former epidemiological data demonstrating that this is the main genotype circulating in Brazil (7,10,22) as well the most widespread genotype in the world (2,23,24). Additionally, we identified the simultaneous presence of sub-genotypes IA and IB in 65 and 35% of cases of HAV infection, respectively.…”

“…Thus, these data suggest that there is a circulation of endemic HAV strains in this region, as demonstrated in other regions of Brazil (7,10). Moreover, the presence of the same strains sharing the same nucleotide sequence might indicate the presence of unidentified epidemic foci, since these isolates were identified in cases that occurred during a short period of time (most of them in December 2002).…”

“…The epidemiology of HAV infection in Brazil is characterized by a heterogeneous pattern, with low endemicity observed in the South and Southeast regions, with an anti-HAV prevalence rate of 55.7%, whereas the highest anti-HAV rates, 92.8 and 76.5%, are observed in the North and Northeast regions, respectively (8). This situation demonstrates the importance of carrying out epidemiological studies in the North and Northeast regions of Brazil. In previous studies by our group on the molecular epidemiology of HAV in Brazil (7,9,10), sub-genotypes IA and IB were detected among acute HAV cases and among HCV-co-infected patients in the Rio de Janeiro population, whereas in other 8 states of Brazil only sub-genotype IA was found. More detailed studies are necessary to determine the real distribution of HAV genotypes in our country, and for this reason we presently evaluated the circulation of HAV subgenotypes in Pernambuco State, one of the most populous states of the Northeast region.…”

“…The presence of both sub-genotypes has not been detected previously in the Northeastern region. de Paula et al (10) observed that all HAV sequences belonged to sub-genotype 1A in other States of the Northeastern region. Only in the Southeastern region was the co-circulation of subgenotype 1A and 1B detected before (7,22).…”

Prevalence of hepatitis A virus infection in Goiânia, Goiás, Brazil, by molecular and serological procedures, 1995-2002

“…This result differs from those of other studies, which show greater molecular marker positivity from anti-HAV-IgM positive samples (Fujiwara et al 1997, Kwon et al 2000, de Paula et al 2002, 2004a, b, Villar et al 2004, Poovorawan et al 2005. This difference could be explained by the fact that the serum samples were stored for a long time and for this reason, the viral RNA could have been degraded.…”