Amnat Yousukh

Possible new hepatitis B virus genotype, southeast Asia.

We conducted a phylogenetic analysis of 19 hepatitis B virus strains from Laos that belonged to 2 subgenotypes of a new genotype I. This emerging new genotype likely developed outside Southeast Asia and is now found in mixed infections and in recombinations with local strains in a geographically confined region.

High genetic diversity including potential new subtypes of hepatitis C virus genotype 6 in Lao People's Democratic Republic

Sera from 105 anti-HCV-positive first-time blood donors collected in 2004, 2005 and 2008 in different provinces in Laos were investigated by PCR. Forty-five samples were positive for HCV (42.86%); two belonged to subtype 1b (2/45, 4.4%) and all others to genotype 6 (43/45, 95.6%), including subtypes 6b, 6h, 6k, 6l, 6n and 6q. Three groups of sequences were not clearly attributable to any genotype 6 subtype, two of which may be regarded as candidates for new subtypes of genotype 6. Two samples were mixed infected with different subtypes or clusters of genotype 6 viruses.

A High Variability of Mixed Infections and Recent Recombinations of Hepatitis B Virus in Laos

In Lao PDR, where more than 8% of the population are chronic carriers of HBsAg, multiple genotypes and subgenotypes co-circulate and are prone to generate recombinant viruses. Phylogenetic analyses of multiple clones per donor revealed mixed infections of subgenotypes B1, B2, B4, C1, C5, I1 and I2 in almost 6% of HBsAg positive rejected blood donors. Recombination analyses and distance calculations furthermore showed that about 65% (17/26) of the mixed infected donors showed recombinations in the S-gene alone, involving the predominant genotypes B and C. These results suggest that, at least in Laos, hepatitis B virus (HBV) mixed infections lead to frequent recombinations. In many donors with recombinant strains, the recombinant fragment and a non-recombinant strain of the same genotype co-existed (127/185 analysed recombinant fragments). For a large proportion of these (60/127), the most closely related known virus was found, although not always exclusively, in the same donor. Recombinant virus strains are largely distinct. This is reflected in an unexpected diversity in recombination breakpoints and the relatively rare recombinations with identical recombination patterns of the same genotypes in different donors. Recent recombination events would explain the limited spread of each of the recombinants. Using a published mutation rate of 4.2×10−5 mutations per site and year, the observed minimum genetic distances of 0–0.60% between parent strain and recombinant fragment would correspond to 0–71 years of evolution from a most recent common ancestor (MRCA). Thus several lines of evidence are suggestive of recent independent recombination events, a proportion of these even occurring within the same donors. In conclusion, our analyses revealed a high variability of mixed infections as a very probable breeding ground of multiple variable recombination events in Laos that so far have not led to new dominant strains.

Clinicopathologic Study of Hepatic Penicillium marneffei in Northern Thailand

CONTEXT Penicillium marneffei, an opportunistic fungus, is endemic in Southeast Asia, especially in human immunodeficiency virus-infected individuals living in northern Thailand. OBJECTIVE We present the results of a clinicopathologic study of hepatic penicilliosis among human immunodeficiency virus/acquired immunodeficiency syndrome patients. DESIGN A search of liver biopsies in one institution from 1998 to 1999 identified 30 cases of penicilliosis. RESULTS Histologically, hepatic lesions could be classified into 1 of 3 patterns: diffuse, granulomatous, and mixed. The diffuse pattern showed a diffuse infiltration of foamy macrophages that contained numerous P marneffei. The granulomatous pattern showed a formation of multiple granulomata with various degrees of inflammatory cell infiltration. The mixed pattern showed features intermediate between the diffuse and granulomatous patterns. Liver function tests of the 3 pathologic pattern groups were evaluated, but there were no statistically significant differences in aspartate aminotransferase, alanine aminotransferase, or alkaline phosphatase levels among the various histologic groups. CONCLUSION To our knowledge, this is the largest series to date that documents the liver pathology that results from this pathogen. We hypothesize that the histologic patterns seen on biopsy reflect the level of the hosts immunity. Hence, in addition to a diagnosis of penicilliosis, a liver biopsy may also provide an assessment of the hosts immune status, whereas liver function tests do not.

Occult hepatitis B infections among blood donors in Lao PDR

In Lao Peoples Democratic Republic, hepatitis B virus is highly endemic. However, blood donations are only screened for HBsAg, leaving a risk of transmission by HBsAg‐negative occult infected donors. Here, we characterized first‐time blood donors to assess prevalence of hepatitis B virus infections and occult infected donors.