Truong Xuan Lien

Identification of a Naturally Occurring Recombinant Genotype 2/6 Hepatitis C Virus

ABSTRACT Hepatitis C viruses (HCVs) display a high level of sequence diversity and are currently classified into six genotypes and an increasing number of subtypes. Most likely, this heterogeneity is caused by genetic drift; evidence for recombination is scarce. To study the molecular heterogeneity of HCV in Vietnam, we analyzed 58 HCV RNA-positive sera from Vietnamese blood donors by sequence analysis of the CORE and NS5B regions. Phylogenetic analyses revealed the presence of genotype 1 (38%), genotype 2 (10.3%), and genotype 6 viruses (51.7%). All samples showed concordant results except for two (D3 and D54). Sample D54 was a mixed infection of genotype 2i and 6h viruses. Whole-genome analysis and bootscan analysis of sample D3, on the other hand, revealed a recombinant virus with genotype 2i and genotype 6p sequences at the 5′ and 3′ ends, respectively. The crossover point was located between nucleotide positions 3405 to 3464 (numbering according to prototype strain HCV-H, M67463) at the NS2/NS3 junction. The identification of this naturally occurring recombinant virus strengthens the concept that recombination may play a role in HCV epidemiology and evolution. Furthermore, the location of the recombination breakpoint may be relevant for constructing infectious chimeric viruses.

HIV infection and risk factors among female sex workers in southern Vietnam.

Objectives:To determine the extent of HIV infection among female commercial sex workers (CSW), to identify risk factors, and to provide baseline data for developing and targeting prevention measures. Subjects and methods:A total of 968 female CSW were enrolled in a cross- sectional study from August 1995 to October 1996. Information was obtained from confidential face-to-face interview, physical examination, and laboratory testing. Results:A total of 65.5% of female CSW reported inconsistent condom use. Overall seroprevalence was 5.2%. The highest seroprevalence (9.5%) was detected in An Giang province, a border area adjacent to Cambodia. Out of seven HIV isolates in An Giang province, six were characterized as Thai subtype E and one as subtype B. Multiple logistic regression analysis showed an independent significant association between HIV seroprevalence and the following: age ≤ 30 years [odds ratio (OR), 5.1; 95% confidence interval (CI), 1.7–15.2]; high frequency of sex (> 20 times per week; OR, 13.5; 95% CI, 3.6–50.2); inconsistent condom use (OR, 2.8; 95% CI, 1.01–8.0; sign of genital ulcers (OR, 18.1; 95% CI, 1.8–182); venereal warts (OR, 9.0; 95% CI, 2.5–33.0); brothels as sex venue (OR, 7.0; 95% CI, 2.0–24.3); and working at the border area (OR, 5.1; 95% CI, 2.4–11.0). Brothels as work-sites were significantly related to inconsistent condom use and the socioeconomic background of clients. Only 0.5% of CSW reported injecting drug use. Conclusions:Female CSW at brothels who reported inconsistent condom use and ulcerous sexually transmitted disease, particularly in the border area with Cambodia, had greater risk of HIV infection. Brothels were more frequently used as sex venues in the border area and were more likely to be visited by occasional clients who were difficult to access. Drug use among female CSW in this region was rare. The development of prevention measures should be based on these results.

Prevalence of hepatitis virus types B through E and genotypic distribution of HBV and HCV in Ho Chi Minh City, Vietnam

A molecular epidemiological survey of various hepatitis viral infections, including hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis D virus (HDV), was carried out in Ho Chi Minh City, Vietnam. This study included of 295 patients with liver disease (234 viral related and 61 non-viral related) and 100 healthy individuals. The infection rates of HBV and HCV in 234 liver disease patients with acute hepatitis, chronic hepatitis, liver cirrhosis and hepatocellular carcinoma, were 31.2 and 19.2%, respectively. On the other hand, detection rates of these viruses in healthy populations were 10 and 2%, respectively (P<0.005 and <0.0001, respectively). None of cases tested was positive for HDV RNA. The most common viral genotypes were type B and C of HBV (43 and 57%) and type 2a of HCV (33.3%). Surprisingly, high prevalence of HBV pre-S2 deletion mutant was found in 22 of 87 (25.3%) patients with chronic liver disease. Moreover, antibody to hepatitis E virus (HEV) immunoglobulin G (IgG) was detected in 78 of 185 (42%) and IgM in 1 of 185 (0.5%) patients. The age prevalence of anti-HEV IgG was reached 61.9% in 21-40-year-olds. These results suggest that these hepatitis viruses, except for HDV, are spreading among liver disease patients in Ho Chi Minh city, Vietnam and HBV was the most important causative agent correlated with liver disease in this area.

Genotyping Hepatitis C Viruses from Southeast Asia by a Novel Line Probe Assay That Simultaneously Detects Core and 5′ Untranslated Regions

ABSTRACT Hepatitis C viruses (HCVs) display a high level of sequence diversity and are currently divided into six genotypes. A line probe assay (LiPA), which targets the 5′ untranslated region (5′UTR) of the HCV genome, is widely used for genotyping. However, this assay cannot distinguish many genotype 6 subtypes from genotype 1 due to high sequence similarity in the 5′UTR. We investigated the accuracy of a new generation LiPA (VERSANT HCV genotype 2.0 assay), in which genotyping is based on 5′UTR and core sequences, by testing 75 selected HCV RNA-positive sera from Southeast Asia (Vietnam and Thailand). For comparison, sera were tested on the 5′UTR based VERSANT HCV genotype assay and processed for sequence analysis of the 5′UTR-to-core and NS5b regions as well. Phylogenetic analysis of both regions revealed the presence of genotype 1, 2, 3, and 6 viruses. Using the new LiPA assay, genotypes 6c to 6l and 1a/b samples were more accurately genotyped than with the previous test only targeting the 5′UTR (96% versus 71%, respectively). These results indicate that the VERSANT HCV genotype 2.0 assay is able to discriminate genotypes 6c to 6l from genotype 1 and allows a more accurate identification of genotype 1a from 1b by using the genotype-specific core information.

HIV type 1 isolates from 200 untreated individuals in Ho Chi Minh City (Vietnam): ANRS 1257 Study. Large predominance of CRF01_AE and presence of major resistance mutations to antiretroviral drugs.

HIV-1 isolates from 200 untreated patients recruited in 2001 and 2002 in the south part of Vietnam and particularly in Ho Chi Minh City were sequenced in the RT, protease, and env genes. Out of 200 isolates 198 belonged to CRF01_AE while only one subtype B and one intersubtype (B-CRF01_AE) recombinant could be observed. Of the isolates 6.5% had major resistance mutations to antiretroviral drugs.

Genetic Similarity of HIV Type 1 Subtype E in a Recent Outbreak among Injecting Drug Users in Northern Vietnam to Strains in Guangxi Province of Southern China

To investigate the molecular epidemiology of a recent HIV-1 outbreak in northern Vietnam and its relation to the epidemic in surrounding areas, we analyzed 17 HIV-positive blood specimens from 3 heterosexuals, 2 sexually transmitted disease patients, and 12 injecting drug users (IDUs), collected in 4 provinces near Hanoi in 1998. These were compared with the specimens from Ho Chi Minh City (n = 10) and An Giang Province (n = 10) in southern Vietnam and with published sequences from neighboring countries. Genetic subtyping based on the env C2/V3 sequences revealed that HIV-1 subtype E predominated throughout Vietnam in all risk populations; the exception was one typical United States-European-type HIV-1 subtype B detected in a patient in Ho Chi Minh City, the first case of HIV infection identified in Vietnam in 1990. The HIV-1 subtype E sequences identified in 9 of the 12 IDUs from northern provinces were closely related phylogenetically to those in IDUs in nearby Guangxi Province of China, and also shared a common amino acid signature downstream of the env V3 loop region. The low interperson nucleotide diversity among IDUs in northern Vietnam supports the view that HIV-1 subtype E was introduced recently among IDUs in northern Vietnam. These data indicate a linkage between HIV-1 circulating among IDUs in northern Vietnam and southern China, and suggest recent transborder introductions as the likely source of HIV-1 subtype E in northern Vietnam.

Characterization of hepatitis C virus deletion mutants circulating in chronically infected patients.

ABSTRACT Hepatitis C virus (HCV) has a linear positive-stranded RNA genome of ∼9,600 nucleotides in length and displays a high level of sequence diversity caused by high mutation rates and recombination. However, when we performed long distance reverse transcription-PCRs on HCV RNA isolated from serum of chronic HCV patients, not only full-length HCV genomes but also HCV RNAs which varied in size from 7,600 to 8,346 nucleotides and contained large in-frame deletions between E1 and NS2 were amplified. Carefully designed control experiments indicated that these deletion mutants are a bona fide natural RNA species, most likely packaged in virions. Moreover, deletion mutants were detected in sera of patients infected with different HCV genotypes. We observed that 7/37 (18.9%) of genotype 1, 5/43 (11.6%) of genotype 3, and 4/13 (30.7%) of genotype 6 samples contained HCV deletion mutant genomes. These observations further exemplify HCVs huge genetic diversity and warrant studies to explore their biological relevance.

Prevalence of Cryptococcal Antigenemia and Cost-Effectiveness of a Cryptococcal Antigen Screening Program – Vietnam

Background An estimated 120,000 HIV-associated cryptococcal meningitis (CM) cases occur each year in South and Southeast Asia; early treatment may improve outcomes. The World Health Organization (WHO) recently recommended screening HIV-infected adults with CD4<100 cells/mm3 for serum cryptococcal antigen (CrAg), a marker of early cryptococcal infection, in areas of high CrAg prevalence. We evaluated CrAg prevalence and cost-effectiveness of this screening strategy in HIV-infected adults in northern and southern Vietnam. Methods Serum samples were collected and stored during 2009–2012 in Hanoi and Ho Chi Minh City, Vietnam, from HIV-infected, ART-naïve patients presenting to care in 12 clinics. All specimens from patients with CD4<100 cells/mm3 were tested using the CrAg lateral flow assay. We obtained cost estimates from laboratory staff, clinicians and hospital administrators in Vietnam, and evaluated cost-effectiveness using WHO guidelines. Results Sera from 226 patients [104 (46%) from North Vietnam and 122 (54%) from the South] with CD4<100 cells/mm3 were available for CrAg testing. Median CD4 count was 40 (range 0–99) cells/mm3. Nine (4%; 95% CI 2–7%) specimens were CrAg-positive. CrAg prevalence was higher in South Vietnam (6%; 95% CI 3–11%) than in North Vietnam (2%; 95% CI 0–6%) (p = 0.18). Cost per life-year gained under a screening scenario was

In-house HIV-1 RNA real-time RT-PCR assays: principle, available tests and usefulness in developing countries

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Complete genome analysis of hepatitis C virus subtypes 6t and 6u

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