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.

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Abstract. An evaluation of three new rapid diagnostic test kits for human immunodeficiency virus types 1 and 2 (HIV-1/2), hepatitis B surface antigen (HBsAg), and syphilis involved a two-phase comparison of rapid diagnostic assays using prospectively collected from hospitals and clinics in Ho Chi Minh City, Vietnam. After specificity and sensitivity testing, three new rapid diagnostic test kits were tested in parallel with six commonly used diagnostic test kits. The Determine HIV-1/2 test had fewer indeterminate or equivocal results than the Capillus HIV-1/HIV-2 or HIV Blot 2.2 tests. However, the Determine HIV-1/2 test yielded one false-positive result when compared with the Serodia HIV, HIV Blot 2.2, and microparticle enzyme immunoassay (IMx) HIV tests. The Serodia HBsAg test yielded more false-negative results when compared with the Determine HBsAg diagnostic test kit. The results of the syphilis diagnostic tests evaluated in this clinical trial consistently agreed with those of the rapid plasma reagin test for syphilis. The Determine Syphilis Treponema pallidum (TP) test had three false-positive results compared with the Serodia TP and the Serodia TP•particle agglutination (PA) tests, which had two false-positive results that were confirmed as negative by an ELISA. Application of these serologic tests within this comparative evaluation framework, using the World Health Organization alternative testing strategies, proved to be an effective way to determine serostatus related to HIV, hepatitis B, and syphilis.In many developing areas worldwide, field and clinic laboratory capabilities may be insufficient for the detection of infectious agents for definitive clinical diagnostic purposes. The absence of simple, rapid diagnostic testing methods for sexually transmitted diseases (STDs) and hepatitis has significantly hampered public health efforts to retard the spread of these diseases. The inability to provide tests for quick recognition of human immunodeficiency virus (HIV), hepatitis B, and syphilis has allowed infected individuals to unknowingly spread the disease through sexual contacts, blood donations, and intravenous needle sharing. In cities throughout Asia, current laboratory evaluation of blood specimens may preclude case follow-up and counseling due to a long time lag between initial sample collection and conventional test completion. High-risk populations typically seek treatment during clinic visits in association with acute episodes and are not likely to return a second time for test results.Diagnostic technology is adapting itself for application in developing countries. Advancements in the laboratory diagnosis of HIV/acquired immunodeficiency syndrome (AIDS), hepatitis B, and syphilis have considered the following conditions, including: 1) speed of results; 2) test validity and accuracy; 3) minimal specimen requirement; 4) variable type of specimen, including whole blood; 5) ease of test kit use, with few requirements for specialized laboratory equipment; and 6) stable reagents, requiring no refri...

BackgroundAn 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.MethodsSerum 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.ResultsSera 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 $190, $137, and $119 at CrAg prevalences of 2%, 4% and 6%, respectively.ConclusionCrAg prevalence was higher in southern compared with northern Vietnam; however, CrAg screening would be considered cost-effective by WHO criteria in both regions. Public health officials in Vietnam should consider adding cryptococcal screening to existing national guidelines for HIV/AIDS care.

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 (5UTR) 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 5UTR. We investigated the accuracy of a new generation LiPA (VERSANT HCV genotype 2.0 assay), in which genotyping is based on 5UTR and core sequences, by testing 75 selected HCV RNA-positive sera from Southeast Asia (Vietnam and Thailand). For comparison, sera were tested on the 5UTR based VERSANT HCV genotype assay and processed for sequence analysis of the 5UTR-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 5UTR (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.

Hepatitis C virus (HCV) has a linear positive-stranded RNA genome of ϳ9,600 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 HCV's huge genetic diversity and warrant studies to explore their biological relevance.Hepatitis C virus (HCV) is an enveloped virus that belongs to the family Flaviviridae. Its linear positive-stranded RNA genome of approximately 9.6 kb in length encodes both structural (core, E1, and E2) and nonstructural (p7, N2, NS3, NS4a/b, and NS5a/b) proteins in a single open reading frame, flanked by short conserved untranslated regions (UTRs) located at the 5Ј and 3Ј ends of the genome that are required for viral replication and protein translation (5,7,8). One of the most striking characteristics of HCV is its capacity to cause a chronic liver disease in a high percentage of individuals (24). To do so, HCV encodes proteins which promote persistence, and sequence variation, especially in the envelope genes (E1 and E2), results in escape from adaptive immune responses (9, 27).Lack of proofreading ability of the viral RNA-dependent RNA polymerase is the driving force behind HCV's genetic diversity. As a result of the large amount (10 12 ) of virions produced each day in chronic hepatitis C patients and the rate of incorrect nucleotide insertions, which reaches the order of 10 Ϫ3 to 10 Ϫ4 base substitutions per site per year, HCV quasispecies are generated (22,26). Recombination may be another mechanism by which genetic diversity is driven, given the recent identification of naturally occurring intergenotypic recombinant viruses (13, 21). Because of the huge genetic diversity, HCVs are currently categorized into six major genotypes and more than 80 subtypes (25).HCV genetic variation has been studied in relation to epidemiology, response to antiviral therapy, and clinical parameters, using different techniques that have focused on short genomic regions. However, analysis of full-length viral genomes may be necessary to better understand the characteristics of HCV. Previously, we analyzed sera from HCV RNA-positive blood donors from Ho Chi Minh City, Vietnam, in order to analyze the molecular heterogeneity of HCV in Southeast Asia (21). Based on sequence analysis of core and NS5b regions in a set of sera, two ...

The ability of current overseas screening to detect tuberculosis among immigrants with abnormal chest radiographs is low. Improved diagnostic methods, enhanced screening measures, and postmigration follow-up are essential to control tuberculosis among immigrants and support US and global tuberculosis elimination.

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.