Validation of a Modified Commercial Enzyme-Linked Immunoassay for Detection of Human Immunodeficiency Virus Type 1 Immunoglobulin G Antibodies in Saliva

This study was performed to evaluate the performance of a saliva collection device (OmniSal) and an enzyme-linked immunoassay (EIA) designed for use on serum samples (Detect HIV1/2) to detect human immunodeficiency virus type 1 (HIV-1) antibodies in the saliva of high-risk women in Mombasa, Kenya. The results of the saliva assay were compared to a “gold standard” of a double-EIA testing algorithm performed on serum. Individuals were considered HIV-1 seropositive if their serum tested positive for antibodies to HIV-1 by two different EIAs. The commercial serum-based EIA was modified to test the saliva samples by altering the dilution and lowering the cutoff point of the assay. Using the saliva sample, the EIA correctly identified 102 of the 103 seropositive individuals, yielding a sensitivity of 99% (95% confidence interval [CI], 94 to 100%), and 96 of the 96 seronegative individuals, yielding a specificity of 100% (95% CI, 95 to 100%). In this high-risk population, the positive predictive value of the assay was 100% and the negative predictive value was 99%. We conclude that HIV-1 antibody testing of saliva samples collected with this device and tested by this EIA is of sufficient sensitivity and specificity to make this protocol useful in epidemiological studies.     

Detection of hepatitis C virus antibodies in oral fluid specimens for prevalence studies

Within the framework of hepatitis C virus (HCV) prevalence monitoring, we evaluated oral fluid (OF), which is richer in IgG than whole saliva, as a possible alternative to serum for the detection of HCV antibodies. Paired OF and serum samples were collected from 90 individuals, including 45 HCV-positives and 45 HCV-negatives. The detection of HCV antibodies in both serum and OF was performed using the Ortho HCV 3.0 SAVe enzyme-linked immunosorbent assay (ELISA) (Ortho-Clinical Diagnostics, Inc., Raritan, NJ), but a modified, more sensitive protocol was used to process OF. The sensitivity and specificity of this assay were 86.67% (95% confidence interval (CI): 72.51–94.46%) and 100% (95% CI: 90.20–99.80%) in OF and 100% in serum. The correlation obtained between both types of clinical specimens was excellent (k: 0.87, 95% CI: 0.66–1.07). However, the negative predictive value (NPV) of the assay in OF decreased with the prevalence of HCV infection in the population studied. Our results suggest that the modified Ortho HCV 3.0 SAVe ELISA is suitable for the detection of HCV antibodies in OF for epidemiological studies. Using this assay, we observed an unadjusted anti-HCV prevalence of 78.6% among a population of intravenous drug users; when adjusted to account for assay sensitivity, this prevalence may be closer to 90%.     

Validation of a modified commercial enzyme-linked immunoassay for detection of human immunodeficiency virus type 1 immunoglobulin G antibodies in saliva

This study was performed to evaluate the performance of a saliva collection device (OmniSal) and an enzyme-linked immunoassay (EIA) designed for use on serum samples (Detect HIV1/2) to detect human immunodeficiency virus type 1 (HIV-1) antibodies in the saliva of high-risk women in Mombasa, Kenya. The results of the saliva assay were compared to a "gold standard" of a double-EIA testing algorithm performed on serum. Individuals were considered HIV-1 seropositive if their serum tested positive for antibodies to HIV-1 by two different EIAs. The commercial serum-based EIA was modified to test the saliva samples by altering the dilution and lowering the cutoff point of the assay. Using the saliva sample, the EIA correctly identified 102 of the 103 seropositive individuals, yielding a sensitivity of 99% (95% confidence interval [CI], 94 to 100%), and 96 of the 96 seronegative individuals, yielding a specificity of 100% (95% CI, 95 to 100%). In this high-risk population, the positive predictive value of the assay was 100% and the negative predictive value was 99%. We conclude that HIV-1 antibody testing of saliva samples collected with this device and tested by this EIA is of sufficient sensitivity and specificity to make this protocol useful in epidemiological studies.     

Evaluation of hepatitis C antibody testing in saliva specimens collected by two different systems in comparison with HCV antibody and HCV RNA in serum

Two different ELISA assays, the Ortho HCV 3.0 ELISA (Ortho Diagnostics Systems) and the Mono-Lisa anti-HCV Plus (Sanofi Diagnostics Pasteur) were evaluated for the detection of hepatitis C virus (HCV) antibody in saliva samples. Specimens were collected from 152 individuals who participated in a longitudinal cohort study on HIV infection, and who used illicit drugs. Saliva specimens were collected using two different systems: Salivette (Sarstedt) and Omni-Sal (Saliva Diagnostic Systems). Saliva specimens were tested following modified protocols by both ELISAs, and the results were compared with serum specimens that were tested according to the instructions of the manufacturer. Serum samples of 102 (67%) participants were positive by both assays, and 50 persons were negative for HCV antibody. A total of 99 of the 102 serum specimens were confirmed as positive using Ortho Riba HCV 3.0 (Ortho Diagnostics System) and Deciscan HCV (Sanofi Diagnostics Pasteur), and 3 yielded discrepant results. As no cut-off level is known for testing saliva samples by ELISA, 3 different levels were chosen: mean (M) + 1 standard deviation (SD), M + 2 SD, and M + 3 SD of the optical densities of saliva tests of the 50 HCV serum antibody negative persons. At a level of M + 1 SD and M + 2 SD the Salivette/Mono-Lisa combination gave the greatest proportion of HCV antibody positive saliva specimens obtained from the 102 HCV serum antibody positive participants, 88% and 79%, respectively. Differences between the various collection systems and assay combinations were not significant statistically. In 76 of the 102 persons with HCV antibodies in serum, HCV RNA was detected in serum. Salivary presence of HCV RNA, however, could not be demonstrated. The results show that the assays compared are unsuitable for diagnostic use, but the sensitivities of the assays are acceptable for use in epidemiological studies.     

Higher prevalence of anti-HCV antibodies among HIV-positive compared to HIV-negative inhabitants of Addis Ababa,Ethiopia

Serum samples (n = 4,593) collected in 1994 as part of a representative household community survey of the population of Addis Ababa who were 0-49 years old were tested for hepatitis C (HCV) antibodies. A third generation ELISA was used for primary screening and a line immunoblot assay for confirmation. HCV antibody prevalence was 0.9% (95% CI, 0.6-1.2%) and higher among HIV-positive compared to HIV-negative individuals (4.5% vs. 0.8%, respectively, P < 0.001). Similar higher prevalence of HCV antibodies was seen among HIV-positive compared to HIV-negative antenatal care attenders (2.9% vs. 0.8%, respectively, P = 0.003, n = 1,725), and sex workers (5.3% vs. 1.3%, respectively, P = 0.02, n = 383). Such association between HCV and HIV infection has not been described previously in Africa. After stratification by HIV status, HCV prevalence among women of the general population was identical to that of sex workers, suggesting that HCV sexual transmission is not common in this population and that HIV infection does not enhance susceptibility to HCV sexual transmission.     

Testing strategy to identify cases of acute hepatitis C virus (HCV) infection and to project HCV incidence rates

Surveillance for hepatitis C virus (HCV) is limited by the challenge of differentiating between acute and chronic infections. In this study, we evaluate a cross-sectional testing strategy that identifies individuals with acute HCV infection and we estimate HCV incidence. Anti-HCV-negative persons from four populations with various risks, i.e., blood donors, Veterans Administration (VA) patients, young injection drug users (IDU), and older IDU, were screened for HCV RNA by minipool or individual sample nucleic acid testing (NAT). The number of detected viremic seronegative infections was combined with the duration of the preseroconversion NAT-positive window period (derived from analysis of frequent serial samples from plasma donors followed from NAT detection to seroconversion) to estimate annual HCV incidence rates. Projected incidence rates were compared to observed incidence rates. Projected HCV incidence rates per 100 person-years were 0.0042 (95% confidence interval [95% CI], 0.0025 to 0.007) for blood donors, 0.86 (95% CI, 0.02 to 0.71) for VA patients, 39.8 (95% CI, 25.9 to 53.7) for young IDU, and 53.7 (95% CI, 23.4 to 108.8) for older IDU. Projected rates were most similar to observed incidence rates for young IDU (33.4; 95% CI, 28.0 to 39.9). This study demonstrates the value of applying a cross-sectional screening strategy to detect acute HCV infections and to estimate HCV incidence.     

A cost-effective algorithm for the diagnosis of Hepatitis C virus infection and prediction of HCV viremia in Cameroon

Conventional tests for antibody to Hepatitis C virus (HCV) and HCV RNA require considerable time before results are available, remain very expensive and are not adapted to many sub-Saharan African countries where HCV is endemic. The aim of this study was to evaluate the accuracy of an algorithm consisting of two HCV rapid tests to diagnose and predict HCV viremia in patients in Cameroon. Three hundred and twenty nine plasma samples were screened by two HCV rapid tests (ImmunoComb II HCV, PBS Orgenics and Hexagon HCV, Human). Previous evaluation of these samples for HCV antibodies (anti-HCV) by conventional third generation ELISA, considered as a reference test, indicated that 168 were anti-HCV negative and 161 positive. Among the 161 anti-HCV positive plasma, 114 (71%) were HCV RNA-positive by RT-PCR assay. The ImmunoComb II HCV test provided the more sensitive detection of anti-HCV (sensitivity: 99.4% with a 95% CI = 96-100%). Surprisingly, the second HCV rapid test, Hexagon HCV, showed a high capacity to identify non-viremic subjects amongst anti-HCV positive cases (93.6% [95% CI: 82-99%]). These results suggest an algorithm using ImmunoComb II HCV as a first test to screen anti-HCV positive subjects, and Hexagon HCV as a second test to discriminate between viremic and non-viremic HCV seropositive subjects.     

Performance of an Early Infant Diagnostic Test,AmpliSens DNA-HIV-FRT,Using Dried Blood Spots Collected from Children Born to Human Immunodeficiency Virus-Infected Mothers in Ukraine

An accurate accessible test for early infant diagnosis (EID) is crucial for identifying HIV-infected infants and linking them to treatment. To improve EID services in Ukraine, dried blood spot (DBS) samples obtained from 237 HIV-exposed children (≤18 months of age) in six regions in Ukraine in 2012 to 2013 were tested with the AmpliSens DNA-HIV-FRT assay, the Roche COBAS AmpliPrep/COBAS TaqMan (CAP/CTM) HIV-1 Qual test, and the Abbott RealTime HIV-1 Qualitative assay. In comparison with the paired whole-blood results generated from AmpliSens testing at the oblast HIV reference laboratories in Ukraine, the sensitivity was 0.99 (95% confidence interval [CI], 0.95 to 1.00) for the AmpliSens and Roche CAP/CTM Qual assays and 0.96 (95% CI, 0.90 to 0.98) for the Abbott Qualitative assay. The specificity was 1.00 (95% CI, 0.97 to 1.00) for the AmpliSens and Abbott Qualitative assays and 0.99 (95% CI, 0.96 to 1.00) for the Roche CAP/CTM Qual assay. McNemar analysis indicated that the proportions of positive results for the tests were not significantly different (P > 0.05). Cohen''s kappa (0.97 to 0.99) indicated almost perfect agreement among the three tests. These results indicated that the AmpliSens DBS and whole-blood tests performed equally well and were comparable to the two commercially available EID tests. More importantly, the performance characteristics of the AmpliSens DBS test meets the World Health Organization EID test requirements; implementing AmpliSens DBS testing might improve EID services in resource-limited settings.     

HCV avidity as a tool for detection of recent HCV infection: Sensitivity depends on HCV genotype

Accurate detection of incident hepatitis C virus (HCV) infection is required to target and evaluate public health interventions, but acute infection is largely asymptomatic and difficult to detect using traditional methods. Our aim was to evaluate a previously developed HCV avidity assay to distinguish acute from chronic HCV infection. Plasma samples collected from recent seroconversion subjects in two large Australian cohorts were tested using the avidity assay, and the avidity index (AI) was calculated. Demographic and clinical characteristics of patients with low/high AI were compared via logistic regression. Sensitivity and specificity of the assay for recent infection and the mean duration of recent infection (MDRI) were estimated stratified by HCV genotype. Avidity was assessed in 567 samples (from 215 participants), including 304 with viraemia (defined as ≥250 IU/mL). An inverse relationship between AI and infection duration was found in viraemic samples only. The adjusted odds of a low AI (<30%) decreased with infection duration (odds ratio [OR] per week of 0.93; 95% CI:0.89‐0.97), and were lower for G1 compared with G3 samples (OR = 0.14; 95% CI:0.05‐0.39). Defining recent infection as <26 weeks, sensitivity (at AI cut‐off of 20%) was estimated at 48% (95% CI:39‐56%), 36% (95% CI:20‐52%), and 65% (95% CI:54‐75%) and MDRI was 116, 83, and 152 days for all genotypes, G1, and G3, respectively. Specificity (≥52 weeks infection duration, all genotypes) was 96% (95% CI:90‐98%). HCV avidity testing has utility for detecting recent HCV infection in patients, and for assessing progress in reaching incidence targets for eliminating transmission, but variation in assay performance across genotype should be recognized.     

Prevalence of hepatitis B and hepatitis C virus infections in France in 2004: Social factors are important predictors after adjusting for known risk factors

To monitor the prevalence of hepatitis B and hepatitis C a cross‐sectional survey was conducted in 2004 among French metropolitan residents. A complex sampling design was used to enroll 14,416 adult participants aged 18–80 years. Data collected included demographic and social characteristics and risk factors. Sera were tested for anti‐HCV, HCV‐RNA, anti‐HBc and HBsAg. Data were analyzed with SUDAAN® software to provide weighted estimates for the French metropolitan resident population. The overall anti‐HCV prevalence was 0.84% (95% CI: 0.65–1.10). Among anti‐HCV positive individuals, 57.4% (95% CI: 43.2–70.5) knew their status. Factors associated independently with positive anti‐HCV were drug use (intravenous and nasal), blood transfusion before 1992, a history of tattoos, low socioeconomic status, being born in a country where anti‐HCV prevalence >2.5%, and age >29 years. The overall anti‐HBc prevalence was 7.3% (95%: 6.5–8.2). Independent risk factors for anti‐HBc were intravenous drug use, being a man who has sex with men, low socioeconomic status, a stay in a psychiatric facility or facility for the mentally disabled, <12 years of education, being born in a country where HBsAg prevalence >2%, age >29 and male sex. The HCV RNA and HBsAg prevalence were 0.53% (95% CI: 0.40–0.70) and 0.65% (95% CI: 0.45–0.93), respectively. Among HBsAg positive individuals, 44.8% (95% CI: 22.8–69.1) knew their status. Anti‐HCV prevalence was close to the 1990s estimates whereas HBsAg prevalence estimate was greater than expected. Screening of hepatitis B and C should be strengthened and should account for social vulnerability. J. Med. Virol. 82:546–555, 2010. © 2010 Wiley‐Liss, Inc.     

An anonymous unlinked sero-prevalence survey of HIVHCV in an urban Emergency Department

BackgroundIn 2002, the sero-prevalence of human immunodeficiency virus-1 (HIV) in the Emergency Department (ED), University Hospital, Newark, New Jersey was 10.4%. Both HIV and hepatitis C virus (HCV) are transmitted by injection drug use (IDU) or sexual contact. However, the degree of concurrent positive HCV antibody status in HIV-infected ED patients is unknown.ObjectivesIn this study we determined the sero-prevalence of HIV and HIVHCV in HIV-positive patients in the ED.Study designA cross-sectional study using an anonymous sero-prevalence survey was conducted from 7/1/2008 to 8/23/2008. Medical records were reviewed and de-identified; remnant blood specimens were also de-identified and tested for HIV antibody, and if positive, HCV antibody.ResultsOf 3488 specimens, 225 (6.5%, 95% CI: 5.7–7.3%) were positive for HIV antibody. Seventy-four patients 74/225 (32.9%, 95% CI: 33.8–46.5%) were unaware of their sero-positivity. Forty percent of HIV positive patients (90/225, 95% CI: 33.8–46.5%) were HCV antibody positive. The highest seroprevalence of HIVHCV antibody was among older patients (≥45 years), and patients with positive urine toxicology and elevated liver function tests.DiscussionGiven the high prevalence of HIV and HIVHCV antibody in the ED, routine testing is important for patients ≥45 years with positive urine toxicology and elevated liver function tests.     

Epidemiology of hepatitis C viral infection in Faisalabad,Pakistan: a retrospective study (2010–2012)

Background

Hepatitis viral infections are major health challenge leading to high morbidity and mortality worldwide.

Objectives

Although the magnitude of hepatitis in Pakistan has been well documented, information regarding the prevalence of hepatitis C virus (HCV) infection in Faisalabad, Pakistan is scarce. The present retrospective study was undertaken to determine the epidemiology of HCV in Faisalabad, Pakistan.

Methods

Between May, 2010 and December, 2012, medical records of 39780 subjects visiting sexually transmitted infections (STIs) clinic, district headquarter (DHQ) hospital, Faisalabad, Pakistan were reviewed. Regression analysis was used to determine independent risk factors

Results

HCV prevalence was 21.99%. With mean age of 49.5 ± 2.7 years (range 27–63 years), majority (67.15%) of the individuals were male. Marital status and low literacy rates were associated with HCV (P<0.05). Reference to the potential risk factors, the injection drug use was the major mode (72.77%) of infection transmission. Age (OR 1.5, 95% CI 1.2–1.9), male gender (OR 1.2, 95% CI 0.9–1.6) and injection use (OR 1.9, 95% CI 1.0–2.7) were significantly associated with HCV.

Conclusions

Most important finding was higher HCV prevalence in Faisalabad region as compared to the previous assessments that demands an urgent need for preventive intervention strategies.     

A Serotyping Assay for Hepatitis C Virus in Southeast Asia

A serotyping assay for hepatitis C virus (HCV) was evaluated with samples from Thailand, where the distribution of HCV genotypes was different from that in Western countries where the assay was designed and validated. The sensitivity of the assay was low (58%) for HCV RNA-positive samples compared to that of the genotyping assay (95%, P < 0.01). In addition, only 36% of anti-HCV-positive but HCV RNA-negative samples could be serotyped. The serotypes and genotypes were identical in 96% of the samples that could be typed by both methods. Most of the samples with genotype 6, which was common in Southeast Asia, were nontypeable by this serotyping assay.     

Sensitivity of an anti-HCV core peptide ELISA.

A newly developed antibody assay based on a synthetic peptide of 15 amino acids derived from the core region of the hepatitis C virus (HCV) genome was evaluated in serum and plasma panels of (A) 225 haemophiliacs and (B) 44 patients with chronic non-A, non-B (NANB) hepatitis, and in (C) sequential serum samples of 9 patients with transfusion transmitted HCV infection. The new anti-core peptide ELISA was compared with the anti-C100 ELISA. For confirmation of HCV infection, samples were tested in a 4-antigen recombinant immunoblot assay (4-RIBA) and samples of panels B and C were also assayed in cDNA-polymerase chain reaction (PCR). In two panels with a high prevalence of HCV infection (88.4 and 70.5% in haemophilia and NANB hepatitis patients, respectively), the sensitivity of the anti-core peptide ELISA did not differ significantly from the sensitivity of the anti-C100 ELISA. The sensitivity of the new assay as compared with the anti-C100 assay was found to be 0.84 [95% confidence interval (CI): 0.78-0.89] versus 0.92 (95% CI: 0.87-0.95) in haemophilia patients and 0.71 (95% CI: 0.52-0.86) versus 0.84 (95% CI: 0.66-0.95) in NANB hepatitis patients. In sequential serum samples of patients with transfusion-transmitted HCV infection antibodies to the core peptide (in 6/9 patients) appeared later than antibodies to C100 (in 7/9 patients): 168 (range: 70-322) and 143 (range: 59-365) days after transfusion, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Change in hepatitis C virus genotype in injecting drug users

Six major genotypes of the hepatitis C virus (HCV) have been described; it is assumed to be uncommon for genotypes to change in chronically infected individuals. Venous blood samples obtained from Vietnamese-Australian injecting drug users who participated in successive studies conducted in Melbourne, Australia, were genotyped using the Bayer line probe assay and genotype confirmed by sequencing whenever possible. Three changes of HCV genotype were observed, and one infection in an individual not exposed previously. The rate of change of genotype was 3 in 11.4 person-years (py), or 26.4 per 100 py (95% CI: 8.5, 81.6). Traditionally-calculated HCV incidence was 1 in 4.3 py, or 23.3 per 100 py (95% CI: 3.3, 165.1). These data imply that HCV genotype change in injecting drug users occurs at least as frequently as infections in naive individuals, and that traditionally-calculated HCV incidence rates represent a minority of actual HCV transmission among practicing injecting drug users.     

Diagnosis of Norwalk Virus Infection by Indirect Enzyme Immunoassay Detection of Salivary Antibodies to Recombinant Norwalk Virus Antigen

Simple diagnostic tests are needed for the detection of norovirus (NoV) outbreaks. Salivary antibody assays provide an attractive alternative to collecting and testing serum or stool samples. Antibodies to Norwalk virus (NV) in oral fluid samples were compared with NV antibodies in serum collected from 38 volunteers challenged with NV inoculum. Pre- and postchallenge (day 4, 8, 14, and 21) saliva and serum samples were examined by enzyme immunoassay (EIA) using recombinant NV antigen. Of 18 infected subjects (those who shed NV in stool or who demonstrated immunoglobulin G [IgG] seroconversion), 15 (83%) had ≥4-fold increases in NV-specific salivary IgA and 15 (83%) had ≥4-fold increases in NV-specific salivary IgG when prechallenge and postchallenge saliva samples were compared. When the results of the IgA and IgG assays were combined, all 18 infected subjects showed ≥4-fold increases in NV-specific salivary IgG or IgA postchallenge titers compared to their prechallenge titers. One of 19 uninfected subjects had a ≥4-fold increase in NV-specific salivary IgG. The sensitivity of the combined assay results was 100%, and the specificity was 95%. NV-specific salivary IgA titers peaked around 14 days postchallenge. NV-specific salivary IgG and serum IgG titers continued to rise through 21 days postchallenge. The application of this EIA to an elementary school outbreak indicated that 67% of the subjects with confirmed infections had >4-fold rises in anti-NoV IgA when an antigen in the same genetic cluster as the outbreak virus was used. This is the first documented mucosal antibody response to NoV in children. This EIA provides a useful approach for diagnosing NoV outbreaks.     

Evaluation of a new rapid test kit to detect hepatitis C virus infection

This study investigated the performance characteristics and diagnostic usefulness of a new rapid device test (RDT) for HCV (SD Bioline, Korea). A total of 200 specimens were used in this study and to assess cross-reactivity, five hepatitis B surface antigen (HBsAg) positive, five anti-hepatitis B surface antibody (anti-HBs) positive, five rheumatoid factor (RF) positive, and six samples from multiple myeloma patients were tested. The early detection capability of the test was assessed using seroconversion panels. Sensitivity and specificity were calculated compared with a recombinant immunoblot assay (RIBA). Sixty-six cases were positive by the RIBA, while 52 cases were positive using the new RDT. The sensitivity and specificity of the new RDT were 78.8% (95% CI: 71.2–86.8%) and 100%, respectively. The kappa value for the agreement between the new RDT and RIBA results was 0.831 (95% CI: 0.746–0.916). The early detection capability of the new RDT and a HCV EIA were similar, with the same window period. The new RDT did not cross-react with HBsAg, anti-HBs, RF and immunoglobulins. In conclusion, the SD Bioline HCV RDT has superior sensitivity and specificity than the GENEDIA^® HCV Rapid LF that is used in Korea. This assay can be used for HCV screening, especially in small hospitals, without the financial burden of expensive equipment.     

Exploring Alternative Biomaterials for Diagnosis of Pulmonary Tuberculosis in HIV-Negative Patients by Use of the GeneXpert MTB/RIF Assay

The utility of the GeneXpert MTB/RIF (Xpert) assay for detection of Mycobacterium tuberculosis in sputum samples has been extensively studied. However, the performance of the Xpert assay as applied to other readily accessible body fluids such as exhaled breath condensate (EBC), saliva, urine, and blood has not been established. We used the Xpert assay to test EBC, saliva, urine, and blood samples from HIV-negative, smear- and culture-positive pulmonary tuberculosis (TB) patients for the presence of M. tuberculosis. To compare the ability of the assay to perform bacterial load measurements on sputum samples with versus without sample processing, the assay was also performed on paired direct and processed sputum samples from each patient. The Xpert assay detected M. tuberculosis in none of the 26 EBC samples (sensitivity, 0.0%; 95% confidence interval [95% CI], 0.0%, 12.9%), 10 of the 26 saliva samples (sensitivity, 38.5%; 95% CI, 22.4%, 57.5%), 1 of 26 urine samples (sensitivity, 3.8%; 95% CI, 0.7%, 18.9%), and 2 of 24 blood samples (sensitivity, 8.3%; 95% CI, 2.3%, 25.8%). For bacterial load measurements in the different types of sputum samples, the cycle thresholds of the two M. tuberculosis-positive sputum types were well correlated (Spearman correlation of 0.834). This study demonstrates that the Xpert assay should not be routinely used to detect M. tuberculosis in EBC, saliva, urine, or blood samples from HIV-negative patients suspected of having pulmonary tuberculosis. As a test of bacterial load, the assay produced similar results when used to test direct versus processed sputum samples. Sputum remains the optimal sample type for diagnosing pulmonary tuberculosis in HIV-negative patients with the Xpert assay.     

Risk behaviors for HCV- and HIV-seroprevalence among female crack users in Porto Alegre, Brazil

Several studies have shown a high prevalence of HIV-seropositive status among crack users, though most refer to North American populations. Few studies evaluate HCV prevalence among female crack users. In addition, there is a particular lack of data about risk behaviors and HIV/HCV prevalence in this population around the world. In order to ascertain the HIV/HCV serostatus and associated risk behaviors for infection of female crack users of Porto Alegre, Brazil. A cross-sectional study of a convenience sample of 73 current female crack users was conducted. Subjects answered NIDA’s Risk Behavior Assessment and an AIDS Information Questionnaire. In addition, blood was collected from subjects for HIV/HCV tests. The overall prevalence of HIV was 37.0%; HCV seroprevalence was 27.7%; of 15.1% the sample was co-infected with HIV and HCV. Four years of schooling or fewer (OR 4.72–CI 95%; 1.49–14.99) and having three or more HIV tests in one’s lifetime (OR 4.26–CI 95% (1.29–14.04)) were associated with HIV infection (after multivariate logistic regression). The single greatest risk factor for HCV infection was having 4 years of schooling or fewer (OR 4.51–CI 95%; 1.18–17.27). We found a very high prevalence of HIV and HCV infection among female crack users, and low education was the most significant risk factor associated with both infections.     

Spontaneous loss of hepatitis C virus RNA from serum is associated with genotype 1 and younger age at exposure

A variety of factors have been associated with spontaneous loss of hepatitis C virus (HCV)‐RNA from serum, including infecting HCV type, although results are conflicting. This study aimed to investigate further whether infecting HCV type was linked to spontaneous loss of HCV‐RNA. Serum samples from 321 untreated HCV antibody positive patients presenting at the Hepatology clinic at Addenbrooke's Hospital, Cambridge between 2004 and 2007 were tested. These individuals were classified either as HCV antibody and HCV‐RNA positive (viremic, n = 219) or HCV antibody positive and repeatedly HCV‐RNA negative (non‐viremic, n = 102). Infecting HCV type was identified by genotyping (viremic) or serotyping (non‐viremic). Binomial regression analysis investigated the independent effect of HCV type on spontaneous loss of HCV‐RNA from serum by comparing the two groups. Ninety‐one percent of patients were found to be either genotype 1 or genotype 3. The prevalence of type 1 infection was greater among non‐viremic (64.5%) than viremic individuals (45%). After controlling for the effects of potential confounding factors, multivariable analyses showed that individuals with type 1 infections were more likely to be non‐viremic than genotype 3 infections (RR = 2.07; 95% CI: 1.25, 3.43; P = 0.005). Individuals infected at an older age were also less likely to become HCV‐RNA negative spontaneously (RR = 0.42 comparing those infected at ≥20 years of age against those infected at <20 years of age, 95% CI: 0.25, 0.72; P = 0.002). In conclusion, the results suggest that HCV genotype 1 infections are more likely than genotype 3 infections to become spontaneously non‐viremic, as are infections acquired at younger age. J. Med. Virol. 83:1338–1344, 2011. © 2011 Wiley‐Liss, Inc.