Fourth-generation ELISA Research Articles

HIV, hepatitis B and C, syphilis and Tuberculosis prevalence in people deprived of liberty for criminal reasons in Argentina. Final results of a national study.

Background: One of the sanitarian policies implemented by the Ministry of Health of Argentina in the last decade was to improve health conditions and access to care for incarcerated people. For this reason, between 2015 and 2017, a nationwide study was conducted to determine the prevalence of HIV, syphilis, hepatitis B and C and Tuberculosis in federal prisons in Argentina. Methods & Materials: An observational cross-sectional study was designed based on a representative sample of the universe of 10300 imprisoned people in federal prisons. Extractions were made to study HIV (fourth generation ELISA), HBV (HBsAg and Anti-HBc), HCV and syphilis (VDRL confirmed by TF-PA). Samples were taken from those who had TB-related symptoms to perform a baciloscopy. A self-administered survey was conducted on sexual practices, care history and drug use. The fieldwork was carried out in 2016. The study was approved by a bioethics committee and was supported by UNAIDS, PAHO and UNODC. The Ministries of Health and Justice signed an agreement that made it possible to enter into prisons. Results: 2181 blood samples were taken and 2277 surveys were carried out in 6 federal prisons (89% men, 10% women and 1% trans). All estimates and prevalence values presented here were adjusted based on prison population structure, through sample weights (taking in account 6 variables). The weighted prevalence of HIV was 2.7% (CI: 2.4% -3%); syphilis 6.8% (5.8%-7.7%); positive HBsAg was 0.51% (0.37%-0.65%); positive Anti-HBc and negative HBsAg was 6.1% (5.5%-6.5%); HCV was 3.3% (3%-3.6%). In one case baciloscopy was positive, so a TB prevalence was 29.6 × 100000. Conclusion: The findings demonstrate the high prevalence of the infections studied in prison population and reinforce the need to develop interventions that facilitate access to prevention, diagnosis and care in this population. This investigation also allowed improving the diagnosis and care circuits of the prisons where it was developed. Federal prisons house 15% of the total number of people incarcerated in Argentina. It is possible that the prevalence of the infections studied is a little higher in the rest of the prisons.

Evaluation of the Architect HIV Ag/Ab Combo Assay in a low-prevalence setting: The role of samples with a low S/CO ratio

BackgroundThe Architect HIV Ag/Ab Combo Assay, a fourth-generation ELISA, has proven to be highly reliable for the diagnosis of HIV infection. However, its high sensitivity may lead to false-positive results. ObjectivesTo evaluate the diagnostic performance of Architect in a low-prevalence population and to assess the role of the sample-to-cutoff ratio (S/CO) in reducing the frequency of false-positive results. Study designWe conducted a retrospective study of samples analyzed by Architect between January 2015 and June 2017. Positive samples were confirmed by immunoblot (RIBA) or nucleic acid amplification tests (NAATs).Different S/CO thresholds (1, 2.5, 10, 25, and 100) were analyzed to determine sensitivity, specificity, and negative and positive predictive values (NPV, PPV). ROC analysis was used to determine the optimal S/CO. ResultsA total of 69,471 samples were analyzed. 709 (1.02%) were positive by Architect. Of these, 63 (8.89%) were false-positive results. Most of them (93.65%) were in samples with S/CO < 100. However, most confirmations by NAATs (12 out of 19 cases) were also recorded for these samples. The optimal S/CO was 2.5, which provided the highest area under the ROC curve (0.9998) and no false-negative results. With this S/CO, sensitivity and specificity were 100.0%, and PPV and NPV were 95.8% and 100.0%, respectively. In addition, the frequency of false-positive results decreased significantly to 4.15%. ConclusionsAlthough Architect generates a relatively high number of false-positive results, raising the S/CO limit too much to increase specificity can lead to false-negative results, especially in newly infected individuals.

Incidence and factors associated with seroconversion to hepatitis C virus seropositivity amongst patients on maintenance hemodialysis, douala-cameroon

Hepatitis C virus (HCV) infection one of the most common blood-borne infections is endemic in Cameroon and a serious problem in hemodialysis (HD). We aimed to determine the annual incidence and factors associated with seroconversion to hepatitis C positivity amongst patients on maintenance HD after an exposition of two years in a center with a high prevalence of hepatitis C (20.6%) and where no isolation policy is practiced. This was a retrospective cohort study carried out in January 2015 in the HD unit of Douala General Hospital in Cameroon including 71 patients on maintenance HD who tested negative for HCV in January 2013. Socio-demographic characteristics and clinical data were recorded, while for each patient 10 mL of blood was collected and patients retested for HCV using a fourth-generation ELISA test (BIOREXR BXEO781A). Fisher's exact test was used for dichotomous variables and using Mann Whitney's test for quantitative variables. Statistical significance was set at P <0.05. Mean age was 47 ± 13 years with 60.6% male. Blood transfusion was the main means for anemia management (85.9%) with a median number of blood units received of 5 (1-44). Facility HCV prevalence was 19.3% in January 2015. Five out of the 71 patients developed anti-HCV antibodies giving us a seroconversion rate of 7.1% and an incidence of 3.6/100 patient years. There was no significant association between age (P = 0.4), number of blood units received (P = 0.8) origin of blood units (P = 0.8), scarifications (P = 0.09) and seroconversion. After two years of exposure seroconversion to HCV positivity was 7.1% in our center with no associated factors. In a setting with high prevalence of HCV, isolation of positive patient may help to reduce the rate of transmission.

Evaluation of preliminary screening strategies for human immunodeficiency virus: a single center experience

Background: To compare and evaluate the available screening tests for human immunodeficiency virus (HIV) antibody screening test. Methods: A retrospective analysis of 331,968 screening specimens for HIV antibody test from the First Affiliated Hospital of Nanjing Medical University between January 2010 and April 2014 was performed. Three hundred and thirty-two cases were screened positive with the third-generation enzyme-linked immunosorbent assay (3G ELISA) and colloidal gold-immunochromatography assay (GICA) and these samples were repeat-tested by the fourth-generation ELISA (4G ELISA). Repeat tested positive samples were again confirmed by western blot (WB) analysis. Comparative study was used to analyze the effectiveness of the 3G ELISA, 4G ELISA and/or combined with GICA, respectively for screening of presence of HIV antibody. Results: Of the 332 positive 3G ELISA screening samples, 189 samples were confirmed to be positive for HIV by WB. The confirmed positive coincidence rate of 3G ELISA with WB was 57.27% and with 4G ELISA was 89.15%. The difference between the 3G and 4G ELISA in HIV antibody detection was statistically significant (P Conclusions: The 4G ELISA is a better HIV antibody screening test than 3G ELISA, especially when combined with GICA. The 4G ELISA combined with GICA appears to be a more suitable strategy for HIV antibody screening test in clinical practice.

Histoplasma capsulatum in the bone marrow of an HIV-infected patient

A 41-year-old man was admitted to the emergency department with a 1-month history of weight loss, intermittent fever, and malaise. Generalized pallor, mild dehydration, and a temperature of 37.5 �C were found on physical examination. Initial blood workup revealed pancytopenia, elevated lactate dehydrogenase, and hypoalbuminemia. A fourth-generation HIV ELISA test was positive. His HIV-1 RNA viral load was 13 800 copies/ml and the CD4+ T-cell count was 3 cells/mm3 . Urine, blood, and cerebrospinal fluid cultures were without microbiological isolation

Hepatitis B virus infection in Aseer Region, south-western Saudi Arabia: a call for an immediate action against a preventable disease

ObjectivesThe present study was designed as a large-scale cross-sectional study to cast some light on the magnitude of hepatitis B virus (HBV) infection in Aseer Region, south-western Saudi Arabia, a region reported to be of the highest endemicity. MethodsDuring the WHO hepatitis day of 2013, an aggressive health education campaign was launched in all the hospitals and primary health care centres in Aseer Region. Posters were distributed to encourage the local population to visit the health facilities to be tested for HBV. They were interviewed using a structured questionnaire. Detection of hepatitis B surface antigen (HBsAg) was done using a fourth-generation ELISA kits. ResultsThe present study included 10,234 persons. The study revealed an overall seroprevalence of 5.9% (95% confidence interval [CI] = 5.5–6.4%). A seroprevalence of 0.8% (95% CI = 0.2–2.1%) was found among persons aged less than 15 years, and a seroprevalence of 1.3% (95% CI = 0.4–2.9%) was found among persons aged 15–24 years. On the other hand, among persons aged 25 years and over (who were born before the expanded programme on immunization [EPI]), a seroprevalence of 6.3% (95% CI = 5.8—6.8%) was found. Pockets of unvaccinated individuals were identified. ConclusionThe present study has documented the efficacy of vaccination in protecting against HBV infection. It also identified the presence of pockets of unvaccinated persons requiring further investigations. Aggressive health education programmes and ‘catch-up’ mass vaccination of those aged over 25 years is mandatory.

Hepatitis C virus infection in southwestern Saudi Arabia: Are we still in the plateau phase?

The aim was to study the seroprevalence of Hepatitis C virus (HCV) infection and related risk factors in Aseer region in southwestern Saudi Arabia, the region known to be of the highest endemicity of viral hepatitis. In a cross-sectional study, all participants were interviewed using structured questionnaire. HCV infection was diagnosed using fourth-generation ELISA. All positive and equivocal HCV serology results were further confirmed by using a qualitative confirmatory RT-PCR. The study enrolled 10,234 participants. A seroprevalence of 2.2% (95%CI: 1.9-2.5%) was found. In multivariate logistic regression analysis, the study showed that males had significantly more risk to become seropositive for HCV (aOR = 1.437, 95%CI: 1.071-1.927) compared to females. Similarly, participants having history of blood transfusion had more than two times the risk of becoming seropositive for HCV (aOR = 2.079, 95%CI: 1.037-4.149). HCV infection in the study area is still high in the plateau phase. It is recommended to have an active educational and media campaign about the risks of HCV infections. Workshops and training of qualified laboratory staff related to blood banking seem mandatory. J. Med. Virol. 89:867-871, 2017. © 2016 Wiley Periodicals, Inc.

Comparative Study of Rapid Diagnostic Test Versus Elisa For HIV Detection At Blood Bank In Tertiary Care Hospital

BACKGROUND: Human immunodeficiency virus leads to development of AIDS which is one of the major public health problem worldwide. 1,2 So it is necessary to diagnose HIV as early as possible for prevention of HIV spread in community AIM: This study help us to evaluate effectiveness of rapid diagnostic kits as compared to ELISA methods. MATERIALS AND METHODS: This study was carried out at tertiary care hospitals (blood bank),Gujarat , India from the date 01/01/2016 to 31/07/2016.We have tested total 9111 donor samples with using fourth generation ELISA kit as well as Rapid diagnostic kit. RESULTS: Rapid diagnostic tests having Sensitivity of 90.90%. specificity was 100%,positive predictive value 100% and negative predictive value 99.98%. and accuracy was 99.98% . CONCLUSION: The rapid diagnostic HIV kits assay gives result in 15 minute can be used in emergency situations when there is less time available to perform ELISA test. So as sensitivity and specitivity of rapid diagnostic tests are high it can be used in emergency situation whenever needed

High prevalence of HIV p24 antigen among HIV antibody negative prospective blood donors in Ile-Ife, Nigeria

ABSTRACTBlood transfusion service centers in Nigeria screen donated blood for markers of HIV infection using antibody- (Ab) based rapid test and in some centers, positives are re-tested using Ab-based ELISA. Paucity of data exists on p24 antigen prevalence among HIV Ab-negative donors in Nigeria. This study aims at detecting HIV p24 antigen among prospective blood donors in Osun State, Nigeria. Prospective blood donors negative for HIV antibodies using Determine test kit were re-tested using BIORAD GENSCREEN Ultra Ag-Ab ELISA kit, a fourth-generation ELISA kit that detects HIV antibodies/p24 antigen. Of the 169 HIV Ab-negative prospective donors, 10 (5.9%) were positive for HIV p24 antigen and 70% (7/10) of them were in the age range 18–30 years. Results of this study show that blood transfusion is still one of the major routes of HIV transmission in Nigeria and a higher proportion is among youth. Inclusion of p24 antigen testing into the blood donor screening will help reduce transfusion associated HIV in Nigeria if Nucleic Acid Testing (NAT) of all blood donor samples is not affordable; also, HIV enlightenment programs tailored toward youth may help reduce this rate among donors since more young people donate blood in low/middle-income countries than in high-income countries.

High rate of missed HIV infections in individuals with indeterminate or negative HIV western blots based on current HIV testing algorithm in China.

It remains unclear if China's current HIV antibody testing algorithm misses a substantial number of HIV infected individuals. Of 196 specimens with indeterminate or negative results on HIV western blot (WB) retrospectively examined by HIV-1 nucleic acid test (NAT), 67.57% (75/111) of indeterminate WB samples, and 16.47% (14/85) of negative WB samples were identified as NAT positive. HIV-1 loads in negative WB samples were significantly higher than those in indeterminate WB samples. Notably, 86.67% (13/15) of samples with negative WB and double positive immunoassay results were NAT positive. The rate of HIV-1 infections missed by China's current HIV testing algorithm is unacceptably high. Thus, China should consider using NAT or integrating fourth generation ELISA into current only antibodies-based HIV confirmation. J. Med. Virol. 88:1462-1466, 2016. © 2016 Wiley Periodicals, Inc.

Role of signal-to-cut-off ratios of anti-hepatitis C virus antibody by enzyme immunoassays along with ID-NAT for screening of whole blood donors in India.

Background:The use of elevated signal-to-cut off ratios (S/CO) as an alternate to further supplemental testing (i.e., RIBA) has been included in the guidelines provided by the Centres for Disease Control and Prevention for HCV diagnostic purposes since 2003. With availability of screening by NAT and non availability of RIBA, further confirmation of HCV infection has been possible at the molecular level (RNA).Aims:To study the role of S/CO ratios of anti hepatitis C virus antibody detection by enzyme immunoassays (EIA) along with ID-NAT for screening of whole blood donors.Methods:In this study we reviewed the donor screening status for anti HCV from January 2013 to May 2014. All the donations were screened for anti HCV with fourth generation ELISA (BioRad Monolisa Ag-Ab Ultra) as well as with ID NAT (Procleix Ultrio). The S/CO ratio of all the anti-HCV reactive samples were analysed for their presence of HCV RNA.Results:On screening 21,115 donors for HCV, 83 donors (0.39%) were found reactive on pilot tube and repeat plasma bag testing (S/Co ratio ≥1) by ELISA. 41 donors were HCV RNA reactive with ID-NAT. 4 samples out of 41 were NAT yields and 37 were concordant reactive with ELISA. The S/Co ratio of anti-HCV reactive samples ranged from 0.9-11.1 [mean = 5.1; SD ± 2.9] whereas S/Co ratio of anti HCV and NAT reactive samples (concordant positives) ranged from 4.1-11.1 [mean 7.3]. In our analysis we found that S/CO ratio of 4 showed positive predictive value (PPV) and sensitivity of 100%.Summary/Conclusions:Our study showed that S/CO of 4 for anti HCV on ELISA would have maximum positive predictive value of having donor with HCV RNA. S/CO ratio of 4 is very close to 3.8 which was the CDC guideline. The presence of anti-HCV does not distinguish between current or past infections but a confirmed anti-HCV-positive result indicates the need for counseling and medical evaluation for HCV infection.

Usefulness of a fourth generation ELISA assay for the reliable identification of HCV infection in HIV-positive adults from Gabon (Central Africa).

Background/ObjectivesGuidelines for optimized HCV screening are urgently required in Africa, especially for patients infected with HIV, who sometimes show false positive or false negative reactivity in anti-HCV antibody assays. Here, we assessed the usefulness of a fourth-generation HCV Ag-Ab ELISA for the identification of active HCV infection in HIV-positive patients.MethodsThis cross-sectional study was conducted between 03/2010 and 01/2013 and included 762 Gabonese HIV-positive adult patients. The results of ELISA (Monolisa HCV Ag-Ab ULTRA, Bio-Rad) were compared with those obtained by RT-PCR (gold standard). The optimal ELISA signal-to-cutoff (S/CO) ratio to identify patients with active hepatitis C (positive HCV RNA) was determined. Specimens were further tested by the INNO-LIA HCV Score assay (Innogenetics) and the Architect HCV Ag kit (Abbott) to define the best diagnostic strategy.ResultsSixty-seven patients tested positive for HCV (S/CO ratio ≥ 1) by ELISA. Of these, 47 (70.1%) tested positive for HCV RNA. The optimal S/CO associated with active HCV infection was 1.7. At this threshold, the sensitivity of ELISA was 97.9% (95% confidence interval (CI) 90.0–99.9%), its specificity was 91.3% (95% CI 85.0–95.5%), and HCV seroprevalence rate was 7.3% (56/762) (95% CI 5.6–9.4%). Among 57 HCV-seropositive patients with available INNO-LIA results, false reactivity was identified in 14 (24.6%), resolved HCV infection in two (3.5%), possible acute HCV infections in nine (15.8%) and likely chronic HCV infections in 32 (56.1%) patients. HCV core Ag was undetectable in 14/15 (93.3%) specimens that tested negative for HCV RNA whereas it was quantified in 34 (out of 39, 87.2%) samples that tested positive for HCV RNA.ConclusionsOur study provides comprehensive guidance for HCV testing in Gabon, and will help greatly clinicians to improve case definitions for both the notification and surveillance of HCV in patients co-infected with HIV.

Evaluation of Commonly Used Rapid Test Kits and Serological Serial Testing Algorithm for Diagnosis of HIV-1 and 2 Antibodies in Port Harcourt, Nigeria

Three diagnostic rapid test kits (Chembio HIV-1/2 Stat-Pak, Alere DetermineTM HIV-1/2, and Core HIV-1/2) for human immunodeficiency virus types 1 and 2 (HIV-1/2) antibodies detection were evaluated against a gold standard fourth generation ELISA (Dia-Pro). Hundred and seventy two serum samples were collected from Lulubriggs Health Center, University of Port Harcourt, Rivers State. All samples were tested for HIV-1/2 using the three rapid test (parallel algorithm and serial algorithm), and retested using the 4th generation ELISA. The results obtained were compared with those from the ELISA. The DetermineTM rapid strips had sensitivity of 66.7%, specificity of 100%, positive predictive value 100%, negative predictive value 89.4% and total agreement of 91.3%. Stat-pak and Core HIV-1/2 rapid strips both had sensitivity of 71.7%, specificity of 100%, positive predictive value 100%, and negative predictive value 90.7% and total agreement of 92.4%. Determine was mostly used by the participant laboratories 18 of 30 (60%). The performance evaluation of the testing algorithm showed that parallel algorithm is more accurate in comparison to serial algorithm. The result of this study reveals that most rapid test are less sensitive and the accuracy of serial testing algorithm is low, this implies that most acute HIV infection will be missed with rapid assay and false negative results will be reported as actual negative with serial algorithm.

First case of recent retroviral infection after accidental occupational non-medical exposure to contaminated HIV blood in National Institute for Infectious Diseases "Prof. Dr. Matei Balş" Bucharest, Romania

In 2013, in the National Institute for Infectious Diseases Prof. Dr. Matei Bals Bucharest has been applied post-exposure guidelines in 112 cases of occupational exposure to blood and other biological products and was not registered any cases of HIV transmission. A 22 year old, young police-officer presented in our service for human bite wounds, resulting from intervention in a case of intrafamilial aggression. The aggressor, was known as drug-addicted, co-infected HCV/HIV and he had bleeding in the mouth. He was under antiretroviral therapy for about nine months (CBV+NVP, viral load = 90.787 copies/mL, CD4 = 200 cells/cmm, HCV-RNA = 6,718,917 IU/mL). Exposed person comes to our service in the first two hours of the incident, without performing initial wound toilet. We started antiretroviral prophylaxis (ARVP) with CBV+LPV/r. At eight days after ARVP, the exposed-person developed a generalized maculopapular rash; in the absence of other clinical manifestations the eruption is interpreted as post-drug side effects. The young man returned to our clinic after another three days (range in which in his own initiative stopped prophylaxis), and we decided to change the antiretroviral regimen with DRV/r + TDF + FTC. Reevaluation after a month recorded that he remained asymptomatic and fourth generation ELISA tests were negative. Reassessment at 12 weeks showed serological tests positive (ELISA, Western blot -p24 = + +), indicating a recent retroviral infection. We find the same HIV sub-type (F) and the same resistance mutations in those two patients, confirming HIV infection to policeman from the aggressor. New patient initially had HIV-RNA = 210,977 copies/mL, CD4 = 789 cells/cmm and was included in the cohort of individuals with recent HIV infection; antiretroviral therapy is initiated with TDF + DRV/r + RAL. After a month of treatment the HIV-RNA = 161 copies/mL blood, HIV-RNA from CFS was undetectable and anti-HCV were negative. It is the first case of accidental post-exposure (medical and non-medical) to contaminated blood HIV infection in which we applied post-exposure protocol. It illustrates: - The importance of adherence to antiretroviral medication; - The consideration of acute retroviral syndrome in the presence of a maculopapular rash; - The importance of choosing prophylactic regimen when we know treatment history and possible resistance mutations if the source person is known to be HIV positive. - Should be monitored more frequently and more complete (HIV-RNA), including people with occupational non-medical exposure.

Prevalence and Trends of Hepatitis B, Hepatitis C and Human Immunodeficiency Viruses among Blood Donors in Islamabad, Pakistan 2005-2013

Background: Pakistan is a developing country of 190 million people with increased burden of infectious diseases. Hepatitis B virus (HBV), Hepatitis C virus (HCV) and Human Immunodeficiency virus (HIV) are the most important agents responsible for transfusion transmitted viral infections. Blood donors are considered as the healthiest population of a community and screening of HBV, HCV & HIV in blood donors will reflect the true prevalence of these infections in a population. Material and Methods: The study was conducted from July 2005 to July 2013 at Pakistan Institute of Medical Sciences (PIMS) hospital, Islamabad, Pakistan. 160,376 blood donors from the age 18 years to 60 years were enrolled in this study. Study was approved by the ethical review committee of PIMS hospital. All the samples were screened for Hepatitis B virus surface Antigen (HBsAg), anti-HCV and anti-HIV by fourth generation ELISA. Statistical analyses were carried out by using SPS software version 17. Results: Among 160,376 donors, 157,920 (98.47%) were replacement donors. The overall seroprevalence of (HBVsAg), anti-HCV and anti-HIV among blood donors were 2.35%, 3.26% & 0.017% respectively. The prevalence of HBV and HCV co-infection was 0.084%. Conclusion: The prevalence of Hepatitis B, Hepatitis C and Human Immunodeficiency viruses are high in blood donors and should not be acceptable. There is a need to educate masses to increase the number of voluntary donors to meet the country’s requirement of blood donation

Combining rapid diagnostic tests and dried blood spot assays for point-of-care testing of human immunodeficiency virus, hepatitis B and hepatitis C infections in Burkina Faso, West Africa

AbstractPeople screened for human immunodeficiency virus (HIV) using rapid diagnostic tests (RDTs) in Africa remain generally unaware of their status for hepatitis B (HBV) and hepatitis C (HCV) infections. We evaluated atwo-step screening strategy in Burkina Faso, using both HIV RDTs and Dried Blood Spot (DBS) assays to confirm an HIV-positive test, and to test for HBV and HCV infections. HIV counselling and point-of-care testing were performed at a voluntary counselling and testing centre with HBV, HCV status and HIV confirmation using DBS specimens, being assessed at a central laboratory. Serological testing on plasma was used as the reference standard assay to control for the performance of DBS assays. Nineteen out of 218 participants included in the study were positive for HIV using RDTs. A fourth-generation HIV ELISA and immunoblot assays on DBS confirmed HIV status. Twenty-four out of 25 participants infected with HBV were found positive for hepatitis B surface antigen (HBsAg) using DBS. One sample with a low HBsAg concentration on plasma was not detected on DBS. Five participants tested positive for HCV antibodies were confirmed positive with an immunoblot assay using DBS specimens. Laboratory results were communicated within 7 days to participants with no loss to follow up of participants between the first and second post-test counselling sessions. In conclusion, DBS collection during HIV point-of-care testing enables screening and confirmation of HBV, HCV and HIV infections. Diagnosis using DBS may assist with implementation of national programmes for HBV, HCV and HIV screening and clinical care in middle- to low-income countries.

The comparison of the performance between third generation ELISA and fourth generation ELISA on acute and early HIV infection

Objective To evaluate the performance of the third generation ELISA and the fourth generation ELISA for HIV-1 diagnosis assays on acute and early HIV-1 infected samples. Methods Sixty-seven acute/early HIV-1 infected samples were collected from the follow-up gays with seroconversion in Shen Yang city and from clinical patients in the First Affiliated Hospital of China Medical University with incomplete HIV-1 specific bands in western blot between 2008 and 2010.Third generation ELISA, fourth generation ELISA, western blot and HIV-1 viral load detecting were used for detecting these samples.The sensitivity, consistency were compared between third generation ELISA and fourth generation ELISA to detect the seroconversion samples and the window periods were abserved.Chi square test was used for statistical analysis. Results In the 67 acute/early HIV-1 infected samples, 56 were HIV positive and 11 were HIV negative by the third generation ELISA.The sensitivity of the third generation ELISA was 83.6% (95%CI:72.5%-91.5%); 63 were HIV positive，1 was at gray zone and 3 were HIV negative by the fourth generation ELISA.The sensitivity of the fourth generation ELISA was 94.0% (95%CI:85.4%-98.3%),higher than the third generation ELISA（χ2=16.1，P<0.01）.The consistency of the third generation ELISA and the fourth generation ELISA was 86.6%(95%CI：76.0%-93.7%).The earliest third generation ELISA positive sample was the sample collected 16 days after HIV infection and the earliest fourth generation ELISA positive sample was the sample collected 9 days after HIV infection.There was significantly different on the window periods between the third generation ELISA and the fourth generation ELISA. Conclusion The fourth generation ELISA had a higher sensitivity and shorter window period on acute/early HIV infected samples than the third generation ELISA, which is more suitable for the HIV early infection screening on high risk populations. （Chin J Lab Med，2012,35：538-543） Key words: HIV infections; HIV-1; Enzyme-linked immunosorbent assay

Hepatitis C virus infection in hemodialysis patients in Maracaibo, Venezuela

Over a two year period, the incidence of hepatitis C virus (HCV) infection was evaluated in 29 hemodialysis patients, aged between 15 and 75 years (mean ± SD: 45 ± 39.5 years), from the University Hospital Hemodyalisis Unit, Maracaibo, Zulia State, Venezuela. Anti-HCV antibodies were determined using a fourth generation ELISA (Innotest HCV Ab IV) kit and positive blood samples were tested using a recombinant assay kit (Inno-LIA HCV Ab III), both kits from Innogenetics N.V., Belgium. The findings indicate a lack of HCV seroconversion in the hemodialysis patients over the study period, confirmed by the recombinant assay. Risk factors for HCV infection were 0.3270 (95% confidence interval: 0.01323-8.080) in patients undergoing hemodialysis. The findings suggest a lack of significant sources for HCV infection due to the preventive measures to avoid its transmission in the hemodialysis unit.

HIV-1 group N: travelling beyond Cameroon

On Jan 21, 2011, a 57-year-old man living in France attended our emergency unit with fever, rash, lymphadenopathy, and genital ulceration, 8 days after returning from Togo. He reported sexual contact with a Togolese partner, and HIV primary infection was suspected. Fourth-generation ELISA (ARCHITECT HIV Ag/Ab Combo, Abbott, Chicago, IL) was weakly positive, and HIV-1 western blot (New Lav Blot I, Biorad, Paris, France) showed weak reactivity with the p55 and p24 antigens. On Feb 1, 2011, his HIV-1 RNA load was 4∙2 log10 copies per mL (Cobas TaqMan HIV-1 v2.0 assay, Roche Molecular Systems, Branchburg, NJ, USA). On Feb 9, 2011, he developed facial paralysis. At this time his CD4 cell count was 219 per μL and his plasma and CSF HIV-1 RNA concentrations were 4∙4 log10 and 4∙5 log10 copies per mL, respectively. In keeping with French guidelines on new cases of HIV infection, we undertook resistance genotyping before starting treatment. We were surprised that we could not amplify the reverse transcriptase and protease genes with the ViroSeq HIV-1 genotyping assay (Abbott, Chicago, IL, USA) and the French National Agency for AIDS Research consensus primers, despite the high viral load. This fi nding prompted us to serotype the samples. Clear reactivity against group-N-specifi c antigens was obtained and we therefore did full-length genome sequencing. Phylogenetic analysis confi rmed that the new sequence clustered strictly within available group-N sequences (sequence designated N1.FR.2011, GenBank accession number JN572926). When last seen for followup after 4 weeks of antiretroviral combination therapy with tenofovir, emtricitabine, darunavir/ritonavir, raltegravir, and maraviroc, our patient’s plasma HIV-1 RNA load was below 20 copies per mL and his CD4 cell count was 483 per μL. HIV-1 group N (non-M, non-O) was fi rst identifi ed in 1998 in a Cameroonian woman with AIDS. This highly divergent HIV variant is more closely related to SIV isolated from wild chimpanzees than to HIV-1 groups M (major), O (outlier), and P. Group-N infection has previously been reported only in HIV-infected patients living in Cameroon. More than 12 000 HIVinfected patients living in Cameroon have been tested for group-N infection, but only 12 cases, including two couples infected by the same strains, have been identifi ed. Although our patient was diagnosed in Paris, the infection was probably acquired in Togo, which suggests that group-N viruses are now circulating outside Cameroon. This case of primary HIV-N infection is particularly important because of the severe clinical manifestations and early decline in the CD4 cell count. A fi ve-drug antiretroviral com bination showed good initial effi cacy, but longer-term immunological and virological follow-up is needed. The viral load of this HIV-N infected patient was positive during the primary infection as assessed by the Cobas TaqMan HIV-1 v2.0 assay, but the validity of the quantitative result is uncertain. The viral load was also assessed using the Abbott RealTime HIV-1 assay (Chicago, IL, USA), but was under-quantifi ed by about 1 log10. Whether other commercial assays can quantify these variants remains to be shown. Standard resistance genotyping methods used for group M failed to amplify the group-N virus, as happened with the fi rst case of group-P virus detected in 2009. Discrepancies between the results of HIV viral load assays and molecular tests should alert clinicians and virologists to the possibility of infection by a variant virus, which has important implications for management of the patient. This case of HIV-1 group-N primary infection indicates that this rare group is now circulating outside Cameroon, which emphasises the need for rigorous HIV epidemiological monitoring.

Prevalence of HIV among blood donors in a tertiary care centre of north India

Background & objectives:India has the second highest HIV population in the world with about 2.5-3.0 million cases. HIV-2 cases among general and blood donor population have also been reported mostly from west and south India. This single centre study was carried out to observe the HIV-1 and HIV-2 prevalence among blood donors from north India.Methods:A total of 2,04,677 people were screened for the presence of HIV infection over the 11 year period (1999 to 2009). Till 2004, a third generation ELISA kit was used. From 2005 till January 2009 all tests were done using the fourth generation ELISA kit which detected the presence of HIV-1 P24 antigen and anti-HIV antibodies. From February 2009 onwards, the kits used were Genscreen ULTRA HIV Ag-Ab Assay.Results:A total of 506 (0.247%) donors were found to be repeat reactive for HIV. Of these, 486 (96%) donors tested using the Western blot were found positive for HIV-1 infection. Twenty (4%) donors showed a negative Western blot result, none of the donors were found reactive for HIV-2 infection.Interpretation & conclusions:The prevalence of HIV was 0.249 per cent among blood donors of north India. No HIV-2 case was found among the studied blood donor population indicating that it is not a threat currently.