23 research outputs found

    Evaluation of antigen based rapid diagnostic test in comparison to RT PCR in diagnosis of Sars CoV2 with respect to duration of illness and Ct value of corresponding RT PCR

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    Background: SARS-CoV-2 is the third highly pathogenic corona virus introduced into mankind after Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) and Middle East Respiratory Syndrome coronavirus (MERS-CoV) in twenty-first century for which the development and validation of rapid and easy-to-perform diagnostic methods are of high priority. Objective: In this study we evaluated performance characteristics of RAT, the STANDARD Q COVID19 Ag by SD-Biosensor for rapid detection of SARS CoV 2. Material and methods: Samples were collected from 1168 patients and we performed both RAT and RT PCR and the results of RAT were compared with that of RT PCR as gold standard. Result: Detection rates of SARS CoV-2 by RAT and RT-PCR were 19.17% and 29.53%, respectively; false positivity rate was 2.67%.False positive and false negative rate was 2.6% and 13.45% respectively.RAT sensitivity, specificity, negative and positive predictive values were 63.18%, 99.27%, 97.32% and 86.54% respectively. Statistical analysis considered the calculation of sensitivity, specificity, positive predictive value, negative predictive value using standard formulae. Conclusion: A high sensitivity, specificity, positive predictive value and fairly high negative predictive value of RAT might prove to be promising in situations where pre-test probability of having infection is high

    Occult hepatitis B virus infection in HIV positive patients at a tertiary healthcare unit in eastern India.

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    Occult HBV infection (OBI), defined by the presence of HBV DNA in absence of hepatitis B surface antigen (HBsAg), is a significant concern in the HIV-infected population. Of 441 HIV+/HBsAg- patients analyzed, the overall prevalence of OBI was 6.3% (28/441). OBI was identified in 21 anti-HBc positives (17.8%), as well as among those who lacked any HBV-specific serological markers (2.2%). Comparison with HIV/HBV co-infection revealed that the levels of CD4, ALT, and HBV DNA were significantly lower during occult infection. Discrete differences were also observed with respect to quasispecies divergence. Additionally, subgenotype D1 was most frequent in occult infection, while D2 was widespread during chronic infection. The majority (~90%) of occult D1 sequences had the sQ129R mutation in the surface gene. This study highlights several distinct features of OBI in India and underscores the need for additional HBV DNA screening in HIV-positive individuals

    Characterization of treatment-naive HIV/HBV co-infected patients attending ART clinic of a tertiary healthcare centre in eastern India.

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    OBJECTIVE: The study was designed to assess the hepatitis B virus (HBV) and hepatitis C virus (HCV) co-infection scenario among the human immunodeficiency virus (HIV) infected patients attending a tertiary healthcare unit in eastern India. Additionally, clinical and virological characterization of these viruses, prior to antiretroviral therapy (ART) initiation was also done for better understanding of the disease profile. METHODS: Pool of ART-naive HIV/HBV co-infected and HIV mono-infected patients, participating in two different studies, were included in this study. HBV DNA was detected by nested-PCR amplification followed by HBV genotype determination and HBV reverse transcriptase (RT) region amplification and direct sequencing for detecting drug resistance. RESULTS: The prevalence of HBsAg (11.3%) was higher compared to anti-HCV (1.9%) among the HIV infected ART-naive patients. Moreover, majority of the HBeAg positive HIV/HBV co-infected patients (87.7%) had HBV DNA ≥20,000 IU/ml with median HBV DNA significantly higher than that of HBeAg negative subjects (5.7 log10 IU/ml vs. 4.2 log10 IU/ml; p<0.0001). Multivariate analysis also showed that HBeAg-positive status was independently associated with higher HBV DNA level (p = <0.001). Notably, 60.9% of the HBeAg negative co-infected subjects had HBV DNA ≥2,000 IU/ml of which 37.0% had HBV DNA ≥20,000 IU/ml. Genotype HBV/D (68.2%) was the predominant genotype followed by HBV/A (24.3%) and HBV/C (7.5%). Anti-HBV drug resistant mutations were detected in two (3.8%) of the ART-naive patients. CONCLUSION: The prevalence of HIV/HBV co-infection was relatively higher in our study subjects. HBeAg testing might provide clue for early treatment initiation. Furthermore, HBeAg negative patients are also associated with high HBV DNA levels and therefore require appropriate medical attention. Pre-treatment screening for anti-HBV drug resistant mutations is not necessary before ART initiation

    Relatedness of 5 occult HBV strains based on complete genome analysis.

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    <p>The phylogenetic analysis was performed by Bayesian inference using a chain length of 50,000,000 and sampling in every 5000<sup>th</sup> generation. The occult HBV strains (represented by in red and also by <b>O</b>-) were compared to complete genome reference sequences from GenBank. Posterior probabilities ≥0.9 are shown.</p

    Comparative analysis of the clinical characteristics associated with chronic versus occult HBV infection in HIV-positive patients.

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    <p>(A) CD4 T-cell count, (B) ALT, and (C) HBV DNA titres are represented as box and whisker plots for both infection groups. The box represents the 25% to 75% inter-quartile (IQR) range, with a line at the median value, while the whiskers represent the lowest and the highest values. The CD4 status, ALT, and AST levels were significantly elevated among the chronic compared to the occult patients.</p

    Signature pattern analysis of HBV surface gene between chronic and occult HBV/D1 strains found in HIV-positive individuals.

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    <p>The complete HBV small surface ORF was compared between chronic HBV/D1 (n = 8) and occult HBV/D1 strains (n = 11). The major substitution to be detected was at the codon 129 where a Glutamine to Arginine substitution took place. Occult HBV sequences are labelled as O-, whereas the chronic HBV sequences are labelled as C-. The analysis was performed with a threshold value of 0.9.</p
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