Variabilité génétique du virus de l'Hépatite A : conséquences sur le diagnostic, l'épidémiologie et la physiopathologie de l'infection

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocSudocFranceF

Etude par séquençage nucléotidique du profil de résistance génotypique aux antirétroviraux du VIH-1 au cours de fenêtres thérapeuthiques

PARIS-BIUP (751062107) / SudocSudocFranceF

Detection of Hepatitis A Virus RNA in Saliva

Hepatitis A virus (HAV) is shed in feces but also in saliva. HAV RNA was detected in saliva in five out of six acutely infected patients with HAV viremia. Serum and saliva sequences were identical. The simplicity of obtaining material allows the recommendation of the use of saliva for investigation of outbreaks

Diagnostic Relevance of Immunoglobulin G Avidity for Hepatitis A Virus

Diagnosis of acute hepatitis A virus (HAV) infection is based on the detection of HAV immunoglobulin M (IgM). However, IgM could be detected due to nonspecific polyclonal activation of the immune system. An avidity test for anti-HAV IgG was developed to distinguish acute infection, where low-avidity antibodies are detected, from immune reactivation. The assay was tested on 104 samples, including 11 sera from patients with past infection, 15 sera from patients with acute infection and 4 collected after recovery, 10 sera from vaccinated subjects, 4 sera from patients with suspected immune reactivation, and 60 unselected HAV-IgM positive sera, collected over 1 year in a routine laboratory. The avidity index (AI) was expressed as percentage. The results were provided as the mean ± one standard deviation. Patients with a history of prior infection had AIs of >70% (mean, 86% ± 10), whereas the mean AI was 36% ± 16 during acute HAV infection (P < 0.001). Within the first month after the onset of hepatitis, avidity was either noncalculable due to a very low IgG titer or <50%. In patients with immune reactivation, avidity was >70% (88% ± 10%), a finding consistent with a prior infection. Among the 60 unselected sera, 35 (58%) had a noncalculable or <50% avidity, and most of them had a detectable HAV RNA, confirming HAV infection. In contrast, 16 (27%) had an avidity of >70%, and none was reverse transcription-PCR positive, suggesting immune reactivation. These 16 patients were significantly older than the others (50 ± 16 years versus 26 ± 14 years). The new anti-HAV IgG avidity assay we developed could improve HAV infection diagnosis, particularly in elderly patients

Epidemiology and Genetic Characterization of Hepatitis A Virus Genotype IIA▿

Three hepatitis A virus (HAV) genotypes, I, II, and III, divided into subtypes A and B, infect humans. Genotype I is the most frequently reported, while genotype II is hardly ever isolated, and its genetic diversity is unknown. From 2002 to 2007, a French epidemiological survey of HAV identified 6 IIA isolates, mostly from patients who did not travel abroad. The possible African origin of IIA strains was investigated by screening the 2008 mandatory notification records of HAV infection: 171 HAV strains from travelers to West Africa and Morocco were identified. Genotyping was performed by sequencing of the VP1/2A junction in 68 available sera. Entire P1 and 5′ untranslated regions of IIA strains were compared to reference sequences of other genotypes. The screening retrieved 5 imported IIA isolates. An additional autochthonous case and 2 more African cases were identified in 2008 and 2009, respectively. A total of 14 IIA isolates (8 African and 6 autochthonous) were analyzed. IIA sequences presented lower nucleotide and amino acid variability than other genotypes. The highest variability was observed in the N-terminal region of VP1, while for other genotypes the highest variability was observed at the VP1/2A junction. Phylogenetic analysis identified 2 clusters, one gathering all African and two autochthonous cases and a second including only autochthonous isolates. In conclusion, most IIA strains isolated in France are imported by travelers returning from West Africa. However, the unexplained contamination mode of autochthonous cases suggests another, still to be discovered geographical origin or a French reservoir to be explored

Performance evaluation of two SARS-CoV-2 IgG/IgM rapid tests (Covid-Presto and NG-Test) and one IgG automated immunoassay (Abbott)

International audienceThe aim of this study was to assess the analytical performances, sensitivity and specificity, of two rapid tests (Covid- Presto® test rapid Covid-19 IgG/IgM and NG-Test® IgM-IgG COVID-19) and one automated immunoassay (Abbott SARS-CoV-2 IgG) for detecting anti- SARS-CoV-2 antibodies. This study was performed with: (i) a positive panel constituted of 88 SARS-CoV-2 specimens collected from patients with a positive SARS-CoV-2 RT-PCR, and (ii) a negative panel of 120 serum samples, all collected before November 2019, including 64 samples with a cross-reactivity panel. Sensitivity of Covid-Presto® test for IgM and IgG was 78.4% and 92.0%, respectively. Sensitivity of NG-Test® for IgM and IgG was 96.6% and 94.9%, respectively. Sensitivity of Abbott IgG assay was 96.5% showing an excellent agreement with the two rapid tests (κ = 0.947 and κ = 0.936 for NGTest ® and Covid-Presto® test, respectively). An excellent agreement was also observed between the two rapid tests (κ = 0.937). Specificity for IgM was 100% and 86.5% for Covid-Presto® test and NG-Test®, respectively. Specificity for IgG was 92.0%, 94.9% and 96.5% for Covid-Presto®, NGTest ®, and Abbott, respectively. Most of the false positive results observed with NG-Test® resulted from samples containing malarial antibodies. In conclusion, performances of these 2 rapid tests are very good and comparable to those obtained with automated immunoassay, except for IgM specificity with the NG-Test®. Thus, isolated IgM should be cautiously interpreted due to the possible false-positive reactions with this test. Finally, before their large use, the rapid tests must be reliably evaluated with adequate and large panel including early seroconversion and possible cross-reactive samples

Early serum HBsAg drop: a strong predictor of sustained virological response to pegylated interferon alfa-2a in HBeAg negative patients. Hepatology

Pegylated interferon alfa-2a (PEG-IFN) may induce sustained virological response (SVR) in infection with a high efficacy in suppressing HBV replication. However, a long duration of treatment is needed to maintain viral suppression, and the major question of whether oral therapy can ever be stopped remains unanswered