Discovery of hantavirus circulating among Rattus rattus in French Mayotte island, Indian Ocean.

Hantaviruses are emerging zoonotic viruses that cause human diseases. In this study, sera from 642 mammals from La Réunion and Mayotte islands (Indian Ocean) were screened for the presence of hantaviruses by molecular analysis. None of the mammals from La Réunion island was positive, but hantavirus genomic RNA was discovered in 29/160 (18 %) Rattus rattus from Mayotte island. The nucleoprotein coding region was sequenced from the liver and spleen of all positive individuals allowing epidemiological and intra-strain variability analyses. Phylogenetic analysis based on complete coding genomic sequences showed that this Murinae-associated hantavirus is a new variant of Thailand virus. Further studies are needed to investigate hantaviruses in rodent hosts and in Haemorrhagic Fever with Renal Syndrome (HFRS) human cases.

Nucleotide variability and translation efficiency of the 5' untranslated region of hepatitis A virus: update from clinical isolates associated with mild and severe hepatitis.

Mutations in the internal ribosome entry site (IRES) of hepatitis A virus (HAV) have been associated with enhanced in vitro replication and viral attenuation in animal models. To address the possible role of IRES variability in clinical presentation, IRES sequences were obtained from HAV isolates associated with benign (n = 8) or severe (n = 4) hepatitis. IRES activity was assessed using a bicistronic dual-luciferase expression system in adenocarcinoma (HeLa) and hepatoma (HuH7) cell lines. Activity was higher in HuH7 than in HeLa cells, except for an infrequently isolated genotype IIA strain. Though globally low, significant variation in IRES-dependent translation efficiency was observed between field isolates, reflecting the low but significant genetic variability of this region (94.2% +/- 0.5% nucleotide identity). No mutation was exclusive of benign or severe hepatitis, and variations in IRES activity were not associated with a clinical phenotype, indirectly supporting the preponderance of host factors in determining the clinical presentation.

Efficacy and safety of boceprevir-based triple therapy in HCV cirrhotic patients awaiting liver transplantation (ANRS HC29 BOCEPRETRANSPLANT).

BACKGROUND AND AIMS: In this French multicentre, open-label study, we analyzed the efficacy, safety and patient-reported outcomes of a boceprevir-based triple therapy in HCV genotype 1 cirrhotic patients awaiting liver transplantation (LT). METHODS: Patients received PEG-IFN/ribavirin (RBV) for 48 weeks (W) and boceprevir from W4 to W48 or until LT. RESULTS: Fifty-one patients (80% males, median age: 56 years) were included. Fifty-seven percent had hepatocellular carcinoma and 43% end-stage liver disease. At enrolment, the median MELD score was 9 (range: 6-18); the Child-Pugh score was A in 65%, B in 35% and C in 2%. Therapy was discontinued because of severe adverse events (SAEs) in 39% of cases and virological inefficacy in 24%. 16% of patients had undetectable HCV RNA 24 weeks after the end of treatment (SVR24). LT was performed in 18 patients (35%). HCV RNA was undetectable in 16.6% at LT. Seven patients (14%) died and three deaths were attributed to treatment. SAEs (n=129) were observed in 84% of patients. Twenty-four percent of patients developed severe infections. Albumin<35g/L was independently associated with severe infection. Compared with baseline values, a significant decrease (P=0.02) of the physical dimension of health-related quality of life was observed between W4 and W24. The mean (95% CI) number of self-reported symptoms doubled during treatment (from 6.3 [4.8-7.7] to 11.8 [9.3-14.3]; P<0.001). CONCLUSIONS: The safety of the PEG-IFN/RBV/boceprevir combination is poor in patients awaiting LT, with a high risk of severe infection. Moreover, the limited efficacy confirms the indication for IFN-free combinations in these patients.

RNA extraction and RT-PCR procedures adapted for the detection of enterovirus sequences from frozen and paraffin-embedded formalin-fixed spinal cord samples.

Methods for detecting enterovirus RNA in both paraffin-embedded, formalin-fixed and frozen spinal cord sections from amyotrophic lateral sclerosis (ALS) patients were established. A proteinase K digestion following the deparaffinization procedure was required for the fixed spinal cord sections, whereas only one step of crushing in phosphate buffered saline was necessary for the frozen samples prior to the extraction of the RNA. With an optimized reverse transcription and PCR procedure, enterovirus RNA could be detected from frozen and fixed archival spinal cord samples.

Cumulative mutations in the genome of Echovirus 6 during establishment of a chronic infection in precursors of glial cells.

Although Enteroviruses are mainly described as responsible for acute diseases, their role in severe chronic pathology has been also established. Echovirus 6-like sequences have been detected by PCR analysis in central nervous system specimens from patients presenting with Amyotrophic Lateral Sclerosis. These findings suggested a persistent infection with viruses that underwent, genetic changes precluding viral particle release. To support this hypothesis, we developed a model system of Echovirus 6 chronic infection in precursors of glial cells. The nucleotide sequences of the 5'non-translated region (5'NTR), 2A and 3C regions of the virus developing persistent genome were analysed during establishment of the chronic phenotype. This study revealed that at day 160 of chronic infection, several mutations were observed: one mutation at nucleotide 108 upstream the domain II of the internal ribosome entry site (IRES) structure, one mutation at nucleotide 30 in the cloverleaf, and two mutations in the 2A region (translated in His48 to Tyr, and Ile 123 to Met). No mutations were detected in the 3C region. The impact of these mutations on viral replication have been analysed in a rabbit reticulocyte lysate (RRL) translation assay supplemented with HeLa cell lysate, and by plaque assay. Viruses with these mutations displayed a phenotype with a significant reduction of replication, while in vitro translation was not affected by the nucleotide 108 mutation. This model allowed the description of molecular changes observed in the genome of Echovirus 6 during the establishment of a chronic infection phenotype, and may be helpful for the understanding of the mechanisms leading Enteroviruses to develop chronic infections in man.

Impaired glutamate uptake and EAAT2 downregulation in an enterovirus chronically infected human glial cell line.

Rapid and efficient uptake of glutamate via the high-affinity glutamate transporter EAAT2 is important for limiting glutamate-mediated excitotoxicity involved in neuronal death. Furthermore, there is evidence of altered glutamate uptake and catabolism in motor neuron diseases. Such a defect has been reported in amyotrophic lateral sclerosis, the major motor neuron disease, and was associated with impairment in EAAT2 processing. We recently reported the presence of enterovirus genome specifically in the anterior horn of amyotrophic lateral sclerosis cases, suggesting the involvement of a chronic/persistent enterovirus infection in amyotrophic lateral sclerosis. To investigate a putative link between enterovirus infection and the glutamate-mediated excitotoxicity observed in amyotrophic lateral sclerosis, we developed an in vitro model consisting of a human glial cell line infected with ECHOvirus 6, one of the enteroviruses with sequences closely related to those detected in patients with amyotrophic lateral sclerosis. In these glial cells, an ECHOvirus 6 chronic infection was established, resulting in altered extracellular glutamate uptake. This correlated with an aberrant splicing of the EAAT2 pre-messenger ribonucleic acid and a significant loss of EAAT2 protein expression, similar to that observed in patients with amyotrophic lateral sclerosis. These results provide convincing evidence that an enterovirus chronic/persistent infection may alter glial glutamate uptake and catabolism. As enteroviruses are extremely common human pathogens, they may act as a trigger in the development of certain motor neuron diseases, such as amyotrophic lateral sclerosis.