Thogoto virus infection induces sustained type I interferon responses that depend on RIG-I-like helicase signaling of conventional dendritic cells.

Type I interferon (IFN-α/β) induction upon viral infection contributes to the early antiviral host defense and ensures survival until the onset of adaptive immunity. Many viral infections lead to an acute, transient IFN expression which peaks a few hours after infection and reverts to initial levels after 24 to 36 h. Robust IFN expression often is conferred by specialized plasmacytoid dendritic cells (pDC) and may depend on positive-feedback amplification via the type I IFN receptor (IFNAR). Here, we show that mice infected with Thogoto virus (THOV), which is an influenza virus-like orthomyxovirus transmitted by ticks, mounted sustained IFN responses that persisted up to 72 h after infection. For this purpose, we used a variant of THOV lacking its IFN-antagonistic protein ML, an elongated version of the matrix (M) protein [THOV(ΔML)]. Of note, large amounts of type I IFN were also found in the serum of mice lacking the IFNAR. Early IFN-α expression seemed to depend on Toll-like receptor (TLR) signaling, whereas prolonged IFN-α responses strictly depended on RIG-I-like helicase (RLH) signaling. Unexpectedly, THOV(ΔML)-infected bone marrow-derived pDC (BM-pDC) produced only moderate IFN levels, whereas myeloid DC (BM-mDC) showed massive IFN induction that was IPS-1-dependent, suggesting that BM-mDC are involved in the massive, sustained IFN production in THOV(ΔML)-infected animals. Thus, our data are compatible with the model that THOV(ΔML) infection is sensed in the acute phase via TLR and RLH systems, whereas at later time points only RLH signaling is responsible for the induction of sustained IFN responses.

Hepatitis E Virus Seroprevalence among Blood Donors in Southwest Switzerland.

Aim: The aim of this study was to determine the seroprevalence of Hepatitis E virus (HEV) among blood donors in southwest Switzerland.Background: HEV is recognized as a food-borne disease in industrialized countries, transmitted mainly through pork meat. Cases of transmission through blood transfusion have also been reported. Recent studies have revealed seroprevalence rates of 13.5%, 16.6% and 20.6% among blood donors in England, France and Denmark, respectively.Methods: We analyzed 550 consecutive blood donor samples collected in the region of Lausanne, canton of Vaud, Switzerland, for the presence of anti-HEV IgG, using the MP Diagnostics HEV ELISA kit. For each donor, we documented age, sex and alanine aminotransferase (ALT) value.Results: The study panel was composed of 332 men (60.4%) and 218 women (39.6%). Overall, anti-HEV IgG was found in 27 of 550 samples (4.9%). The seroprevalence was 5.4% (18/332) in men and 4.1% (9/218) in women. The presence of anti-HEV IgG was not correlated with age, gender or ALT values. However, we observed a peak in seroprevalence of 5.3% in individuals aged 51 to 70 years old.Conclusions: Compared with other European countries, HEV seroprevalence among blood donors in southwest Switzerland is low. The low seroprevalence may be explained by the sensitivity of commercial tests used and/or the strict regulation of animal and meat imports. Data regarding HEV prevalence in Swiss livestock are lacking and merit exploration.

The promise of advanced imaging techniques for the detection of hepatitis C virus antigens in the infected liver.

Injection drug use before and after liver transplantation: a retrospective multicenter analysis on incidence and outcome. Clin Transplant 2009 DOI: 10.1111/j.1399-0012.2009.01121.x. Background and aims: Injecting drug use (IDU) before and after liver transplantation (LT) is poorly described. The aim of this study was to quantify relapse and survival in this population and to describe the causes of mortality after LT. Methods: Past injection drug users were identified from the LT listing protocols from four centers in Switzerland and France. Data on survival and relapse were collected and used for uni- and multivariate analysis. Results: Between 1988 and 2006, we identified 59 patients with a past history of IDU. The mean age at transplantation was 42.4 yr and the majority of patients were men (84.7%). The indication for LT was for the vast majority viral cirrhosis accounting for 91.5% of cases, while alcoholic cirrhosis was 5.1%. There were 16.9% of patients who had a substitution therapy before and 6.8% who continued after LT. Two patients (3.4%) relapsed into IDU after LT and died at 18 and 41 months. The mean follow-up was 51 months. Overall survival was 84%, 66%, and 61% at 1, 5, and 10 yr after transplantation. Conclusions: Documented IDU was rare in liver transplanted patients. Past IDU was not associated with poorer survival after LT, and relapse after LT occurred in 3.4%.

Analytical validation of a lymphocytic choriomeningitis virus real-time RT-PCR assay.

Lymphocytic choriomeningitis virus (LCMV) is a rare cause of central nervous system disease in humans. Screening by real-time RT-PCR assay is of interest in the case of aseptic meningitis of unknown etiology. A specific LCMV real-time RT-PCR assay, based on the detection of genomic sequences of the viral nucleoprotein (NP), was developed to assess the presence of LCMV in cerebrospinal fluids (CSF) sent for viral screening to a Swiss university hospital laboratory. A 10-fold dilution series assay using a plasmid containing the cDNA of the viral NP of the LCMV isolate Armstrong (Arm) 53b demonstrated the high sensitivity of the assay with a lowest detection limit of ≤50 copies per reaction. High sensitivity was confirmed by dilution series assays in a pool of human CSF using four different LCMV isolates (Arm53b, WE54, Traub and E350) with observed detection limits of ≤10PFU/ml (Arm53b and WE54) and 1PFU/ml (Traub and E350). Analysis of 130 CSF showed no cases of acute infection. The absence of positive cases was confirmed by a published PCR assay detecting all Old World arenaviruses. This study validates a specific and sensitive real-time RT-PCR assay for the diagnosis of LCMV infections. Results showed that LCMV infections are extremely rare in hospitalized patients western in Switzerland.