Hepatitis C Virus as a Possible Helper Virus in Human Hepatitis Delta Virus Infection.

Previous studies reported that the hepatitis C virus (HCV) could help disseminate the hepatitis D virus (HDV) in vivo through the unrelated hepatitis B virus (HBV), but with essentially inconclusive results. To try to shed light on this still-debated topic, 146 anti-HCV-positive subjects (of whom 91 HCV/HIV co-infected, and 43 with prior HCV eradication) were screened for anti-HDV antibodies (anti-HD), after careful selection for negativity to any serologic or virologic marker of current or past HBV infection. One single HCV/HIV co-infected patient (0.7%) tested highly positive for anti-HD, but with no positive HDV-RNA. Her husband, in turn, was a HCV/HIV co-infected subject with a previous contact with HBV. While conducting a thorough review of the relevant literature, the authors attempted to exhaustively describe the medical history of both the anti-HD-positive patient and her partner, believing it to be the key to dissecting the possible complex mechanisms of HDV transmission from one subject to another, and speculating that in the present case, it may have been HCV itself that behaved as an HDV helper virus. In conclusion, this preliminary research, while needing further validation in large prospective studies, provided some further evidence of a role of HCV in HDV dissemination in humans.

Complete coding sequence of an Aedes flavivirus strain isolated from Aedes albopictus collected in Northern Italy.

Complete genome data for the globally distributed Aedes flavivirus (AEFV) is scarce. We analyzed a new Italian AEFV strain isolated from Aedes albopictus. The results demonstrated genetic diversity among Italian AEFVs. The high similarity between AEFV genomes across geographically distant regions suggests long distance spreading via invasive host mosquito species.

Baseline plasma SARS-CoV-2 RNA detection predicts an adverse COVID-19 evolution in moderate to severe hospitalized patients.

BACKGROUND: SARS-CoV-2 is a single-stranded RNA virus, known to be the causative agent of COVID-19. As the resulting disease shows a very heterogeneous range of clinical manifestations, the identification of early biomarkers allowing patients stratification according to the expected disease severity is still an unmet clinical need. METHODS: In this observational prospective cohort study, 137 consecutive patients, testing positive for SARS-CoV-2 infection by nasopharyngeal swab RT-PCR or antigenic test, were enrolled to evaluate their plasma viral load at the time of hospitalization. RESULTS: Even if all of them had a molecular diagnosis of COVID-19, only 29 patients showed a detectable plasma SARS-CoV-2 RNAemia. Such viremic patients also showed other clinical and laboratory finding alterations (increased troponin I, IL-6, RDW-CV, and creatinine levels along with decreased platelet count and glomerular filtration rate). A plasma detectable RNA viral load predicted in hospital death or ICU admission with an odds ratio of 3.53 (CI: 1.44-8.64, P=0.0058), while the lack of a detectable viral load was associated with a faster recovery, with an odds ratio of 4.06 (CI: 1.72-9.59, P=0.0014). These findings were confirmed in multivariate models including age, sex and baseline National Early Warning Score 2 and arterial oxygen tension over inspired oxygen fraction ratio. CONCLUSIONS: Our data thus suggest that plasma viral RNA load at the time of hospital admission could represent a useful independent biomarker allowing early patients' stratification according to the expected disease evolution, and driving clinical decisions tailored on the specific needs of the individual patient.

Sindbis Virus Strains of Divergent Origin Isolated from Humans and Mosquitoes During a Recent Outbreak in Finland.

Sindbis virus (SINV) is a mosquito-borne avian hosted virus that is widely distributed in Europe, Africa, Asia, and Oceania. Disease in humans is documented mainly from Northern Europe and South Africa and associated with genotype I. In 2018 under extremely warm climatic conditions, a small outbreak of 71 diagnosed SINV infections was recorded in Finland. We screened 52 mosquito pools (570 mosquitoes) and 223 human sera for SINV with real-time RT-PCR and the positive samples with virus isolation. One SINV strain was isolated from a pool (n = 13) of genus Ochlerotatus mosquitoes and three strains from patient serum samples. Complete genome analysis suggested all the isolates to be divergent from one another and related to previous Finnish, Swedish, and German strains. The study provides evidence of SINV strain transfer within Europe across regions with different epidemiological characteristics. Whether these are influenced by different mosquito genera involved in the transmission remains to be studied.

A novel negevirus isolated from Aedes vexans mosquitoes in Finland.

Negeviruses are insect-specific enveloped RNA viruses that have been detected in mosquitoes and sandflies from various geographical locations. Here, we describe a new negevirus from Northern Europe, isolated from pool of Aedes vexans mosquitoes collected in Finland, designated as Mekrijärvi negevirus (MEJNV). MEJNV had a typical negevirus genome organization, is 9,740 nucleotides in length, and has a GC content of 47.53%. The MEJNV genome contains three ORFs, each containing the following identified conserved domains: ORF1 (7,068 nt) encodes a viral methyltransferase, an FtsJ-like methyltransferase, a viral RNA helicase, and an RNA-dependent RNA polymerase, ORF2 (1,242 nt) encodes a putative virion glycoprotein, and ORF3 (660 nt) encodes a putative virion membrane protein. A distinctive feature relative to other currently known negeviruses is a 7-nucleotide-long overlap between ORF1 and ORF2. MEJNV shares the highest sequence identity with Ying Kou virus from China, with 67.71% nucleotide and 75.19% and 59.00% amino acid sequence identity in ORF 1 and ORF 2, respectively. ORF3 had the highest amino acid sequence similarity to Daeseongdong virus 1 and negevirus Nona 1, both with 77.61% identity, and to Ying Kou virus, with 71.22% identity. MEJNV is currently the northernmost negevirus described. Our report supports the view that negeviruses are a globally distributed, diverse group of viruses that can be found from mosquitoes in a wide range of terrestrial biomes from tropical to boreal forests.

Interferon signature in immunosuppressed patients with lower respiratory tract infections: dosage on bronchoalveolar lavage.

BACKGROUND: Interferon signature (IS) is the measure of transcripts belonging to pathways of interferon activation. Viral infections can interfere with the interferon pathway, in particular herpesvirus present in immunocompromised hosts. The aim of our study was to evaluate if herpesvirus infections in immunocompromised patients with lower respiratory tract infections (LRTI) could lead to IS alterations. METHODS: We measured IS transcription of six genes on bronchoalveolar lavage of immunocompromised patients with LRTI (IFI27, IFI44, IFIT1, ISG15, RSAD2, SIGLEC1). Patients were divided in three groups based on Epstein-Barr virus (EBV) and other herpesviruses coinfections. RESULTS: We included 56 patients, 10 without and 17 with only EBV reactivation (respectively N and E groups) and 29 with EBV and other herpesviruses (group C). IS was higher in group C (P=0.01) compared to other ones, but single gene expressions were different among groups: IFI27 was higher whereas IFIT1 and ISG15 were lower in group C (P<0.05). CONCLUSIONS: The continuous stimulation of interferon cascade by herpesviruses enhances IS. The analysis of IS in immunocompromised population is possible by limiting the use of IFI27, IFIT1, ISG15 genes. Our preliminary results seem to indicate that IS is a useful biomarker of cellular response to herpesvirus infection in immunocompromised patients.