Isolation and Characterisation of Alongshan Virus in Russia.

In recent decades, many new flavi-like viruses have been discovered predominantly in different invertebrates and, as was recently shown, some of them may cause disease in humans. The Jingmenvirus (JMV) group holds a special place among flaviviruses and flavi-like viruses because they have a segmented ssRNA(+) genome. We detected Alongshan virus (ALSV), which is a representative of the JMV group, in ten pools of adult Ixodes persulcatus ticks collected in two geographically-separated Russian regions. Three of the ten strains were isolated in the tick cell line IRE/CTVM19. One of the strains persisted in the IRE/CTVM19 cells without cytopathic effect for three years. Most ALSV virions purified from tick cells were spherical with a diameter of approximately 40.5 nm. In addition, we found smaller particles of approximately 13.1 nm in diameter. We obtained full genome sequences of all four segments of two of the isolated ALSV strains, and partial sequences of one segment from the third strain. Phylogenetic analysis on genome segment 2 of the JMV group clustered our novel strains with other ALSV strains. We found evidence for the existence of a novel upstream open reading frame in the glycoprotein-coding segment of ALSV and other members of the JMV group.

Effect of human pegivirus route of transmission on the genetic distribution of the virus: an institution based cross-sectional study.

INTRODUCTION: Human pegivirus (HPgV), formally called GB virus C (GBV-C), is a member of the pegivirus genus in Flaviviridae family. High prevalence of HPgV infection is seen among sex workers, blood transfusion recipients and intravenous drug users (IDUs). So far, there are seven genotypes and many subtypes identified in different countries. The predominant genotype in Asia including China is genotype 3, although genotype 7 has been reported recently in China. The aim of this study was to evaluate the effect of the transmission routes of HPgV infection on the genotype distribution of the virus, to determine the prevalence rate, and identify the dominant genotype among men who have sex with men (MSM) and IDUs co-infected with human immunodeficiency virus type one (HIV-1) in Guangzhou, China. METHODS: A total of 131 MSM and 70 IDUs co-infected with HIV-1 were randomly selected in Guangdong Dermatology Hospital. HPgV RNA was detected by nested reverse transcriptase polymerase chain reaction (RT-PCR) using primers. The PCR products were sequenced and phylogenetically analyzed by using MEGA6.06 version software to determine the genotypes. Chi-square and Fisher exact test were implemented for comparing the proportion between different variables. RESULTS: The prevalence of HPgV infection was 32.9% among IDUs and 18.3% in MSM with a statistically significant difference between the two groups (p = 0.02). In IDU group, 82.6% infected with genotype 3 and the rest (17.4%) were categorized to genotype 7. Similarly, in MSM group, 83.3% belonged to genotype 3, and the remaining 16.7% were classified as sub-genotype 2a and 2b. CONCLUSION: In Guangzhou, China, the prevalence rate of HPgV infection in IDUs was higher than MSM. The dominant genotype in the two groups was genotype 3. Our results indicated that routes of transmission did not affect the genotype distribution but did affect the prevalence rate of HPgV infection.

High prevalence and autochtonous transmission of human pegivirus (HPgV-1) in blood donors in the extreme southern of Brazil.

Recent studies have suggested that human pegivirus 1 (HPgV-1) may have some pathogenic potential. In the southernmost region of Brazil, studies on HPgV-1 are scarce, and circulating genotypes have not yet been identified. The current study aimed to evaluate the prevalence of HPgV-1 among blood donors from the southernmost region of Brazil and identify the genotypes involved with associated factors. A cross-sectional study was conducted with 281 blood donors, who had their plasma subjected to RNA extraction, complementary DNA synthesis, HPgV-1 detection by nested polymerase chain reaction, and subsequent genotyping. The observed prevalence of HPgV-1-RNA was 21.7%. The only variable that was significantly associated with virus infection was the relationship status of the donor. Single or no fixed partner blood donors were twice as likely to have HPgV-1 (95% CI, 1.12 to 4.56; P = 0.02). Genotype 2-subtypes 2b (69%) and 2a (29%)-was the most prevalent. In the absence of risk factors for parenteral transmission, it is likely that sexual transmission was the route of infection in the individuals studied. Further work will be needed to determine whether this virus is inert in the population, or if there are potential deleterious effects in infected individuals.

Subverting the mechanisms of cell death: flavivirus manipulation of host cell responses to infection.

Viruses exploit host metabolic and defence machinery for their own replication. The flaviviruses, which include Dengue (DENV), Yellow Fever (YFV), Japanese Encephalitis (JEV), West Nile (WNV) and Zika (ZIKV) viruses, infect a broad range of hosts, cells and tissues. Flaviviruses are largely transmitted by mosquito bites and humans are usually incidental, dead-end hosts, with the notable exceptions of YFV, DENV and ZIKV. Infection by flaviviruses elicits cellular responses including cell death via necrosis, pyroptosis (involving inflammation) or apoptosis (which avoids inflammation). Flaviviruses exploit these mechanisms and subvert them to prolong viral replication. The different effects induced by DENV, WNV, JEV and ZIKV are reviewed. Host cell surface proteoglycans (PGs) bearing glycosaminoglycan (GAG) polysaccharides - heparan/chondroitin sulfate (HS/CS) - are involved in initial flavivirus attachment and during the expression of non-structural viral proteins play a role in disease aetiology. Recent work has shown that ZIKV-infected cells are protected from cell death by exogenous heparin (a GAG structurally similar to host cell surface HS), raising the possibility of further subtle involvement of HS PGs in flavivirus disease processes. The aim of this review is to synthesize information regarding DENV, WNV, JEV and ZIKV from two areas that are usually treated separately: the response of host cells to infection by flaviviruses and the involvement of cell surface GAGs in response to those infections.

First detection of human hepegivirus-1 (HHpgV-1) in Iranian patients with hemophilia.

A novel blood-borne virus called the human hepegivirus 1 (HHpgV-1) was recently discovered in hemophilia patients. The present study aimed to investigate the presence of HHpgV-1 in hemophilia patients. A total of 436 serum samples were investigated for the presence of hepatitis C virus (HCV), human pegivirus-1 (HPgV-1), torque teno virus (TTV), and HHpgV-1. Out of the 436 patients, 163 (37.4%), 19 (4.4%), 76 (17.4%), and four (0.9%) patients were positive for HCV, HPgV-1, TTV, and HHpgV-1, respectively. HHpgV-1 patients had a mean viral load of 4.9 ± 0.3 log RNA copies/mL and were co-infected with HCV-1a, HPgV-1, and TTV. Moreover, three HHpgV-1-positive patients exhibited stage F0 liver fibrosis. HCV viral load in HHpgV-1-positive patients was lower than those of HHpgV-1-negative patients. Results also revealed that co-infection of HHpgV-1 with HPgV-1 and HCV may play a protective role in patients with chronic HCV. In conclusion, we detected a low frequency of HHpgV-1 infection in hemophilia patients, and results suggested that HHpgV-1 infection was correlated with the presence of other blood-borne viruses and is likely to also correlate with low HCV viral load and reduced severity of liver disease. Additional studies are required to further investigate the clinical importance of HHpgV-1.

The human pegivirus: A new name for an "ancient" virus. Can transfusion medicine come up with something new?

Human pegivirus (HPgV, formerly called GB virus C/hepatitis G virus) is a poorly understood RNA virus of the Flaviviridae family. The HPgV infection is common worldwide and the virus is likely transmitted by blood products. At this time, no causal association between HPgV and human diseases has been identified. While waiting for new findings to better understand the Pegivirus genus, the aim of our narrative review is to discuss the currently available information on HPgV focusing on its prevalence in blood donors and its potential threat to transfusion safety.

Prevalence of human pegivirus-1 and sequence variability of its E2 glycoprotein estimated from screening donors of fetal stem cell-containing material.

BACKGROUND: Human pegivirus-1 (HPgV-1) is a member of the Flaviviridae family whose genomic organization and mode of cellular entry is similar to that of hepatitis C virus (HCV). The E2 glycoprotein of HPgV-1 is the principle mediator in the virus-cell interaction and as such harbors most of HPgV-1's antigenic determinants. HPgV-1 persists in blood cell precursors which are increasingly used for cell therapy. METHODS: We studied HPgV-1 prevalence in a large cohort of females donating fetal tissues for clinical use. PCR was used for screening and estimation of viral load in viremic plasma and fetal samples. Sequence analysis was performed for portions of the 5'-untranslated and E2 regions of HPgV-1 purified from donor plasmas. Sequencing was followed by phylogenetic analysis. RESULTS: HPgV-1 was revealed in 13.7% of plasmas, 5.0% of fetal tissues, 5.4% of chorions, exceeding the prevalence of HCV in these types of samples. Transmission of HPgV-1 occurred in 25.8% of traceable mother-chorion-fetal tissues triads. For HPgV-1-positive donors, a high viral load in plasma appears to be a prerequisite for transmission. However, about one third of fetal samples acquired infection from non-viremic individuals. Sequencing of 5'-untranslated region placed most HPgV-1 samples to genotype 2a. At the same time, a portion of E2 sequence provided a much weaker support for this grouping apparently due to a higher variability. Polymorphisms were detected in important structural and antigenic motifs of E2. CONCLUSION: HPgV-1 is efficiently transmitted to fetus at early embryonic stages. A high variability in E2 may pose a risk of generation of pathogenic subtypes. Although HPgV-1 is considered benign and no longer tested mandatorily in blood banks, the virus may have adversary effects at target niches if delivered with infected graft upon cell transplantation. This argues for the necessity of HPgV-1 testing of cell samples aimed for clinical use.

A Review of Flaviviruses that Have No Known Arthropod Vector.

Most viruses in the genus Flavivirus are horizontally transmitted between hematophagous arthropods and vertebrate hosts, but some are maintained in arthropod- or vertebrate-restricted transmission cycles. Flaviviruses maintained by vertebrate-only transmission are commonly referred to as no known vector (NKV) flaviviruses. Fourteen species and two subtypes of NKV flaviviruses are recognized by the International Committee on Taxonomy of Viruses (ICTV), and Tamana bat virus potentially belongs to this group. NKV flaviviruses have been isolated in nature almost exclusively from bats and rodents; exceptions are the two isolates of Dakar bat virus recovered from febrile humans and the recent isolations of Sokoluk virus from field-collected ticks, which raises questions as to whether it should remain classified as an NKV flavivirus. There is evidence to suggest that two other NKV flaviviruses, Entebbe bat virus and Yokose virus, may also infect arthropods in nature. The best characterized bat- and rodent-associated NKV flaviviruses are Rio Bravo and Modoc viruses, respectively, but both have received limited research attention compared to many of their arthropod-infecting counterparts. Herein, we provide a comprehensive review of NKV flaviviruses, placing a particular emphasis on their classification, host range, geographic distribution, replication kinetics, pathogenesis, transmissibility and molecular biology.

Prevalence and vertical transmission of human pegivirus among pregnant women infected with HIV.

OBJECTIVE: To determine the prevalence of human pegivirus (HPgV) and factors associated with vertical transmission among pregnant women infected with HIV. METHOD: A retrospective cross-sectional study was conducted among pregnant women treated at an HIV reference service in Rio Grande, Brazil, between January 1, 2010, and January 1, 2015. The polymerase chain reaction was used to diagnose HPgV infection among the women and their neonates. Clinical, obstetric, and neonatal data were obtained from medical records. RESULTS: Infection with HPgV was detected among 16 (25%) of 63 women and 5 (8%) of 63 newborns, corresponding to a vertical transmission rate of 31%. Multivariate analysis demonstrated that the absence of prenatal care was the only risk factor for vertical transmission of HPgV (prevalence ratio 19.61, 95% confidence interval 1.29-297.48; P=0.032). CONCLUSION: Prenatal care could protect against vertical transmission of HPgV among women infected with HIV; however, studies among HIV-negative individuals are still required to verify this correlation.

ICTV Virus Taxonomy Profile: Flaviviridae.

The Flaviviridae is a family of small enveloped viruses with RNA genomes of 9000-13 000 bases. Most infect mammals and birds. Many flaviviruses are host-specific and pathogenic, such as hepatitis C virus in the genus Hepacivirus. The majority of known members in the genus Flavivirus are arthropod borne, and many are important human and veterinary pathogens (e.g. yellow fever virus, dengue virus). This is a summary of the current International Committee on Taxonomy of Viruses (ICTV) report on the taxonomy of the Flaviviridae, which is available at www.ictv.global/report/flaviviridae.

Infección importada por virus Zika en una zona colonizada por Aedes albopictus / Infection imported virus Zika in an area settled by Aedes albopictus

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Analysis of Mosquito-Borne Flavivirus Superinfection in Culex tritaeniorhynchus (Diptera: Culicidae) Cells Persistently Infected with Culex Flavivirus (Flaviviridae).

Superinfection exclusion is generally defined as a phenomenon in which a pre-existing viral infection prevents a secondary viral infection; this has also been observed in infections with mosquito-borne viruses. In this study, we examined the superinfection exclusion of the vertebrate-infecting flaviviruses, Japanese encephalitis virus (JEV) and dengue virus (DENV), by stable and persistent infection with an insect-specific flavivirus, Culex flavivirus (CxFV), in a Culex tritaeniorhynchus Giles cell line (CTR cells). Our experimental system was designed based on the premise that wild Cx. tritaeniorhynchus mosquitoes naturally infected with CxFV are superinfected with JEV by feeding on JEV-infected animals. As a result, we found no evidence of the superinfection exclusion of both JEV and DENV by pre-existing CxFV infection at the cellular level. However, JEV superinfection induced severe cytopathic effects on persistently CxFV-infected CTR cells. These observations imply the possibility that JEV superinfection in CxFV-infected Cx. tritaeniorhynchus mosquitoes has an adverse effect on their fitness.

Risk assessment of flavivirus transmission in Namibia.

The role of arboviruses causing acute febrile illness in sub-Saharan Africa is receiving more attention. Reports of dengue in tourists were published nearly 10 years ago in Namibia, but the current epidemiology of arboviruses is unknown and surveys of mosquito vectors have not been carried out since the 1950s. To begin addressing this knowledge gap, a prospective cross-sectional study was conducted using samples from volunteer blood donors linked to questionnaire. Serum samples were tested using a Dengue IgG Indirect ELISA which measured exposure to dengue virus/flaviviruses. Entomological samples were collected from tires during the rainy season (February-March 2012) in six locations across Namibia's capital city, Windhoek. Among 312 blood donors tested, 25 (8.0%) were positive for dengue virus/flavivirus exposure. The only significant risk factor was age group with high exposure rates among those older than 50 (29%) compared with those below 40 years old (between 2.9% and 8.3%) (P<0.002). Larvae and pupae of Aedes aegypti and Culex pipiens complex accounted for 100% of the 2751 samples collected, of which only 12.2% (n=336) were Ae. aegypti. Each site demonstrated high variability of species composition between sampling times. While the significant dengue virus/flavivirus exposure rate among those above 50 years old is likely indicative of the West Nile epidemic in the 70s and 80s, the low exposure among those under 50 suggests that flaviviruses are still circulating in Namibia. While Ae. aegypti and C. pipiens sp. may play a role in future epidemics, the significance of presence may be reduced due to short rain periods, dry, arid, cold winters and policies and social understandings that limit non-structured storage and use of tires in low income areas. Future studies should further characterize the circulating arboviruses and investigate mosquito ecology nationally to map areas at higher risk for future arbovirus outbreaks.

Human pegivirus molecular epidemiology in Argentina: potential contribution of Latin American migration to genotype 3 circulation.

In order to determine the human pegivirus (HPgV) genotypic diversity in Argentina taking into account the potential contribution of human migration from neighboring countries, samples from 130 Argentine injecting drug users, 116 Argentine- and 50 immigrant-pregnant women were analyzed. HPgV RNA prevalence among human immunodeficiency virus (HIV)-positive injecting drug users was similar to HIV-positive pregnant women, as was the case when comparing HIV-negative injecting drug users and HIV-negative pregnant women (P > 0.05). HPgV genotype 2 (HPgV/2) was prevalent among both Argentine injecting drug users and pregnant women, in contrast to HPgV/3 observed among pregnant women from Latin American countries with predominant indigenous populations and who had experienced their initial sexual intercourses--and possibly their source of infection--in those countries (P < 0.01). In addition, HPgV vertical and horizontal transmission was proven by molecular analysis of E2 gene and construction of identity matrixes with epidemiologically non-related isolates. This study shows that human migration from neighboring Latin American countries with predominant indigenous populations might contribute to HPgV/3 circulation in Argentina.

Large scale screening of human sera for HCV RNA and GBV-C RNA.

North Carolina locates acute HIV cases by pooled nucleic acid testing of HIV-antibody negative serum samples. Here, 224 pools of 80 HIV-negative samples (N = 17,920) were screened for viral RNA from HCV, GBV-C, and influenza A. No evidence of influenza A was found, but HCV and GBV-C were common (1.2% and 1.7% prevalence, respectively), demonstrating the utility of pooled testing in locating individuals that may remain undiagnosed otherwise. By sequencing positive pools, potential transmission clusters may be located as well.

[Genetic characterisation of Powassan virus (POWV) isolated from Haemophysalis longicornis ticks in Primorye and two strains of Tick-borne encephalitis virus (TBEV) (Flaviviridae, Flavivirus): Alma-Arasan virus (AAV) isolated from Ixodes persulcatus ticks in Kazakhstan and Malyshevo virus isolated from Aedes vexans nipponii mosquitoes in Khabarovsk kray].

The complete genomes of the three tick-borne flaviviruses (genus Flavivirus, fam. Bunyaviridae) were sequenced: Povassan virus (POWV, strain LEIV-3070Prm, isolated from Haemophysalis logicornis in Primorsky Krai, Russia in 1977), Alma-Arasan virus (AAV, strain LEIV-1380Kaz, isolated from Ixodes persulcatus ticks in Kazakhstan in 1977) and Malyshevo virus (isolated from a pool of Aedes vexans nipponii mosquitoes, in the Khabarovsk Krai, Russia in 1978). It is shown that AAV and Malyshevo virus are the strains of Tick-borne encephalitis virus (TBEV) and belong to Sibirian and Far-Eastern genotypes, respectively (GenBank ID: AAV KJ744033; strain Malyshevo KJ744034). Phylogenetically AAV is closest related (94,6% nt and 98,3% aa identity) to TBEV strains, isolated in Sibiria (Vasilchenko, Aino, Chita-653, Irkutsk-12). Malyshevo virus is closest related (96,4% nt and 98,3% nt identity) to strains of TBEV, isolated in Far Eastern part of Russia (1230, Spassk-72, Primorye-89). POWV LEIV-3070Prm has 99.7% identity with the prototype strain POWV LB, isolated in Canada and 99.5% of isolates with Far-Eastern strains of POWV (Spassk-9 and Nadezdinsk-1991).

[When some Flaviviruses are throwing our certainties]. / Quand certains flavivirus remettent en cause nos certitudes.

During the past two decades, a number of mosquito-borne flaviviruses, mainly of African origin, have invaded new geographical areas where they have never been active. This was the case for the Japanese encephalitis virus which reached the northeastern part of Australia (1995) and, above all, for the West Nile virus which, since 1999, entirely colonized the American continent. Then, the Usutu virus invaded a large part of the Western Europe (2001) while the Zika virus caused a large epidemic in an island of Micronesia (2007). Finally, in 2010, the Tembusu virus devastated many duck farms in China while the Bagaza virus, after having provoked human encephalitis in India, reached the southern part of Spain. In the affected areas, new pathogenic outcomes were observed in humans and animals while new vertebrate hosts and mosquito species were infected. Moreover, unusual ways of contamination were described. The origins of this unprecedented evolution remain to be clarified.

Role of GB virus C in modulating HIV disease.

GB virus C (GBV-C) is a member of the Flaviviridae family and the most closely related human virus to HCV. However, GBV-C does not replicate in hepatocytes, but rather in lymphocytes. GBV-C has a worldwide distribution and is transmitted sexually, parenterally and through mother-to-child transmission. Thus, co-infection with HCV and HIV is common. Until now, no human disease has been associated with GBV-C infection. However, there are several reports of a beneficial effect of GBV-C on HIV disease progression in vivo. Different mechanisms to explain these observations have been proposed, including modification of antiviral cytokine production, HIV co-receptor expression, direct inhibition of HIV-1 entry, T-cell activation and Fas-mediated apoptosis. Further understanding of these mechanisms may open new strategies for the treatment of HIV/AIDS.

Transmission of GB virus type C via transfusion in a cohort of HIV-infected patients.

BACKGROUND: GB virus C (GBV-C) infection is transmitted by blood exposure and associated with lower human immunodeficiency virus (HIV) load and slower HIV disease progression. Few studies describe predictors of acute GBV-C infection following transfusion in HIV-infected patients. METHODS: We used a limited-access database from the National Heart Lung and Blood Institute's Viral Activation Transfusion Study, a randomized controlled trial of leukoreduced versus nonleukoreduced transfusions received by HIV-infected, transfusion-naive patients. Blood samples from 489 subjects were tested for GBV-C markers in pretransfusion and posttransfusion samples. We estimated the risk of acquiring GBV-C RNA and predictors of GBV-C acquisition, using pooled logistic regression. RESULTS: GBV-C RNA was detected ≤120 days following the first transfusion in 22 (7.5%) of 294 subjects who were GBV-C negative before transfusion. The risk of GBV-C RNA acquisition increased with each unit transfused (odds ratio, 1.09; 95% confidence interval, 1.06-1.11). Lower baseline HIV load and use of antiretroviral therapy were associated with subsequent GBV-C RNA acquisition, after control for units of blood transfused. Leukoreduced status of transfused units was not associated with GBV-C transmission. CONCLUSIONS: Blood transfusion is associated with a significant risk of GBV-C acquisition among HIV-infected patients. Transmission of GBV-C by blood transfusion was inversely related to HIV load.

GBV-C: state of the art and future prospects.

The GB virus C is a common non-pathogenic virus, member of the Flaviviridae family with worldwide distribution. Favorable clinical course and reduced mortality among HIV-infected patients was demonstrated by several studies with patients co-infected with the GB virus C (GBV-C). This potential benefit of GBV-C has been demonstrated in the pre-HAART and post-HAART eras; however, this effect was not observed in all studies and the discrepancy may be due to changes during the course of HIV infection, characteristic of the cohort, and the degree of therapeutic response. The GBV-C has been found to decrease HIV replication in in vitro models, highlighting the interference of persistent GBV-C viremia. The mechanism of the beneficial effect of GBV-C appears to be mediated by changes in the cellular immune response, and elucidation of putative protective effects of GBV-C in HIV co-infection could potentially identify novel targets for anti-HIV agents.