Beyond members of the #Flaviviridae family, #sofosbuvir also inhibits #chikungunya virus #replication (Antimicrob Agents Chemother., abstract)

[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]

Beyond members of the Flaviviridae family, sofosbuvir also inhibits chikungunya virus replication

André C. Ferreira, Patrícia A. Reis, Caroline S. de Freitas, Carolina Q. Sacramento, Lucas Villas Bôas Hoelz, Mônica M. Bastos, Mayara Mattos, Natasha Rocha,Isaclaudia Gomes de Azevedo Quintanilha, Carolina da Silva Gouveia Pedrosa, Leticia Rocha Quintino Souza, Erick Correia Loiola, Pablo Trindade, Yasmine Rangel Vieira,Giselle Barbosa-Lima, Hugo C. de Castro Faria Neto, Nubia Boechat, Stevens K. Rehen, Karin Brüning, Fernando A. Bozza, Patrícia T. Bozza, Thiago Moreno L. Souza

DOI: 10.1128/AAC.01389-18

 

ABSTRACT

Chikungunya virus (CHIKV) causes a febrile disease associated with chronic arthralgia, which may progress to neurological impairment. Chikungunya fever (CF) is an ongoing public health problem in tropical and subtropical regions of the world, where control of the CHIKV vector, Aedes mosquitos, has failed. As there is no vaccine or specific treatment for CHIKV, patients receive only palliative care to alleviate pain and arthralgia. Thus, drug repurposing is necessary to identify antivirals against CHIKV. CHIKV RNA polymerase is similar to the orthologue enzyme of other positive-sense RNA viruses, such as members of the Flaviviridae family. Among the Flaviviridae, not only is hepatitis C virus RNA polymerase susceptible to sofosbuvir, a clinically approved nucleotide analogue, but so is dengue, Zika, and yellow fever virus replication. Here, we found that sofosbuvir was three times more selective in inhibiting CHIKV production in human hepatoma cells than ribavirin, a pan-antiviral drug. Although CHIKV replication in human induced pluripotent stem cell–derived astrocytes was less susceptible to sofosbuvir compared to the hepatoma cells, sofosbuvir nevertheless impaired virus production and cell death in a multiplicity of infection–dependent manner. Sofosbuvir also exhibited antiviral activity in vivo by preventing CHIKV-induced paw edema in adult mice at a dose of 20 mg/kg/day, and prevented mortality in a neonate mouse model at 40 and 80 mg/kg/day doses. Our data demonstrate that a prototypic alphavirus, CHIKV, is also susceptible to sofosbuvir. As sofosbuvir is a clinically approved drug, our findings could pave the way to it becoming a therapeutic option against CF.

Copyright © 2018 American Society for Microbiology. All Rights Reserved.

Keywords: Arbovirus; Alphavirus; Flavivirus; Antivirals; Sofosbuvir.

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Vertical #transmission of naturally occurring #Bunyamwera and insect-specific #flavivirus #infections in #mosquitoes from islands and mainland shores of Lakes Victoria and Baringo in #Kenya (PLoS Negl Trop Dis., abstract)

[Source: PLoS Neglected Tropical Diseases, full page: (LINK). Abstract, edited.]

OPEN ACCESS /  PEER-REVIEWED / RESEARCH ARTICLE

Vertical transmission of naturally occurring Bunyamwera and insect-specific flavivirus infections in mosquitoes from islands and mainland shores of Lakes Victoria and Baringo in Kenya

Yvonne Ukamaka Ajamma, Thomas Ogao Onchuru , Daniel O. Ouso , David Omondi, Daniel K. Masiga, Jandouwe Villinger

Published: November 19, 2018 / DOI: https://doi.org/10.1371/journal.pntd.0006949 / This is an uncorrected proof.

 

Abstract

Background

Many arboviruses transmitted by mosquitoes have been implicated as causative agents of both human and animal illnesses in East Africa. Although epidemics of arboviral emerging infectious diseases have risen in frequency in recent years, the extent to which mosquitoes maintain pathogens in circulation during inter-epidemic periods is still poorly understood. This study aimed to investigate whether arboviruses may be maintained by vertical transmission via immature life stages of different mosquito vector species.

Methodology

We collected immature mosquitoes (egg, larva, pupa) on the shores and islands of Lake Baringo and Lake Victoria in western Kenya and reared them to adults. Mosquito pools (≤25 specimens/pool) of each species were screened for mosquito-borne viruses by high-resolution melting analysis and sequencing of multiplex PCR products of genus-specific primers (alphaviruses, flaviviruses, phleboviruses and Bunyamwera-group orthobunyaviruses). We further confirmed positive samples by culturing in baby hamster kidney and Aedes mosquito cell lines and re-sequencing.

Principal findings

Culex univittatus (2/31pools) and Anopheles gambiae (1/77 pools) from the Lake Victoria region were positive for Bunyamwera virus, a pathogenic virus that is of public health concern. In addition, Aedes aegypti (3/50), Aedes luteocephalus (3/13), Aedes spp. (2/15), and Culex pipiens (1/140) pools were positive for Aedes flaviviruses at Lake Victoria, whereas at Lake Baringo, three pools of An. gambiae mosquitoes were positive for Anopheles flavivirus. These insect-specific flaviviruses (ISFVs), which are presumably non-pathogenic to vertebrates, were found in known medically important arbovirus and malaria vectors.

Conclusions

Our results suggest that not only ISFVs, but also a pathogenic arbovirus, are naturally maintained within mosquito populations by vertical transmission, even in the absence of vertebrate hosts. Therefore, virus and vector surveillance, even during inter-epidemics, and the study of vector-arbovirus-ISFV interactions, may aid in identifying arbovirus transmission risks, with the potential to inform control strategies that lead to disease prevention.

 

Author summary

The East African region is endemic to diverse mosquito-transmitted arboviruses, though little is known about the role of vertical transmission in maintaining these viruses within mosquito vector populations during inter-epidemic periods. We sampled mosquito larvae from the Lake Baringo and Lake Victoria regions of Kenya and reared them to adults in the laboratory before screening them for mosquito-associated viruses by multiplex RT-PCR-HRM, cell culture, and sequencing. From the Lake Victoria region, we detected the arbovirus, Bunyamwera, which can cause febrile illness in humans, in Culex univittatus and vector competent Anopheles gambiaemosquitoes. We also identified diverse insect-specific flaviviruses in Aedes aegypti, Aedes luteocephalus, Aedes spp. and Culex pipiens mosquitoes. From the Lake Baringo region, we detected Anopheles flavivirus in An. gambiae mosquitoes. These findings demonstrate that naturally occurring vertical transmission potentially maintains viruses in circulation within the sampled vector species populations. Therefore, mosquitoes may potentially transmit a pathogenic arbovirus during their first bite after emergence. Because various insect-specific flaviviruses have recently been found to either inhibit or enhance replication of specific arboviruses in mosquitoes, their vertical transmission, as observed in this study, has implications as to their potential impact on both horizontal and vertical transmission of medically important arboviruses.

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Citation: Ajamma YU, Onchuru TO, Ouso DO, Omondi D, Masiga DK, Villinger J (2018) Vertical transmission of naturally occurring Bunyamwera and insect-specific flavivirus infections in mosquitoes from islands and mainland shores of Lakes Victoria and Baringo in Kenya. PLoS Negl Trop Dis 12(11): e0006949. https://doi.org/10.1371/journal.pntd.0006949

Editor: Michael J. Turell, INDEPENDENT RESEARCHER, UNITED STATES

Received: May 3, 2018; Accepted: October 26, 2018; Published: November 19, 2018

Copyright: © 2018 Ajamma et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All ISFV sequences are available from the GenBank nucleotide database (accession MG372051-MG372060, MK015647- MK015648).

Funding: This work was supported by the Swedish International Development Cooperation Agency (Sida) (www.sida.se), grant number 75000529 to YUA as an African Regional Postgraduate Programme in Insect Science (ARPPIS) scholar; and institutional financial support from UK Aid (www.ukaiddirect.org) from the UK Government; Sida; the Swiss Agency for Development and Cooperation (SDC) (www.eda.admin.ch/sdc); and the Kenyan Government (www.mygov.go.ke). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The views expressed herein do not necessarily reflect the official opinion of the donors.

Competing interests: The authors have declared that no competing interests exist.

Keywords: Arbovirus; Flavivirus; Orthobunyavirus; Bunyamwera Virus; Mosquitoes; Culex spp.; Anopheles spp.; Kenya.

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Reemergence of St. Louis #Encephalitis Virus in the #Americas (Emerg Infect Dis., abstract)

[Source: US Centers for Disease Control and Prevention (CDC), Emerging Infectious Diseases Journal, full page: (LINK). Abstract, edited.]

Volume 24, Number 12—December 2018 / CME ACTIVITY – Synopsis

Reemergence of St. Louis Encephalitis Virus in the Americas

Adrián Diaz  , Lark L. Coffey, Nathan Burkett-Cadena, and Jonathan F. Day

Author affiliations: Universidad Nacional de Córdoba, Córdoba, Argentina (A. Diaz); University of California, Davis, California, USA (L.L. Coffey); University of Florida, Vero Beach, Florida, USA (N. Burkett-Cadena, J.F. Day)

 

Abstract

We summarize and analyze historical and current data regarding the reemergence of St. Louis encephalitis virus (SLEV; genus Flavivirus) in the Americas. Historically, SLEV caused encephalitis outbreaks in the United States; however, it was not considered a public health concern in the rest of the Americas. After the introduction of West Nile virus in 1999, activity of SLEV decreased considerably in the United States. During 2014–2015, SLEV caused a human outbreak in Arizona and caused isolated human cases in California in 2016 and 2017. Phylogenetic analyses indicate that the emerging SLEV in the western United States is related to the epidemic strains isolated during a human encephalitis outbreak in Córdoba, Argentina, in 2005. Ecoepidemiologic studies suggest that the emergence of SLEV in Argentina was caused by the introduction of a more pathogenic strain and increasing populations of the eared dove (amplifying host).

Keywords: St Louis Encephalitis Virus; Flavivirus; American Region; USA; Argentina; Human; Wildlife.

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Lack of #serological and molecular evidence of #arbovirus #infections in #bats from #Brazil (PLoS One, abstract)

[Source: PLoS One, full page: (LINK). Abstract, edited.]

OPEN ACCESS /  PEER-REVIEWED / RESEARCH ARTICLE

Lack of serological and molecular evidence of arbovirus infections in bats from Brazil

Cíntia Bittar , Rafael R. G. Machado  , Manuela T. Comelis, Larissa M. Bueno, Eliana Morielle-Versute, Matheus R. Beguelini, Renato P. de Souza, Maurício L. Nogueira, Paula Rahal

Published: November 7, 2018 / DOI: https://doi.org/10.1371/journal.pone.0207010

 

Abstract

Viruses are important agents of emerging zoonoses and are a substantial public health issue. Among emerging viruses, an important group are arboviruses, which are characterized by being maintained in nature in cycles involving hematophagous arthropod vectors and a wide range of vertebrate hosts. Recently, bats have received increasing attention as an important source for the emergence of zoonoses and as possible viral reservoirs. Among the arboviruses, there are many representatives of the genera Flavivirus and Alphavirus, which are responsible for important epidemics such as Dengue virus, Zika virus and Chikungunya virus. Due to the importance of analyzing potential viral reservoirs for zoonosis control and expanding our knowledge of bat viruses, this study aimed to investigate the presence of viruses of the Alphavirus and Flavivirus genera in bats. We analyzed serum, liver, lungs and intestine from 103 bats sampled in northeast and southern Brazil via Nested-PCR and the hemagglutination inhibition test. All samples tested in this study were negative for arboviruses, suggesting that no active or past infection was present in the captured bats. These data indicate that the bats examined herein probably do not constitute a reservoir for these viruses in the studied areas. Further studies are needed to clarify the role of bats as reservoirs and sources of infection of these viral zoonoses.

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Citation: Bittar C, Machado RRG, Comelis MT, Bueno LM, Morielle-Versute E, Beguelini MR, et al. (2018) Lack of serological and molecular evidence of arbovirus infections in bats from Brazil. PLoS ONE 13(11): e0207010. https://doi.org/10.1371/journal.pone.0207010

Editor: Naomi Forrester, Keele University Faculty of Natural Sciences, UNITED KINGDOM

Received: May 16, 2018; Accepted: October 23, 2018; Published: November 7, 2018

Copyright: © 2018 Bittar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the paper and its Supporting Information files.

Funding: This work was financially supported by FAPESP (São Paulo Research Foundation – http://www.fapesp.br/) grant number 2015/09704-6, received by RRGM and by CNPq (National Council for Scientific and Technological Development – http://cnpq.br/) grant number 165802/2015-4, received by CB.

Competing interests: The authors have declared that no competing interests exist.

Keywords: Arbovirus; Flavivirus; Alphavirus; Bats; Brazil; Seroprevalence.

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#Favipiravir inhibits in vitro #Usutu virus replication and delays disease progression in an #infection model in mice (Antiviral Res., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Antiviral Res. 2018 Oct 29. pii: S0166-3542(18)30467-4. doi: 10.1016/j.antiviral.2018.10.026. [Epub ahead of print]

Favipiravir inhibits in vitro Usutu virus replication and delays disease progression in an infection model in mice.

Segura Guerrero NA1, Sharma S2, Neyts J3, Kaptein SJF2.

Author information: 1 KU Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Leuven, Belgium; Universidad Pedagógica y Tecnológica de Colombia, Tunja, Colombia. 2 KU Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Leuven, Belgium. 3 KU Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Leuven, Belgium. Electronic address: johan.neyts@kuleuven.be.

 

Abstract

Usutu virus (USUV) is an emerging flavivirus that causes Usutu disease mainly in birds, but infection of mammals such as rodents, bats and horses has also been demonstrated. In addition, human cases (both in immunocompromised and -competent individuals) were also reported. Large outbreaks with other flaviviruses, such as West Nile virus and Zika virus, indicate that one should be vigilant for yet other outbreaks. To allow the identification of inhibitors of USUV replication, we established in vitro antiviral assays, which were validated using a small selection of known flavivirus inhibitors, including the broad-spectrum viral RNA polymerase inhibitor favipiravir (T-705). Next, an USUV infection model in AG129 (IFN-α/β and IFN-γ receptor knockout) mice was established. AG129 mice proved highly susceptible to USUV; an inoculum as low as 102 PFU (1.3 × 105 TCID50) resulted in the development of symptoms as early as 3 days post infection with viral RNA being detectable in various tissues. Treatment of mice with favipiravir (150 mg/kg/dose, BID, oral gavage) significantly reduced viral load in blood and tissues and significantly delayed virus-induced disease. This USUV mouse model is thus amenable for assessing the potential in vivo efficacy of (novel) USUV/flavivirus inhibitors.

KEYWORDS: AG129 mice; Antivirals; Emerging flavivirus; Mouse model; Usutu virus

PMID: 30385306 DOI: 10.1016/j.antiviral.2018.10.026

Keywords: Flavivirus; Usutu virus; Antivirals; Favipiravir; Animal models.

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#Surveillance and #Diagnosis of #WestNile Virus in the Face of #Flavivirus Cross-Reactivity (Front Microbiol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Front Microbiol. 2018 Oct 11;9:2421. doi: 10.3389/fmicb.2018.02421. eCollection 2018.

Surveillance and Diagnosis of West Nile Virus in the Face of Flavivirus Cross-Reactivity.

Lustig Y1, Sofer D1, Bucris ED1, Mendelson E1,2.

Author information: 1 Central Virology Laboratory, Ministry of Health, Sheba Medical Center, Ramat Gan, Israel. 2 School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.

 

Abstract

West Nile Virus (WNV) is an arthropod-borne flavivirus whose zoonotic cycle includes both mosquitoes and birds as amplifiers and humans and horses as dead-end hosts. In recent years WNV has been spreading globally and is currently endemic in Africa, The Middle East, India, Australia, central and southern Europe, and the Americas. Integrated surveillance schemes and environmental data aim to detect viral circulation and reduce the risk of infection for the human population emphasizing the critical role for One Health principles in public health. Approximately 20% of WNV infected patients develop West Nile Fever while in less than 1%, infection results in West Nile Neurological Disease. Currently, the diagnosis of WNV infection is primarily based on serology, since molecular identification of WNV RNA is unreliable due to the short viremia. The recent emergence of Zika virus epidemic in America and Asia has added another layer of complexity to WNV diagnosis due to significant cross-reactivity between several members of the Flaviviridae family such as Zika, dengue, Usutu, and West Nile viruses. Diagnosis is especially challenging in persons living in regions with flavivirus co-circulation as well as in travelers from WNV endemic countries traveling to Zika or dengue infected areas or vise-versa. Here, we review the recent studies implementing WNV surveillance of mosquitoes and birds within the One Health initiative. Furthermore, we discuss the utility of novel molecular methods, alongside traditional molecular and serological methods, in WNV diagnosis and epidemiological research.

KEYWORDS: WNV; West Nile; Zika; diagnosis; flavivirus; mosquitoes; one health; surveillance

PMID: 30369916 PMCID: PMC6194321 DOI: 10.3389/fmicb.2018.02421

Keywords: Flavivirus; Zika Virus; WNV; WNND; Usutu Virus; Dengue Fever.

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The recently identified #flavivirus #Bamaga virus is transmitted horizontally by #Culex #mosquitoes and interferes with #WNV #replication in vitro and transmission in vivo (PLoS Negl Trop Dis., abstract)

[Source: PLoS Neglected Tropical Diseases, full page: (LINK). Abstract, edited.]

OPEN ACCESS /  PEER-REVIEWED / RESEARCH ARTICLE

The recently identified flavivirus Bamaga virus is transmitted horizontally by Culex mosquitoes and interferes with West Nile virus replication in vitro and transmission in vivo

Agathe M. G. Colmant , Sonja Hall-Mendelin , Scott A. Ritchie, Helle Bielefeldt-Ohmann, Jessica J. Harrison, Natalee D. Newton, Caitlin A. O’Brien, Chris Cazier, Cheryl A. Johansen, Jody Hobson-Peters, Roy A. Hall , Andrew F. van den Hurk

Published: October 24, 2018 / DOI: https://doi.org/10.1371/journal.pntd.0006886

 

Abstract

Arthropod-borne flaviviruses such as yellow fever (YFV), Zika and dengue viruses continue to cause significant human disease globally. These viruses are transmitted by mosquitoes when a female imbibes an infected blood-meal from a viremic vertebrate host and expectorates the virus into a subsequent host. Bamaga virus (BgV) is a flavivirus recently discovered in Culex sitiens subgroup mosquitoes collected from Cape York Peninsula, Australia. This virus phylogenetically clusters with the YFV group, but is potentially restricted in most vertebrates. However, high levels of replication in an opossum cell line (OK) indicate a potential association with marsupials. To ascertain whether BgV could be horizontally transmitted by mosquitoes, the vector competence of two members of the Cx. sitiens subgroup, Cx. annulirostris and Cx. sitiens, for BgV was investigated. Eleven to thirteen days after imbibing an infectious blood-meal, infection rates were 11.3% and 18.8% for Cx. annulirostris and Cx. sitiens, respectively. Cx. annulirostris transmitted the virus at low levels (5.6% had BgV-positive saliva overall); Cx. sitiens did not transmit the virus. When mosquitoes were injected intrathoracially with BgV, the infection and transmission rates were 100% and 82%, respectively, for both species. These results provided evidence for the first time that BgV can be transmitted horizontally by Cx. annulirostris, the primary vector of pathogenic zoonotic flaviviruses in Australia. We also assessed whether BgV could interfere with replication in vitro, and infection and transmission in vivo of super-infecting pathogenic Culex-associated flaviviruses. BgV significantly reduced growth of Murray Valley encephalitis and West Nile (WNV) viruses in vitro. While prior infection with BgV by injection did not inhibit WNV super-infection of Cx. annulirostris, significantly fewer BgV-infected mosquitoes could transmit WNV than mock-injected mosquitoes. Overall, these data contribute to our understanding of flavivirus ecology, modes of transmission by Australian mosquitoes and mechanisms for super-infection interference.

 

Author summary

Mosquito-borne flaviviruses include medically significant members such as the dengue viruses, yellow fever virus and Zika virus. These viruses regularly cause outbreaks globally, notably in tropical regions. The ability of mosquitoes to transmit these viruses to vertebrate hosts plays a major role in determining the scale of these outbreaks. It is essential to assess the risk of emergence of flaviviruses in a given region by investigating the vector competence of local mosquitoes for these viruses. Bamaga virus was recently discovered in Australia in Culexmosquitoes and shown to be related to yellow fever virus. In this article, we investigated the potential for Bamaga virus to emerge as an arthropod-borne viral pathogen by assessing the vector competence of Cx. annulirostris and Cx. sitiens mosquitoes for this virus. We showed that Bamaga virus could be detected in the saliva of Cx. annulirostris after an infectious blood-meal, demonstrating that the virus could be horizontally transmitted. In addition, we showed that Bamaga virus could interfere with the replication in vitro and transmission in vivo of the pathogenic flavivirus West Nile virus. These data provide further insight on how interactions between viruses in their vector can influence the efficiency of pathogen transmission.

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Citation: Colmant AMG, Hall-Mendelin S, Ritchie SA, Bielefeldt-Ohmann H, Harrison JJ, Newton ND, et al. (2018) The recently identified flavivirus Bamaga virus is transmitted horizontally by Culex mosquitoes and interferes with West Nile virus replication in vitro and transmission in vivo. PLoS Negl Trop Dis 12(10): e0006886. https://doi.org/10.1371/journal.pntd.0006886

Editor: Nikos Vasilakis, University of Texas Medical Branch, UNITED STATES

Received: August 28, 2018; Accepted: September 29, 2018; Published: October 24, 2018

Copyright: © 2018 Colmant et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the manuscript.

Funding: The Australian Government Research Training Program Scholarship (https://www.education.gov.au/research-training-program) funded Ph.D. students AMGC, JJH and CAO. This research was supported by the Funding initiatives for mosquito management in Western Australia (FIMMWA), Western Australian Health Department, (https://ww2.health.wa.gov.au/Articles/F_I/Funding-initiatives-for-mosquito-management-in-Western-Australia), awarded to SHM, HBO, CAJ, JHP, RAH. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Keywords: Flavivirus; Bamaga Virus; Murray Valley Encephalitis Virus; WNV; Australia; Mosquitoes; Culex spp.

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