Previous #dengue or #Zika virus #exposure can drive to #infection #enhancement or neutralisation of other #flaviviruses (Mem Inst Oswaldo Cruz, abstract)

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

Mem Inst Oswaldo Cruz. 2019;114:e190098. doi: 10.1590/0074-02760190098. Epub 2019 Aug 12.

Previous dengue or Zika virus exposure can drive to infection enhancement or neutralisation of other flaviviruses.

Oliveira RA1,2, de Oliveira-Filho EF1,3, Fernandes AI4,5, Brito CA6, Marques ET1,7, Tenório MC1, Gil LH1.

Author information: 1 Fundação Oswaldo Cruz, Instituto Aggeu Magalhães, Departamento de Virologia, Recife, PE, Brasil. 2 Universidade Federal da Paraíba, Departamento de Fisiologia e Patologia, João Pessoa, PB, Brasil. 3 Charité-Universitätsmedizin Berlin, Berlin, Germany. 4 Universidade Federal da Paraíba, Hospital Universitário Lauro Wanderley, Serviço de Doenças Infecciosas e Parasitárias, João Pessoa, PB, Brasil. 5 Universidade Federal da Paraíba, Escola Técnica de Saúde, Grupo de Estudos e Pesquisas em Imunologia Humana, João Pessoa, PB, Brasil. 6 Universidade Federal de Pernambuco, Departamento de Medicina Clínica, Recife, PE, Brasil. 7 University of Pittsburgh, Center for Vaccine Research, Department of Infectious Diseases and Microbiology, Pittsburgh, PA, USA.

 

Abstract

BACKGROUND:

Dengue virus (DENV) has circulated in Brazil for over 30 years. During this time, one serotype has cyclically replaced the other, until recently, when all four distinct serotypes began to circulate together. Persistent circulation of DENV for long time periods makes sequential infections throughout a person’s life possible. After primary DENV infection, life-long immunity is developed for the infecting serotype. Since DENV and Zika virus (ZIKV) are antigenically similar, the possibility of cross-reactions has attracted attention and has been demonstrated in vitro.

OBJECTIVE:

The aim of this study was to investigate whether immune-sera from DENV and ZIKV infected patients would cross-react in vitro with other Flaviviridae family members.

METHODS:

Cross-reaction of the studied samples with yellow fever virus (YFV), West Nile virus (WNV), Rocio virus (ROCV), Saint Louis virus (SLEV) and Ilheus virus (ILHV) has been investigated by plaque reduction neutralisation test (PRNT) and the antibody-dependent enhancement (ADE) by flow-cytometry.

FINDINGS:

Antibodies against ZIKV and DENV virus cross-reacted with other flaviviruses either neutralising or enhancing the infection. Thus, viral entrance into FcRFcɣRII-expressing cells were influenced by the cross-reactive antibodies. ZIKV or DENV immune sera enhanced cellular infection by WNV, ILHV, ROCV and SLEV. Finally, DENV immune sera presented higher neutralising activity for YFV and SLEV. While ZIKV immune sera neutralised WNV, ILHV and ROCV with high frequencies of positivity.

MAIN CONCLUSIONS:

The co-circulation of those viruses in the same area represents a risk for the development of severe infections if they spread throughout the country. Successive flavivirus infections may have an impact on disease pathogenesis, as well as on the development of safe vaccine strategies.

PMID: 31411310 DOI: 10.1590/0074-02760190098

Keywords: Flavivirus; Dengue fever; Zika Virus; WNV; Rocio Virus; St Louis Virus; Ilheus virus; Yellow Fever; Serology; ADE; Brazil.

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#Extraordinary increase in #WNV cases and first confirmed #human #Usutu virus #infection in #Hungary, 2018 (Euro Surveill., abstract)

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

Extraordinary increase in West Nile virus cases and first confirmed human Usutu virus infection in Hungary, 2018

Anna Nagy1,2, Eszter Mezei2,3, Orsolya Nagy1,4, Tamás Bakonyi5,6, Nikolett Csonka1, Magdolna Kaposi1, Anita Koroknai1, Katalin Szomor7, Zita Rigó7, Zsuzsanna Molnár3, Ágnes Dánielisz3, Mária Takács1,4

Affiliations: 1 National Reference Laboratory for Viral Zoonoses; National Public Health Center, Budapest, Hungary; 2 These authors contributed equally to this work; 3 Department of Communicable Diseases Epidemiology and Infection Control; National Public Health Center, Budapest, Hungary; 4 Institute of Medical Microbiology, Semmelweis University, Budapest, Hungary; 5 Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, Budapest, Hungary; 6 Viral Zoonoses, Emerging and Vector-borne Infections Group, Institute of Virology, University of Veterinary Medicine, Vienna, Austria; 7 National Reference Laboratory for Viral Exanthematous Diseases; National Public Health Center, Budapest, Hungary

Correspondence: Anna Nagynagy.annannk.gov.hu

Citation style for this article: Nagy Anna, Mezei Eszter, Nagy Orsolya, Bakonyi Tamás, Csonka Nikolett, Kaposi Magdolna, Koroknai Anita, Szomor Katalin, Rigó Zita, Molnár Zsuzsanna, Dánielisz Ágnes, Takács Mária. Extraordinary increase in West Nile virus cases and first confirmed human Usutu virus infection in Hungary, 2018. Euro Surveill. 2019;24(28):pii=1900038. https://doi.org/10.2807/1560-7917.ES.2019.24.28.1900038

Received: 07 Jan 2019;   Accepted: 02 Apr 2019

 

Abstract

Background

During the 2018 WNV transmission season, similarly to other endemic areas in Europe, a large number of human West Nile virus (WNV) infections were reported in Hungary.

Aims

We summarise the epidemiological and laboratory findings of the 2018 transmission season and expand experiences in flavivirus differential diagnostics.

Methods

Every patient with clinical suspicion of acute WNV infection was in parallel tested for WNV, tick-borne encephalitis virus and Usutu virus (USUV) by serological methods. Sera, whole blood and urine samples were also tested for the presence of viral nucleic acid.

Results

Until the end of December 2018, 215 locally acquired and 10 imported human WNV infections were notified in Hungary. All reported cases were symptomatic; most of them exhibited neurological symptoms. In a large proportion of tested individuals, whole blood was the most appropriate sample type for viral nucleic acid detection, but because whole blood samples were not always available, testing of urine samples also extended diagnostic possibilities. In addition, the first human USUV infection was confirmed in 2018 in a patient with aseptic meningitis. Serological cross-reactions with WNV in different serological assays were experienced, but subsequent molecular biological testing and sequence analysis identified Europe lineage 2 USUV infection.

Conclusion

Careful interpretation and simultaneous application of different laboratory methods are necessary to avoid misdiagnosis of human USUV cases. Expansion of the laboratory-confirmed case definition criteria for detection of viral RNA in any clinical specimens to include urine samples could increase diagnostic sensitivity.

© This work is licensed under a Creative Commons Attribution 4.0 International License.

Keywords: WNV; Usutu virus; Hungary.

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#Seroreactivity to #Chikungunya and #WNV Viruses in #Rwandan #Blood Donors (Vector Borne Zoo Dis., abstract)

[Source: Vector Borne and Zoonotic Diseases, full page: (LINK). Abstract, edited.]

Seroreactivity to Chikungunya and West Nile Viruses in Rwandan Blood Donors

Eric Seruyange, Karl Ljungberg, Claude Mambo Muvunyi, Jean Bosco Gahutu, Swaibu Katare, José Nyamusore, Yong-Dae Gwon, Magnus Evander, Heléne Norder, Peter Liljeström, and Tomas Bergström

Published Online: 27 Jun 2019

 

Abstract

Introduction:

Chikungunya virus (CHIKV) and West Nile virus (WNV) have previously been reported from several African countries, including those bordering Rwanda where they may have originated. However, there have been no serosurveillance reports from Rwanda regarding these two viral pathogens.

In this article, we present the first study of immunoglobulin G (IgG) seroreactivity of CHIKV and WNV in Rwandan blood donor samples.

Methods:

Blood donors from Rwanda (n = 874) and Sweden (n = 199) were tested for IgG reactivity against CHIKV, using an in-house enzyme-linked immunosorbent assay with the E1 envelope protein fused with p62 as antigen, and against WNV using a commercial kit. Data on mosquito distribution were obtained from the 2012 assessment of yellow fever virus circulation in Rwanda.

Results:

Seroreactivity to CHIKV was high in Rwanda (63.0%), when compared with Swedish donors, where only 8.5% were IgG positive. However, a cross-reactivity to O’nyong’nyong virus in neutralization test was noted in Rwandan donors. No significant difference in WNV seroreactivity was found (10.4% for Rwandan and 14.1% for Swedish donors). The relatively high seroreactivity to WNV among Swedish donors could partly be explained by cross-reactivity with tick-borne encephalitis virus prevalent in Sweden. Donors from the Eastern Province of Rwanda had the highest IgG reactivity to the two investigated viruses (86.7% for CHIKV and 33.3% for WNV). Five genera of mosquitoes were found in Rwanda where Culex was the most common (82.5%). The vector of CHIKV, Aedes, accounted for 9.6% of mosquitoes and this species was most commonly found in the Eastern Province.

Conclusions:

Our results showed high seroreactivity to CHIKV in Rwandan donors. The highest IgG reactivity to CHIKV, and to WNV, was found in the Eastern Province, the area reporting the highest number of mosquito vectors for these two viruses. Infection control by eliminating mosquito-breeding sites in population-dense areas is recommended, especially in eastern Rwanda.

Keywords: Arbovirus; Chikungunya virus; WNV; Serology; Seroprevalence; Rwanda.

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#WNV #Seroprevalence Among #Blood #Donors in #Hungary (Vector Borne Zoo Dis., abstract)

[Source: Vector Borne and Zoonotic Diseases, full page: (LINK). Abstract, edited.]

West Nile Virus Seroprevalence Among Blood Donors in Hungary

Anna Nagy, Tímea Szöllősi, Mária Takács, Nóra Magyar, and Éva Barabás

Published Online: 11 Jun 2019 / DOI: https://doi.org/10.1089/vbz.2018.2401

 

Abstract

Background and Objectives:

West Nile virus (WNV) is one of the most important viral zoonotic infections in Hungary; however, no transfusion-transmitted WNV infections have been confirmed so far. In 2016, the number of clinical cases of WNV reported was 44, but the seasonal WNV screening of whole-blood donors has not yet been implemented. Our aims were to assess the WNV RNA reactivity and the prevalence of WNV-specific antibodies in the samples of blood donors collected in 2016.

Materials and Methods:

WNV RNA with Cobas TaqScreen and anti-WNV antibody determination from plasma samples of 2112 donors was performed. Cross-reactivity to tick-borne encephalitis virus was excluded. WNV neutralization test was used for the confirmation of anti-WNV IgG reactive results, and the presence of anti-WNV IgM antibodies was also determined.

Results:

None of the samples showed WNV RNA reactivity. The total weighted anti-WNV IgG prevalence was 2.34% (95% confidence interval 1.65–3.03), and in addition, three donors were found to be IgM positive. There was a comparable tendency between the data of WNV seroprevalence and cumulative incidence in six out of seven statistical regions in Hungary.

Conclusion:

Our results show a comparable data with publications that estimated the WNV seroprevalence in some other European endemic areas. As protective measures, both the 30-day deferral of blood donors who spent at least 24 h in WNV-exposed areas and the exclusion of affected Hungarian territories from blood donation are enforced by the Hungarian National Blood Transfusion Service. Our study is the first comprehensive serological survey to obtain actual data about WNV seroprevalence in the Hungarian human population.

Keywords: WNV; Serology; Seroprevalence; Blood safety; Hungary.

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#WNV #infection in individuals with pre-existing #Usutu virus #immunity, northern #Italy, 2018 (Euro Surveill., abstract)

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

West Nile virus infection in individuals with pre-existing Usutu virus immunity, northern Italy, 2018

Alessandro Sinigaglia1, Monia Pacenti2, Thomas Martello1, Silvana Pagni1,2, Elisa Franchin1,2, Luisa Barzon1,2

Affiliations: 1 Department of Molecular Medicine, University of Padova, Padova, Italy; 2 Microbiology and Virology Unit, Padova University Hospital, Padova, Italy

Correspondence:  Luisa Barzon

Citation style for this article: Sinigaglia Alessandro, Pacenti Monia, Martello Thomas, Pagni Silvana, Franchin Elisa, Barzon Luisa. West Nile virus infection in individuals with pre-existing Usutu virus immunity, northern Italy, 2018. Euro Surveill. 2019;24(21):pii=1900261. https://doi.org/10.2807/1560-7917.ES.2019.24.21.1900261

Received: 27 Apr 2019;   Accepted: 22 May 2019

 

Abstract

In 2018, there was a large West Nile virus (WNV) outbreak in northern Italy. We observed five atypical cases of WNV infection that were characterised by the presence of WNV RNA and WNV IgG at the time of diagnosis, but no IgM response during follow-up. Neutralisation assays demonstrated pre-existing Usutu virus immunity in all patients. Besides challenging diagnosis, the immunological crosstalk between the two viruses warrants further investigation on possible cross-protection or infection enhancement effects.

©  This work is licensed under a Creative Commons Attribution 4.0 International License.

Keywords: WNV; Usutu virus; ADE; Italy.

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Schlafen 11 Restricts #Flavivirus #Replication (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

Schlafen 11 Restricts Flavivirus Replication.

Federico Valdez, Julienne Salvador, Pedro M. Palermo, Jonathon E. Mohl, Kathryn A. Hanley, Douglas Watts, Manuel Llano

DOI: 10.1128/JVI.00104-19

 

ABSTRACT

Schlafen 11 (Slfn11) is an interferon-stimulated gene that controls synthesis of proteins by regulating tRNA abundance. Likely through this mechanism, Slfn11 has previously been shown to impair human immunodeficiency virus 1 (HIV-1) infection and the expression of codon-biased open reading frames. Because replication of positive-sense single-stranded RNA [(+)ssRNA] viruses requires the immediate translation of the incoming viral genome whereas negative-sense, single-stranded RNA [(-)ssRNA] viruses carry at infection an RNA replicase that makes multiple translation competent copies of the incoming viral genome, we reasoned that (+)ssRNA viruses will be more sensitive to the effect of Slfn11 on protein synthesis than (-)ssRNA viruses. To evaluate this hypothesis, we tested the effects of Slfn11 on the replication of a panel of ssRNA viruses in the human glioblastoma cell line A172, which naturally expresses Slfn11. Depletion of Slfn11 significantly increased the replication of (+)ssRNA viruses from the Flavivirus genus, including West Nile (WNV), dengue (DENV), and Zika virus (ZIKV) but had no significant effect on the replication of the (-)ssRNA viruses vesicular stomatitis (VSV, Rhabdoviridae family) and Rift Valley fever (RVFV, Phenuiviridae family). Quantification of the genome-containing viral particles to plaque forming units ratio indicated that Slfn11 impairs WNV infectivity. Intriguingly, Slfn11 prevented WNV-induced down-regulation of a subset of tRNAs implicated in the translation of 11.8% of the viral polyprotein. Low abundance tRNAs might promote optimal protein folding and enhance viral infectivity, as previously reported. In summary, this study demonstrates that Slfn11 restricts flavivirus replication by impairing viral infectivity.

 

AUTHOR SUMMARY

We provide evidence that the cellular protein Schlafen 11 (Slfn11) impairs replication of flaviviruses, including West Nile (WNV), dengue (DENV), and Zika virus (ZIKV). However, replication of single-stranded, negative RNA viruses was not affected. Specifically, Slfn11 decreases the infectivity of WNV potentially by preventing virus-induced modifications of the host tRNA repertoire that could lead to enhanced viral protein folding. Furthermore, we demonstrated that Slfn11 is not the limiting factor of this novel broad anti-viral pathway.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Flavivirus; Zika virus; WNV; Dengue fever; Interferons.

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#Serological #evidence of #Flavivirus #circulation in #human populations in Northern #Kenya: an assessment of disease risk 2016-2017 (Virol J., abstract)

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

Virol J. 2019 May 17;16(1):65. doi: 10.1186/s12985-019-1176-y.

Serological evidence of Flavivirus circulation in human populations in Northern Kenya: an assessment of disease risk 2016-2017.

Chepkorir E1,2, Tchouassi DP3, Konongoi SL4, Lutomiah J4, Tigoi C3, Irura Z5, Eyase F6, Venter M7, Sang R3.

Author information: 1 International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya. echepkorir@icipe.org. 2 Center for Viral Zoonoses, Department of Medical Virology, University of Pretoria, P. O. Box 323, Arcadia, 0007, South Africa. echepkorir@icipe.org. 3 International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya. 4 Center for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya. 5 Division of Disease Surveillance and Response, Ministry of Health, P. O. Box 20781-00202, Nairobi, Kenya. 6 Jomo Kenyatta University of Agriculture and Technology, P.O. Box 606, Village Market, Nairobi, Kenya. 7 Center for Viral Zoonoses, Department of Medical Virology, University of Pretoria, P. O. Box 323, Arcadia, 0007, South Africa.

 

Abstract

BACKGROUND:

Yellow fever, Dengue, West Nile and Zika viruses are re-emerging mosquito-borne Flaviviruses of public health concern. However, the extent of human exposure to these viruses and associated disease burden in Kenya and Africa at large remains unknown. We assessed the seroprevalence of Yellow fever and other Flaviviruses in human populations in West Pokot and Turkana Counties of Kenya. These areas border Uganda, South Sudan and Ethiopia where recent outbreaks of Yellow fever and Dengue have been reported, with possibility of spillover to Kenya.

METHODOLOGY:

Human serum samples collected through a cross-sectional survey in West Pokot and Turkana Counties were screened for neutralizing antibodies to Yellow fever, Dengue-2, West Nile and Zika virus using the Plaque Reduction Neutralization Test (PRNT). Seroprevalence was compared by county, site and important human demographic characteristics. Adjusted odds ratios (aOR) were estimated using Firth logistic regression model.

RESULTS:

Of 877 samples tested, 127 neutralized with at least one of the four flaviviruses (14.5, 95% CI 12.3-17.0%), with a higher proportion in Turkana (21.1%, n = 87/413) than in West Pokot (8.6%, n = 40/464). Zika virus seroprevalence was significantly higher in West Pokot (7.11%) than in Turkana County (0.24%; χ2 P < 0.0001). A significantly higher Yellow fever virus seroprevalence was also observed in Turkana (10.7%) compared to West Pokot (1.29%; χ2 P < 0.0001). A high prevalence of West Nile virus was detected in Turkana County only (10.2%) while Dengue was only detected in one sample, from West Pokot. The odds of infection with West Nile virus was significantly higher in males than in females (aOR = 2.55, 95% CI 1.22-5.34). Similarly, the risk of Zika virus infection in West Pokot was twice higher in males than females (aOR = 2.01, 95% CI 0.91-4.41).

CONCLUSION:

Evidence of neutralizing antibodies to West Nile and Zika viruses indicates that they have been circulating undetected in human populations in these areas. While the observed Yellow Fever prevalence in Turkana and West Pokot Counties may imply virus activity, we speculate that this could also be as a result of vaccination following the Yellow Fever outbreak in the Omo river valley, South Sudan and Uganda across the border.

KEYWORDS: Dengue virus; Flaviviruses risk assessment; Northern Kenya; Plaque reduction neutralization test; Seroprevalence; West Nile virus; Yellow fever virus; Zika virus

PMID: 31101058 DOI: 10.1186/s12985-019-1176-y

Keywords: Flavivirus; WNV; Zika Virus; Dengue Fever; Yellow Fever; Serology; Seroprevalence; Kenya.

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