#Vector #Competence: What Has #Zika Virus Taught Us? (Viruses, abstract)

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

Viruses. 2019 Sep 17;11(9). pii: E867. doi: 10.3390/v11090867.

Vector Competence: What Has Zika Virus Taught Us?

Azar SR1,2,3, Weaver SC4,5,6.

Author information: 1 Department of Microbiology and Immunology, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. srazar@utmb.edu. 2 Institute for Translational Sciences, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. srazar@utmb.edu. 3 Institute for Human Infections and Immunity, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. srazar@utmb.edu. 4 Department of Microbiology and Immunology, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. sweaver@utmb.edu. 5 Institute for Translational Sciences, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. sweaver@utmb.edu. 6 Institute for Human Infections and Immunity, University of Texas Medical Branch, 300 University Blvd, Galveston, TX 77555, USA. sweaver@utmb.edu.



The unprecedented outbreak of Zika virus (ZIKV) infection in the Americas from 2015 to 2017 prompted the publication of a large body of vector competence data in a relatively short period of time. Although differences in vector competence as a result of disparities in mosquito populations and viral strains are to be expected, the limited competence of many populations of the urban mosquito vector, Aedes aegypti, from the Americas (when its susceptibility is viewed relative to other circulating/reemerging mosquito-borne viruses such as dengue (DENV), yellow fever (YFV), and chikungunya viruses (CHIKV)) has proven a paradox for the field. This has been further complicated by the lack of standardization in the methodologies utilized in laboratory vector competence experiments, precluding meta-analyses of this large data set. As the calls for the standardization of such studies continue to grow in number, it is critical to examine the elements of vector competence experimental design. Herein, we review the various techniques and considerations intrinsic to vector competence studies, with respect to contemporary findings for ZIKV, as well as historical findings for other arboviruses, and discuss potential avenues of standardization going forward.

KEYWORDS: Aedes aegypti; Flaviviruses; Zika virus; arbovirus; mosquitoes; vector competence

PMID: 31533267 DOI: 10.3390/v11090867

Keywords: Mosquitoes; Aedes aegypti; Flavivirus; Zika Virus.



Insights into the #ZIKV NS1 #Virology from Different #Strains through a Fine Analysis of #Physicochemical Properties (ACS Omega, abstract)

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

ACS Omega. 2018 Nov 29;3(11):16212-16229. doi: 10.1021/acsomega.8b02081. eCollection 2018 Nov 30.

Insights into the ZIKV NS1 Virology from Different Strains through a Fine Analysis of Physicochemical Properties.

Poveda-Cuevas SA1,2,3, Etchebest C4,5,6,3, Barroso da Silva FL1,2,3,7.

Author information: 1 Programa Interunidades em Bioinformática, Universidade de São Paulo, São Paulo 05508-090, Brazil. 2 Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo 14040-903, Brazil. 3 University of São Paulo and Université Sorbonne Paris Cité Joint International Laboratory in Structural Bioinformatics. 4 Institut National de la Transfusion Sanguine, Paris 75015, France. 5 Biologie Intégrée du Globule Rouge, Equipe 2, Dynamique des Structures et des Interactions Moléculaires, Institut National de la Santé et de la Recherche Médicale, UMR_S 1134, Paris 75015, France. 6 Université Sorbonne Paris Cité and Université Paris Diderot, 75013 Paris, France. 7 Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States.



The flavivirus genus has several organisms responsible for generating various diseases in humans. Recently, especially in tropical regions, Zika virus (ZIKV) has raised great health concerns due to the high number of cases affecting the area during the last years that has been accompanied by a rise in the cases of the Guillain-Barré syndrome and fetal and neonatal microcephaly. Diagnosis is still difficult since the clinical symptoms between ZIKV and other flaviviruses (e.g., dengue and yellow fever) are highly similar. The understanding of their common physicochemical properties that are pH-dependent and biomolecular interaction features and their differences sheds light on the relation strain-virulence and might suggest alternative strategies toward differential serological diagnostics and therapeutic intervention. Due to their immunogenicity, the primary focus of this study was on the ZIKV nonstructural proteins 1 (NS1). By means of computational studies and semiquantitative theoretical analyses, we calculated the main physicochemical properties of this protein from different strains that are directly responsible for the biomolecular interactions and, therefore, can be related to the differential infectivity of the strains. We also mapped the electrostatic differences at both the sequence and structural levels for the strains from Uganda to Brazil, which could suggest possible molecular mechanisms for the increase of the virulence of ZIKV in Brazil. Exploring the interfaces used by NS1 to self-associate in some different oligomeric states and interact with membranes and the antibody, we could map the strategy used by the ZIKV during its evolutionary process. This indicates possible molecular mechanisms that can be correlated with the different immunological responses. By comparing with the known antibody structure available for the West Nile virus, we demonstrated that this antibody would have difficulties to neutralize the NS1 from the Brazilian strain. The present study also opens up perspectives to computationally design high-specificity antibodies.

PMID: 31458257 PMCID: PMC6643396 DOI: 10.1021/acsomega.8b02081

Keywords: Flavivirus; Zika Virus; Brazil.


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.




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.


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.


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.


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.


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.


#Vertical #Transmission of #Zika Virus (Flaviviridae, #Flavivirus) in #Amazonian #Aedes aegypti (Diptera: Culicidae) Delays Egg Hatching and Larval Development of Progeny (J Med Entomol., abstract)

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

J Med Entomol. 2019 Jul 6. pii: tjz110. doi: 10.1093/jme/tjz110. [Epub ahead of print]

Vertical Transmission of Zika Virus (Flaviviridae, Flavivirus) in Amazonian Aedes aegypti (Diptera: Culicidae) Delays Egg Hatching and Larval Development of Progeny.

Chaves BA1,2, Junior ABV1, Silveira KRD3, Paz ADC1, Vaz EBDC1, Araujo RGP3, Rodrigues NB3, Campolina TB3, Orfano ADS3, Nacif-Pimenta R3, Villegas LEM3, Melo FF4, Silva BM5, Monteiro WM1,2, Guerra MDGVB1,2, Lacerda MVG1,6, Norris DE7, Secundino NFC3, Pimenta PFP1,3.

Author information: 1 Tropical Medicine Foundation Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil. 2 Amazonas State University, Minas Gerais, Belo Horizonte, Brazil. 3 Laboratory of Medical Entomology, Rene Rachou Research Institute – FIOCRUZ, Minas Gerais, Belo Horizonte, Brazil. 4 Multidisciplinary Health Institute, Federal University of Bahia, Bahia, Brazil. 5 Department of Biological Sciences, Federal University of Ouro Preto, Minas Gerais, Ouro Preto, Brazil. 6 Leonidas and Maria Deane Research institute – FIOCRUZ, Amazonas, Brazil. 7 The Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD.



Zika virus (ZIKV) has emerged as a globally important arbovirus and has been reported from all states of Brazil. The virus is primarily transmitted to humans through the bite of an infective Aedes aegypti (Linnaeus, 1762) or Aedes albopictus (Skuse, 1895). However, it is important to know if ZIKV transmission also occurs from Ae. aegypti through infected eggs to her offspring. Therefore, a ZIKV and dengue virus (DENV) free colony was established from eggs collected in Manaus and maintained until the third-fourth generation in order to conduct ZIKV vertical transmission (VT) experiments which used an infectious bloodmeal as the route of virus exposure. The eggs from ZIKV-infected females were allowed to hatch. The resulting F1 progeny (larvae, pupae, and adults) were quantitative polymerase chain reaction (qPCR) assayed for ZIKV. The viability of ZIKV vertically transmitted to F1 progeny was evaluated by cultivation in C6/36 cells. The effects of ZIKV on immature development of Ae. aegypti was assessed and compared with noninfected mosquitoes. AmazonianAe. aegypti were highly susceptible to ZIKV infection (96.7%), and viable virus passed to their progeny via VT. Moreover, eggs from the ZIKV-infected mosquitoes had a significantly lower hatch rate and the slowest hatching. In addition, the larval development period was slower when compared to noninfected, control mosquitoes. This is the first study to illustrate VT initiated by oral infection of the parental population by using mosquitoes, which originated from the field and a ZIKV strain that is naturally circulating in-country. Additionally, this study suggests that ZIKV present in the Ae. aegypti can modify the mosquito life cycle. The data reported here suggest that VT of ZIKV to progeny from naturally infected females may have a critical epidemiological role in the dissemination and maintenance of the virus circulating in the vector.

© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America.

KEYWORDS: Aedes aegypti ; Zika virus; fitness cost; vertical transmission

PMID: 31278737 DOI: 10.1093/jme/tjz110

Keywords: Flavivirus; Zika Virus; Aedes aegypti.


#Zika Virus Non-Structural Protein 1 Disrupts Glycosaminoglycans and Causes #Permeability in Developing #Human #Placentas (J Infect Dis., abstract)

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

Zika Virus Non-Structural Protein 1 Disrupts Glycosaminoglycans and Causes Permeability in Developing Human Placentas

Henry Puerta-Guardo, Takako Tabata, Matthew Petitt, Milena Dimitrova, Dustin R Glasner, Lenore Pereira, Eva Harris

The Journal of Infectious Diseases, jiz331, https://doi.org/10.1093/infdis/jiz331

Published: 27 June 2019




During pregnancy, the Zika flavivirus (ZIKV) infects human placentas, inducing defects in the developing fetus. The flavivirus nonstructural protein 1 (NS1) alters glycosaminoglycans on the endothelium, causing hyperpermeability in vitro and vascular leakage in vivo in a tissue-dependent manner. The contribution of ZIKV NS1 to placental dysfunction during ZIKV infection remains unknown.


We examined the effect of ZIKV NS1 on expression and release of heparan sulfate (HS), hyaluronic acid (HA), and sialic acid (Sia) on human trophoblast cell lines and anchoring villous explants from first-trimester placentas infected with ZIKV ex vivo. We measured changes in permeability in trophoblasts and stromal cores using a dextran-based fluorescence assay and changes in HA receptor expression using immunofluorescent microscopy.


ZIKV NS1 in the presence and absence of ZIKV increased the permeability of anchoring villous explants. ZIKV NS1 induced shedding of HA and HS and altered expression of CD44 and LYVE-1 HA receptors on stromal fibroblasts and Hofbauer macrophages in villous cores. Hyaluronidase was also stimulated in NS1-treated trophoblasts.


These findings suggest that ZIKV NS1 contributes to placental dysfunction via modulation of glycosaminoglycans on trophoblasts and chorionic villi, resulting in increased permeability of human placentas.

ZIKV NS1, chorionic villi, glycosaminoglycans, permeability, hyaluronic acid, heparan sulfate, hyaluronidase, CD44, LYVE-1, Hofbauer cells

Issue Section: Major Article

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This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Keywords: Flavivirus; Zika Virus; Pregnancy; Viral pathogenesis.


Establishment of a #Cell #Culture Model of Persistent #Flaviviral #Infection: #Usutu Virus Shows Sustained Replication during Passages and Resistance to Extinction by Antiviral Nucleosides (Viruses, abstract)

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

Viruses. 2019 Jun 17;11(6). pii: E560. doi: 10.3390/v11060560.

Establishment of a Cell Culture Model of Persistent Flaviviral Infection: Usutu Virus Shows Sustained Replication during Passages and Resistance to Extinction by Antiviral Nucleosides.

Sempere RN1,2, Arias A3.

Author information: 1 Life Science & Bioengineering Building, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. rnsempere@abiopep.com. 2 Abiopep Sociedad Limitada, Parque Científico de Murcia, 30100 Murcia, Spain. rnsempere@abiopep.com. 3 Life Science & Bioengineering Building, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. aaesteban2@gmail.com.



Chronic viral disease constitutes a major global health problem, with several hundred million people affected and an associated elevated number of deaths. An increasing number of disorders caused by human flaviviruses are related to their capacity to establish a persistent infection. Here we show that Usutu virus (USUV), an emerging zoonotic flavivirus linked to sporadic neurologic disease in humans, can establish a persistent infection in cell culture. Two independent lineages of Vero cells surviving USUV lytic infection were cultured over 82 days (41 cell transfers) without any apparent cytopathology crisis associated. We found elevated titers in the supernatant of these cells, with modest fluctuations during passages but no overall tendency towards increased or decreased infectivity. In addition to full-length genomes, viral RNA isolated from these cells at passage 40 revealed the presence of defective genomes, containing different deletions at the 5′ end. These truncated transcripts were all predicted to encode shorter polyprotein products lacking membrane and envelope structural proteins, and most of non-structural protein 1. Treatment with different broad-range antiviral nucleosides revealed that USUV is sensitive to these compounds in the context of a persistent infection, in agreement with previous observations during lytic infections. The exposure of infected cells to prolonged treatment (10 days) with favipiravir and/or ribavirin resulted in the complete clearance of infectivity in the cellular supernatants (decrease of ~5 log10 in virus titers and RNA levels), although modest changes in intracellular viral RNA levels were recorded (<2 log10 decrease). Drug withdrawal after treatment day 10 resulted in a relapse in virus titers. These results encourage the use of persistently-infected cultures as a surrogate system in the identification of improved antivirals against flaviviral chronic disease.

KEYWORDS: antiviral therapies; chronic viral infection; defective viral genomes; emerging arboviruses; lethal mutagenesis

PMID: 31212939 DOI: 10.3390/v11060560

Keywords: Flavivirus; Usutu virus; Antivirals; Favipiravir; Ribavirin.


First report of collapsing variant of focal segmental #glomerulosclerosis triggered by #arbovirus: #dengue and #Zika virus #infection (Clin Kidney J., abstract)

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

Clin Kidney J. 2018 Nov 19;12(3):355-361. doi: 10.1093/ckj/sfy104. eCollection 2019 Jun.

First report of collapsing variant of focal segmental glomerulosclerosis triggered by arbovirus: dengue and Zika virus infection.

Araújo SA1,2, Cordeiro TME2, Belisário AR2, Araújo RFA1,2, Marinho PES3, Kroon EG3, de Oliveira DB4, Teixeira MM2,5, Simões E Silva AC2.

Author information: 1 Instituto de Nefro Patologia, Belo Horizonte, Brazil. 2 Laboratório Interdisciplinar de Investigação Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Brazil. 3 Departamento de Microbiologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. 4 Faculdade de Medicina de Diamantina, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, Brazil. 5 National Institute of Science and Technology in Dengue, Laboratory of Immunopharmacology, Institute of Biological Sciences, UFMG, Brazil.




The collapsing variant of focal segmental glomerulosclerosis (FSGS) is the most aggressive form of FSGS and is characterized by at least one glomerulus with segmental or global collapse and overlying podocyte hypertrophy and hyperplasia. Viruses can act as aetiological agents of secondary FSGS. This study aims to establish an aetiological link between dengue virus (DENV) infection and the collapsing variant of FSGS and to analyse possible influences of the apolipoprotein 1 (APOL1) gene risk alleles on the disease.


Biopsies and medical records were gathered from 700 patients of the Instituto de Nefropatologia, Belo Horizonte, Brazil. Screening for the collapsing variant of FSGS was performed and serological, immunohistochemical, tissue polymerase chain reaction (PCR) and genetic analysis were conducted.


Eight patients were identified with positive DENV serology and negative serological and/or tissue markers for hepatitis B virus, hepatitis C virus, Epstein-Barr virus, human immunodeficiency virus, cytomegalovirus and parvovirus B19. In PCR analysis, six patients had positive markers for DENV strain genetic material, one patient had positive markers for co-infection of Zika virus (ZIKV) and DENV and one patient had positive markers only for ZIKV infection. Six of the eight patients did not show risk alleles of the APOL1 gene. One patient had only one risk allele (G1) and the sample from another did not contain enough DNA for genetic analysis to be performed.


This study provided strong evidence that DENV can infect renal tissue and possibly functions as a second hit to the development of the collapsing variant of FSGS. Nonetheless, this study also highlights the possible implication of ZIKV infection in FSGS and supports the argument that risk alleles of the APOL1 gene may not be implicated in the susceptibility to FSGS in these patients.

KEYWORDS: arbovirus; chronic kidney disease; dengue infection; focal segmental glomerulosclerosis; renal histopahology

PMID: 31198534 PMCID: PMC6543975 DOI: 10.1093/ckj/sfy104

Keywords: Arbovirus; Flavivirus; Dengue fever; Zika Virus; Brazil.