#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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© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

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.


An E460D #substitution in the #NS5 protein of #TBE virus confers #resistance to the #inhibitor #Galidesivir (BCX4430) and also attenuates the virus for mice (J Virol., abstract)

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

An E460D substitution in the NS5 protein of tick-borne encephalitis virus confers resistance to the inhibitor Galidesivir (BCX4430) and also attenuates the virus for mice

Ludek Eyer, Antoine Nougairède, Marie Uhlířová, Jean-Sélim Driouich, Darina Zouharová, James J. Valdés, Jan Haviernik, Ernest A. Gould, Erik De Clercq, Xavier de Lamballerie, Daniel Ruzek

DOI: 10.1128/JVI.00367-19



The adenosine analogue Galidesivir (BCX4430), a broad-spectrum RNA virus inhibitor, has entered a Phase 1 clinical safety and pharmacokinetics study in healthy subjects and is under clinical development for treatment of Ebola virus infection. Moreover, Galidesivir also inhibits the reproduction of tick-borne encephalitis virus (TBEV) and numerous other medically important flaviviruses. Until now, studies of this antiviral agent have not yielded resistant viruses. Here, we demonstrate that an E460D substitution, in the active site of TBEV RNA-dependent-RNA-polymerase (RdRp), confers resistance to Galidesivir in cell culture. Galidesivir-resistant TBEV exhibited no cross-resistance to structurally different antiviral nucleoside analogues, such as 7-deaza-2′-C-methyladenosine, 2′-C-methyladenosine and 4′-azido-aracytidine. Although, the E460D substitution led only to a subtle decrease in viral fitness in cell culture, Galidesivir-resistant TBEV was highly attenuated in vivo, with 100% survival rate and no clinical signs observed in infected mice. Furthermore, no virus was detected in serum, spleen or brain of mice inoculated with the Galidesivir-resistant TBEV. Our results contribute to understanding the molecular basis of Galidesivir antiviral activity, flavivirus resistance to nucleoside inhibitors and the potential contribution of viral RdRp to flavivirus neurovirulence.



Tick-borne encephalitis virus (TBEV) is a pathogen that causes severe human neuroinfections in Europe and Asia and for which there is currently no specific therapy. We have previously found that Galidesivir (BCX4430), a broad-spectrum RNA virus inhibitor, which is under clinical development for treatment of Ebola virus infection, has a strong antiviral effect against TBEV. For any antiviral drug, it is important to generate drug-resistant mutants to understand how the drug works. Here, we produced TBEV mutants resistant to Galidesivir and found that the resistance is caused by a single amino acid substitution in an active site of the viral RNA-dependent RNA polymerase, an enzyme which is crucial for replication of viral RNA genome. Although, this substitution led only to a subtle decrease in viral fitness in cell culture, Galidesivir-resistant TBEV was highly attenuated in a mouse model. Our results contribute to understanding the molecular basis of Galidesivir antiviral activity.

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

Keywords: Antivirals; Drugs Resistance; Galidesivir; Flavivirus; Tick-Borne Encephalitis Virus.


A New Segmented #Virus Associated with #Human Febrile #Illness in #China (N Engl J Med., abstract)

[Source: The New England Journal of Medicine, full page: (LINK). Abstract, edited.]

A New Segmented Virus Associated with Human Febrile Illness in China

Ze-Dong Wang, Ph.D., Bo Wang, M.D., Feng Wei, Ph.D., Shu-Zheng Han, M.S., Li Zhang, B.Sc., Zheng-Tao Yang, Ph.D., Yan Yan, Ph.D., Xiao-Long Lv, M.S., Liang Li, Ph.D., Shu-Chao Wang, Ph.D., Ming-Xin Song, Ph.D., Hao-Ji Zhang, Ph.D., et al.




In 2017, surveillance for tickborne diseases in China led to the identification of a patient who presented to a hospital in Inner Mongolia with a febrile illness that had an unknown cause. The clinical manifestation of the illness was similar to that of tickborne encephalitis virus (TBEV) infection, but neither TBEV RNA nor antibodies against the virus were detected.


We obtained a blood specimen from the index patient and attempted to isolate and identify a causative pathogen, using genome sequence analysis and electron microscopy. We also initiated a heightened surveillance program in the same hospital to screen for other patients who presented with fever, headache, and a history of tick bites. We used reverse-transcriptase–polymerase-chain-reaction (RT-PCR) and cell-culture assays to detect the pathogen and immunofluorescence and neutralization assays to determine the levels of virus-specific antibodies in serum specimens from the patients.


We found that the index patient was infected with a previously unknown segmented RNA virus, which we designated Alongshan virus (ALSV) and which belongs to the jingmenvirus group of the family Flaviviridae. ALSV infection was confirmed by RT-PCR assay in 86 patients from Inner Mongolia and Heilongjiang who presented with fever, headache, and a history of tick bites. Serologic assays showed that seroconversion had occurred in all 19 patients for whom specimens were available from the acute phase and the convalescent phase of the illness.


A newly discovered segmented virus was found to be associated with a febrile illness in northeastern China. (Funded by the National Key Research and Development Program of China and the National Natural Science Foundation of China.)


Supported by grants from the National Key Research and Development Program of China(2017YFD0501700) and the National Natural Science Foundation of China (31672542 and 31372430).

Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.

Drs. Z.-D. Wang, B. Wang, and F. Wei, Ms. S.-Z. Han, Ms. L. Zhang, and Drs. Z.-T. Yang and Y. Yan contributed equally to this article.

We thank Profs. Ningyi Jin and Changchun Tu (Military Veterinary Institute, Academy of Military Medical Sciences), Prof. Xing-Quan Zhu (Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences), and Dr. Chengfeng Qin (Department of Virology, Beijing Institute of Microbiology and Epidemiology) for their discussions and suggestions.

Author Affiliations

From the School of Life Sciences and Engineering, Foshan University, Foshan, Guangdong Province (Z.-D.W., Z.-T.Y., H.-J.Z., S.-J.H., J.C., F.-Q.H., Q.L.), the Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, Jilin Province (Z.-D.W., L.L., S.-C.W., Q.L.), MOA Key Laboratory of Animal Virology and Department of Veterinary Medicine, Zhejiang University, Hangzhou, Zhejiang Province (Z.-D.W., Y.Y., J.H., Y.-L.J., J.-Y.Z.), the Second Affiliated Hospital of Inner Mongolia University for the Nationalities, Inner Mongolia General Forestry Hospital, Yakeshi, Inner Mongolia Autonomous Region (B.W., S.-Z.H., X.-L.L., W.W.), the College of Life Science, Jilin Agricultural University, Changchun, Jilin Province (F.W., L.Z., S.L., H.-H.L.), the College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang Province (M.-X.S.), and the Department of Experimental Pathology, Institute of Radiation Medicine, Beijing (B.W.) — all in China.
Address reprint requests to Dr. Q. Liu at the School of Life Sciences and Engineering, Foshan University, Foshan, China, or at liuquan1973@hotmail.com; or to Dr. Zhou at the Key Laboratory of Animal Virology of Ministry of Agriculture, Zhejiang University, or at jyzhou@zju.edu.cn; or to Dr. W. Wang at the Second Clinical Medical School of Inner Mongolia University for the Nationalities, or at hlbewangwei@163.com.

Keywords: Flavivirus; Tick-borne virus; Alongshan virus; China.


Boosting #Global #YellowFever #Vaccine #Supply for #Epidemic #Preparedness: 3 Actions for #China and the #USA (Virol Sin., abstract)

[Source: Virologica Sinica, full page: (LINK). Summary, edited.]

Boosting Global Yellow Fever Vaccine Supply for Epidemic Preparedness: 3 Actions for China and the USA

Authors: Daniel R. Lucey, Kristen R. Kent

Perspective / First Online: 24 May 2019


Yellow fever (YF) is an acute disease caused by a flavivirus that infects the liver. It can cause jaundice, bleeding, kidney damage, and death. No antiviral therapy exists. A vaccine does exist, however, and fortunately confers life-long immunity after a single dose (Monath et al.2016; WHO 2017a, b).




Compliance with Ethical Standards

Conflict of interest: The authors declare that they have no conflict of interest.

Animal and Human Rights Statement: This article does not contain any studies with human or animal subjects performed by any of the authors.

Keywords: Yellow Fever; Vaccines; USA; China.