scholarly journals A Reverse Genetics Platform That Spans the Zika Virus Family Tree

mBio ◽  
2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Douglas G. Widman ◽  
Ellen Young ◽  
Boyd L. Yount ◽  
Kenneth S. Plante ◽  
Emily N. Gallichotte ◽  
...  
Keyword(s):  
Cell Culture ◽  
Latin America ◽  
Zika Virus ◽  
Recombinant Virus ◽  
Reverse Genetics ◽  
Family Tree ◽  
Immunodeficient Mice ◽  
Recombinant Viruses ◽  
Viral Emergence ◽  
The Caribbean

ABSTRACT Zika virus (ZIKV), a mosquito-borne flavivirus discovered in 1947, has only recently caused large outbreaks and emerged as a significant human pathogen. In 2015, ZIKV was detected in Brazil, and the resulting epidemic has spread throughout the Western Hemisphere. Severe complications from ZIKV infection include neurological disorders such as Guillain-Barré syndrome in adults and a variety of fetal abnormalities, including microcephaly, blindness, placental insufficiency, and fetal demise. There is an urgent need for tools and reagents to study the pathogenesis of epidemic ZIKV and for testing vaccines and antivirals. Using a reverse genetics platform, we generated six ZIKV infectious clones and derivative viruses representing diverse temporal and geographic origins. These include three versions of MR766, the prototype 1947 strain (with and without a glycosylation site in the envelope protein), and H/PF/2013, a 2013 human isolate from French Polynesia representative of the virus introduced to Brazil. In the course of synthesizing a clone of a circulating Brazilian strain, phylogenetic studies identified two distinct ZIKV clades in Brazil. We reconstructed viable clones of strains SPH2015 and BeH819015, representing ancestral members of each clade. We assessed recombinant virus replication, binding to monoclonal antibodies, and virulence in mice. This panel of molecular clones and recombinant virus isolates will enable targeted studies of viral determinants of pathogenesis, adaptation, and evolution, as well as the rational attenuation of contemporary outbreak strains to facilitate the design of vaccines and therapeutics. IMPORTANCE Viral emergence is a poorly understood process as evidenced by the sudden emergence of Zika virus in Latin America and the Caribbean. Malleable reagents that both predate and span an expanding epidemic are key to understanding the virologic determinants that regulate pathogenesis and transmission. We have generated representative cDNA molecular clones and recombinant viruses that span the known ZIKV family tree, including early Brazilian isolates. Recombinant viruses replicated efficiently in cell culture and were pathogenic in immunodeficient mice, providing a genetic platform for rational vaccine and therapeutic design. IMPORTANCE Viral emergence is a poorly understood process as evidenced by the sudden emergence of Zika virus in Latin America and the Caribbean. Malleable reagents that both predate and span an expanding epidemic are key to understanding the virologic determinants that regulate pathogenesis and transmission. We have generated representative cDNA molecular clones and recombinant viruses that span the known ZIKV family tree, including early Brazilian isolates. Recombinant viruses replicated efficiently in cell culture and were pathogenic in immunodeficient mice, providing a genetic platform for rational vaccine and therapeutic design.

scholarly journals After the epidemic: Zika virus projections for Latin America and the Caribbean

2017 ◽  
Vol 11 (11) ◽  
pp. e0006007 ◽  
Author(s):  
Felipe J. Colón-González ◽  
Carlos A. Peres ◽  
Christine Steiner São Bernardo ◽  
Paul R. Hunter ◽  
Iain R. Lake
Keyword(s):  
Latin America ◽  
Zika Virus ◽  
The Caribbean

scholarly journals How Did Zika Virus Emerge in the Pacific Islands and Latin America?

mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
John H.-O. Pettersson ◽  
Vegard Eldholm ◽  
Stephen J. Seligman ◽  
Åke Lundkvist ◽  
Andrew K. Falconar ◽  
...  
Keyword(s):  
Latin America ◽  
Amino Acid ◽  
Zika Virus ◽  
Reverse Genetics ◽  
Pacific Islands ◽  
Vector Competence ◽  
Phylogenetic Analyses ◽  
Human Populations ◽  
Amino Acid Substitutions ◽  
The Pacific

ABSTRACT The unexpected emergence of Zika virus (ZIKV) in the Pacific Islands and Latin America and its association with congenital Zika virus syndrome (CZVS) (which includes microcephaly) and Guillain-Barré syndrome (GBS) have stimulated wide-ranging research. High densities of susceptible Aedes spp., immunologically naive human populations, global population growth with increased urbanization, and escalation of global transportation of humans and commercial goods carrying vectors and ZIKV undoubtedly enhanced the emergence of ZIKV. However, flavivirus mutations accumulate with time, increasing the likelihood that genetic viral differences are determinants of change in viral phenotype. Based on comparative ZIKV complete genome phylogenetic analyses and temporal estimates, we identify amino acid substitutions that may be associated with increased viral epidemicity, CZVS, and GBS. Reverse genetics, vector competence, and seroepidemiological studies will test our hypothesis that these amino acid substitutions are determinants of epidemic and neurotropic ZIKV emergence.

scholarly journals Transfection of exogenous rotavirus rearranged RNA segments in cells infected with a WT rotavirus results in subsequent gene rearrangements

2014 ◽  
Vol 95 (9) ◽  
pp. 2089-2098 ◽  
Author(s):  
Sarah Duponchel ◽  
Cécile Troupin ◽  
Lan Trang Vu ◽  
Aurélie Schnuriger ◽  
Germain Trugnan ◽  
...  
Keyword(s):  
Cell Culture ◽  
Acute Gastroenteritis ◽  
Reverse Genetics ◽  
Gene Rearrangements ◽  
Recombinant Viruses ◽  
Bovine Strain ◽  
The Family ◽  
Viral Progeny ◽  
Group A Rotaviruses ◽  
Group A

Group A rotaviruses, members of the family Reoviridae, are a major cause of infantile acute gastroenteritis. The rotavirus genome consists of 11 dsRNA segments. In some cases, an RNA segment is replaced by a rearranged RNA segment, which is derived from its standard counterpart by partial sequence duplication. It has been shown that some rearranged segments are preferentially encapsidated into viral progenies after serial passages in cell culture. Based on this characteristic, a reverse genetics system was used previously to introduce exogenous segment 7 rearrangements into an infectious rotavirus. This study extends this reverse genetics system to RNA segments 5 and 11. Transfection of exogenous rotavirus rearranged RNA segment 5 or 11 into cells infected with a WT helper rotavirus (bovine strain RF) resulted in subsequent gene rearrangements in the viral progeny. Whilst recombinant viruses were rescued with an exogenous rearranged segment 11, the exogenous segment was modified by a secondary rearrangement. The occurrence of spontaneous rearrangements of WT or exogenous segments is a major hindrance to the use of this reverse genetics approach.

scholarly journals Use of infectious disease surveillance reports to monitor the Zika virus epidemic in Latin America and the Caribbean from 2015 to 2017: strengths and deficiencies

BMJ Open ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. e042869
Author(s):  
Joan K Morris ◽  
Helen Dolk ◽  
Pablo Durán ◽  
Ieda Maria Orioli
Keyword(s):  
Infectious Disease ◽  
Latin America ◽  
Virus Infection ◽  
Outcome Measures ◽  
Zika Virus ◽  
Disease Surveillance ◽  
Virus Infections ◽  
Infectious Disease Surveillance ◽  
Zika Virus Infection ◽  
The Caribbean

ObjectivesTo summarise the occurrence of congenital Zika syndrome (CZS) in Latin America and the Caribbean from 2015 to 2017 using two outcome measures derived from infectious disease surveillance reports and to assess the completeness of these reports.DesignSurveillance study.SettingPan American Health Organization (PAHO)/WHO epidemiology reports on confirmed and suspected Zika virus infection and cases of CZS.ParticipantsPopulations of 47 countries in the South and Central Americas, Mexico and the Caribbean.Primary and secondary outcome measuresThe number of CZS cases per 1000 births (using 2016–2017 births as a denominator) and the number of CZS cases per 1000 births in women with Zika virus infection during pregnancy.ResultsBy 4 January 2018, 548623 suspected and 239063 confirmed Zika virus infections had been reported to PAHO/WHO from 47 countries. In 25 countries, over 80% of infections were reported as suspected. There were 3617 confirmed CZS cases in 25 countries; 2952 (82%) had occurred in Brazil. The number of CZS cases per 1000 births varied considerably with Brazil and several Caribbean island communities (Puerto Rico, St Martin, Martinique, Guadeloupe and Grenada) having the highest CZS prevalence above 0.5 per 1000 births. Analysing the number of CZS cases per 1000 births in women infected with Zika virus during their pregnancy highlighted the inaccuracies of the data, with Venezuela likely to have had severe under-reporting of CZS.ConclusionsExpressing data on CZS in relation to total births, rather than as absolute numbers, better illustrates the burden of disease, providing that under-reporting of CZS is not too severe. Data on infections in pregnant women enable potential under-reporting of CZS to be identified. Both measures are recommended for future PAHO/WHO publications. Evidence of severe under-reporting of Zika virus infections and CZS makes interpretation of the data and comparisons between countries challenging.

scholarly journals Reverse Genetics with a Full-length Infectious cDNA Clone of Bovine Torovirus

2020 ◽  
Author(s):  
Ujike Makoto ◽  
Etoh Yuka ◽  
Urushiyama Naoya ◽  
Taguchi Fumihiro ◽  
Enjuanes Luis ◽  
...  
Keyword(s):  
Cell Growth ◽  
Cdna Clone ◽  
Recombinant Virus ◽  
Reverse Genetics ◽  
Infectious Cdna Clone ◽  
Full Length ◽  
Egfp Expression ◽  
Egfp Gene ◽  
Viral Growth ◽  
Recombinant Viruses

AbstractTorovirus (ToV) has recently been classified in the new family Tobaniviridae, although it belonged to the Coronavirus (CoV) family historically. Reverse genetics systems for many CoVs have been established, but none exist for ToVs. Here, we describe a reverse genetics system using a full-length infectious cDNA clone of bovine ToV (BToV) in a bacterial artificial chromosome (BAC). Recombinant BToV containing genetic markers had the same phenotype as wild-type (wt) BToV. To generate two types of recombinant virus, the Hemagglutinin-esterase (HE) gene was manipulated, since cell-adapted wtBToV generally loses the full-length HE (HEf), resulting in soluble HE (HEs). First, recombinant viruses with HEf and HA-tagged HEf or HEs genes were rescued; these showed no significant differences in cell growth, suggesting that HE is not essential for viral growth in cells. Then, recombinant virus in which HE was replaced by the Enhanced Green Fluorescent Protein (EGFP) gene expressed EGFP in infected cells, but showed significantly reduced viral growth compared to wtBToV. Moreover, the recombinant virus readily deleted the EGFP gene after one passage. Interestingly, one variant with mutations in non-structural proteins (NSPs) showed improved EGFP expression and viral growth during serial passages, although it eventually deleted the EGFP gene, suggesting that these mutations contributed to EGFP gene acceptance. These recombinant viruses provide new insights regarding BToV and its reverse genetics will help advance understanding of this neglected pathogen.ImportanceToVs are diarrhea-causing pathogens that have been detected in many species, including humans. BToV has spread worldwide, leading to economic losses. We developed the first reverse genetics system for Tobaniviridae using a BAC-based BToV. Using this system, we showed that recombinant BToVs with HEf and HEs showed no significant differences in cell growth. In contrast, clinical BToVs generally lose the HE gene after a few passages but some recombinant viruses retained the HE gene for up to 20 passages, suggesting some benefits of HE retention. The EGFP gene of the recombinant viruses was unstable and was rapidly deleted, likely via negative selection. Interestingly, one virus variant with mutations in NSPs was more stable, resulting in improved EGFP-expression and viral growth, suggesting that the mutations contributed to some acceptance of the exogenous EGFP gene without clear positive selection. The recombinant BToVs and reverse genetics developed here are powerful tools for understanding fundamental viral processes and their pathogenesis and for developing BToV vaccines.

Uphill Task: Can We Ever Conquer Against New Emerging Viruses?

JMS SKIMS ◽  
2017 ◽  
Vol 20 (2) ◽  
pp. 109-110
Author(s):  
Farooq A Sheikh
Keyword(s):  
Latin America ◽  
Zika Virus ◽  
French Polynesia ◽  
Genetic Mutation ◽  
Emerging Viruses ◽  
Infectious Disease Outbreak ◽  
Asian Strain ◽  
The Caribbean ◽  
Single Genetic Mutation ◽  
Major Infectious Disease

Every time there is a major infectious disease outbreak that scares us, such as Ebola in West Africa, Middle East Respiratory Syndrome (MERS) on the Arabian Peninsula and South Africa, and Zika virus in South and Central America and the Caribbean; this time arising from a mosquito-borne agent that has spread stealth around the globe [ 1]. It remains one of the great mysteries of the Zika epidemic: Why did a virus that existed for decades elsewhere in the world suddenly seem to become more destructive when it landed in Latin America? An intriguing study in mice, which has prompted some skepticism among experts, suggests that a single genetic mutation- called S139N, first arose in an Asian strain of the Zika virus in 2013, just before a small outbreak in French Polynesia, helped transform the Zika virus into a devastating force in Latin America [2 ]. JMS 2017;20(2):115-116

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