Aims: The presence of a C-terminally extended form of NS1 (NS1’ protein) has been previously reported in encephalitic flaviviruses, due to the presence of -1 programmed ribosomal frameshift at the N-terminal of NS2A protein. This present study is aimed to further confirm that the NS1’ protein production is independent of the authentic cleavage at NS1-2A junction. Methodology and results: Six different constructs (P1-Leu, P2-Asp, P3-Phe, P3-Leu, P3-Gly and P5-8 Ala) containing various mutations at conserved and variable amino acids at C-terminal of NS1 protein were generated by site-directed mutagenesis and analysed with transient polyprotein expression assay. While analysis on the NS1-2A cleavage of the mutants exhibited extremely poor to efficient cleavage ranging from 6-89%, significant amount of NS1’ being expressed in all mutants irrespective of their NS1-2A cleavage outcome. Conclusion, significance and impact study: In this analysis, we showed for the first time that the abolishment of the authentic NS1-2A cleavage in Murray Valley encephalitis virus (MVEV) did not impact on NS1’ production. This observation extend on previous studies to show that NS1 and NS2A proteins are the product of NS1-2A cleavage which is catalysed by an unknown host protease while NS1’ protein is a product of ribosomal frameshift, independent of the authentic cleavage at NS1-2A junction.
Flavivirus

Flaviviruses have been important human pathogens after emerging and resurging flavivirus diseases over the past decades. Although effective therapeutic agents are not yet commercially available for use in humans, significant progress has been made toward developing effective therapeutics and treatments. Several studies have shown that antibodies against the flaviviral E and NS1 proteins play a central role in prophylaxis and/or treatment of flavivirus infection through passive immunization. In addition, many anti-flavivirals, including interferons, oligonucleotide-based platforms, and small compounds, have been developed and evaluated for their antiviral effects. This review provides an overview of various approaches to the development of anti-flaviviral candidates and new insights that could improve our strategies for designing effective therapeutics against flaviviruses.
Antibodies ; Flavivirus ; Flavivirus Infections ; Humans ; Immunization, Passive ; Interferons ; Proteins

Background:\r\n', u'There are two virus known as Nam Dinh Virus, and Colti group B be found in Viet Nam. These viruses have appeared in the South, the Middle and the Highland. They haven\u2019t been reported in the Southern provinces and Can Thoas well. \r\n', u'Objectives: \r\n', u'To identify the circulation of Nam Dinh virus strain, and coltivirus group B strain in Can Tho, Southern Viet Nam, and their existence in nature.\r\n', u'Subjects and method: \r\n', u'Thirty-four mosquito samples (7, 453 individual mosquitoes) from Culex quinque faciatus and Culex pseudovishnui were collected in Can Tho provice, southern Vietnam 2005.\r\n', u'Isolatingviruses on Aedes albopictuc clone C6/36, Vero cells, and using PT- PCR and ELISA Sandwich for identification. \r\n', u'Results:\r\n', u'2 Nam Dinh virus strains, 2 coltivirus group B strains and 1 flavivirus strain (insect flavivirus) were isolated from Culex quinque faciatus, and no virus was isolated from Culex pseudovishnui.\r\n', u'Conclusion: \r\n', u'The identification of the transmission of Nam dinh Virus, and coltivirus group B in Can Tho province by isolating virus from Culex quinque faciatus has shown the evidence for natural vertical transmission of these viruses.\r\n', u'
Viruses ; Coltivirus ; Flavivirus ; Arboviruses ; Culex ;

Humans ; Animals ; Culicidae ; Flavivirus ; Cell Line ; Spiramycin

This study aims to analyse the value of CODEHOP RT-PCR in the detection of Flavivirus. According to the amino acid sequences of polyproteins of different flaviviruses published in GenBank, a pair of primers was designed using the CODEHOP method. One-step RT-PCR was used to detect Japanese encephalitis virus strain JEV1201, Dengue virus strain JKD001, and yellow fever virus vaccine YV6161. BLAST analysis and phylogenetic analysis were performed after the RT-PCR products of nucleocapsid genes were sequenced. The results showed that this method could amplify Flavivirus specifically, and the size and sequence of the target fragment accorded with the anticipated result. JEV1201 had the highest homology to Japanese encephalitis virus strain YL2009-4/YC2009-3, belonging to the branch of the phylogenetic tree of Japanese encephalitis virus strains. JKD001 had the highest homology to Dengue virus strain DENV-2/ID/1022DN/1975, belonging to the branch of the phylogenetic tree of Dengue virus strains. YV6161 had the highest homology to Yellow fever virus strain 17D, belonging to the branch of the phylogenetic tree of Yellow fever virus strains. In conclusion, the method of CODEHOP RT-PCR can be effectively used to detect, identify, and phylogenetically analyse Flavivirus.
DNA Primers ; genetics ; Flavivirus ; classification ; genetics ; isolation & purification ; Flavivirus Infections ; virology ; Humans ; Molecular Sequence Data ; Phylogeny ; Reverse Transcriptase Polymerase Chain Reaction ; methods ; Viral Nonstructural Proteins ; genetics

Dengue fever, which is caused by a mosquito-borne flavivirus, has become a major infectious- disease threat in tropical and subtropical areas. Dengue fever has also become a common cause of febrile infections in persons who have recently traveled. On December 26, 2004 the tsunami hit Southeast Asia. People who survived in those areas were infected with endemic disease such as dengue fever, malaria and cholera. We sent six members of the Korean medical relief team to the tsunami region. Three workers developed fever, chills and headache after leaving the tsunami region, and were diagnosed with Dengue fever. Such an outbreak of Dengue Fever in travelers is rarely reported.
Asia, Southeastern ; Chills ; Cholera ; Dengue* ; Disease Outbreaks ; Endemic Diseases ; Fever ; Flavivirus ; Headache ; Humans ; Malaria ; Tsunamis*

Dengue fever is an acute febrile disease that is caused by a mosquito-borne flavivirus. It has become a major infectious disease threat in tropical and subtropical areas. In Korea, travel-associated dengue fever is increasing. Thirty-five Koreans went to Sri Lanka to do volunteer activities. Eight of the volunteers developed fever, myalgia, and rash; they were diagnosed with dengue fever. Two patients had macular hemorrhages and edema with no ophthalmic symptoms. The maculopathy caused by the dengue fever improved without specific treatment.
Communicable Diseases ; Dengue* ; Edema ; Exanthema ; Eye Manifestations ; Fever ; Flavivirus ; Hemorrhage ; Humans ; Korea ; Myalgia ; Sri Lanka* ; Volunteers*

Animals ; Culex ; virology ; Flavivirus ; genetics ; isolation & purification ; Real-Time Polymerase Chain Reaction

Zika virus (ZIKV) is a vector-borne flavivirus. It was initially identified in Uganda in 1947, and the first human infection was reported in Nigeria in 1953. Since 2015, ZIKV has been spreading rapidly in Brazil and the Americas. Given its general symptoms, ZIKV is considered to be a mild, febrile illness, although it is associated with severe neurologic complications. On February 1, 2016, the World Health Organization (WHO) declared a Public Health Emergency of International Concern (PHEIC). We conducted a review of the literature on the epidemiology and transmission, clinical manifestations, and diagnosis of ZIKV. Additionally, we introduce original literature on the current ZIKV outbreak in this review.
Americas ; Brazil ; Diagnosis ; Emergencies ; Epidemiology ; Flavivirus ; Humans ; Nigeria ; Public Health ; Uganda ; World Health Organization ; Zika Virus*

Flavivirus ; Humans ; Immunity ; Vaccines ; Zika Virus ; Zika Virus Infection/prevention & control*