From 2013 to 2015, the National Institute of Health, Pakistan, received 1,270 blood samples of suspected dengue cases reported from inpatient and outpatient departments of various hospitals in Khyber Pakhtunkhwa (KPK) province. In this study, we determined the circulating dengue virus (DENV) serotypes using real-time reverse transcriptase (RT)-PCR to understand the serotype-based epidemiology of DENV. All four serotypes (DENV-1 [6%], DENV-2 [33%], DENV-3 [47%], and DENV-4 [0.1%]) were found circulating during the study period. Our findings suggest the need for an active surveillance system coupled with the laboratory diagnosis, especially in the chronic endemic areas of the country. Public awareness programs are needed for effective control and prevention of outbreaks in the future.
Adolescent ; Adult ; Dengue/diagnosis/*epidemiology/virology ; Dengue Virus/genetics/*isolation & purification ; Disease Outbreaks ; Female ; Humans ; Male ; Middle Aged ; Pakistan/epidemiology ; RNA, Viral/genetics/metabolism ; Real-Time Polymerase Chain Reaction ; Serogroup ; Young Adult

In order to facilitate the detection of newly emerging or rare viral infectious diseases, a negative-strand RNA virus-severe fever with thrombocytopenia syndrome bunyavirus, and a positive-strand RNA virus-dengue virus, were used to investigate RNA viral genome unspecific amplification by multiple displacement amplification technique from clinical samples. Series of 10-fold diluted purified viral RNA were utilized as analog samples with different pathogen loads, after a series of reactions were sequentially processed, single-strand cDNA, double-strand cDNA, double-strand cDNA treated with ligation without or with supplemental RNA were generated, then a Phi29 DNA polymerase depended isothermal amplification was employed, and finally the target gene copies were detected by real time PCR assays to evaluate the amplification efficiencies of various methods. The results showed that multiple displacement amplification effects of single-strand or double-strand cDNA templates were limited, while the fold increases of double-strand cDNA templates treated with ligation could be up to 6 X 10(3), even 2 X 10(5) when supplemental RNA existed, and better results were obtained when viral RNA loads were lower. A RNA viral genome amplification system using multiple displacement amplification technique was established in this study and effective amplification of RNA viral genome with low load was achieved, which could provide a tool to synthesize adequate viral genome for multiplex pathogens detection.
Bunyaviridae Infections ; diagnosis ; virology ; Cell Line ; DNA Ligases ; metabolism ; DNA, Complementary ; analysis ; genetics ; DNA-Directed DNA Polymerase ; metabolism ; Dengue ; diagnosis ; virology ; Dengue Virus ; genetics ; isolation & purification ; Genome, Viral ; genetics ; Humans ; Phlebovirus ; genetics ; isolation & purification ; RNA, Viral ; analysis ; genetics ; Reference Standards ; Reverse Transcriptase Polymerase Chain Reaction ; methods ; Viral Load

Dengue ; epidemiology ; Dengue Virus ; genetics ; isolation & purification ; Evolution, Molecular ; Genes, Viral ; Humans ; Viral Envelope Proteins ; genetics

OBJECTIVETo determine a dengue fever outbreak in Yiwu city, Zhejiang Province in 2009 and to trace the origin of the pathogen.

METHODSThe dengue virus IgM, IgG antibodies and viral nucleic acid were detected and virus was isolated using 40 serum samples from the suspected patients. The viral RNA of the isolated virus strains was extracted and the E gene was amplified by RT-PCR. The amplicons were sequenced and the phylogenetic and homological analyses were also constructed.

RESULTSAmong 40 serum samples from dengue fever suspected patients, 17 were positive from for dengue IgM (42.5%); 4 were IgG positive (10.0%); 34 samples were dengue virus RNA positive (85.0%), 28 dengue virus type 3 (D3) strains were isolated (70.0%). The complete coding region of envelope genes (E) from 13 D3 strains was all 1479 nt without any insertion or deletion, which encoded with 493 amino acids (aa). E gene from the 13 D3 strains from Zhejiang in 2009 (D3/ZJ/2009) was 100.0% identical. The strain from Saudi Arabia shared the highest similarity with the D3 strain, 99.3% and 100.0% of their E genes and deduced amino acids were identical, respectively, whereas they were 93.4% and 97.4% between D3/ZJ/2009 strain and its prototype strain (D3/H87/1956), and 93.6% and 97.4% between D3/ZJ/2009 and a D3 strain isolated in Guangxi Province in 1980. The phylogenetic tree of E genes also indicated that D3/ZJ/2009 had maximum similarity with the D3/Saudi Arabia/2004. They all belonged to the D3/GIII branch, which was originated from Indian Subcontinent.

CONCLUSIONThe outbreak of dengue fever in Zhejiang in 2009 was caused by type 3 dengue virus III genotype. The virus was most likely originated from Saudi Arabia.

Adolescent ; Adult ; Aged, 80 and over ; China ; epidemiology ; Dengue ; epidemiology ; virology ; Dengue Virus ; classification ; genetics ; isolation & purification ; Disease Outbreaks ; Female ; Humans ; Male ; Middle Aged

OBJECTIVETo express the domain III of DENV II envelop protein in Escherichia coli, obtain the purified recombinant protein and identify its immunoreactivity.

METHODSSuckling mice were inoculated with live DENV II in the brain. The total RNA was extracted from the brain of the infected mice, and the envelope protein DNA fragment was amplified by RT-PCR and ligated into pMD 18-T to construct pMD 18-T-DV2-E. The domain III DNA fragment of the envelope protein was amplified by PCR with pMD 18-T-DV2-E as the template and cloned into pET-32a(+) to construct the expression plasmid pET-32a(+)-DV2-E-DIII. The recombinant plasmid was transformed into E.coli BL21(DE3) and induced by IPTG, and the expressed products were analyzed by SDS-PAGE and Western blotting.

RESULTSAfter RT-PCR amplification, a specific DNA fragment of about 1.5 kb was obtained and ligated into pMD 18-T to construct pMD 18-T-DV2-E. With pMD 18-T-DV2-E as the template, the domain III DNA fragment about 320 bp in length was amplified and the expression plasmid pET-32a(+)-DV2-E-DIII was successfully constructed. After induction with IPTG, a specific soluble protein with a relative molecular mass of 29000 was obtained and the expression product accounted for 52.50 percent; of the total protein of the cell lysate. Western blotting demonstrated reactivity of the recombinant protein with His-Tag McAb and DENV (Type I-IV) McAb.

CONCLUSIONThe recombinant plasmid can be highly expressed in E.coli BL21(DE3) in a soluble form and the recombinant protein can react with DENV (Type I-IV) McAb.

Animals ; Dengue Virus ; genetics ; isolation & purification ; Escherichia coli ; metabolism ; Genetic Vectors ; Mice ; Mice, Inbred Strains ; Plasmids ; Protein Interaction Domains and Motifs ; Viral Envelope Proteins ; genetics ; isolation & purification

OBJECTIVETo isolate viruses from mosquitoes in the south of Xinjiang and identify these viruses primarily.

METHODSA total of 13 491 mosquitoes were collected in the south of Xinjiang from Jul to Aug, 2005. These mosquitoes were divided into 130 groups and grinded respectively. The supernates were inoculated in C6/36 and Vero cells. Viruses isolated were detected, the genomic nucleic types by electrophoresis of viral genomes and the morphologies observed under electronmicroscope.

RESULTSAll 42 viruses were isolated, which caused CPEs on C6/36 but not on Vero cells. 27 viruses showed similar genomic profiles with 12 dsRNA segments. 1 virus displayed genomic profile with 10 dsRNA segments. 5 viruses took on similar genomic profiles with about 4 kbp DNA band. 9 viruses did not get any taxonomy information. Electromicroscopic pictures of these viruses revealed that above four types of viruses had distinguished morphologies indicating different virus species.

CONCLUSIONThere should be several virus species in the mosquitoes in the south of Xinjiang. dsRNA virus with 12 genomic segments should play analysis a predominant role in the south of Xinjiang.

Animals ; Bluetongue virus ; classification ; genetics ; isolation & purification ; Cercopithecus aethiops ; China ; Culicidae ; virology ; Dengue Virus ; classification ; genetics ; isolation & purification ; Genome, Viral ; Insect Viruses ; classification ; genetics ; isolation & purification ; RNA, Double-Stranded ; genetics ; RNA, Viral ; genetics ; Reassortant Viruses ; genetics ; Sequence Analysis, DNA ; Vero Cells

OBJECTIVETo isolate and identify the pathogen of Dengue fever from Shenzhen city in 2005 - 2006, and to analyze the molecular characteristics of the isolated Dengue virus strain as well as to explore its possible origin.

METHODSIgM and IgG of serum samples taken from 60 suspected Dengue fever patients were detected by ELISA and immunochromatography, and 9 specimens were positive. Nine samples from patients with early stage Dengue fever were used to isolate virus with C6/36 cell line and the positive cell cultures were identified by MGB fluorescent PCR. The type of isolated virus strain was determined by RT-semi-nested-PCR and fluorescent PCR. E gene of isolated virus strain was amplified by RT-PCR and sequenced. Homology and phylogenetic tree of E gene of Shenzhen Dengue virus with the strains isolated from other areas were constructed.

RESULTSOf nine antibody-positive serum samples, one strain of Dengue virus was successfully isolated. The isolated virus strain was confirmed as Dengue virus type 2 and designated as DEN2-SZ0521. The homology of nucleotide sequence and the deduced amino acid sequence of E gene of SZ0521 with standard type 2 Dengue virus NGC strain was 94.2% and 98.2%, but the homology with standard Dengue virus 1, 3, 4 in the same fragment were 59.1%, 57.2%, 58.5% and 68.1%, 66.7%, 63.2%, respectively. The phylogenetic tree indicated that SZ0521 had the greatest similarity with the Malay0412a/Tw strain and they lied in the same branch of the phylogenetic tree. The corresponding homology of nucleotide sequence and amino acid sequence was 99.8% and 100%, respectively. The isolated Dengue virus type 2 belonged to genotype IV with Indonesia-76, Somalia-84 and Sri Lanka-90.

CONCLUSIONDengue virus was isolated from Shenzhen for the first time, and it was classified as type 2. It was confirmed that the type 2 Dengue virus may come from the epidemic area in Malaysia.

Aedes ; virology ; Animals ; China ; Dengue ; virology ; Dengue Virus ; classification ; genetics ; isolation & purification ; Genes, Viral ; Humans ; Phylogeny ; Sequence Analysis, Protein ; Sequence Analysis, RNA

OBJECTIVETo generate rescued viruses with deletion mutation of capsid protein from dengue virus type 2 isolated in China (DEN2-43).

METHODSOn the basis of infectious full-length cDNA clone pD212 of DEN2-43 strain virus, the deletion mutants were constructed by fusion PCR, from which the rescued viruses with deletion mutation of capsid protein were generated by transcription in vitro and electroporation.

RESULT AND CONCLUSIONSequence analysis demonstrated that the deletion mutations had been successfully inserted into the rescued viruses obtained. These mutant viruses may hold the key for elucidating the effects of deletion mutation of capsid protein on the biological characteristics of dengue virus.

Amino Acid Sequence ; Animals ; Base Sequence ; Capsid Proteins ; genetics ; Cell Line ; Cloning, Molecular ; DNA Mutational Analysis ; Dengue Virus ; genetics ; isolation & purification ; Electroporation ; Molecular Sequence Data ; Sequence Deletion ; Sequence Homology, Nucleic Acid ; Transcription, Genetic ; Virus Replication ; genetics

OBJECTIVETo study the clinical characteristics of the patients with dengue fever (DF) seen from 2002 to 2006 in Guangzhou in order to prevent and treat dengue fever better.

METHODSClinical data from 1342 inpatients with DF seen from 2002 to 2006 were retrospectively analyzed. The dengue virus was isolated by C6/36 cell culture and genotyped by reverse transcriptase-polymerase chain reaction and gene sequence analysis.

RESULTSThe average age of the patients was 34.4 years, without sex difference in distribution. Most of the patients had obvious toxemic symptoms including fever (100 percent), headache (85.9 percent), myalgia (64.5 percent), bone soreness (46.6 percent) and skin rash (65.9 percent). Leukopenia, thrombocytopenia, elevated alanine aminotransferase, elevated aspartate aminotransferase and hypokalemia were found in 66.0 percent, 61.3 percent, 69.0 percent , 85.7 percent and 28.4 percent of patients, respectively. DF-IgM could be detected in 90 percent of patients. The virus was identified as dengue virus type-I.

CONCLUSIONSThe epidemic of DF was caused by dengue virus- I from 2002 to 2006 in Guangzhou. Most of the patients had classic DF clinical manifestation with high percentage of hepatic injury. Few patients progressed to dengue hemorrhagic fever.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Antibodies, Viral ; blood ; Child ; Child, Preschool ; China ; epidemiology ; Dengue ; diagnosis ; epidemiology ; immunology ; physiopathology ; Dengue Virus ; genetics ; isolation & purification ; Female ; Humans ; Infant ; Male ; Middle Aged ; Retrospective Studies ; Young Adult

OBJECTIVETo study the epidemiology and etiologic characteristics of a Dengue fever outbreak in Fuzhou from the beginning of September to the end of October in 2004 in order to understand the source of infection.

METHODSData on descriptive epidemiology was collected to study the characteristics and related factors to the epidemic. Dengue virus was isolated through the use of C6/36 cell line while viral serotypes were identified by indirect immunofluorecent assay with type-specific monoclonal antibody. The sources of infection were traced by nucleotide sequencing.

RESULTSDuring the epidemic, 93 cases occured consistently with the region entomoplily growth and decay. The viruses of 6 strains isolated from 10 patients' blood specimens were identified as dengue virus type 1. Phylogenetic evidence suggested that the viral isolate had high genetic relation with the isolates from Kampuchea (DENV-1/KHM/2001; GenBank Accession No. L0904278).

CONCLUSIONThe epidemic was caused by introduction of patients migrating into Fuzhou.

China ; epidemiology ; Dengue ; epidemiology ; Dengue Virus ; genetics ; isolation & purification ; Disease Outbreaks ; Emigration and Immigration ; Genetic Variation ; Humans ; Phylogeny