Mesocyclops were collected from 631 water areas and fresh water containers over 31 provinces and city between 1998 - 1999. It was found 10 species that involved in Mesocyclops gender. Messocyclops distribute widely and are available in fresh water containers in crowded regions. They can reproduce and develop easily under natural conditions. They have high potential in killing Aedes aegypti larvae. Mesocyclops can become an effective biological agent in preventing actively the Dengue fever/Dengue hemorrhage vector in Viet Nam
Copepoda ; Densovirinae

Background: Vietnam is one of eight countries with dengue fever / dengue hemorrhagic fever circulating seriously in the region. Some recent studies showed Mesocyclops dropping is one of effectively dengue fever/dengue hemorrhagic fever preventive approaches.\r\n', u'Objectives: To survey the distribution and role of mesocyclops in preventing dengue fever/dengue hemorrhagic fever in three communes in Thanh Hoa province.\r\n', u'Subjects and methods: The study was conducted in Dong Hai, Thanh Hoa, Hai Chau communes of Tinh Gia district, Nga Lien commune of Nga Son district. Research subjects are Mesocyclops collected in the artificial water containers and Adesaegypti mosquito larvae in water containers.\r\n', u'Results: Two species found are M.woutersi mesocyclops and M.thermo. M.woutersi exits in all of three local studied Mesocyclops rate in the water containers is 8.2%. Mesocyclops rate in water containers in Nga Son district is highest (13.26%) and in city is lower (13.26%). Of the experimental five species dropped on field, there are four species survived after a long-term period. Among them, M. Woutersi is highest (65.51%), M.aspericornis (15:52%). They breed and grow very fast, easy to adapt to natural conditions in Thanh Hoa.\r\n', u'Conclusion: The results show that Mesocyclops can be cultured in Thanh Hoa province.\r\n', u'\r\n', u'\r\n', u'
Dengue ; Dengue Hemorrhagic Fever ; Copepoda ; Densovirinae ;

OBJECTIVETo probe the primary characteristic of 0507JS11 virus isolated from Culex sp. and determine the classification of 0507JS11 virus in taxonomy.

METHODS0507JS11 virus was cultured in Aedes albopictus C6/36 cells and cytopathic effects (CPEs) were recorded. Electro-microscopic morphology of 0507JS11 virus was observed. Total DNA extract of 0507JS11 virus was detected by 1% Agarose Gel Electrophoresis. Complete genomic sequence of 0507JS11 virus was sequenced and then made phylogenetic analysis.

RESULTS0507JS11 virus could cause CPEs in Aedes albopictus C6/36 cells. Viral particles have no envelope and appear icosahedron symmetry with diameter of 20 nm. The genome of 0507JS11 virus was positive single strand DNA (ssDNA) with full length of 3977 nt. However, a DNA band about 4 kbp was observed in the electrophoresis of total DNA extract of 0507JS11 virus. The coding region of the genome included three ORFs, ORF1 and ORF2 code NSP1 and NSP2, ORF3 codes VP. Phylogenetic analysis of the complete genomic sequence of 0507JS11 virus indicated an independent linear in Brevidensovirus.

CONCLUSION0507JS11 virus is a new member in Brevidensovirus.

Animals ; Culex ; virology ; DNA, Viral ; genetics ; Densovirinae ; classification ; genetics ; isolation & purification ; Genome, Viral ; Sequence Analysis, DNA

Loop-mediated isothermal amplification (LAMP) assay is a novel method of gene amplification with high specificity, sensitivity and rapidity, which can be applied for disease diagnosis in shrimp aquaculture. The method is performed under isothermal conditions with a set of four specially designed primers that recognize six distinct sequences of the target. In the present study, according to the conservative regions of non-structural protein gene NS1, a set of four specific primers were designed, and a rapid detection of IHHNV was established by LAMP assay. The parameters of reaction time and temperature were optimized, and its specificity and sensitivity were assessed. The reactions were carried out at 60 degrees C, 62 degrees C, 63 degrees C, 64 degrees C, 65 degrees C, 66 degrees C, 67 degrees C, 68 degrees C for different time (0 min; 15 min; 30 min; 45 min; 60 min; 75 min). A plasmid pMDIHHNV carrying target sequence of LAMP detection was constructed. Ten-fold serially diluted pMDIHHNV (10(7)-10(0)copies/microL) was used as template for LAMP assay to investigate the detection limit. To determine the specificity, LAMP assays were carried out with DNA templates from other pathogens (White spot syndrome virus; WSSV, Taura Syndrome Virus; TSV, Aeromonas. hydrophila, V. alginolyticus, Vibrio. parahaemolytious, Escherichia. coli). The results showed the optimized LAMP assay for the rapid detection of IHHNV was performed at 65 degrees C for 60 min. The LAMP assay had an unequivocal detection limit of 100 copies/microL, and it was 1,000 times lower than that of PCR. The nucleic acids of other pathogens were not amplified by this LAMP system with the specific primers, which showed a good specificity. The resulting amplicons were detected using visual observation after the addition of SYBR Green I and gel electrophoresis. We investigated the efficacy of UNG (uracil-N-glycosylase) and dUTP in avoiding carry-over contamination in the LAMP assay procedure and explored its effect on the amplification efficiency. Products of LAMP with dUTP adding could be lysed by UNG to avoid LAMP products carry-over contamination effectively. The LAMP assay could be finished within an hour, requiring only a regular laboratory water bath or heat block for reaction and the result could easily be detected using visual observation. Clinically suspected IHHNV-infected shrimp samples were detected by both LAMP and PCR assay, and the result indicated that IHHNV was detected rapidly by LAMP instead of by PCR.
Animals ; DNA Primers ; genetics ; Densovirinae ; genetics ; isolation & purification ; Nucleic Acid Amplification Techniques ; methods ; Penaeidae ; virology ; Viral Proteins ; genetics

Several virus families have been shown to encode microRNAs (miRNAs), which have roles in the infection and replication of viruses in host cells. These virus-encoded miRNAs are identified in double-stranded DNA virus (dsDNA virus) and in several RNA virus families, but not in single-stranded DNA virus (ssDNA virus). We used a bioinformatics approach based on VMir, miRNAFold and MaturePred software to predict virus-encoded miRNA-like small RNAs from the genome of a ssDNA virus: Aedes aegypti densovirus (AaeDV). Northern blotting and stem-loop reverse transcription-polymerase chain reaction (RT-PCR) were used to detect predicted small RNAs. A miRNA-like small RNA termed "AaeDVMD" was identified by stem-loop RT-PCR from predicted candidates. This is the first report demonstrating that a ssDNA virus can encode miRNA-like small RNAs. These data will aid further exploration of the interaction between the AaeDV and its mosquito host.
Aedes ; virology ; Animals ; Base Sequence ; Computational Biology ; Densovirinae ; chemistry ; genetics ; metabolism ; MicroRNAs ; chemistry ; genetics ; metabolism ; Molecular Sequence Data ; RNA, Viral ; chemistry ; genetics ; metabolism