Search

To develop a clinical diagnosis technique for bluetongue virus infection, we established serotype-specific methods to detect serotype 4 of bluetongue virus (BTV-4). Two monoclonal antibodies (mAbs) against VP2 protein of BTV-4, named 4A-1G7 and 4B-1B6, were used as competitive antibodies in the competitive enzyme-linked immunosorbent assays (C-ELISA). We detected 50 negative serum samples from sheep, goats and cattle by C-ELISA. The cut-off values of 4A-1G7 and 4B-1B6 mAbs were 49% and 40%, respectively. The results of the sensitivity, specificity and repeatability by detecting standard positive serum, were consistent with the general standard of Office International Des Epizooties. Furthermore, serum samples of BTV-4, BTV-18 and BTV-20 infection could be screened out through the combined C-ELISAs by 4A-1G7 and 4B-1B6 mAbs. Thus, this technique may diagnose BTV-4, BTV-18 and BTV-20 infections.

Objective: To isolate viruses from mosquitoes in the south of Xinjiang and identify these viruses primarily., Methods: A 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., Results: All 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., Conclusion: There 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.

S10 gene sequences of 1 attenuated vaccine strain and 31 Chinese field isolates & 1 South Africa strain of BTV were determined. The results revealed that all 33 S10 gene segments have 822 nucleotides in length with two in-frame initiation codons (nucleotides 20 to 22 and 59 to 61) and a common termination codon (nucleotides 707 to 709), which encodes two proteins (NS3 and NS3A). Nucleotide difference in the sequence of all S10 gene were from zero to 107 bp (86.4% - 100% identity). NS3/NS3A protein showed a light difference from zero to 10 amino acid (95.6% - 100% identity). Phylogenetic analysis of the S10 gene of above strains sequenced and 9 other strains from GenBank, segregated the Chinese viruses into a monophyletic group distinct from US viruses; Nucleotide identity was 85% between China Group and US group. The various Chinese isolates segregated into two phyletic subgroups based on S10 gene sequences. The clustering of viruses was dependent of geographical origin, and independent of host species of isolation, serotype & year of isolation.