A novel test for diagnosis of influenza / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To set up a novel, simple, sensitive, specific, repeatable and rapid assay for diagnosis of influenza.</p><p><b>METHODS</b>Monolayers of MDCK cells were inoculated with the specimens for amplifying viral yield, the feature of receptors on cell surface was changed by treatment of neuraminidases of influenza A and B viruses. Afterward, based on the lectin binds to receptors on cell surface with strict specificity,the phenomenon of red blood cell aggregation was observed under the conventional microscope. Finally, the tested results could be determined by the extent of red blood cell aggregation.</p><p><b>RESULTS</b>There was a complete (%) consistency rate (100%) for viral isolation between new and routine tests. In general, the results were detected with new assay within 20 h. The sensitivity of new assay was over 100-10,000 times higher than that of routine method. Meanwhile, the novel test could not only be used for rapid diagnosis in the clinic, but also be used for influenza surveillance. The best concentration of red blood cells was 1 in the detection assay. The testing result was not effected by red blood cells taken from either different red blood cell type of human or different individual of guinea pigs.</p><p><b>CONCLUSIONS</b>The novel method has several advantages: simple, high sensitivity and specificity, accurate and suitable for multiple purposes.</p>

Characterization of HA1 gene of influenza B virus circulated in 1990 through 2000 in China / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To characterize HA1 gene of influenza B virus circulated in 1990 through 2000 in China.</p><p><b>METHODS</b>Viral RNA was extracted and transcribed into cDNA by reverse transcriptase and amplified by PCR. The product of PCR was purified and sequenced by ABI377. The sequence data were analyzed with epidemic records.</p><p><b>RESULTS</b>1. Two major lineages of influenza B virus always circulated during the period of 1990-2000 in China; the Yamagata lineage was the main lineage, but in 1994 and 1997 the Victoria lineage was more active. 2. During 1992-2000 the Yamagata lineage evolved into two minor groups whose distance in HAI amino acid sequences was about 6%. 3. Large and non-reverse mutators led the development of influenza B epidemics in 1990-2000 in China. 4. Except for a few strains, there was little difference among the influenza B viruses of the same major lineages circulated in the same year in China.</p><p><b>CONCLUSIONS</b>Two major lineages of influenza B virus always circulated during the period from 1990-2000 in China,and the Yamagata lineage diverged into two minor groups in recent years. Exchanges of the lineages and the appearance of large non-reverse mutators possibly had important epidemic significance.</p>

Characterization of genome of A/Guangzhou/333/99(H9N2) virus / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To understand the characterization of genome of a strain of avian influenza A H9N2 virus repeatedly isolated from a child with influenza illness. Thereafter to reveal the origin of this H9N2 virus.</p><p><b>METHODS</b>Viruses were passed in embryonated hen eggs and virion RNA was extracted from allantoic fluid and reverse transcribed to synthesize cDNA. cDNA was amplified by PCR and the PCR product was purified with a purification kit. Afterwards RNA sequence analysis was performed by dideoxynucleotide chain termination and a cloning method. Finally, phylogenetic analysis of the sequencing data was performed with MegAlign (Version 1.03) and Editseg (Version 3.69) softwares.</p><p><b>RESULTS</b>Genome of A/Guangzhou/333/99 (H9N2) virus was closely related to avian influenza A H9N2 virus, but obvious difference from that of A/Duck/Hong Kong/Y439/97(H9N2) virus, as well as its genome did not include any RNA segment derived from human influenza A virus. However, the genes encoding the HA,NA,NP and NS proteins of A/Guangzhou/333/99 virus were derived from those of G9 lineage virus, the rest genes encoding the M and three polymerase (PB2,PB1 and PA) proteins were derived from G1 lineage strain.</p><p><b>CONCLUSIONS</b>A/Guangzhou/333/99 virus was a reassortant derived from reassortment betweenG9 and G1 lineages of avian influenzaA(H9N2) viruses. Therefore, the most possibility is that it is derived from avian influenza A virus directly. The results do not only demonstrate that avian influenza A (H9N2) virus could infect men, but also firstly prove that the genetic reassortment could be occurred between different genetic lineages of avian influenza A (H9N2) viruses in the nature.</p>