ABSTRACT
To understand the genetic characteristics of hemagglutinin (HA) and neuraminidase (NA) of type B influenza viruses in Guangzhou in 2006, three virus strains from etiology surveillance and seven strains from outbreaks were investigated. Genome RNAs of type B influenza viruses were extracted and reverse-transcripted into cDNAs using random primers. The whole-length DNA of HA and NA were amplified by polymerase chain reaction (PCR), cloned into T-A plasmid and sequenced, and analyzed phylogenetically by DNAstar software. The results showed that the HA of type B influenza viruses were similar and the homology were more than 99%. The type B influenza viruses belong to Victoria lineage. The NA of the type B influenza viruses were similar and the homology were more than 98%. Phylogenetic trees of HA and NA showed that the isolates from etiology surveillance formed a cluster, and the isolates from outbreaks were separated from the cluster. The homology of the type B influenza viruses with B/Shanghai/361/2002, which is the WHO recommended influenza vaccine strain in 2005-2006, were 88.9%-89.7%. It suggested the protective effect of influenza vaccine against type B influenza viruses used in 2005-2006 in Guangzhou may not be afforded.
Subject(s)
China , Hemagglutinin Glycoproteins, Influenza Virus , Genetics , Influenza B virus , Genetics , Neuraminidase , Genetics , Phylogeny , Time FactorsABSTRACT
<p><b>OBJECTIVE</b>To probe blood serum Ab-IgG characteristics of severe acute respiratory syndrome (SARS) patients in Guangzhou and investigate the related factors.</p><p><b>METHODS</b>The serum of such population diagnosed as SARS convalescent patients, non-SARS patients, family consanguineous contraction persons, wild animal and vegetable salesman and community common people was collected. The lab detective method of ELISA was adopted for these serum samples. And the epidemic investigations for the SARS patients were also carried out.</p><p><b>RESULTS</b>Of these populations, the detective rate of Ab-IgG for the clinic diagnosed SARS patients, which was 53.7%; That for the wild animal salesman and community common people were 16.7% and 0.9%, respectively. Among the clinic diagnosed SARS patients, the positive antibody detective rate was 90.4% for those which had specific contact history or infectivity, which was higher than that for other population. Among the specific contact history or infectivity cases, the antibody positive rate for the young and the old was lower than that for the adult. Meanwhile the difference did not exist among other cases. The antibody positive rate was identical between the male and the female. And the antibody detective rate was decreased by the month.</p><p><b>CONCLUSION</b>As a whole SARS-CoV Ab-IgG detective rate for the clinic diagnosed SARS patients was 53.7% only. The reasons for that mainly lie in the wrong clinic diagnosis besides these factors such as age, hormone use and reagent and so on. The combination of lab detection results and epidemic investigation was propitious to the diagnosis veracity. It was impossible for the sub-clinic infection of SARS-CoV virus. The importance in the virus transmitting course need to be further studied.</p>