The virus isolation analysis of the H5N1 subtype human avain influenza cases in mainland China from 2005 to 2009 / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To analyse the correlation between the virus isolation and the specimen collection of the H5N1 human high pathogenic avain influenza cases in Mainland China.</p><p><b>METHODS</b>The specimens were collected in Mainland China from 2005.10 to 2009.3 and the H5N1 viruses were isolated by passage in embryonated chicken eggs.</p><p><b>RESULTS</b>Most specimens were obtained within 14 days after disease onset. For the specimens collected within 7 days, the isolation rate was relatively high and the difference of the positive rate between different years was lower than those specimens collected after 7 days. Most of the samples in our study were collected from the upper or lower respiratory tract with few from blood, feces, et al. The isolation rate of lower respiratory specimens was higher and the difference of the positive rate between different years was relatively lower than those from upper respiratory specimens.</p><p><b>CONCLUSION</b>We suggest that the samples should be collected from lower respiratory tract during the acute phase to get the higher isolation rate.</p>

Laboratory diagnosis and molecular characterization of highly pathogenic avian influenza virus (H5N1) in human in Hunan Province in 2005-2006 / 病毒学报

To determine the etiologic agents of two atypical pneumonia human cases in Hunan Province in 2005-2006 and to study their pathogenic potential, the patients' respiratory tract samples and sera were collected. The respiratory tract samples were tested by real-time RT-PCR and RT-PCR methods, and the sera by hemagglutination-inhibition assay. Virus was isolated from case 2 and its genome was sequenced and analyzed. Results showed the H5 nucleic acid tests of two cases were positive. The H5-specific antibody titer of the convalescence serum of case 1 showed a 4-fold greater rise than that of the acute phase. And case 2's antibody titer of acute phase was negative. The two atypical pneumonia cases were confirmed as the avian influenza A (H5N1) infection cases. Viral strain A/Hunan/1/2006 was isolated from case 2. Phylogenetic and molecular analysis suggested that 8 gene segments of A/Hunan/1/2006 originated from avian viruses. And A/Hunan/1/2006 was similar with viruses isolated from avian in Hunan Province. The isolated virus did not recombine with human influenza viruses and no obvious variation was observed.

Analysis of human H5N1 virus hemagglutinin gene isolated from the mainland of China / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To analyze the genetic and antigenic characteristics of human H5N1 virus isolated from the mainland of China.</p><p><b>METHODS</b>The hemagglutinin (HA) gene of human H5N1 virus were sequenced and analyzed.</p><p><b>RESULTS</b>The results of HA gene sequencing showed that all the virus isolates belong to the same group because of the high similarity, but they were different from the virus isolated from Thailand and Vietnam. The sequence data also showed that the receptor specificity and the connecting peptide between HA1 and HA2 are still avian influenza origin.</p><p><b>CONCLUSION</b>The virus isolates from mainland of China until now belong to the same group and are different from the virus isolated from Thailand and Vietnam, and there is no evidence showing the human-avian influenza reassortant and recombination.</p>

Stability of SARS coronavirus in human specimens and environment and its sensitivity to heating and UV irradiation / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>The causal agent for SARS is considered as a novel coronavirus that has never been described both in human and animals previously. The stability of SARS coronavirus in human specimens and in environments was studied.</p><p><b>METHODS</b>Using a SARS coronavirus strain CoV-P9, which was isolated from pharyngeal swab of a probable SARS case in Beijing, its stability in mimic human specimens and in mimic environment including surfaces of commonly used materials or in household conditions, as well as its resistance to temperature and UV irradiation were analyzed. A total of 10(6) TCID50 viruses were placed in each tested condition, and changes of the viral infectivity in samples after treatments were measured by evaluating cytopathic effect (CPE) in cell line Vero-E6 at 48 h after infection.</p><p><b>RESULTS</b>The results showed that SARS coronavirus in the testing condition could survive in serum, 1:20 diluted sputum and feces for at least 96 h, whereas it could remain alive in urine for at least 72 h with a low level of infectivity. The survival abilities on the surfaces of eight different materials and in water were quite comparable, revealing reduction of infectivity after 72 to 96 h exposure. Viruses stayed stable at 4 degrees C, at room temperature (20 degrees C) and at 37 degrees C for at least 2 h without remarkable change in the infectious ability in cells, but were converted to be non-infectious after 90-, 60- and 30-min exposure at 56 degrees C, at 67 degrees C and at 75 degrees C, respectively. Irradiation of UV for 60 min on the virus in culture medium resulted in the destruction of viral infectivity at an undetectable level.</p><p><b>CONCLUSION</b>The survival ability of SARS coronavirus in human specimens and in environments seems to be relatively strong. Heating and UV irradiation can efficiently eliminate the viral infectivity.</p>