Analysis on epidemiological characteristics of dengue fever and E gene evolution of dengue virus in Guangzhou, 2020 / 中华流行病学杂志

Objective: To assess the incidence of dengue fever and E gene evolution of dengue virus in Guangzhou in 2020 and understand the local epidemiological characteristics of dengue fever and spreading of dengue virus. Methods: The information of dengue fever cases in Guangzhou in 2020 was collected from Notifiable Infectious Disease System of Chinese Center for Disease Control and Prevention Information System. Serum samples from the cases were detected by real-time PCR. The E gene was sequenced and analyzed. Maximum likelihood phylogenetic trees were constructed using software MEGA 5.05. The statistical analysis was conducted using software SPSS 20.0. Results: A total of 33 dengue fever cases were reported in Guangzhou in 2020, including 31 (93.94%) imported cases and 2 (6.06%) local cases. Compared with the data during 2016 to 2019, the number of cases, overall incidence and local incidence all decreased with statistically significant differences (all P<0.05). The imported cases from Southeast Asia constituted 90.32% (28/31) of imported cases. The E gene sequences and the phylogenetic trees of imported and local cases demonstrated close relationship with the virus sequences from Southeast Asian, and they were less homologous with the sequences of dengue virus isolated in Guangzhou in previous years. Conclusions: The incidence of dengue in Guangzhou in 2020 was significantly affected by the imported cases, especially those from Southeast Asian countries. The study result demonstrated that dengue fever was not endemic in Guangzhou and it was caused by imported ones.

Effect of Chaijie Yiganxian on Hepatic Fibrosis Induced by Thioacetamide in Rats / 中国实验方剂学杂志

Objective: To research the effect of traditional Chinese medicine compound Chaijie Yiganxian (CJYGX) on the hepatic fibrosis in rats and explore the mechanism. Method: Totally 60 SD rats were randomly divided into normal group, model group, positive group (Biejia Jianwan), and low, medium and high-dose CJYGX groups. Except for the normal group, the remaining five groups were involved in establishing the hepatic fibrosis model through the intraperitoneal injection of thioacetamide (TAA). Fourth weeks after modeling, the positive group was given Biejiajian pill (1 g·kg-1·d-1), and high, medium and low-dose CJYGX groups were given CJYGX(7.96, 3.98, 1.99 g·kg-1·d-1), respectively. The model group was given normal saline once a day for 5 weeks. 24 h after the last intragastric administration with chloral hydrate, the rats were anesthetized slightly. Serum and liver tissues were collected. The liver wet weight was weighed electronically, and the liver index was calculated. Liver function indexes[alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP)] and serum markers[laminin (LN), hyaluronidase (HA), Ⅳ collagen (CⅣ), procollagen Ⅲ (PCⅢ)] of hepatic fibrosis were detected by enzyme linked immunosorbent assay (ELISA). The degree of hepatic fibrosis by Masson stain, mRNA expressions of transforming growth factor-β1 (TGF-β1), Smad2, Smad3, Smad4, Smad7 were detected by Real-time fluorescence quantitative polymerase chain reaction (Real-time PCR), and protein expression levels of platelet derived growth factor (PDGF), TGF-β1 and α-smooth muscle actin (α-SMA) were detected by immunohistochemical or Western blot. Result: Compared with the blank group, the model group liver index was significantly increased; the contents of ALP, AST and ALT were significantly increased; the liver fibrosis indexes LN, HA, Ⅳ-C, PCⅢ and HYP were significantly increased; the degree of liver fibrosis was significantly increased in Masson tissue; the mRNA expressions of TGF-β1, Smad2, Smad3, Smad4 were significantly increased; and the Smad7 mRNA expression was significantly decreased. The protein expressions of TGF-β1, PDGF and α-SMA increased significantly (Pβ1, Smad2, Smad3, Smad4 and up-regulate mRNA expression of Smad7.Immunohistochemical and Western blot analysis show that, compared with model group, CJYGX could significantly reduce the protein expressions of TGF-β1, PDGF and α-SMA (PPConclusion: Traditional Chinese medicine compound CJYGX may protect TAA-induced hepatic fibrosis injury by interfering with TGF-β1/Smad signaling pathway.

The molecular epidemiology characteristics of norovirus in environment and clinical samples in Guangzhou from 2009 to 2011 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the molecular epidemiological characteristics of norovirus in Guangzhou from 2009 to 2011.</p><p><b>METHODS</b>A total of 183 water samples, 1162 seafood samples and 1066 diarrhea stool specimens were collected from January 2010 to May 2011, June 2009 to June 2011 and July 2009 to December 2010 respectively in Guangzhou. Norovirus was detected by real time reverse transcript-PCR (qRT-PCR). The partial polymerase gene was amplified from norovirus positive samples, then sequenced and compared with the sequences of norovirus in GenBank. The phylogenetic tree was created.</p><p><b>RESULTS</b>The positive rate was 19.67% (36/183), 8.26% (96/1162) and 37.05% (395/1066) in water samples, seafood and diarrhea patients respectively. Noroviruses from positive samples could be divided into 10 representative strains, in which 7 representative strains of genotype of 208 samples was type G2-4. The sequences from water, seafood and stool specimens were highly homologous with the similarity of 94% - 100%.</p><p><b>CONCLUSION</b>In Guangzhou, the predominant Norovirus genotype was G2-4 and the positive rate of samples was high.</p>

Epidemiological situation and the E gene evolution of dengue virus in Guangzhou, 2011 / 中华流行病学杂志

Objective To investigate the epidemiological characteristics of Dengue and the E gene of the new isolated strains.Methods Epidemiological data and serum samples were collected.Serotypes were detected by real-time PCR and virus was isolated in C6/36.E gene of the new isolated strains were sequenced and analyzed by Mega 4.0.Results The cases of Dengue reached at the peak during September and November,with Serotype 1,2 and 4 were involved.Five strains of serotype 1 were isolated,with 4 of them fell into the clad of Asia genotype,and 1 belonged to America/Africa genotype.Conclusion The strains isolated in Guangzhou showed a high identity to the Southeast Asian strains.There seemed high risk of outbreak of Dengue in this area,However,the Dengue virus might have already been localized.

Study on the inhibitory effect of RNA interference on replication of dengue virus / 病毒学报

To investigate the inhibitory effect of RNA interference (RNAi) on dengue virus I (DENV-1) replication. Small interfering RNA (siRNA) against the PreM gene of dengue virus was synthesized and transfected into C6/36 cells with liposome, which was then attacked by DENV-1 virus. The antiviral effect of siRNA was evaluated by cytopathic effect (CPE), the cell survival rate measured by MTT, and virus RNA quantified by real-time RT-PCR. The results showed that after 7 days post infection of dengue virus, the transfected C6/36 cells showed less CPE. The cell survival rate of the transfected C6/36 cells increased by 2.26 fold, and the amount of virus RNA in the transfected cells was reduced by about 97.54% as well. These findings indicated that the siRNA could effectively inhibit dengue virus RNA replication, and protect C6/36 cells from viral attack, indicating its potential role in prevention and treatment of dengue fever.

Molecular epidemiologic analysis on new emerged type 3 dengue virus in Guangzhou in 2009 / 中华流行病学杂志

Objective To analyze and trace the infection source the envelope(E) gene of the new emerged type 3 dengue virus in Guangzhou in 2009. Methods Sera were collected from patients infected with local dengue fever. Dengue virus was cultured and isolated by C6/36 cells. The whole length E gene was amplified from the positive specimen by RT-PCR, thereby sequenced and phylogenetic tree drawn by neighbor-joining method. Both data on epidemiologic and molecular studies were processed and analysed. Results 7 strains of type 3 dengue virus were isolated from samples of the 19 patients. E gene of these strains was amplified. The complete E genes of 7 strains belonged to 1479 nucleotides in length, encoding a polyprotein of 493 amino acids. Data from the phylogenetic analysis showed that 09/GZ/1081, 09/GZ/1483 and 09/GZ/10806 strains fell within the Southeast Asia/South Pacific group. 09/GZ/10616, 09/GZ/11144, 09/GZ/11194 while 09/GZ/13105 strains fell within the India group. Conclusion The type 3 dengue virus identified in Guangzhou area in 2009 was imported and could be devided into two genotypes.

Risk assessment of H5N1 human infection after an outbreak of avian influenza in water fowl / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the risk of human infection after the outbreak of avian influenza H5N1 in animals, and probe the possibility for virus transmission.</p><p><b>METHODS</b>By means of field epidemiological study, molecular epidemiology, serology and emergency surveillance, persons who had ever closely contacted with sick or dead poultry were observed. While, the RT-PCR and gene sequencing method were used to detect H5 nucleic acid from environmental swabs from 4 epidemic spots, and hemagglutination inhibition assay was also used to detect H5 antibody.</p><p><b>RESULTS</b>Of 22 environmental swabs detected from 4 epidemic spots, one was positive for H5 nucleic acid, and the homogeneity was 95.9% as compared with H5N1 virus A/China/GD01/2006 (H5N1) found in Guangzhou in 2006 by gene sequence analysis. 62 environmental swabs from live poultry stalls of food markets near epidemic spot were detected negative. Six of 68 blood samples of contacts were positive for H9 antibody, and all were negative for H5 antibody. 68 throat swabs of contacts were detected negative for H5 nucleic acid. No close contact was found abnormal after 7 days medical observation. 337 influenza-like cases were reported in emergency surveillance, and no suspicious case was found.</p><p><b>CONCLUSION</b>The current outbreak of H5N1 avian influenza in water fowls has not yet caused further transmission, and human avian influenza case has not been observed. It indicates that the ability of H5N1 virus to transmit to human is not strong yet, and the risk of human infection for H5N1 is still low.</p>

Epidemiological characteristic of first case of locally identified A/H1N1 secondary cases caused by imported source of infection in China / 中华流行病学杂志

Objective To study the first locally identifcd A/HINI secondary cases outbreak in China. Methods Interview and field investigation were integrated to describe the whole process of transmission on each case and to illustrate the relationships between the onset of the disease and the retated factors. Results Two contact persons appearanced fever and whose throat swabs were tested positive to H1N1 viral nucleic acid. The two had a history of contact in a short distance with the initial imported case without any protective measure in the poor air ventilation. The patients clinical situation was slight. The incubation was between 37 hours and 57 hours. No other new case was found after intervention as isolation and antisepsis were taken. Conclusion This event was proved to be an outbreak of local A/H1N1 secondary cases caused by the imported case. The main mode of transmission was personal contact in a short distance without protection, through air and droplet. The locus with poor air ventilation was high risk place. Contact persons should be observed seven days and tested continuously.Infectivity and pathogenicity of the A/H1N1 virus were limited and appeared weakened by generations. Patient's condition was related with persistence and frequency of contact with the infection sources. Enhancing management of contact persons, health education, early diagnose, early treatment and early insulation were effective measures of controling and prenventing the spread A/H1N1.

Study on human case of avian influenza in Guangzhou 2006 without causing human-to-human transmission among close contacts / 中华流行病学杂志

<p><b>UNLABELLED</b>Study on human case of avian influenza in Guangzhou 2006 without causing human-to-human transmission</p><p><b>OBJECTIVE</b>To explore the possibility of transmission from a human case of avian influenza to his close contacts.</p><p><b>METHODS</b>Close contacts of the human case of avian influenza in Guangzhou 2006 were found out according to the definition and methods publicized by the Ministry of Health, People's Republic of China. Epidemiological investigation and medical observation were carried out. Serum antibodies were tested in some of the close contacts.</p><p><b>RESULTS</b>The avian influenza patient had never left Guangzhou in the month prior to disease onset. No contact history with dead or diseased poultry was found. A total of 56 close contacts, including his girl friend, relatives, friends and medical staff who had taken care of him, were brought under medical observation for 7 days but none of them showed signs of infection.</p><p><b>CONCLUSION</b>Unlike SARS, direct contact with patient contracted with avian influenza at the end of incubation period and in the stage of illness through flying droplets, saliva, mucous membrane and skin injuries will not lead to human-to-human transmission, indicating the virus' ability to pass from human to human is limited.</p>