Progress in prevention and control of Nipah virus disease / 中华流行病学杂志

Nipah virus disease (NVD) is a newly emerged zoonosis with a case fatality rate of 40%-75%. NVD is a severe threat to human health and the development of livestock farming. NVD has become one of the emerging infectious diseases with great concern globally during more than 20 years. Nipah virus (NiV) is a pathogen for NVD, the natural host of which is Fruit bats of the Pteropodidae family. The clinical spectrum of NiV infection is broad, including asymptomatic infection, acute respiratory infection, fatal encephalitis, and even death. Since NiV was first identified in Malaysia in 1999, it has been prevalent mainly in Southeast Asia and South Asia. NiV is primarily transmitted to humans through bat-pig-human, contaminated food. Currently, there are no specific therapeutic drugs and vaccines for NVD. Although there are no cases of NVD reported in China, which has close personnel and trade exchanges with major NVD-endemic countries, and NiV antibody has also been detected in relevant bats. There is a potential risk of importing NVD and domestic outbreaks in the future in this country. This paper provides a systematic review of the research progress in the prevention and control of NVD etiology, epidemiology, clinical manifestations and laboratory diagnosis to help relevant staff to understand NVD more comprehensively and systematically.

An assessment of epidemiological capacity of infectious disease in institutions of disease control and prevention / 预防医学

Objective To evaluate epidemiological capacity of infectious disease in institutions of disease control and prevention,and to improve the ability of infectious disease control and prevention. Methods Questionnaires of epidemiological capacity of infectious disease evaluation in institutions of disease control and prevention which contained surveillance analysis,emergency response,plan system and so on were used to evaluate epidemiological capacity of infectious disease in all of city,district or county level of center for disease control and prevention in Ningbo,Shaoxing, Quzhou.The degree of attainment for the ability or (and)resources was divided into vary bad,bad,average,and good. Descriptive epidemiological methods were used to perform analysis and evaluation.Results The capability for monitoring notifiable infectious diseases reaching to good was 1 9 (76.00%),greater than that in non -statutory communicable diseases 2 (8.00%). Twenty four (96.00%) institutions reported that the most important factor limiting the epidemiological capacity of infectious disease was lack of human resources,and 20 (80.00%)of institutions supported infectious disease epidemiology staff to publish articles in academic journals,but scientific research ability reaching to good was 3(1 2.00%).Training subordinate institution capacity reaching to good was 1 0(40.00%),with 2 (8.00%)reporting very bad.Most abilities were not significant across different regions,only significant in non -statutory communicable diseases surveillance (χ2 =7.04,P =0.03).Conclusion Institutions of disease control and prevention had a certain epidemiological capacity of infectious disease,and almost balance in different regions.For further enhancing the ability,it is necessary to increase the number of personnel,and to improve the ability of education and training.

A Cross-sectional study on tick-borne Rickettsiae infections among murine-like animals / 预防医学

Objective Toinvestigatethestatusoftick-borneRickettsiaeinfectionsamongmurine-likeanimalsin differentareasofZhejiangprovince.Methods Liverandspleensamplesofmurine-likeanimalscapturedthroughnight trapping method were collected from Anji,Jinhua and Tiantai County according to their geographic locations and historical detection of Rickettsiae .Nest-PCR tests were used to determine the presence of the 16S rRNA genes of Anaplasma and Ehrlichia ,and the heat shock protein genes (groEL)of Rickettsiae (including typhus and spotted fever group)and Orientiainthesesamples.Results Atotalof851murine-likeanimalsbelongingto14specieswerecaptured.The predominant species were Rattus confucianus (30.32%),Apodemus agrarius (18.80%) and Thallomys paedulcus (1 1.75%)and they were significantly different among three areas (P<0.05 ).48 Rickettsia positive were found in 562 tested samples with the positive rate of 8.54%,among which the percentage of Anaplasma,typhus group Rickettsia, Orientia,Ehrlichia and spotted fever group Rickettsia were 3.38%,1.78%,1.78%,1.07% and 0.53% respectively. The positive rates of Anaplasma in Jindong (4.76%)and Anji (4.27%)were significantly higher than that in Tiantai (P<0.05 )while the spotted fever group Rickettsia were found only in Tiantai County.Moreover,Rattus confucianus-the predominant species of Zhejiang Province-had the highest infection rate of tick-borne Rickettsiae up to 14.97%.Co-infections with several Rickettsiae were existed among the same species.Conclusion Rickettsiae infections exist widely among different areas of Zhejiang province and the positive rates are significantly different among species.

Clinical and epidemiological characteristics of the 6 confirmed human cases with novel influenza A (H7N9) virus infection in Zhejiang / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the clinical spectrum, geographic location of human H7N9 avian influenza as well as the characteristics of population at high risk of infection, in order to develop strategies for the prevention and control of the infection. Clinical and epidemiological characteristics on the 6 confirmed human cases in Zhejiang were also analyzed.</p><p><b>METHODS</b>Real-time fluorescent quantitative PCR was used to test the nucleic acid of human H7N9 avian influenza infection, from pharyngeal swabs of the patients and their close contacts. Face to face interview and descriptive method were used to collect related clinical and epidemiological data. Statistical analysis was performed by SPSS 17.0.</p><p><b>RESULTS</b>Six confirmed cases were distributed in Hangzhou and Huzhou cities. The 6 confirmed human cases, including 5 males and 1 female were all confirmed with novel influenza A (H7N9) virus infection, with an average age as 60.83 years (with median as 64.50 years). Cough was the most common initial symptom to be noticed. The clinical manifestations would include fever, dizziness, pain of muscles, coughing, expectoration and short of breath. All the X-ray chest films showed severe pneumonia, and 5 of them having had other chronic diseases. None of the cases admitted to have had a history of exposure to ill/death avians. However, all of the cases had been frequently exposed to the agricultural-byproduct-trading-markets where the positive rate of novel influenza A (H7N9) virus in environmental specimens was up to 43.21%. 32 of the 375 close contacts (8.53%) to the 6 cases appeared abnormal symptoms, but no positive result related to novel influenza A (H7N9) virus nucleic acid was detected from their throat swabs.</p><p><b>CONCLUSION</b>Acute infection on the respiratory system seemed the main clinical manifestation. Elderly men, especially those with chronic diseases were under high risk of human infection with H7N9 avian influenza. The source of infection might be associated with the exposure to poultry. There was still lack of evidence to confirm the route of person to person transmission on H7N9 avian influenza.</p>

Study on the efficacy of hepatitis B virus vaccination and its influencing factors among children in rural area of Jiangsu province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To evaluate the efficacy of hepatitis B viruse (HBV) vaccination and its influencing factors among children in rural area of Jiangsu province.</p><p><b>METHODS</b>Twenty-five hundred and twenty-two children born after 1998 in rural area were selected as the study population using multistage cluster sampling method. HBsAg and anti-HBs were detected by enzyme linked immunoassay (ELISA) and radio-immunoassay (RIA), respectively. Anti-HBs negative children were boosted using different hepatitis B vaccines and the efficacy was compared. Factors causing HBV infection in HBsAg positive children were also investigated.</p><p><b>RESULTS</b>HBsAg positive rates in 1-7 year olds were 0.28%-1.28%, and the anti-HBs positive rates decreased from 76.7% to 45.5%. The HBsAg positive rate in children not timely vaccinated was significantly higher than those with HBV vaccine injection within 24 hours after birth (1.4% vs. 0.5%, P = 0.031). More than 90% of the anti-HBs negative children had protective level of anti-HBs after boosted with HBV vaccine.</p><p><b>CONCLUSION</b>HBsAg positive rate in children born after 1998 in rural area of Jiangsu province decreased significantly, with an average of 0.8%. The reason for HBsAg carriage in children might be attributed to mother-to-infant transmission or not timely HBV vaccination.</p>

Study on the kinesis of cellular immunity in adults vaccinated with recombinant hepatitis B vaccine / 中华流行病学杂志

<p><b>OBJECTIVE</b>To evaluate the kinesis of cellular immunity in adults who were vaccinated with yeast recombinant hepatitis B(rHB) vaccine and the correlation between cellular and humoral immune responses induced by the vaccine.</p><p><b>METHODS</b>Eight adults were vaccinated with rHB vaccine according to 0, 1,2 month schedule. The peripheral blood mononuclear cells(PBMCs) were collected at the 3, 8, 21, 34 and 65 days after the first dose. The high purity of CD4+ and CD8+ T cells obtained by sorting from PBMCs were restimulated with recombinant hepatitis B surface antigens (rHBsAg) or peptides. The spot forming cell (SFC) of IFN-gamma, IL-2 and IL-4 of CD4+ and CD8+ T cells were detected by enzyme-linked immunospot (ELISPOT).</p><p><b>RESULTS</b>The characteristics of IFN-gamma, IL-2 and IL-4 of CD4+ and CD8+ T cells appeared different after immunization with rHB vaccine. IFN-gamma of CD8+ and CD4+ T cells could be detected early with stable SFC, while the IL-2 and IL-4 of CD4+ T cells appeared late but increased after the second and third dose of vaccination. The positive rate of IL-4 of CD4+ T cells were significantly correlated with the positive rate of anti-HBs, while the SFCs of IL-4 and IL-2 of CD4+ T cells were also significantly related to the titers of anti-FIBs.</p><p><b>CONCLUSION</b>IFN-gamma could be detected early after rHB vaccination in adults, and the positive rates of IL-4 and IL-2 were correlated with that of anti-HBs.</p>

Interruption failure of heptitis B virus vaccination in mother-to-infant transmission and heptitis B virus genotypes and preC/BCP mutations / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the association of heptitis B virus (HBV) genotypes and precore(PreC)/basal core promoter(BCP) mutation with interruption failure of HBV vaccination in mother-to-infant transmission.</p><p><b>METHODS</b>A total number of 208 serum samples were collected from infants and mothers,including 16 infants who had become HBsAg-positive despite a complete and timely course of immunization and another 88 infants successfully protected from mother-to infant HBV transmission. HBV genotypes were determined by type-specific primers PCR method. PreC/BCP mutations were detected by direct sequencing of PCR products, and Clustal W 1.8 software was applied to analyzing the sequences.</p><p><b>RESULTS</b>Of 16 mothers who were having vaccine failure infants, 15 (93.8%) were HBeAg positive and infected with genotype C (15/15, 100%). Among 88 mothers of having children being protected by vaccine, 51 (58.0%) were HBeAg positive, with 45.1% (23/51) of genotype C. The proportion of genotype C in HBeAg mothers of infants with vaccine failure, was significantly higher than that of mothers with vaccine protected infants (chi2 = 14.3, P = 0.003). However, the frequencies of T1762/A1764 mutations had no significant differences between genotype C HBeAg positive mothers with vaccine failure or protected infants (33.3% and 13.3%, respectively, P = 0.4). No A1896 mutation was found in these two groups.</p><p><b>CONCLUSION</b>HBV genotype C might contribute to the immune failure of HBV vaccination in mother-to-infant transmission, while PreC/BCP mutation might not have correlation with it.</p>

Role of mutations on the "hepatitis B virus 'a' determinant hotpoint" to the efficacy of hepatitis B vaccine / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study how hepatitis B virus(HBV) 'a' determinant hotpoint mutations were influecing the hepatitis B vaccine efficacy.</p><p><b>METHODS</b>Primers were designed in HBV conservative region, and the degenerate probes for detecting 16 'a' determinant hotpoint mutations were developed for gene chips. Sensitivity and specificity of the gene chips were evaluated by clone sequencing. Sera of 47 pairs of mothers and infants with immune failure and 323 mothers of children with immune protection of HB vaccine were detected by the gene chips.</p><p><b>RESULTS</b>Result from clone sequencing demonstrated that the gene chips were specific for the detection of 'a' determinant hotpoint mutations. The wild type of HBV was still dominant, with the prevalence of 78.66%, and the mutation frequencies of 126A, 145R, 126S-1, 126S-2, 129H, 144A, and 129R were 11.27%, 5.76%, 5.28%, 4.56%, 1.20%, 0.72% and 0.24%, respectively. The prevalence of 126A mutation was significantly higher than that of other mutations(P < 0.01). No significant differences were found in mother-infant transmission rates of 126A, 126S-1, 126S-2 and 145R variants.</p><p><b>CONCLUSION</b>The currently available hepatitis B vaccine could block mother-infant transmission of 126A, 126S and 145R variants. It appears that there is no need to develop a new hepatitis B vaccine against 126 and 145 variants at present, but the consistent epidemiological surveillance on HBV mutants should be carried out.</p>

Genotyping of hepatitis E virus by PCR combining with single restriction endonuclease analysis / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To develop a simple method for genotyping of hepatitis E virus (HEV) and to investigate HEV genotype distribution in Nanjing area.</p><p><b>METHODS</b>Twenty-seven full HEV sequences currently-available in GenBank were analyzed with MegAlign and MapDraw programs of DNA STAR software. Degenerate primers were designed and applied to amplify a fragment in HEV ORF1 region. HEV genotypes were determined by the size of the PCR products and by single restriction endonuclease analysis.</p><p><b>RESULTS</b>The PCR products of HEV genotype 1 and 2 were 275 bp and 269 bp in size. Distinctively, the PCR products of genotype 3 and 4 were 317 bp and 314 bp in size. Moreover, the PCR products of genotype 1 could be digested by Nae 1, but the products of genotype 2 could not. Distinctively, the PCR products of HEV genotype 3 could be digested by Not 1, but the products of genotype 4 could not. Six HEV reference strains standing for different HEV genotypes were clustered into their own types as predicted. Within 43 HEV IgM-positive clinical specimens collected in Nanjing, 19 were HEV PCR-positive and identified as genotype 4.</p><p><b>CONCLUSION</b>A simple method of PCR combined with single restriction endonuclease analysis is developed for HEV genotyping. This assay allows rapid identification of a large number of HEV isolates directly from clinical specimens. Among patients with hepatitis E in Nanjing, most were infected with HEV genotype 4.</p>