Field epidemiological study on news reports that related to public health emergencies / 中华流行病学杂志

Objective All news reports (NR) that were related to public health emergency (PHE) were collected from the Southern Metropolis Daily (SMD) to explore the characteristics of epidemiology in the fields.Methods Based on the theory of communication that including both case and text analysis,qualitative analysis on all the NR regarding PHE published in SMD from the years of 2008 to 2012,was carried out and input to database using the EpiData.Numbers of articles as indicators were compared to show the yearly change of different types of events.Various features of the NR including coverage,source of information,location of the incident,style and size of news,with or without editorials etc.were statistically analyzed by SPSS version 18.0.Results Among all the 998 reports related to PHE,higher proportion was found in the events of Infectious diseases (35.3％)and food safety (34.1％) respectively.Events on vaccines and drugs used for disease prevention and control (8.9％),environmental pollution caused incidents (8.0％) appeared to be less frequent.Events related to occupational disease,poisoning,bioterrorism and biochemical events were rare.Looking at the monthly distribution of reports,we noticed that the peaks occurred in 2008 and in 2009,which were caused by the Melamine-contamination events and the 2009 H1N1 pandemic.Between 2010 and 2012,figures of monthly reports were smooth,including some critical events from the interests of the media.Most events took place in Guangdong province (34.3％) and other provinces (50.9％),with some were from Hong Kong,Macao and Taiwan regions (9.5％).However,international events (5.2％) were less seen.Extensive coverage accounted for 17.6％ of all of reports,and 11.5％ allotted the editorials or other forms of in-depth reports.Most of the source of reports on infectious diseases and food safety were from the official release,however.The main sources of occupational diseases and poisoning,vaccines and drug incidents,environmental pollution related incidents were reported by active journalists through interview.Reports on hand,foot and mouth disease,influenza,milk safety,AIDS and lead pollution showed continued concern in the past five years by SMD.Conclusion NR on public health emergencies by SM had encompassed all 10 categories-related events formulated by the Ministry of Health.Sustained and in-depth coverage were more commonly seen.Fieldepidemiologists should learn interdisciplinary sciences on the theory and methodology of communication.They also need to interact with media people during the whole processes of public health emergency preparedness and responses.

Field epidemiological study on a varicella outbreak among schoolchildren in Shenzhen / 中华流行病学杂志

Objective Both epidemiologic characteristics and transmission mode of a varicella outbreak among schoolchildren in Shenzhen city were studied and related control measures were discussed.Methods Case definition was established.Case-finding and face-to-face investigation were conducted,followed by analysis on distributions of time,place and persons of the outbreak.Association between possible modes of transmission and the outbreak was explored.Retrospective cohort study was carried out.Results The overall attack rate of this outbreak was 4.4％ (122 of 2742).The attack rate among primary schoolchildren (8.3％,118/1419) was higher than that in the middle-school children (0.3％,4/1323).There were no statistically significant differences on the attack rates between male and female students.A total of 22 classes from the 9 grades were affected by this outbreak and the aggregation of varicella cases was found in classes.The highest attack rates was found in the students of fifth grade (23.7％),followed by from the third grade (13.4％).The main transmission mode appeared to be close personal contact.The outbreak,with four peaks of incidence,lasted 72 days.Data from the investigation suggested that the primary case was introduced into the school during military training involved by the students.Activities related to physical examination for all the schoolchildren seemed to have contributed to the spread of this disease among classes.Delayed isolation of cases appeared to be the major factor causing the spread of disease among classes.Intensive off-school activities or free community bus for children did not seem to be associated with the spreading of the disease.52.5％ (64/122) of the cases had received one-dose of varicella vaccine,with the median of onset after the vaccination as 7 years.The results demonstrated that one single-dose vaccine or long vaccination period were factors related to the insufficient immunity that causing the outbreak of disease.Conclusion Varicella outbreak has been one of the most grievous public health problems in schools,posting challenges on the implementation of isolation measures,in particular.Once the chain of transmission is in place,it is difficult to make the universal measures effective within a short period.

A nitrite poisoning event associated with intentional chemical releases / 中华流行病学杂志

<p><b>OBJECTIVE</b>To compare the field epidemiological investigation and the criminal investigation on a nitrite poisoning event caused by deliberate contamination.</p><p><b>METHODS</b>Cases were searched according to the definition of the disease. Information on the histories of onset and diet of all the cases and normal population on site, were investigated face to face. Information as ingredients, processing and sales of foods was also gathered. Samples were collected and nitrite detection were performed. Relevant materials were searched, cases were interviewed and data related to criminal results were collected.</p><p><b>RESULTS</b>Poisoned persons were staff of a big company in Longgang district of Shenzhen. The overall attack rate was 56.25% (63/112), with suspected and confirmed rates as 41.96% and 14.28%, respectively. The fatality rate was 3.17% (2/63). Clinical manifestation and effect of treatment were in accordance with the characteristics of an episode related to acute nitrite food poisoning in terms of factors as the time of onset, involving different age, sex and jobs of the patients. A total of 191 samples, including vomits from patients and seven batches of food and environment samples, were collected, with a positive detected rate of nitrite as 18.84%. Information gathered from the field environment, food distribution and processing supported the assumption that this was an incident of nitrite poisoning event with intention.</p><p><b>RESULTS</b>from the criminal investigation showed that the suspect stemmed from the market management rivalry, bought nitrite, dissolved and spread on food stalls F9 and F10.</p><p><b>CONCLUSION</b>This event of intentional nitrite release resulting in food contamination which further leading to food poisoning, was completely proved by the joint efforts of the teams and expertise from the field epidemiology survey and the criminal investigation.</p>

Decision tree and cost-benefit analysis on strategies related to preventing maternal-infantile transmission of hepatitis B virus infection / 中华流行病学杂志

Objective To synthesize relevant data and to analyze the benefit-cost ratio on strategies related to preventing the maternal-infantile transmission of hepatitis B virus infection and to explore the optimal strategy.Methods A decision tree model was constructed according to the strategies of hepatitis B immunization and a Markov model was conducted to simulate the complex disease progress after HBV infection.Parameters in the models were drawn from meta-analysis and information was collected from field study and review of literature.Economic evaluation was performed to calculate costs,benefit,and the benefit-cost ratio.Sensitivity analysis was also conducted and a tornado graph was drawn.Results In view of the current six possible strategies in preventing maternal-infantile transmission of hepatitis B virus infection,a multi-stage decision tree model was constructed to screen hepatitis B surface antigen (HBsAg) or screen for HBsAg then hepatitis B e antigen (HBeAg).Dose and the number of injections of HBIG and hepatitis B vaccine were taken into consideration in the model.All the strategies were considered to be cost-saving,while the strategy of screening for HBsAg and then offering hepatitis B vaccine of 10 μg × 3 for all neonates with hepatitis B immunoglobulin (HBIG) of 100 IU × 1 for the neonates born to mothers who tested positive for HBsAg appeared with most cost-saving.In the strategies,the benefit-cost ratio of using 100 IU HBIG was similar to 200 IU HBIG,and one shot of HBIG was superior to two shots.Results from sensitivity analysis suggested that the rates of immunization and the efficacy of the strategy in preventing maternal-infantile transmission were the main sensitive variables in the model.Conclusion The passive-active immune-prophylaxis strategy that using 10μg hepatitis B vaccine combined with 100 IU HBIG seemed to be the optimal strategy in preventing maternal-infantile transmission,while the rates of immunization and the efficacy of the strategy played the key roles in choosing the ideal strategy.

Estimation on the intangible cost and influencing factors for patients with hepatitis B-related diseases / 中华流行病学杂志

Objective To estimate the intangible cost and associated factors on patients with hepatitis B-related diseases, so as to explore the differences of the three elicitation techniques on the health economics-related information by trained investigators, using a structured questionnaire. WTP was employed to estimate the intangible cost while an open-ended question format, together with iterative bidding game and payment card were respectively used to elicit WTP for the hypothetical cure of hepatitis B-related diseases. A Multiple linear stepwise regression model was determined to identify those factors potentially affecting the intangible cost. Results A total of 564 subjects from 641 patients with hepatitis B-related diseases were identified for the inclusion of this study. The average annual intangible cost of patient with hepatitis B-related diseases was 54 320.4 Yuan (Ren Minbi).The intangible cost accounted for 53.0% of the total cost, which was much more than the proportions of the direct and indirect costs (38.5% and 8.5%, respectively). Among annual personal and the household income of the patient, proportions of intangible cost were 262.6% and 67.6% respectively,suggesting that the patients were under huge spiritual and psychological pressure. Response rate of the approach, combined open-ended questions with iterative bidding game, was the highest (76.6%) among the three elicitation formats. Considered the characteristics of data being gathered, the approach seemed to be more reasonable. Further studies were needed to examine the results yielded from other WTP elicitation formats. We also noticed that the progression of disease was associated with the increase of direct and indirect costs, but not with the intangible cost. Data from the multiple linear stepwise regression analysis indicated that the types of hospital and commercial medical insurance were significantly different in explaining the variation of the intangible cost. Conclusion Measures should be taken to reduce the intangible cost of hepatitis B-related diseases. The approach regarding the combination of open-ended questions with iterative bidding game should be recommended when carrying our further WTP studies of this kind.

Financial burden of hepatitis B-related diseases and factors influencing the costs in Shenzhen,China / 中华流行病学杂志

Objective To investigate the direct, indirect and intangible costs due to hepatitis B-related diseases and to explore main factors associated with the costs in Shenzhen. Methods Cluster sampling for cases collected consecutively during the study period was administrated. Subjects were selected fiom eligible hepatitis B-related patients. By pre-trained professional investigators,health economics-related information was collected, using a structured questionnaire. Hospitalization expenses were obtained through hospital records after the patients were discharged from hospital.Total economic burden of hepatitis B-related patients would involve direct, indirect and intangible costs. Direct costs were further divided into direct medical costs and direct nonmedical costs. Human Capital Approach was employed to measure the indirect costs both on patients and the caregivers in 1-year time span. Willing to pay method was used to estimate the intangible costs. Multiple linear stepwise regression models were conducted to determine the factors linked to the economic burden.Results On average, the total annual cost of per patient with hepatitis B-related diseases was 81 590.23 RMB Yuan. Among which, direct, indirect and intangible costs were 30 914.79 Yuan (account for 37.9% ), 15 258.01 Yuan (18.7% ), 35 417.43 Yuan (43.4%), respectively. The total annual costs per patient for hepatocellular carcinoma, severe hepatitis B, decompensated cirrhosis,compensated cirrhosis, chronic hepatitis B and acute hepatitis B were 194 858.40 Yuan, 144 549.20 Yuan, 120 333.60 Yuan, 79 528.81 Yuan, 66 282.46 Yuan and 39 286.81 Yuan, respectively. The ratio of direct to indirect costs based on the base-case estimation foot add to 2.0∶1, increased from hepato-eellular carcinoma (0.7∶1)to compensated cirrhosis (3.5∶ 1 ), followed by acute hepatitis B (3.3∶1 ), severe hepatitis B (2.8∶1 ), decompensate cirrhosis (2.3:1)and chronic hepatitis B(2.2∶1 ).Direct medical costs were more than direct nonmedical. Ratio between the sum total was 16∶1. The proportions of total annual cost per patient with hepatitis B-related diseases accounted for annual patient income were 285.3%, and 75.4% for annual household income. Furthermore, proportions of direct costs accounted for annual patient income and annual household income were 108.1% and 28.6%. The total annual indirect cost per person was 8123.38 Yuan for patients of all hepatitis B-related diseases, while 7134.63 Yuan for caregivers. Corresponding work-loss days were 55.74 days for patients and 19.83 days for caregivers. Based on multiple linear stepwise regression analysis, age of patients was a common influencing factor to all kinds of costs. Other factors were as follows:complicated with other diseases, antiviral medication, monthly household income and selfmedications. Conclusion The economic burden of hepatitis B-related diseases was substantial for patients and their families. All costs tended to increase with the severity of disease. The direct costs were larger than the indirect costs. And the direct medical costs were more than the direct ones.Indirect costs based on patients were larger than the ones of caregivers.

Epidemiological and molecular characterization of seasonal influenza A/H3N2 viruses circulating in Shenzhen, 2005 - 2007 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To determine the epidemiological characteristics of seasonal influenza in Shenzhen from 2005 to 2007 and the molecular variation of HA1 domain of influenza H3N2 viruses.</p><p><b>METHODS</b>The consultation rate for influenza-like illness (ILI) were calculated weekly for indicating the influenza activities (the Shenzhen Influenza Surveillance System mainly consisted of 16 institutions with 9 hospitals, 6 districts and one municipal centers of disease control and prevention). Pharyngeal swabs from the cases of ILI, which were collected during 2005 to 2007 from the city-wide and quality-controlled surveillance network, were used to propagate the viruses. The HA1 region of the influenza A/H3N2 viruses were detected by RT-PCR and sequenced subsequently. The analyses of pairwise amino acid variations, genetic clustering and phylogenetics was performed.</p><p><b>RESULTS</b>The activity levels of influenza showed certain changes during each year from 2005 to 2007, and there were summer peaks from May to July in 2006 and 2007. The positive rates of influenza virus were 4.78% (114/2385), 5.77% (212/3674) and 12.12% (343/2831) from 2005 to 2007 respectively. The weekly isolating rates changed accordingly with the trend of the percentages of ILI. The proportions of influenza H3N2 virus were 25.46% (28/114) and 2.83% (6/212) in 2005 and in 2006 respectively, but the proportion increased to 62.68% (215/343), which indicated that H3N2 virus became the predominant strain in 2007. Phylogenetic clustering analysis of influenza H3N2 virus revealed that there were 5 clades. The viruses which were isolated in 2005 contained in the clade I and II, the viruses in 2006 were comprised in clade III, and clade IV and V included the viruses isolated in 2007. Although the stem of cladogram developed with one accord of the time isolated viruses, the viruses which were similar to vaccine strains had circulated in Shenzhen before a given strain was determined as vaccine strain by WHO. It was also noticed that more amino acid changes at antigenic sites, especially at sites A and B in the H3N2 viruses, were found in 2007 than that in 2005 and in 2006. But the sequences at the receptor-binding sites and disulphide bond sites were conserved and no new circulating strain for genetic reassortment had been found in the period.</p><p><b>CONCLUSION</b>Shenzhen might be one of areas where the ongoing genetic drift of influenza H3N2 viruses appeared earlier in China. The changes of influenza H3N2 virus showed the active status in the population. The results suggested that monitoring seasonal influenza viruses by sequence analysis could provide important and timely information on the appearance of strains with epidemiologic significance.</p>

Analysis of pulsed-field gel electrophoresis molecular subtyping of Shigella strains in Shenzhen / 中华预防医学杂志

<p><b>OBJECTIVE</b>To analyze the genetic relations of Shigella isolated from Shenzhen in 2001-2006 and develop primary molecular subtyping surveillance network of Shigella.</p><p><b>METHODS</b>Chromosomal DNAs from 55 isolated in agarose were digested with the restriction enzyme Xba I, and then were analyzed by pulsed-field gel electrophoresis. Pulsed-field gel electrophoresis (PFGE) patterns were clustered using BioNumerics software.</p><p><b>RESULTS</b>All 41 distinctive PFGE patterns were identified among 55 strains. 32 strains belonged to one cluster. Differences were observed in other strains.</p><p><b>CONCLUSION</b>Both genetic-related clones and non-related clones of Shigella existed in Shenzhen. The development of PFGE molecular subtyping surveillance network would contribute to the active surveillance, outbreak investigation and source tracking for Shigellosis.</p>

Study on the molecular characteristic of natural infection of rodents with Hantaviruses in Shenzhen city / 中华预防医学杂志

<p><b>OBJECTIVE</b>In order to investigate Hantavirus (HV) infection of captured rodents and to understand the genotypes and the molecular characteristic of Hantaviruses in Shenzhen.</p><p><b>METHODS</b>The captured rodents were classified and the density of distribution was calculated. A total of 472 animals were captured, among which Rattus norvegicus was the dominant group. The total viral RNA was extracted from the lung tissues positive with HV antigens by immunofluorescent assay and gene sequence of M fragment was amplified with RT-nested-PCR by using the Hantavirus genotype specific primers. The amplified genes were then sequenced, and subjected to genotyping and homology analysis.</p><p><b>RESULTS</b>The results of genotype analysis showed that the Hantaviruses taken from twenty-one lung specimens in Rattus norvegicus in Shenzhen city belonged to the Hantavirus type II (SEOV). Results in homology analysis suggested that the homology among twenty-one samples should be rather high with 95.4% of nucleotide sequence identity and they belonged to the same subtype. Phylogenetic tree analysis showed that they were branched into at least six different lineages, and were highly homologized with SZ2083. We also found that these virus strains had not shown more highly homology of nucleotide sequence in nearest district, whereas revealed consistency in farther district.</p><p><b>CONCLUSION</b>The major hosts of Hantaviruses in Shenzhen city were Rattus norvegicus and the epidemic strains were genotyped as SEO-type. Nucleotide sequence and deduced amino acid sequence from different rodents were highly homologous, while nucleotide mutation had also been observed. Further studies are required to explore the possible viruses' sequence mutation.</p>

Laboratory diagnosis and molecular characterization analysis of the H5N1 influenza virus isolated from the first human case in Shenzhen, China / 病毒学报

The tracheal aspirates and serum samples of a suspected human case of high-pathogenic avian influenza (firstly found in Shenzhen, China) were collected and tested by a series of assays. The results showed that the RNA extracted from the tracheal aspirate specimens of the patient was confirmed positive for H5N1 avian influenza virus by Real-time PCR. The H5N1 avian influenza virus was isolated from patient's tracheal aspirates on MDCK cell and was named A/Guangdong/2/06(H5N1). The viral load of tracheal aspirates collected at different time points were detected by Real-time PCR. The virus microneutralization and the antigenic ratio of human H5N1 isolated were also assayed. It was found that when the virus load decreased gradually after the disease onset, the serum neutralizing antibody titer in the patient increased to 1 : 160 and subsequently decreased gradually. By molecular analysis, the eight gene segments of A/Guangdong/2/06 revealed to be similar to that of H5N1 avian influenza viruses isolated from south China in 2005-2006. However, there were obvious differences in the gene sequence of the detected H5N1 viral RNA as compared with that of the strains isolated from Vietnam, Thailand and Indonesia.

Study on molecular epidemiological characteristics of influenza H1N1 viruses circulating in Shenzhen,China from 2005 to 2007 / 中华流行病学杂志

Objective To study the genetic and epidemiological characteristics of HA1 of influenza H1N1 viruses circulating in Shenzhen from 2005 to 2007. Methods The HA1 region was analyzed by RT-PCR and subsequently sequenced to analyze the HA1 genetic evolution. Phylogenetic analysis was confirmed on the homology of nucleitide comparing with the reference viruses of vaccines recommended by WHO and representative virus confirmed by China CDC. Relationship between isolation rates and genetic evolutions was explored. Results The average isolation rate from 2005 to 2007 was 7.16%. Of the isolates, the proportions of influenza H1N1 viruses in 2005, 2006 and 2007 were 56.14%, 66.03%,3.61% ,respectively. Data from HA1 phylogenetic analysis showed that there were at least three clades circulated in Shenzhen. Different viruses isolated during January to April were clustered with A/New Caledonia/20/1999 viruses isolated in the latter months of 2005 clustered with A/Solomon Island/3/2006 and viruses from 2006 to 2007 were in the same clade with A/GDLH/219/2006. Results showed that most viruses had a deletion of lysine at position 130. Compared with A/New Caledonia/20/1999, the virus isolated after May of 2005 occurred T82K, Y94H, R146K, R209K, T267N amino acid substitution, while some virus isolated after May 2006 took place the amino acid substitutions of A190T, H193Y,E195D (located at antigenic site B) and R146K(antigenic site A). The sequences at the receptor-binding sites and glycosylation sites were conserved. Compared with referring viruses, A/SZ/68/2007 had 50 amino acid substitutions in the HA1 region.Of these,eleven and six were located at antigenic sites and receptor-binding sites,respectively.Four amino acid substitution resulted in the deletion of glycosylation site.Conclusion Three different genetic lineages of influenza H1N1 virus were circulated in the population in Shenzhen during 2005-2007.The special virus named A/SZ/68/2007 should be paid further attention on its antigenic and epidemiological characteristics.

A case of human highly pathogenic avian influenza in Shenzhen, China: application of field epidemiological study / 中华流行病学杂志

<p><b>OBJECTIVE</b>Based on analyzing the characteristics of a case with human avian influenza and the effects of field epidemiological study.</p><p><b>METHODS</b>An emergency-response-system was started up to follow the probable human Highly Pathogenic Avian Influenza case initially detected by the "Undefined Pneumonia Surveillance System of Shenzhen". Public health professionals administered several epidemiologic investigations and giving all the contacts of the patient with a 7-day-long medical observation for temporally related influenza-like illness. Reverse transcriptase-polymerase chain reaction (RT-PCR) with primers for H5 and N1 was applied to test respiratory tract samples and/or throat swabs of the patient and all his contacts specific for the hemagglutinin gene of influenza A H5N1. Activities and strategies such as media response,notification in the public, communications with multiple related sectors, social participation and information exchange with Hong Kong were involved in field control and management.</p><p><b>RESULTS</b>The patient was a male, 31 years old,with an occupation as a truck driver in a factory,and had been residing in Shenzhen for 7 years. Started with an influenza-like syndrome, the patient received treatment on the 4th day of the onset, from a clinic and on the 6th day from a regular hospital. On the 8th day of the disease course, he was confirmed by Shenzhen Center for Disease Control and Prevention as human avian flu case and was then transferred to Intensive Care Unit (ICU). On the 83rd day of commence, the patients was healed and released from the hospital. The patient had no significant exposure to sick poultry or poultry that died from the illness before the onset of the disease. The patient and five family members lived together, but no family member was affected and no contact showed positive results for H5N1. A small food market with live poultry, which was under formal supervision and before illness the patient once visited, located near his apartment. Totally, 35 swabs from live birds and bird's coops in the market for H5 nucleic acid were tested and all were negative. The influenza H5N1 virus isolated for the case was named as A/Guangdong/02/2006 (H5N1) or GD/2/06. Phylogenetic relationships and molecular characterization analysis revealed that all the segments of the H5N1 virus named GD/2/06 still belonged to avian segments. Investigation process and control measures were released to the general public through the media. Soon after the laboratory confirmation, information was released to the society, as well as Hong Kong Center for Health Protection. Local Departments of Agriculture, Industries & Business, and Entry-Exit Inspection & Quarantine Bureau together with the Public Health Department put up combined actions. A computer-based telephone survey was initiated to investigate attitudes and knowledge of residents in town, revealing that positive atmosphere dominated and no panic existed.</p><p><b>CONCLUSION</b>Rapid laboratory diagnosis of the virus was the key for successful treatment and survival result of the case. Still, the pathogen was from birds resources. No human-to-human transmission was observed, however, source of infection was unclear. Field epidemiological study could offer special methods for the responses of emergency public health problems.</p>

Analysis on economic efficacy regarding previous strategies and current recommendations for vaccination against hepatitis B virus in China / 中华流行病学杂志

Objective To evaluate the outcome of hepatitis B vaccination strategies performed over the past 14 years and different alternatives recommended for future immunization programs from the point of view of economic efficacy.Methods Methods used would include:process of decision analysis including building the tree:populating the model with parameters;estimating expected cost benefit and effectiveness and deterministic and probabilistic sensitivity and threshold analysis.Results In China，over the past 14 vears from 1992 to 2005.around 5.348 billion Chinese Yuan were provided for hepatitis B vaccination but the total benefits were 272.825 billion Yuan,with net benefits as 267.477 billion Yuan.The cost for each infection averted was 81.99 Yuan while the benefit of one Yuan being invested had 51.01 Ynan in return.For the future recommendations,data from the study revealed that the priority of hepatitis B vaccination for new borns and vaccinations plus passive immunization of newborns of HBsAg positive mothers were most effective approaches.If the other population as adolescents was included into the vaccination program,then screening for hepatitis B virus markers before accepting the vaccination appeared to be one of the most cost-saving strategies.Sensitivity and threshold analyses showed that hepatitis B virus marker Was the most important factor,followed by the cost of vaccine,vaccination coverage and vaccine efficacy,in order.Conclusion Routine vaccination of infants in successive birth cohorts to prevent HBV transmission was a cost-effective strategy administrated over the past 14 years in China.In the following years,the immunization of newborns was still the preferential strategy from a societal perspective.However,vaccination provided to other population including adolescents seemed economically less attractive.

Molecular subtyping of Vibrio cholerae isolates by pulsed-field gel electrophoresis in Shenzhen from 1993 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To determine the genetic relationships between different Vibrio cholerae isolates in Shenzhen from 1993 to 2002.</p><p><b>METHODS</b>Chromosomal DNA from 60 isolates was digested in seakem gold agrose with restriction enzyme Not I and plugs were then analyzed by pulsed-field gel electrophoresis. Pulsed-field gel electrophoresis (PFGE) patterns of V. cholerae isolates were clustered using BioNumerics software.</p><p><b>RESULTS</b>39 distinctive PFGE patterns were identified with each pattern having 20 to 30 bands. Most PFGE patterns were divided into cluster A or cluster B.</p><p><b>CONCLUSION</b>The closely related pandemic clone clusters of V. cholerae strains did exist in Shenzhen. PFGE of V. cholerae could be used for active surveillance and tracking for cholerae.</p>

Surveillance on natural infection of rodents with hantavirus in Shenzhen city and identification of a hantavirus strain SZ2083 / 中华流行病学杂志

<p><b>OBJECTIVE</b>For clarifying the situation of the natural infection of rodents having hemorrhagic fever with renal syndrome (HFRS) virus and to type Hantavirus (HV) using molecular technique in Shenzhen city in 2005, and offering guidance for prevention and control of HFRS.</p><p><b>METHODS</b>Data on the host animals was collected from the city of Shenzhen. ELISA and indirect immunofluorscent antibody(IFA) test were applied to the specific antibodies against HV in the sera of captured rats. Direct immunofluorscece assay was adopted to determine HFRS antigens and the lung tissues of the HV infected rats were inoculated into Meriones unguiculata to isolate HV. The whole viral RNA was extracted from the lung tissues of the HV infected rats and amplified the partial M fragments with RT-nested-PCR, using the HV genotype specific primers. The amplified genes were then sequenced, and subjected to genotyping and homology analysis.</p><p><b>RESULTS</b>472 rodents were captured from Shenzhen in 2005. Surveillance on rats demonstrated 9.96% rats carrying HV (with a density of 8.25%) and the main host was Rattus norvegicus. In the blood samples of rats, anti-HV IgG antibodies were detectable in 56 cases by IFA, and proved to be positive in 76 cases by ELISA. We successfully isolated a HV strain designated as SZ2083 from Rattus norvegicus for the first time in Shenzhen and was identified to SEO type by RT-nested-PCR. Compared with the coding region of the M gene of HV L99 virus strain, the homologies of nucleotide among them were 97%, but the homology was 76% of the SZ2083 with HTN 76-118 virus strain.</p><p><b>CONCLUSION</b>Results showed the existence of natural epidemic areas of HFRS in Shenzhen city. Based on the results of sequencing, it is possible that the Seoul strain of HV might be the predominant serotype of virus harbored.</p>

Rapid simultaneous detection of Salmonella and Shigella using modified molecular beacons and real-time PCR / 中华流行病学杂志

<p><b>OBJECTIVE</b>Dual detection of Salmonella and Shigella using modified molecular beacons and real-time PCR was developed. The established method was applied to rapid diagnosis of Salmonella and Shigella' food poisoning, and for routine monitoring programs.</p><p><b>METHODS</b>Two sets of primers were designed based on the core sequence of invA gene and ssaR gene published on GenBank to detect Salmonella, and ipaH gene were selected to detect Shigella. Three corresponding modified molecular beacons labeled with different fluorophors were designed. The molecular beacons and primer sets were tested against numerous strains from 55 different bacterial species. Then the two assays were combined to establish the dual real-time PCR assay, and were applied to the food poisoning diagnosis and surveillance.</p><p><b>RESULTS</b>For the modified molecular beacons-based dual real-time PCR assay, the sensitivity achieved was 69-93 fg/microl, 32-64 CFU/ml or 1-2 CFU/PCR reaction. There was no cross-reaction with other bacteria served as control. The dual real-time PCR assay was used to detect 134 Salmonella strains and 67 Shigella strains but no false signals were observed. 1100 food poisoning samples were tested with 569 Salmonella and 42 were Shigella identified by real time PCR. Among the positive samples, 551 were detected Salmonella and 41 were Shigella by traditional culture method. The overall test could be finished within 2 hours to one day starting from sample preparation.</p><p><b>CONCLUSION</b>The modified molecular beacons-based dual real-time PCR assay was rapid, sensitive, and specific. It could be applied to the rapid diagnosis of Salmonella and Shigella' food poisoning.</p>

Role of mass media during the severe acute respiratory syndrome epidemic / 中华流行病学杂志

<p><b>OBJECTIVE</b>To understand the impact of effective interaction between public and media on the prevention and control of severe acute respiratory syndrome (SARS).</p><p><b>METHODS</b>Based on the theory of field epidemiology, the traditional and modern technologies were brought forward. In the late period of SARS epidemic, investigation on knowledge, attitude and practice on SARS prevention and control among general population was conducted.</p><p><b>RESULTS</b>During the 3 month period of SARS epidemic in Shenzhen, techniques of the "E-health and public health informatics" as an emerging fields were used to focus on population to eventually improve the health of entire population. Methods as television, radio, newspapers, magazines, printing and distribution of specific materials on SARS were included, and hotlines of telephone and mobile phone, web-based sites, electronic screening advertisements, and consultation or forum for the public etc. were used. Among 3405 subjects interviewed, more than 95% gave right answers on the SARS related questions. Most of them held the optimistic and scientific attitude. 80% of the population had taken the measures as recommended. 82.4% of the citizens were happy about the local government's action and 93.8% thought hospitals and healthcare workers should be respected and honored.</p><p><b>CONCLUSION</b>Dealing with the urgent public health problems and emerging infectious diseases outbreak, epidemiologists need to keep good relations with media, and making use of modern electronic technologies to communicate with the public.</p>