OBJECTIVETo identify the epidemical characteristics of suicidal tendency among middle-school students in cities of China and to explore the main factors leading to suicidal tendency in adolescents.

METHODSMulti-stage cluster sampling method was used to select 9015 students in grades 1, 2, 3 and 4 respectively from 25 general middle schools in Beijing, Hangzhou, Wuhan and Urumqi of China in June 2006 and field investigation was carried out through "China Global School-based Student Health Survey (GSHS) Questionnaire".

RESULTSAmong the students in the four cities, the incidence rates of suicidal ideation were from 14.4% to 20.8% with an average of 17.4%. The incidence rates of suicidal plan were from 6.8% to 9.7% with an average of 8.2% and were different among cities. 15.0% of the boys had suicidal ideation and 6.7% of them made a suicidal plan comparing to 19.7% of girls having had suicidal ideation and 9.5% of them made a suicidal plan. The two kinds of suicidal tendency in girls were all higher than those in boys. City, age, gender, grade, days and type of being bullied, depression, close friends and having received health education on coping with stresses were factors influencing suicidal tendency of students. Days of being bullied and suicidal tendency showed a dose-response relation.

CONCLUSIONSuicidal tendency seemed common in middle-school students. Training on 'coping the issue' should be strengthened and harmonious environment should be improved in middle-schools.

Adolescent ; China ; epidemiology ; Data Collection ; Female ; Humans ; Incidence ; Male ; Students ; psychology ; Suicide ; psychology ; statistics & numerical data ; Urban Population

Objective To develop an emergency clinical laboratory system for civilian and military uses to enhance medical support of filed medical unit for mass casualties.Methods The missions of field medical unit were analyzed in the actual confrontation,and an emergency clinical laboratory system for civilian and military uses was built to fulfill clinical laboratory support.The factors were explored for clinical laboratory examination,and some measures were taken accordingly.Results The requirements of field medical unit were met by the developed system.Conclusion The system can be applied in largescale military exercises to enhance clinical laboratory support ability of field medical unit.

OBJECTIVETo study the epidemic pattern and trend of HBV infection in the area where the people had been immunized by HBV vaccine for 20 years.

METHODSThe whole sampling method was applied in combination with cross-sectional investigation. Blood samples were taken from every member of families. Markers of HBV infection were determined by using solid-phase radioimmunoassay (SPRIA).

RESULTS(1) The average HBsAg positive rate was 7.5%. The positive rate of markers for HBV infection of 0-19 years old subjects were lower than those of > or = 20 years old subjects. (2) The positive rate of HBsAg of 0-19 years old subjects in 1985 was higher than that in 2005. The anti-HBs positive rate in 1985 stemmed to be higher with age. It was 12.4% in 1- age group to 53.8% in >60 years age group. While the result of 2005 showed that the anti-HBs positive rate of 0-19 years old subjects dropped with age. The anti-HBc positive rate in 1985 also tended to be higher with age. But the result of 2005 showed that the rate of 0-19 years old subjects was just 1.4% to 16.8%.

CONCLUSIONThe epidemic patterns of HBV infection have had significant variations in the target population. HBV vaccine immunization has obtained excellent efficacy.

Adolescent ; Adult ; Aged ; Child ; Child, Preschool ; China ; epidemiology ; Cross-Sectional Studies ; Female ; Hepatitis B ; blood ; epidemiology ; prevention & control ; Hepatitis B Vaccines ; administration & dosage ; therapeutic use ; Humans ; Immunization ; Infant ; Infant, Newborn ; Male ; Middle Aged ; Seroepidemiologic Studies ; Time Factors ; Treatment Outcome ; Young Adult

OBJECTIVETo study the epidemiological pattern and trends of hepatitis B virus (HBV) in the area where people had been immunized by HBV vaccine for long time.

METHODSThrough cluster sampling and cross-sectional study, relative information and blood samples from people in Long-an county by families were collected. Signals of HBV infection were tested by solid-phase reverse immunosorbent test.

RESULTS(1) The average HBsAg positive rate was 7.5% with anti-HBs as 44.5 %, and anti-HBc as 47.8%. The positive rates of HBsAg and anti-HBc among 0-19 year-olds were lower than those of > or = 20 year-olds. (2) The positive rates of HBsAg, anti-HBc and HBV infection among HBV vaccine immunized group were 2.8%, 12.0% and 12.5% respectively, comparing with which among the un-immunized group as 10.2%, 69.8% and 71.2% respectively. (3) The HBsAg positive rate of male was higher than the female's but with no significant difference of anti-HBs and anti-HBc between different sexes. (4) The average HBsAg positive rate of 0-19 years old group was only 2.4%, while that of 20-30 years old group was 13.6%-17.7% and dropped from 60 years old group and on. The anti-HBs positive rate of 0-19 years old people started to drop significantly by age. The anti-HBs and anti-HBc positive rates of > or = 20 years people were showing a rising trend by ages.

CONCLUSIONIt seemed obviously that the HBV epidemiological patterns had changed after HBV vaccine had been universally used for long time in newborns. The age peak of infection had been pushed backward for nearly 20 years. It had been proved that the HBV vaccine immunization program had obtained excellent efficacy.

Adolescent ; Adult ; Age Distribution ; Aged ; Aged, 80 and over ; Child ; Child, Preschool ; Female ; Hepatitis B ; epidemiology ; immunology ; prevention & control ; Hepatitis B Antibodies ; immunology ; Hepatitis B Surface Antigens ; immunology ; Hepatitis B Vaccines ; therapeutic use ; Humans ; Infant ; Infant, Newborn ; Male ; Middle Aged ; Young Adult

Objective: To analyze the course of disease and epidemiological parameters of COVID-19 and provide evidence for making prevention and control strategies. Methods: To display the distribution of course of disease of the infectors who had close contacts with COVID-19 cases from January 1 to March 15, 2020 in Guangdong Provincial, the models of Lognormal, Weibull and gamma distribution were applied. A descriptive analysis was conducted on the basic characteristics and epidemiological parameters of course of disease. Results: In total, 515 of 11 580 close contacts were infected, with an attack rate about 4.4%, including 449 confirmed cases and 66 asymptomatic cases. Lognormal distribution was fitting best for latent period, incubation period, pre-symptomatic infection period of confirmed cases and infection period of asymptomatic cases; Gamma distribution was fitting best for infectious period and clinical symptom period of confirmed cases; Weibull distribution was fitting best for latent period of asymptomatic cases. The latent period, incubation period, pre-symptomatic infection period, infectious period and clinical symptoms period of confirmed cases were 4.50 (95%CI:3.86-5.13) days, 5.12 (95%CI:4.63-5.62) days, 0.87 (95%CI:0.67-1.07) days, 11.89 (95%CI:9.81-13.98) days and 22.00 (95%CI:21.24-22.77) days, respectively. The latent period and infectious period of asymptomatic cases were 8.88 (95%CI:6.89-10.86) days and 6.18 (95%CI:1.89-10.47) days, respectively. Conclusion: The estimated course of COVID-19 and related epidemiological parameters are similar to the existing data.
COVID-19 ; Cohort Studies ; Contact Tracing ; Humans ; Incidence ; Prospective Studies

Objective To analyze the genetic subtypes of human immunodeficiency virus (HIV) and the prevalence of pretreatment drug resistance in the newly reported HIV-infected men in Guangxi. Methods The stratified random sampling method was employed to select the newly reported HIV-infected men aged≥50 years old in 14 cities of Guangxi from January to June in 2020.The pol gene of HIV-1 was amplified by nested reverse transcription polymerase chain reaction and then sequenced.The mutation sites associated with drug resistance and the degree of drug resistance were then analyzed. Results A total of 615 HIV-infected men were included in the study.The genetic subtypes of CRF01_AE,CRF07_BC,and CRF08_BC accounted for 57.4% (353/615),17.1% (105/615),and 22.4% (138/615),respectively.The mutations associated with the resistance to nucleoside reverse transcriptase inhibitors (NRTI),non-nucleoside reverse transcriptase inhibitors (NNRTI),and protease inhibitors occurred in 8 (1.3%),18 (2.9%),and 0 patients,respectively.M184V (0.7%) and K103N (1.8%) were the mutations with the highest occurrence rates for the resistance to NRTIs and NNRTIs,respectively.Twenty-two (3.6%) patients were resistant to at least one type of inhibitors.Specifically,4 (0.7%),14 (2.3%),4 (0.7%),and 0 patients were resistant to NRTIs,NNRTIs,both NRTIs and NNRTIs,and protease inhibitors,respectively.The pretreatment resistance to NNRTIs had much higher frequency than that to NRTIs (2.9% vs.1.3%;χ²=3.929,P=0.047).The prevalence of pretreatment resistance to lamivudine,zidovudine,tenofovir,abacavir,rilpivirine,efavirenz,nevirapine,and lopinavir/ritonavir was 0.8%, 0.3%, 0.7%, 1.0%, 1.3%, 2.8%, 2.9%, and 0, respectively. Conclusions CRF01_AE,CRF07_BC,and CRF08_BC are the three major strains of HIV-infected men≥50 years old newly reported in Guangxi,2020,and the pretreatment drug resistance demonstrates low prevalence.
Male ; Humans ; Middle Aged ; Reverse Transcriptase Inhibitors/therapeutic use* ; HIV Infections/drug therapy* ; Drug Resistance, Viral/genetics* ; China/epidemiology* ; Mutation ; HIV-1/genetics* ; Protease Inhibitors/therapeutic use* ; Genotype