催化模型在弓形体感染流行病学调查中的应用

本文应用简单催化模型对广西等地弓形体感染率进行了流行病学分析,发现弓形体的易感人群达85~95%,传播速度为0.0521~0.1286。说明每1000人中每年将约有50~130人接触而感染弓形体。与国外一些地区相比具有易感人群多、传播速度快的特点。弓形体感染应引起重视。     

应用两级催化模型对自然人群乙肝表面抗原携带率年龄分布的分析

1959年Muench,H介绍了流行病学催化模型的简单、可逆、两级三个基本型的原理、方法和应用,之后,国内外一些学者,在疾病防治实践中,越来越多地应用该模型阐明某些疾病的流行特征、人群感染和免疫的规律,评价防治效果,定量地测量传染病在人群中的传播速度等,收到了满意的效果.本文试用两级催化模型,对泰安市自然人群乙型肝炎病毒表面抗原(HBsAg)年龄别阳性资料进行拟合,以分析人群年龄分布特征、流行程度及感染力等.1 模型与材料1.2 模型 设某易感人群暴露于一恒定的感染力中,人群易感者以a频率转变为感染者x,又以b频率     

大学生人群乙肝疫苗免疫前后配对追踪观察HBV感染率和新感染率比较研究

１９８６年９月对大学生某人群进行ＨＢＣ感染状态调查，并于当年１２月对多数易感者接种乙肝疫苗。１９８９年６月对该人群４９２名大学生进行免疫前后配对观察比较其ＨＢＣ感染率和新感染率。用固相放射免疫法进行ＨＢＶ感染指标的检测。结果表明免疫前后感染率分别为６９．９％和５７．１％，后者明显下降。在免疫前ＨＢｓＡｇ、抗－ＨＢｓ和抗ＨＢｃ３指标全阴性者１４８名中，接种疫苗１２１人和未接种者２７人的新感染率分别为４．１％和１８．５％。其ＨＢｓＡｇ阳性率各为４．１％和２５．９％，抗－ＨＢｃ阳性率各有３．３％和２２．２％前者均明显低于后者。表明乙肝疫苗预防措施有效地保护了易感人群，降低了该人群的感染率和新感染率，从而产生了人群整体预防效果。     

应用催化模型拟合钩虫感染年龄结果分析

目的 为了解催化模型是否能够应用于寄生虫病感染。方法 试用人群钩虫感染率分别拟合简单催化模型、可逆催化模型、两级催化模型。用χ^2和R^2进行拟合度的比较。结果 拟合可逆催化模型效果满意。结论 从模型拟合结果可以看出，粪检两次比粪检一次更加满意。证实在一个月内粪检两次可提高检出率，更接近人群实际感染状况。     

部队人群中甲、乙型肝炎感染率的催化模型分析

应用催化模型拟合部队人群中甲、乙型肝炎感染率的横断面调查资料,并用随后一年半时间的随访结果加以验证,结果尚称满意。所计算的人群平均感染力(r值)可以基本反映相对固定人群中甲、乙型肝炎的感染动态,可以用于甲、乙型肝炎感染在人群中动态的预测。本文通过对某航校2053人1983年12月普查结果进行分析,用简单催化模型拟合HAV感染率,计算结果:ŷ=0.9849(1-e^-0.1117t),r (感染力)=0.1117,与横断面调查结果符合良好,R²=0.9758;与随访一年半HAV新感染密度111.8/1000人年十分相近。用可逆催化模型拟合HBV感染率,计算结果为:ŷ=0.6736(1-e^-0.06t),r (感染力)=(a+b)=0.06,其中a (阳转率)=0.041,b (阴转率)=0.019,拟合结果与实际调查结果十分相近,R²=0.9487。经过一年半随访,看到HBV感染标记在相对固定人群中确呈双向改变,其阳转率大于阴转率(77.08/1000人年对10.11/1000人年),与计算的a>b总趋势相符。人群HBV感染是受多因素影响的复杂过程,所用于拟合的公式需进一步改进。     

复合催化模型在结核免疫力监测研究中的应用

自50年代对人群实施卡介苗免疫以来,结核病发病率已降到45/10万,为进一步探讨人群结核免疫力的变化规律及其影响因素,评价防制措施效果、提供防制措施依据,本文试用了简单与可逆复合催化模型对不同人群结核菌素试验(结素试验)阳性率监测资料进行了分析,报告如下。1原理与方法1.1原理假设人出生后对结核易感概率为A,即结素试验阴性,在任何时间t,由于接种卡介苗和自然感染(显性或隐性感     

应用复合型催化模型评价卡介苗生物效应的探讨

本文试用简单与可逆复合型催化模型对本县结核病定点监测资料进行拟合,获得较满意的结果,报告如下。模型一、复合型催化模型的基本设想假设易感者总量T为1,经过t时间,在自     

部队乙型肝炎疫苗预防接种的成本效果分析

目的：应用成本－效果分析对部队不同乙型肝炎（乙肝）疫苗接种方案进行比较,为制定经济有效的全军乙肝疫苗预防接种策略提供依据。方法：建立决策树和乙肝转归树,采用催化模型推算不同接种方案下易感人群年新感染率,用失能调整生命年（disability-affectiveness ratio,CER)分别为392.70和251.90。用部队干部实际年龄构成进行加权,得到筛检再接种方案和直接接种方案的CER分别为251.9和392.7,即每获得一个健康生命年所需成本前者少于后者。结论：筛检再接种方案优于直接接种方案;年龄越小接种的效果越好。     

应用仿真模型模拟甲型H1N1流感的街道社区传播

采用可视化仿真模型对甲型H1N1流感在不同人口密度街道、社区的传播进行模拟仿真,探寻传播规律和特点,为采取合理防控措施提供科学依据.将全部人群按易感-感染-移出(SIR)模型划分为易感人群、感染人群和免疫人群,人群的年龄构成根据第五次人口普查基本情况设置,个体依据网络随机接触模型进行接触与运动,致死率与感染方式按照甲型H1N1流感医学描述进行设定.实例分析结果表明,感染率与社区街道人口密度有密切关系,疫情前期人口感染率增长速度较快,人口密度在50人/hm2以上的社区持续传播甲型H1N1流感的概率较大;对照组试验表明,在社区内接种疫苗可以有效地抑制甲型H1N1流感的传播.结论 :人口密度、是否接种疫苗是甲型H1N1流感流行的危险因素.     

医院住院易感人群呼吸道感染病原及耐药分析

随着激素、免疫抑制剂、广谱抗生素的广泛使用，医院内感染率逐年上升，已成为当今世界的棘手难题，其中重症监护病房（ICU）患、气管插管患、老年患及免疫功能低下患均属于医院感染的易感人群。为掌握细菌感染的种类与耐药性，及时诊断和治疗，本收集易感人群送检标本，培养分离病原菌，进行培养鉴定和耐药性分析。结果报告如下。     

Epidemiologic programs for computers and calculators. Simple algorithms for the representation of deterministic and stochastic versions of the Reed-Frost epidemic model using a programmable calculator

Two programs are described for the emulation of the dynamics of Reed-Frost progressive epidemics in a handheld programmable calculator (HP-41C series). The programs provide a complete record of cases, susceptibles, and immunes at each epidemic period using either the deterministic formulation or the trough analogue of the mechanical model for the stochastic version. Both programs can compute epidemics that include a constant rate of influx or outflux of susceptibles and single or double infectivity time periods.     

上海甲型肝炎流行因素分析

1988年,上海市区甲型肝炎流行。流行期间随机抽取1830份居民血清,用Abbott酶标试剂检测抗-HAV与抗-HAV IgM,并询问食毛蚶、发病情况。易感人群食毛蚶率达41.46％,食毛蚶者罹患率为32.35％,隐性感染率为5.51％。未食毛蚶人群依次为1.82％、3.13％。显性感染与隐性感染相对危险度分别为17.75和1.76。87.43％的病例与食蚶有关。食蚶量越大,发病率越高,呈剂量效应关系,20～49岁年龄组,食蚶率最高(46％～58％),罹患率亦最高(21％～29％),流行前、后人群易感率分别为35.85％和29.18％,1988年1～2月份出现的3次发病高峰,同3次毛蚶大量供应的日期分别相距30天左右。相当于一个平均潜伏期。1月4日禁止毛蚶出售,40天后发病高峰下降。本次血清流行病学研究表明,该次流行由生食毛蚶所致。     

On the measurement of susceptibility in epidemiologic studies

Although relative effects of risk factors (relative risks) are commonly used in epidemiologic studies of disease, these measures do not provide estimates of the proportion of persons who are "susceptible" to the risk factor. Susceptibility may be defined under a simple sufficient cause model as the underlying factor (or set of factors) sufficient to make a person contract a disease following exposure. The authors derive simple estimates of the proportion of susceptibles in a population based on relative risk, and disease and exposure frequencies. The proportion of susceptibles increases with increasing disease frequency and relative risk but declines at high exposure frequency. For many chronic diseases with a lifetime risk in the range of 1-10 per cent, rare exposures suggest the presence of a large proportion of susceptibles, whereas common exposures suggest fewer susceptibles in the population. The estimation of the proportion of susceptibles is important in the search for genetic and environmental factors that interact with measured risk factors in etiologic studies of disease.     

灰色模型在血吸虫病感染率预测中的应用

[目的]探讨灰色GM(1,1)模型在血吸虫病人群感染率预测中的应用。[方法]资料来自于四川省西昌市川兴监测点2000～2005年连续6年血吸虫病监测数据,采用灰色GM(1,1)模型对该资料进行拟合,确定GM(1,1)预测模型,并对今后3年血吸虫病感染率进行预测。[结果]人群感染率预测模型为X(1)(i 1)=-54.4781e-0.37524i 84.4281,连续3年预测值分别为2.61%,1.79%和1.23%。[结论]GM(1,1)模型可以用于血吸虫病感染率的预测,为合理分配卫生资源提供决策依据。     

The future of measles in highly immunized populations. A modeling approach

Little is known about how an intensive measles elimination program changes the overall immune status of the population. A computer model was created to study the effect of the measles elimination program in the United States on the number of susceptibles in the population. The simulation reveals that in the prevaccine era, approximately 10.6% of the population was susceptible to measles, most of whom were children less than 10 years of age. With the institution of the measles immunization program, the proportion of susceptibles in the population fell to 3.1% from 1978 through 1981, but then began to rise by approximately 0.1% per year to reach about 10.9% in the year 2050. The susceptibles at this time were distributed evenly throughout all age groups. The model did not consider the potential effect of waning immunity. The results of this study suggest that measles elimination in the United States has been achieved by an effective immunization program aimed at young susceptibles combined with a highly, naturally immunized adult population. However, despite short-term success in eliminating the disease, long-range projections demonstrate that the proportion of susceptibles in the year 2050 may be greater than in the prevaccine era. Present vaccine technology and public health policy must be altered to deal with this eventuality.     

The use of mathematical models in the epidemiological study of infectious diseases and in the design of mass immunization programmes

The relationship between the number of people vaccinated for an infectious disease and the resulting decrease in incidence of the disease is not straightforward and linear because many independent variables determine the course of infection. However, these variables are quantifiable and can therefore by used to model the course of an infectious disease and impact of mass vaccination. Before one can construct a model, one must know for any specific infectious disease the number of individuals in the community protected by maternally derived antibodies, the number susceptible to infectious the number infected but not yet infectious (i.e., with latent infection), the number of infectious individuals, and the number of recovered (i.e., immune) individuals. Compartmental models are sets of differential equations which describe the rates of flow of individuals between these categories. Several major epidemiologic concepts comprise the ingredients of the model: the net rate of infection (i.e., incidence), the per capita rate of infection, the Force of Infection, and the basic reproductive rate of infection. When a community attains a high level of vaccination coverage, it is no longer necessary to vaccinate everyone because the herd immunity of the population protects the unvaccinated because it lowers the likelihood of their coming into contact with an infectious individual. Many infections that confer lasting immunity tend to have interepidemic periods when the number of susceptibles is too low to sustain an epidemic. Mass vacination programs reduce the net rate of transmission of the infective organism; they also increase the length of the interepidemic period. Many diseases primawrily associated with children have much more serious consequences in older people and the question arises as to at what point childhood immunization will successfully prevent the more dangerous incidence of the disease in older cohorts. Mathematical models of disease transmission enable one to predict the course of epidemics, design mass vaccination programs, and be guided as to what are the relevant data that should be collected.     

Analysis of the incubation period for measles in the epidemic in Greenland in 1951 using a variance components model.

This paper presents a model for analysing the incubation period of highly infectious diseases in populations where almost all susceptibles become infected during an epidemic. The model leads to a simple method for estimating the variance of the duration of the incubation period without any distributional assumptions. Further, the influence of covariates on the duration of the incubation period can be analysed. Data from the epidemic of measles in Greenland in 1951 are analysed and it is found that intersymptom times are correlated within households, suggesting that secondary cases are infected almost simultaneously. This result is inconsistent with a variation in the times of infection of secondary cases within a household which is often assumed when analysing data on measles. Prophylactic treatment did not prevent infection in the epidemic in Greenland, but it is found that the incubation period tended to be shorter for persons not receiving prophylactic treatment.     

应用灰色预测模型GM(1,1)对四川省血吸虫病人群感染率进行分析及预测

目的分析四川省2003-2010年血吸虫病人群感染率变化趋势,应用GM(1,1)模型对今后3年人群感染率进行预测,为下一步制定全省血吸虫病防控措施提供参考。方法收集四川省2003-2010年血吸虫病人群感染率资料,应用GM(1,1)模型进行拟合,建立预测模型。结果四川省血吸虫病人群感染率呈逐年下降趋势;人群感染率预测模型为(1)(t+1)=-103.1157e-0.4950t+132.6545,模型拟合精度高(后验差比值C=0.1672,小误差概率P=1),2003-2010年感染率GM(1,1)模型预测值与实际值吻合程度较好,预测2011-2013年感染率分别为1.2590/万、0.7675/万和0.4678/万。结论该模型的拟合效果较好,预测结果显示今后3年内全省血吸虫病人群感染率将呈下降趋势;在血吸虫病低感染率和低感染度地区建立该模型进行疫情预测对制定防控策略具有重要参考价值。     

女性泌尿生殖道炎症患者支原体感染现状及其对抗生素的敏感性研究

目的了解女性泌尿生殖道炎症患者支原体的感染现状及其对抗生素的敏感性。方法回顾性分析清苑县妇幼保健院2010年1月-2011年8月收治的女性泌尿生殖道炎症患者560例的临床资料,支原体感染254例,对该254例泌尿生殖道炎症患者做体外支原体培养鉴定及药物敏感试验。结果支原体感染阳性率为45.4%。单纯解脲脲原体(Uu)感染率为63.8%(162/254),明显高于单纯人型支原体(Mh)及Uu+Mh混合感染率9.5%(24/254)、26.8%(68/254),组间差异有统计学意义(P<0.05)。单纯Uu感染对克拉霉素、交沙霉素敏感,Uu与Mh混合感染者对强力霉素敏感,单纯Mh感染对强力霉素敏感。结论本院女性泌尿生殖道炎症患者支原体的感染以单纯Uu感染为主,不同生物型支原体感染对抗生素敏感率不同,临床医师应根据支原体的感染现状及其对抗生素的敏感性选用合适的抗生素。     

Viral hepatitis: enzyme assays and serologic procedures in the study of an epidemic.

An epidemic of viral hepatitis beginning in late 1975 in a residence for multiply handicapped children, recognized very early in its course, was investigated prospectively to permit comparison of enzymatic and serologic tests. Thirty-three residents of the institution and 46 full- and part-time employees were studied by the immune adherence hemagglutination procedure for antibody (anti-HAV) to hepatitis A virus (HAV). Of these, 31 residents and 37 staff members were susceptible at the beginning of the epidemic. Nineteen and six, respectively, had anti-HAV seroconversion indicating HAV infection. Thus, 12 children (39%) and 31 staff members (81%) of presumed susceptibles did not have serologic evidence of infection. The subclinical/clinical ratio for the children was 1.1:1; for personnel, it was 1:1. Serum alanine aminotransferase (ALT) levels compatible with viral hepatitis occurred in 21 persons (84%) who had anti-HAV seroconversion; conversely, there were 10 persons who had ALT abnormality without detectable anti-HAV in late specimens among the total of 68 susceptibles. There was no evidence the latter could be attributed to hepatitis B virus infection; therefore, they may represent the endemic occurrence of non-A, non-B agent(s).