Department of Epidemiology

Public Health College of Harbin Medical University

1

传染病流行病学

Infectious Disease Epidemiology

哈尔滨医科大学流行病学教研室

Department of epidemiology ， Harbin Medical University

讲 授 内 容 Teaching Content

研究传染病的意义 传染病流行趋势 传染病流行病学基本原理 和方法 疫源地 传染病的预防和控制

study importance

epidemic trends

basic principles and

methods

infectious focus

prevention & control

研究传染病的意义Study Importance

危害严重

重治轻防，后果惨重

死灰复燃

新发传染病不断出现

生物恐怖威胁存在

Seriously burden of

diseases

Neglect of prevention ,the

consequences of heavy

The resurgence of relapse

The new emerging

infectious

diseases

Threat of bioterrorism

19981998 年鼠疫世界分布年鼠疫世界分布

新出现的传染病（ emerging infections or emerging infectious diseases ， EID ）是指新确定的和先前未知的可引起局部或在世界范围内公共卫生问题的传染病。

--- David Heymann 1997 “emerging infections ”refers to newly ident

ified and previously unknown infectious diseases which cause public health problems ， either locally or internationally 。

重新出现的传染病（ re-emerging infectious d

iseases ）是指那些我们已经熟知的，且其传播水平已降低到不再成为公共卫生问题的感染又重新回复到具有流行程度传播状态的疾病。

Re-emerging infectious diseases are infections that ha

ve been known about for some time but had fallen to

such low levels that they were no longer considered a

public health problem 。 They often reappear in epid

emic proportions.

新出现的传染病的流行具有某些引人注目的特点

The characteristic of EID悄然出现 Silent beginning 全球化趋势 Globalization 动物→人 ? Jump of infectious agent across the species barrier from animal to human being新出现的病原体通常具有较大的毒力和 / 或传染性 More virulent and/or epidemic

EID 产生的原因The cause of EID

人口数量及人的行为变化 The change of population and people's behavior

技术进步和工业化时间的变化 Technological progress and industrialization

EID 产生的原因The cause of EID

经济发展和土地使用模式的变化 Economic development and land-use patterns change 国际旅游、商贸的发展以及人口流动的数量迅速增加 The development of International travel, and commerce, and population movement

EID 产生的原因The cause of EID

病原生物适应性变异

Pathogens variation在世界范围内，从地区、国家到全球多个不同层次和水

平上，因投入大幅下降，而致应对传染病的公共卫生能

力被削弱，以至破坏

Lack of health resources

其他与 EID 产生相关的原因Other causes of EID

全球气候持续变暖，导致热带、亚热带的范围不断扩大，直接影响了动植物生态系统，使生物群落、传播疾病的啮齿类动物及昆虫媒介的种属、分布区域和密度等发生改变

The global climate continues to warm

生物恐怖主义的潜在威胁 Bioterrorism

美国脊髓灰质炎美国脊髓灰质炎 1967—19971967—1997 发病趋势发病趋势

传染病流行趋势 The epidemic trends of Infectious disease

Major achievements of infectious diseases prevention and control till 1970s

Total morbidity decreased

Total mortality decreased

Fatality rate of the majority

decreased

Modes of Transmission changed

Large scale epidemics decreased

总的发病率降低 总的死亡率降低 大多数传染病病死率下降 不同传播途径疾病构成改变 大规模流行减少

全球传染病的主要防治成果

Global burden of disease(DALY)(2000)

DALY = Disability adjusted life-year

Non communicableNon communicable

Injury

communicableMalnutritionEtc.

Africa

East-Med

%

75

50

25

EuropeAmerica

E-S Asia

West Pacific

2000 年全球各地区疾病负担（ DALY ）

Reporting data of legal infectious disease in China (1950-2003)

0.00

1000.00

2000.00

3000.00

4000.00

5000.00

6000.00

7000.00

8000.00

50 53 56 59 62 65 68 71 74 77 80 83 86 89 92 95 98 01

morb

idit

y （

1/1

00

,00

0)

0.00

10.00

20.00

30.00

40.00

50.00

60.00

morta

lity

（1

/10

0,0

00

)

Total morbidityTotal mortality

1950-2003年全国法定传染病报告情况

Leading infectious killers

全球传染病的流行现状

100-250/per 100 000

Distribution of Tuberculosis Worldwide （ 2000 ）

结核病的全球分布（ 2000 ）

3% ~

丙型肝炎的全球分布（ 2000 ）Distribution of C Hepatitis Worldwide （ 2000 ）

The HIV epidemic in the Worldwide (2005)

全球艾滋病流行现状 (2005)

The Morbidity of Main Infectious Diseases in China

TB 5 Million

Schistosomiasis 1 Million

HIV 1 Million

HBV 120 Million

中国传染病的发病现状

The Reported STD Cases in China

432626

632307

837357

853000

300466

199733

23534

49234139724

175528 240848

362654

157108

398512

85977

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

1985 ～ 2001 年全国报告的 STD 发病率

1955-2003 年全国狂犬病发病率

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

发病

率(1

/10万

)

The Morbidity of Lupomania in China

传染病流行病学基本原理和方法

The basic principles and methods of

infectious disease epidemiology

（一）传染源Source of Infection

定义 体内有病原体生长、繁殖并且能排出病原体的人和动物。

分类 病人 cases 病原携带者 carriers 受感染的动物 animals

1 、病人 (cases)

体内存在大量病原体 In vivo existence massive pathogen

具有利于病原体排出的临床症状 Clinical symptoms are advantageous for the pa

thogen discharges

潜伏期（ Incubation period ）

自病原体侵入机体到最早临床症状出现这一段

时间 The time interval between invasion by an

infectious agent and appearance of the first signor symptom of the disease in question

潜伏期的意义Significance of Incubation Period

判断患者受感染时间 To Determine The Infected Time 追踪传染源 Tracing Sources Of Infection查明传播途径 To Identified The Route Of Transmission 确定接触者的留验、检疫和医学观察期限 To Determine The Quarantine And Medical Observation Period

潜伏期的意义 Significance of Incubation Period

确定免疫接种时间

To Determine The Time Of Immunization

评价预防措施效果

Evaluation Of Effectiveness Of Preventive Measures

潜伏期长短还可影响流行特征

Can Affect The Epidemic Characteristics

2 、病原携带者（ carrier ）

没有任何临床症状而能排出病原体的人或动物 A person or animal that harbors a specific infecti

ous agent in the absence of discernible clinical d

isease and serves as a potential source of infecti

on

3 、受感染的动物（ infectious animal ）

自然疫源性疾病（ natural focal disease ） 病原体在自然界中的动物间传播，在一定条件下

可以传给人所致的疾病。具有严格的地方性特点。

鹦鹉热、鼠疫、莱姆病、登革热

流行性出血热、 西尼罗热

人畜共患疾病：在脊椎动物和人之间自然传播的疾病和感染，即人和脊椎动物由共同的病原体引起的并在流行病学上有关联的疾病。

Transmission of infectious agent from

animal to

human called ZOONOSES

美洲狮 pumapuma

乌鸦 乌鸦 crowcrow

传播西尼罗热的动物Animals can transmit West Nile fever

牛牛 -------- 疯牛病疯牛病

老鼠老鼠 ---------- 鼠疫鼠疫

病原体从传染源排出后，侵入新的易感宿主前，在外环境中所经历的全部过程。

（二）传播途径 Route of Transmission

The whole process that the pathogens

experienced in the outer environment

when they passed from an infected

individual or group to a previously

uninfected individual or group.

传染病之传播方式

Air-borne transmission Water-borne transmission Food-borne transmission

Contact-transmitted diseases

Vector-borne diseases

Soil-transmitted diseases

Nosocomial infection Vertical transmission

经空气传播 经水传播 经食物传播 接触传播 虫媒传播 经土壤传播 医源性传播 垂直传播

Modes of Infectious Disease Transmission

1 、空气传播传染病（ Air-borne diseases ） 传播途径易实现，易爆发流行 Transmission easy to comply, easy to outbreak 冬春季高发 Mostly occurs in winter and spring 少年儿童多见 Mostly occurs in Children 未免疫预防人群周期性升高 A cycle period in non-immunity population 受居住条件和人口密度的影响 Overcrowded live conditions and high population densi

ty

2-1 、饮用水污染（ Drinking Water Pollutio

n ）

病例分布与供水范围一致

Distribution Of Cases Consistent With The Water Supply Coverage

除哺乳婴儿外，其余人群均可发病

Except To Lactated Infants, All Population Can Be

2-1 、饮用水污染（ Drinking Water Pollution ）

如经常被污染，可表现为慢性流行经过 If Often Contaminated, Can Be Expressed As Chr

onic Epidemic 如一次性严重污染，可出现爆发流行 A Serious Pollution Can Cause An Outbreak 水源停用或净化后，爆发或流行可平息 Stop Drink Or Purified Water, Can Quell The Out

break Or Epidemic

2-2 、疫水接触 （ Exposure to infected water ）

疫水接触史 History of exposure to infected water 地区、季节与职业上的差别 There are regional, seasonal and occupational characteristics 多见于与疫水接触的人群 More common in people who contact with infected water 大量易感人群与疫水接触可爆发 A large number of susceptible who contact with infected wate

r easy occur outbreaks 对疫水采取措施可控制发生 Taken against measures can be controlled

人们接触血吸虫疫水人们接触血吸虫疫水

3、经食物传播（ Food-borne Diseases ）

吃污染食物者发病，不食者不发病 Involved Are Limited To Those Who Eat Contaminated Food 一次性大量污染，可形成爆发 A Large Number Of Contamination, The Outbreak Can Be Occ

ur 停止供应该食物后，爆发即可平息 To Stop Supplying The Contaminated Food , The Outbreak Ca

n Be Stop 潜伏期较短 The Incubation Period Is Shorter

                                                                                                                                                                                                                        

                                                                                                                                                                                                                        

1988 年上海市甲型肝炎爆发和毛蚶

上海市 1988 年 1—3月急性肝炎发病动态

4、经接触传播Contact-transmitted diseases

方式 直接接触 Direct contact

没有外界因素参与下，传染源直接与易感者接触。 间接接触 Indirect contact

易感者接触了被传染源的排出物或分泌物污染的用品所造成的传播。

5 、经节肢动物传播 （ Vector-borne diseases ）

特征 地区性 Regional 西尼罗热 职业性 Occupational 森林脑炎 季节性 Seasonal 疟疾 青壮年多发 More Young adults 地方性斑疹伤寒

媒介节肢动物

埃及伊蚊

蜱

白蛉

库蚊

疟疾、丝虫病、乙脑、登革热、黄热病、西尼罗脑炎等

新疆出血热、蜱媒脑炎、莱姆病

白蛉热、利夫特谷热

蚊子传播西尼罗热蚊子传播西尼罗热

6 、医源性传播（ Nosocomial infection ）

医疗、预防工作中，由于未严格地执行规章制

度和操作规程而造成的传播。

Nosocomial infections (pronounced, nos-uh-KOH-mee-uhl), are infections which are a result of treatment in a hospital or a healthcare service unit.

7 、围产期传播（ Vertical transmisssion ）定义

在围产期病原体通过母体传给子代，也称垂直传播或母婴传播。方式

经胎盘传播 By placenta 上行性感染 By genital 分娩时传播 By labour

HIVHIV母婴传播率母婴传播率

全球 全球 15%--25%15%--25%

我国高流行区 我国高流行区 30%30%

HIVHIV干预母婴传播率（法国）干预母婴传播率（法国）

拉米夫定组 拉米夫定组 6.8%6.8%

拉米夫定与齐多夫定组 拉米夫定与齐多夫定组 1.6%1.6%

人群作为一个整体对传染病的易感程度。

The susceptibility degree of population, as

a whole, to infectious diseases

（三）人群易感性 Herd Susceptibility

升高的因素 （ The Increase Factors ）

新生儿增加 Increased Neonatal 易感人口迁入 Susceptible Population Move In 免疫人口免疫力自然消退 Mmuno-population Immunity To Natural Healing 免疫人口死亡 Immuno-population Has Been Dead

降低的因素 （ Reduction Factor ）

计划免疫 EPI

传染病流行 Epidemics

隐性感染 Subclinical infection

1 、概念 (concept)

在一定条件下，传染源向其周围传播病原体所能波及的范围。

（四）疫源地 Infectious focus

The range that the sources of infection

spread pathogens around can reach to under

certain conditions.

2 、形成条件 (the formation conditions)

传染源存在 The source of infection exists 病原体能够继续传播 Pathogens can continue to spread

3 、消灭条件 (eliminate conditions)

传染源被移走或消除了携带状态 The source of infection has been removed or

eliminate the carrier state 进行了终末消毒 Carried out terminal disinfection 经过最长潜伏期，易感者中没有新的感染发生 After the longest incubation period, no new i

nfections occur among susceptible

（五）影响流行过程的因素The factors that affect the epidemic process

1 、自然因素（ Natural factors ）

气候 （ Climate ） 地理因素 （ Geography ） 媒介昆虫和宿主动物的特异性栖息习性 （ Vector insects and host ）

2 、社会因素（ Social factors ）

全球旅游业的急剧发展 The rapid development of global travel

环境污染和破坏造成生态恶化 Ecological deterioration caused by environmental pollution and destruction

2 、社会因素（ Social factors ）

抗生素和杀虫剂的滥用 The abuse of antibiotics and pesticides 城市化和人口爆炸 Urbanization and population explosion战争、动乱、难民潮和饥荒 War, riots, refugee flows and famine

传染病的预防和控制Prevention and control of infectious diseases

Immunization of people

–boosters frequently required

–100% immunization is not necessary (herd

immunity)

Blocking vehicle-mediated transmission

–water purification

–effective cooking

–prevention of food contamination with

infectious agents

Public Health Measures for Control of EpidemicsInvolves strategies which break the "chain of

transmission"

Quarantine –limiting freedom of movement of individuals carrying infectious agents –minimum time required for a quarantine period is equal to longest period of communicability (transmissibility) of the disease

Elimination of animal reservoirs –immunization of animals that act as reservoirs of diseases such as bovine tuberculosis, brucellosis (highly effective when monitored properly) –eradication of animals that act as reservoirs of diseases such as tularemia, plague, Lyme disease (sometimes effective, difficult to monitor properly) 

Prevention, Intervention, Control, and Eradication of Diseases

PreventionPrevention– implies the planning for and taking action to implies the planning for and taking action to

prevent or forestall the occurrence of an prevent or forestall the occurrence of an undesirable event and is therefore more undesirable event and is therefore more desirable than . . .desirable than . . .

InterventionIntervention– which is defined as taking of action during an which is defined as taking of action during an

eventeventControlControl– general term used in the containment of general term used in the containment of

diseasediseaseEradicationEradication– total elimination of the diseasetotal elimination of the disease

Control of Infectious diseases

HUMAN1. Change behavior2. Health education3. Vaccination

ENVIRONMENT1. Habitat improvement2. Water (or soil) treatment3. Revise agriculture pattern

Control of Infectious diseases

RESERVOIRS1. Treatment

2. Vaccination

3. Eradication

VECTORS1. Chemical control

2. Non-chemical control

加强传染病监测 Communicable disease surveillance

传染病报告 Report infectious diseases

针对传染源的措施The control measures for the source of infection

（ 1）病人 Cases 早发现 Early detection 早诊断 Early diagnosis 早报告 Early reporting 早隔离 Early isolation 早治疗 Early treatment

病原携带者 Carriers

措施 Measures 登记 Registration 管理 Management 随访 Follow up

期限 Time limit

接触者 Contacts

检疫 Quarantine

留验 (隔离观察 ) Isolated observation

医学观察 Medical observation

动物传染源 Animal

彻底消灭 Wipe 捕杀、焚烧或深埋 Killing, burning or deep 隔离治疗 Isolation and treatment 预防接种和检疫 Vaccination and quarantine

对传播途径的措施measures for route of transmission

消毒 Disinfection

分类

预防性消毒 Preventive disinfection

疫源地消毒 Foci disinfection

随时消毒 Disinfection at any time

终末消毒 Terminal disinfection

分类

针对易感者的措施Measures for the susceptible

免疫预防 Immunization

药物预防 Drug prevention 个人防护 Personal Protection

谢 谢谢 谢