Transcript 12第十二章传染病流行病学

Department of Epidemiology
Public Health College of Harbin Medical University
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
1
讲 授 内 容
Teaching Content
 研究传染病的意义
 study importance
 传染病流行趋势
 epidemic trends
 传染病流行病学基本原理
 basic principles and
和方法
methods
 疫源地
 infectious focus
 传染病的预防和控制
 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
1998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 identified
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
diseases）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
have 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
epidemic 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1967—1997发病趋势
传染病流行趋势
The epidemic trends of Infectious disease
全球传染病的主要防治成果
Major achievements of infectious diseases prevention
and control till 1970s
 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
Total morbidity decreased
Total mortality decreased
Fatality rate of the majority
decreased
Modes of Transmission changed
Large scale epidemics decreased
Global burden of disease(DALY)(2000)
2000年全球各地区疾病负担（DALY）
DALY = Disability adjusted life-year
%
75
50
Non communicable
Injury
25
communicable
Malnutrition
Etc.
1950-2003年全国法定传染病报告情况
Reporting data of legal infectious disease in China (1950-2003)
60.00
7000.00
6000.00
5000.00
4000.00
3000.00
Total morbidity
Total mortality
50.00
40.00
30.00
20.00
2000.00
1000.00
0.00
10.00
0.00
mortality （1/100,000)
morbidity （1/100,000)
8000.00
全球传染病的流行现状
Leading infectious killers
结核病的全球分布（2000）
Distribution of Tuberculosis Worldwide（2000）
100-250/per 100 000
丙型肝炎的全球分布（2000）
Distribution of C Hepatitis Worldwide（2000）
3% ~
全球艾滋病流行现状 (2005)
The HIV epidemic in the Worldwide (2005)
中国传染病的发病现
状
The Morbidity of Main Infectious Diseases in China
TB
5 Million
Schistosomiasis
1 Million
HIV
1 Million
HBV
120 Million
1985～2001年全国报告的STD发病率
The Reported STD Cases in China
900000
853000
837357
800000
700000
632307
600000
500000
432626
400000
362654
398512
300000
175528
300466
240848
200000
139724
100000
199733
49234
85977
0
157108
23534
1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
1955-2003年全国狂犬病发病率
The Morbidity of Lupomania in China
0.8
发病率(1/10万)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
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
病原携带者
受感染的动物
cases
carriers
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
pathogen 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
infectious agent in the absence of discernible
clinical disease and serves as a potential source
of infection
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
乌鸦 crow
美洲狮 puma
传播西尼罗热的动物
Animals can transmit West Nile fever
牛----疯牛病
老鼠-----鼠疫
（二）传播途径
Route of Transmission
 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。

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
Modes of Infectious Disease Transmission
 经空气传播

Air-borne transmission
 经水传播

Water-borne transmission
 经食物传播

Food-borne transmission
 接触传播

Contact-transmitted diseases
 虫媒传播

Vector-borne diseases
 经土壤传播

Soil-transmitted diseases
 医源性传播

Nosocomial infection
 垂直传播

Vertical 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 density
2-1、饮用水污染（Drinking Water Pollution）

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
Chronic 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
Outbreak 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
water 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
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
Occur

停止供应该食物后，爆发即可平息
To Stop Supplying The Contaminated Food , The Outbreak
Can 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
 季节性 Seasonal
森林脑炎
疟疾
 青壮年多发 More Young adults
地方性斑疹伤寒
媒介节肢动物
疟疾、
丝虫病、
乙脑、
登革热、
黄热病、
西尼罗脑炎
等
白蛉热、
利夫特谷热
埃及伊蚊
白蛉
新疆出血热、
蜱媒脑炎、
莱姆病
库蚊
蜱
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-KOHmee-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
HIV母婴传播率
全球 15%--25%
我国高流行区 30%
HIV干预母婴传播率（法国）
拉米夫定组 6.8%
拉米夫定与齐多夫定组 1.6%
（三）人群易感性
Herd Susceptibility
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
升高的因素 （The Increase Factors）

新生儿增加

易感人口迁入

免疫人口免疫力自然消退

免疫人口死亡
Increased Neonatal
Susceptible Population Move In
Mmuno-population Immunity To Natural Healing
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
（四）疫源地
Infectious focus
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。
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
infections 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
Public Health Measures for Control of Epidemics
Involves strategies which break the "chain of transmission"
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
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
Prevention
– implies the planning for and taking action to prevent
or forestall the occurrence of an undesirable event and
is therefore more desirable than . . .
Intervention
– which is defined as taking of action during an event
Control
– general term used in the containment of disease
Eradication
– total elimination of the disease
Control of Infectious diseases
HUMAN
1. Change behavior
2. Health education
3. Vaccination
ENVIRONMENT
1. Habitat improvement
2. Water (or soil) treatment
3. Revise agriculture pattern
Control of Infectious diseases
RESERVOIRS
1. Treatment
2. Vaccination
3. Eradication
VECTORS
1. 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
早报告
早隔离
早治疗



Early diagnosis
Early reporting
Early isolation
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
 分类
 随时消毒 Disinfection at any time
 终末消毒 Terminal disinfection
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