传染病流行病学 Infectious Disease Epidemiology

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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 - PowerPoint PPT Presentation

Text of 传染病流行病学 Infectious Disease Epidemiology

  • Teaching Content

    study importance epidemic trends basic principles and methods infectious focus prevention & control

  • Study Importance Seriously burden of diseasesNeglect of prevention ,the consequences of heavyThe resurgence of relapseThe new emerging infectious diseases Threat of bioterrorism

  • 1998

  • emerging infections or emerging infectious diseasesEID --- David Heymann 1997emerging infections refers to newly identified and previously unknown infectious diseases which cause public health problemseither locally or internationally

  • re-emerging infectious diseasesRe-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 problemThey often reappear in epidemic proportions.

  • The characteristic of EID Silent beginning Globalization ? Jump of infectious agent across the species barrier from animal to human being/ More virulent and/or epidemic

  • EIDThe cause of EID The change of population and people's behavior Technological progress and industrialization

  • EIDThe cause of EID Economic development and land-use patterns change The development of International travel, and commerce, and population movement

  • EIDThe cause of EID Pathogens variation Lack of health resources

  • EIDOther causes of EID The global climate continues to warm Bioterrorism

  • 19671997

  • 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

  • Global burden of disease(DALY)(2000)DALY = Disability adjusted life-yearNon communicableInjurycommunicableMalnutritionEtc.AfricaEast-MedEuropeAmericaE-S AsiaWest Pacific2000DALY

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

  • Leading infectious killers

  • 100-250/per 100 000Distribution of Tuberculosis Worldwide20002000

  • 3% ~2000Distribution of C Hepatitis Worldwide2000

  • The HIV epidemic in the Worldwide (2005) (2005)

  • The Morbidity of Main Infectious Diseases in China

  • The Reported STD Cases in China19852001STD

  • 1955-2003The Morbidity of Lupomania in China

  • The basic principles and methods of infectious disease epidemiology

  • Source of Infection cases carriers animals

  • 1 (cases)

    In vivo existence massive pathogen

    Clinical symptoms are advantageous for the pathogen discharges

  • Incubation period The time interval between invasion by an infectious agent and appearance of the first signor symptom of the disease in question

  • Significance of Incubation Period To Determine The Infected Time Tracing Sources Of Infection To Identified The Route Of Transmission To Determine The Quarantine And Medical Observation Period

  • Significance of Incubation Period To Determine The Time Of Immunization Evaluation Of Effectiveness Of Preventive Measures Can Affect The Epidemic Characteristics

  • 2carrier

    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

  • 3infectious animal natural focal disease

  • Transmission of infectious agent from animal to human called ZOONOSES

  • puma crow Animals can transmit West Nile fever

  • ---- -----

  • Route of TransmissionThe 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.

  • Air-borne transmissionWater-borne transmissionFood-borne transmission Contact-transmitted diseasesVector-borne diseasesSoil-transmitted diseasesNosocomial infectionVertical transmission

    Modes of Infectious Disease Transmission

  • 1Air-borne diseases Transmission easy to comply, easy to outbreak Mostly occurs in winter and spring Mostly occurs in Children A cycle period in non-immunity population Overcrowded live conditions and high population density

  • 2-1Drinking Water Pollution Distribution Of Cases Consistent With The Water Supply Coverage Except To Lactated Infants, All Population Can Be

  • 2-1Drinking Water Pollution If Often Contaminated, Can Be Expressed As Chronic Epidemic A Serious Pollution Can Cause An Outbreak Stop Drink Or Purified Water, Can Quell The Outbreak Or Epidemic

  • 2-2 Exposure to infected water History of exposure to infected water There are regional, seasonal and occupational characteristics More common in people who contact with infected water A large number of susceptible who contact with infected water easy occur outbreaks Taken against measures can be controlled

  • 3Food-borne Diseases Involved Are Limited To Those Who Eat Contaminated Food A Large Number Of Contamination, The Outbreak Can Be Occur To Stop Supplying The Contaminated Food , The Outbreak Can Be Stop The Incubation Period Is Shorter

  • 1988 198813

  • 4Contact-transmitted diseases Direct contact Indirect contact

  • 5 Vector-borne diseases Regional Occupational Seasonal More Young adults

  • 6Nosocomial infection Nosocomial infections (pronounced, nos-uh-KOH-mee-uhl), are infections which are a result of treatment in a hospital or a healthcare service unit.

  • 7Vertical transmisssion By placenta By genital By labour

  • HIV 15%--25% 30%

    HIV 6.8% 1.6%

  • The susceptibility degree of population, as a whole, to infectious diseases Herd Susceptibility

  • The Increase Factors Increased Neonatal

    Susceptible Population Move In

    Mmuno-population Immunity To Natural Healing

    Immuno-population Has Been Dead

  • Reduction Factor EPI Epidemics Subclinical infection

  • 1 (concept)

    Infectious focus The range that the sources of infection spread pathogens around can reach to under certain conditions.

  • 2 (the formation conditions) The source of infection exists Pathogens can continue to spread

  • 3 (eliminate conditions) The source of infection has been removed or eliminate the carrier state Carried out terminal disinfection After the longest incubation period, no new infections occur among susceptible

  • The factors that affect the epidemic process 1Natural factors Climate Geography Vector insects and host

  • 2Social factors The rapid development of global travel Ecological deterioration caused by environmental pollution and destruction

  • 2Social factors The abuse of antibiotics and pesticides Urbanization and population explosion War, riots, refugee flows and famine

  • 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 agentsPublic 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 DiseasesPreventionimplies the planning for and taking action to prevent or forestall the occurrence of an undesirable event and is therefore more desirable than . . .Interventionwhich is defined as taking of action during an eventControlgeneral term used in the containment of diseaseEradicationtotal elimination of the disease

  • Control of Infectious diseasesHUMAN1. Change behavior2. Health education3. Vaccination

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

  • Control of Infectious diseasesRESERVOIRS1. Treatment2. Vaccination3. EradicationVECTORS1. Chemical control2. Non-chemical control

  • Communicable disease surveillance

    Report infectious diseases

  • The control measures for the source of infection1 Cases Early detection Early diagnosis Early reporting Early isolation Early treatment

  • Carriers

    Measures Registration Management Follow up

    Time limit

  • Contacts

    Quarantine () Isolated observation Medical observation

  • Animal Wipe Killing, burning or deep Isolation and treatment Vaccination and quarantine

  • measures for route of transmission Di