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Surveillance and Demographic Transition Theory dow.pptx
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- 2. SURVEILLANCE • Epidemiological surveillanceis “the ongoing systematic collection, analysis, and interpretation of health data essential to the planning, implementation, and evaluation of public health practice, closely integrated with the timely dissemination of these data to those who need to know.” • Mortality and Transmission Rates of Disease must be known in a population for surveillance to Occur.
- 3. SURVEILLANCE Surveillance ingeneral means to watch over carefully or to observe any event. Surveillance in public health is the continuous, watching of the incidence and distribution of health-related events through systematic collection, analysis and interpretation of data needed for the planning, implementation, and evaluation of public health practice. It can be carried out to monitor changes in disease frequency or to monitor changes in the levels of risk factors. Surveillance is systematic and ongoing process
- 4. Passive surveillance • Passivesurveillance denotes surveillance in which available data on reportable diseases are used, or in which disease reporting is mandated or requested by the government or the local health authority, with the responsibility for the reporting often falling on the health care provider or district health officer. This type of reporting is also called passive reporting
- 5. Active surveillance Active surveillancedenotes a system in which project staff are specifically recruited to carry out a surveillance program. They are recruited to make periodic field visits to health care facilities such as clinics, primary health care centers, and hospitals in order to identify new cases of a disease or diseases or deaths from the disease that have occurred (case finding)
- 6. CONTI… Active surveillancemay involve interviewing physicians and patients, reviewing medical records, and, in developing countries and rural areas, surveying villages and towns to detect cases either periodically (at regular interval of time) on a routine basis or after an index case has been reported. Reporting is generally more accurate when surveillance is active than when it is passive because active surveillance is conducted by individuals who have been specifically e employed and trained to carry out this responsibility.
- 7. Characteristics of idealsurveillance • An ideal surveillance should be: • Simple • Timely • Representative • Flexible • Sensitive • Strong predictive value • Acceptable to – The public – Health care providers • Cost-effective
- 8. Importance of surveillance •To assess the health status – All the data collected are the reflection of health of people – Keeps the record of existing health problems – Helps in the interpretation of mortality and morbidity status • To detect the change in the disease trend and health practices – Continue recording of data notifies about the disease trend – Keeps the track of disease – Surveillance is also helpful for finding the natural history of disease. • Collection of data for Planning, Monitoring and Evaluation – The data required for PME is provided by surveillance – It is the base for evidence-based policy formation – Helps the program developer in priority setting – Also helps in assessing the effectiveness of the interventions
- 9. Importance of surveillance •Early warning and detection of outbreaks – Surveillance notifies about the disease – All the data too helps in detecting the outbreaks – Hence helps in preparedness • To estimate the size of a health problem • To detect epidemics or define a problem • To facilitate emergency planning
- 10. Types of Surveillance 1.)Active Surveillance • Refers to active finding of the cases. • Designated staffs review the records physically, visits the health facility, and confirms with the health practitioner to find the particular cases. • Often used for the disease which is at the verge of elimination and eradication and also in the time of outbreak investigation. • Requires more resources; as requires staff- healthcare professionals to visit hospitals • Active Surveillance can be also used to check the validity of passive surveillance • Reporting is usually more accurate here as it is performed by those specially assigned to conduct this activity
- 11. Types of Surveillance •2.) Passive Surveillance • Surveillance in which the available data on diseases or conditions are used • It refers to regular monitoring or reporting of the cases without active involvement in identification/reporting by the health personnel • Simple and very easy to carry out • All institutions that provide health services to general people are the part of this surveillance. • They forward their records to the designated departments where all the reports are compiled • Uniform format of reporting is followed • Health management information system of government is an example of passive surveillance • Inconsistency of recording can cause problem as things may not be taken seriously all the time
- 12. Types of Surveillance •3.) Sentinel Surveillance • It is a surveillance system which is used when the need of high quality data cannot be met through passive surveillance • It is a system where specific catchment area is selected for surveillance. • Selection of sentinel surveillance site depends on possibility of high probability of cases/disease • It deliberately involves limited network of carefully selected reporting sites. Example: a network of large hospitals might be used to collect high-quality data on various diseases • Sites are selected on the basis of population flow, previous outbreak of disease, high presence of risk group, etc. • Sentinel Surveillance is not suitable for detecting rare disease • This type of surveillance helps identify rapidly changing health condition of a specified disease at a particularly specified time
- 13. Steps of surveillance •Reporting: • Data has to be reported by the health worker, staffs , etc • Data needs to be reported in pre-specified format • Accumulation • The reported data needs to be collected and compiled • The data are collected in a designated departments • Data collection follows the certain chain • Data Analysis • All the collected are then analyzed • The data are converted in terms of rates, ratios, proportion, figures etc • Interpretation and action • Surveillance doesn’t stops in data collection • Wise judgement needs to be made • The information needs to be disseminated so that the further action are taken
- 14. LIMITATIONS OF SURVEILLANCE •Surveillance depends upon the reporting so under-reporting could be a problem. • Inconsistency in reporting • Reporting may not be representative • Takes time for data collection, analysis and interpretation • Surveillance is on the tool of epidemiology it is not the solution to health problem.
- 16. SCREENING SURVEILLANCE Gives abetter idea of progress of disease from sub clinical or covered to clinical or overt. Gives a better idea for the prevention and control of diseases It is a part of secondary prevention It is a part of primary and tertiary prevention. Has mass screening that indicates large- screening of whole population groups. Active surveillance has special searches for cases limited to specific disease in intervals of time. Selective screening refers to selected high risk groups in a population. Passive surveillance is for mainly long term secular trends at one time.
- 17. SCREENING SURVEILLANCE Multiple screeningrefers to combination of the mass and selective screening. Sentinel surveillance helps identify rapidly changing health condition of a specified disease at a certain time. Used for Case detection, control of disease, research, etc. Used for mainly prevention and control. Examples of screening tests include mammography for breast cancer, pre-natal amniocentesis for detecting congenital malformations, or psychological tests to identify early signs of cognitive decline. Examples of surveillance includes Surveillance of communicable disease, Non communicable disease, Influenza, HIV/AIDS in Thailand, etc.
- 18. LEVEL OF DISEASEOCCURENCE • ENDEMIC The amount of a particular disease that is usually present in a community is referred to as the baseline or endemic level of the disease. • This level is not necessarily the desired level, which may in fact be zero, but rather is the observed level. • In the absence of intervention and assuming that the level is not high enough to deplete the pool of susceptible persons, the disease may continue to occur at this level indefinitely. • Thus, the baseline level is often regarded as the expected level of the disease.
- 19. LEVEL OF DISEASEOCCURENCE • Sporadic refers to a disease that occurs infrequently and irregularly. • Endemic refers to the constant presence and/or usual prevalence of a disease or infectious agent in a population within a geographic area. • Hyperendemic refers to persistent, high levels of disease occurrence. • Occasionally, the amount of disease in a community rises above the expected level. • Epidemic refers to an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area. • Outbreak carries the same definition of epidemic, but is often used for a more limited geographic area.
- 20. LEVEL OF DISEASEOCCURENCE • Cluster refers to an aggregation of cases grouped in place and time that are suspected to be greater than the number expected, even though the expected number may not be known • Pandemic refers to an epidemic that has spread over several countries or continents, usually affecting a large number of people. Epidemics occur when an agent and susceptible hosts are present in adequate numbers, and the agent can be effectively conveyed from a source to the susceptible hosts. More specifically, an epidemic may result from: • A recent increase in amount or virulence of the agent, • The recent introduction of the agent into a setting where it has not been before, • An enhanced mode of transmission so that more susceptible persons are exposed,
- 21. EXAM QUESTION SAMPLE 1._________22 cases of legionellosis occurred within 3 weeks among residents of a particular neighborhood (usually 0 or 1 per year) 2. _____________Average annual incidence was 364 cases of pulmonary tuberculosis per 100,000 population in one area, compared with national average of 134 cases per 100,000 population 3. ________________Over 20 million people worldwide died from influenza in 1918–1919 A.Sporadic disease B.Endemic disease C.Hyper-endemic dx D.Pandemic disease E.Epidemic disease
- 22. ANSWERS TO SAMPLEEXAM QUESTIONS 1. E 2. C 3. D 4. A 5. B
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- 24. DEMOGRAPHIC TRANSITION THEORY •The word ‘Demography’ came from the prefix ‘demo’ meaning people and ‘graphy’ meaning description or measurement. Similarly, ‘transition’ means process of changing from one state to another • So, the phrase ‘Demographic Transition Theory’ clearly reflects from the name itself that it is a theory/model which describes the population change that occurs over a period of time • Demographic Transition is a gradual process in which a society moves from high birth rate and death rate to low birth rate and death rate • It deals with population change occurring from the past to the change that may occur in future • Furthermore, the theory shows the transition of population from high birth and death rate to low birth and death rate as the country (or any region) moves from pre-industrial era to an industrialized era. Thus the major emphasis of the theory is given to the economic development which results in change in population • The theory was 1st propounded and interpreted by an American demographer Warren Thompson who saw changes in the population pattern all over the world in due course of time
- 25. DEMOGRAPHIC TRANSITION THEORY •It looks at three major indicators for assessing and predicting population change: fertility, mortality and growth rate • There are usually 4-5 stages for categorizing demographic transition. This is because earlier categorization was done in 4 stages. However, with the change in population pattern which could not be addressed by 4 stages, a new 5th stage has been added to it. • This theory considering all 5 stages.
- 26. 1. High Stationarystage • The stage before industrial revolution. Also known as Pre-transition phase • The country or region in this stage are characterized by high fertility (birth rate) and high mortality (death rate) • This stage has low or stable growth rate i.e. population remains constant due to high birth and death rate • Reasons for high birth rate were: lack of family planning methods, high infant mortality rate convincing couples to have more babies, more family members = more source of economic assets • Reasons for high mortality rate were: poor health and health services, famine, lack of proper education and unavailability of clean water and sanitation • Relatively low people in older age
- 28. 2. Early expandingphase • In this stage, birth rate keeps on increasing while death rates begin to fall rapidly/sharply. This results in high/rapid population growth • It is also known as population explosion stage • Reasons for decline in death rates were: increase in food supply due to agricultural revolution and improvement in health and sanitation causing reduction in child mortality • High birth rate results in larger cohort of younger population • Most of the least developed countries are in this stage
- 30. 3. Late expandingphase • In this stage the birth rate also starts to fall/decrease • However, the major point is that, while birth rate starts to decrease slowly and gradually, death rate also keeps on falling slowly. This leads to the narrowed gap between birth and death rate compared to early expanding stage • Result of this stage is low population growth or natural increase in population • Reasons for gradual decrease in birth rates were: the introduction of contraceptive devices, increase in women’s status and rise in economic conditions and education level of the people • Most of the developing countries are in this stage
- 32. 4. Low stationary/low fluctuating stage • It is known as the stage of stationary population • In this stage, birth rates and death rates both are low. Also both of them are approximately equal to each other • This results in stability/slow rise in population--- STATIC population • Most of the developed countries are in this stage
- 34. 5. Declining PHASE •This stage is characterized by low death rate, lower birth rate and excess deaths over births • In this stage birth rates are below death rates i.e. fertility rate is below the replacement level (2 children). This leads to increase in elderly population compared to the younger populations • This stage is resulted due to continuous desire of the families to have a smaller family • Some parts of Europe like Russia, Sweden and Germany and Japan are reaching towards this stage