EPIDEMIOLOGY Flashcards
What is the definition of Epidemiology?
The study of the frequency, distribution, and determinants of diseases and other health-related conditions in human populations, and the application of this study to the promotion of health and the prevention and control of health problems.
What is the main focus of epidemiology?
The effect of disease on the population rather than individuals.
How is frequency measured in epidemiology?
By morbidity and mortality rates.
What are health-related conditions?
Conditions which directly or indirectly affect or influence health, such as injuries, births, and health-related behaviors.
What does distribution refer to in epidemiology?
The geographical distribution of diseases, the distribution in time, and distribution by type of persons affected.
What are determinants in the context of epidemiology?
Factors which determine whether or not a person will get a disease.
What was a significant contribution of Hippocrates to epidemiology?
He displayed awareness of the impact of environment and behavior on personal well-being.
Who formulated a hypothesis about cholera transmission and in what year?
John Snow in 1849.
What is the primary use of epidemiology in a community?
To identify and describe health problems.
What are primary causes of disease?
Factors necessary for a disease to occur, without which the disease will not occur.
What are risk factors in disease causation?
Factors associated with an increased occurrence of a disease.
What does the epidemiologic triangle illustrate?
The relationship among agent, host, and environment in the occurrence of disease.
What are the four stages in the natural history of a disease?
- Stage of susceptibility
- Stage of pre-symptomatic disease
- Stage of clinical disease
- Stage of disability or death
What is primary prevention?
Promoting health, preventing exposure, and preventing disease to keep the disease process from becoming established.
What is secondary prevention?
Stopping or slowing the progression of disease to prevent or limit permanent damage.
What is tertiary prevention?
Targeted towards people with permanent damage or disability.
Fill in the blank: The natural history of disease refers to the progression of disease process in an individual over time, in the absence of _______.
[intervention]
True or False: The clinical stage of a disease has no signs or symptoms.
False
What is primary prevention?
Strategies aimed at preventing disease before it occurs
Examples include vaccinations and health education.
What is secondary prevention?
Strategies focused on early detection and treatment of disease to prevent progression
Examples include screenings for breast cancer and treatment for trachoma.
What is tertiary prevention?
Strategies aimed at managing and mitigating the impact of disease after it has caused permanent damage
Includes rehabilitation and support for individuals with disabilities.
What is a communicable disease?
An illness caused by a specific infectious agent that can be transmitted from an infected person or animal to a susceptible host.
What are the components of the infectious process?
The Agent, Reservoirs, Portal of Exit, Mode of Transmission, Portals of Entry, Human Host.
Define ‘Reservoir’ in terms of infectious diseases.
An organism or habitat where an infectious agent normally lives, develops, and multiplies.
What is a Carrier in infectious disease context?
An infected person who does not show symptoms but can transmit the infection to others.
What is the Portal of Exit?
The route through which an infectious agent leaves its reservoir.
What are the modes of transmission in infectious diseases?
Direct and Indirect transmission, including contact, projection, transplacental, vehicle-borne, vector-borne, and airborne.
What is herd immunity?
Resistance of a population to the introduction of an infectious agent based on immunity of a high proportion of individuals.
What is descriptive epidemiology?
A branch of epidemiology concerned with describing the frequency and distribution of diseases by time, place, and person.
What are the major variables in descriptive epidemiology?
Person, Place, and Time.
What is a cross-sectional study?
A descriptive study design assessing the presence or absence of exposure and disease at a single point in time.
What are the advantages of cross-sectional studies?
Less expensive, easier to conduct, provide useful information for planning health services.
Define Ratio in epidemiological terms.
The relationship between two occurrences or conditions expressed in the form of x:y or x/y.
What is a Proportion?
A specific type of ratio where the numerator is included in the denominator, expressed as a percentage.
What is a Rate in epidemiology?
A measure that includes time, representing the probability of disease occurrence in a defined population over a specified period.
What is incidence rate?
The number of new cases of a disease occurring during a specified period in a population at risk.
What is the difference between incidence and prevalence?
Incidence measures new cases, while prevalence measures all existing cases at a given time.
What is the appropriate denominator for incidence rate?
Population at risk
Knowing the population at risk can be difficult, so total population can also be used.
What must be specified for incidence to be a measure of risk?
A period of time
All individuals in the denominator must be followed up for that entire period.
How can the incidence rate be calculated?
Incidence Rate = (No. of new cases / Total population) X K
K is a constant for scaling, often 1000.
What does a high incidence rate in an area indicate?
A high risk of acquiring that disease by healthy individuals.
What is an attack rate?
A type of incidence rate used during epidemics.
How is the attack rate calculated?
Attack Rate = (No. of new cases during epidemic / Total population at risk) X K
K is a constant for scaling.
What does the point prevalence rate measure?
The proportion of a population with a certain condition at a given point in time.
How is point prevalence rate calculated?
Point Prevalence Rate = (All persons with a specific Condition at one point in time / Total population) X K
What is the Crude Death Rate (CDR)?
CDR = (Total no. of deaths during a given time interval / Estimated mid-interval population) X 1000
What does the Age-specific mortality rate measure?
No. of deaths in a specific age group during a given time / Estimated mid-interval population of specific age group X 1000
What is the Case Fatality Rate (CFR)?
CFR = (No. of deaths from a specific disease during a given time / No. of cases of that disease during the same time) X 100
What does the Neonatal Mortality Rate measure?
NMR = (No. of deaths under 28 days of age reported during a given time / No. of live births reported during the same time) X 1000
What is the Infant Mortality Rate (IMR)?
IMR = (No. of deaths under 1 year of age during a given time / No. of live births reported during the same time) X 1000
What is the Under-five mortality rate?
U5MR = (No. of deaths of 0-4 years old during a given time / Average population of the same age at the same time) X 1000
What does the Maternal Mortality Rate reflect?
The standards of all aspects of maternal care (antenatal, delivery, and postnatal).
What is a census?
A periodic count or enumeration of a population.
What are vital statistics?
A system of registering and compiling all births and deaths occurring nationwide.
What is the main advantage of health service records?
Easily obtainable and available at low cost.
What is a limitation of health surveys?
They are expensive and dependent on the memory and cooperation of the interviewee.
What are the main methods of data collection?
- Observation
- Interview and questionnaires
- Documentary sources
What is the purpose of health surveys?
To obtain comprehensive data for monitoring the health status of a population.
What are the different sources of health information?
What is the major source of health information in the Philippines?
What problems are related to health service records as a source of health data?
Which method of data collection would be appropriate to know the number of people in a kebele using latrines?
Define epidemic.
The occurrence of disease or other health-related condition in excess of the usual frequency in a given area or among a specific group of people over a particular period of time.
What are the types of epidemics?
- Common Source Epidemics
- Propagated/Progressive Epidemics
- Mixed Epidemics
What is endemic?
Presence of a disease at more or less stable level.
What is hyper endemic?
Persistently high level of disease occurrence.
What does sporadic mean in the context of disease occurrence?
Occasional or irregular occurrence of a disease.
What defines a pandemic?
An epidemic involving several countries or continents affecting a large number of people.
What is a point source epidemic?
Disease occurs as a result of exposure of a group of susceptible persons to a common source of a pathogen, often at the same time.
What characterizes a propagated epidemic?
The infectious agent is transferred from one host to another, causing a gradual increase in cases.
What is a mixed epidemic?
An epidemic that begins with a single, common source of an infectious agent with subsequent propagated spread.
What is the purpose of investigating an epidemic?
To determine the specific cause or causes of the outbreak and take appropriate measures for control.
What are the steps in the investigation of an epidemic?
- Prepare for fieldwork
- Verify the existence of an epidemic
- Confirm the diagnosis
- Identify and count cases
- Describe the epidemic with respect to person, place, and time
- Identify the causes of the epidemic
- Manage the epidemic and follow up
What is a case definition?
A standard set of criteria to differentiate between cases and non-cases.
What are the types of case definitions?
- Confirmed/definite: Laboratory verification
- Probable: Typical clinical features without laboratory confirmation
- Possible: Fewer typical clinical features
What is an epidemic curve?
A graphical representation of the distribution of cases plotted over time.
What is the role of a spot map in epidemic investigation?
To study the geographic distribution of cases.
What should be assessed to identify the causes of an epidemic?
- Susceptibility of individuals
- Environmental conditions
- Breeding sites for vectors
What are general principles in the management of epidemics?
- Measures directed against the reservoir
- Measures that interrupt transmission
- Measures that reduce host susceptibility
What is passive surveillance?
A mechanism for routine surveillance based on passive case detection and routine reporting.
What are the advantages of passive surveillance?
- Covers a wide range of problems
- Does not require special arrangement
- Relatively cheap
- Covers a wider area
What are the disadvantages of passive surveillance?
- Unreliable, incomplete, and inaccurate data
- Data may not be available on time
- Lack of representativeness of the whole population
What is active surveillance?
A method where health officials proactively seek out cases and collect data.
What is passive surveillance?
A method of data collection that covers a wide range of problems without requiring special arrangements.
List advantages of passive surveillance.
- Covers a wide range of problems
- Does not require special arrangement
- It is relatively cheap
- Covers a wider area
What are the disadvantages of passive surveillance?
- Information is often unreliable, incomplete, and inaccurate
- Data is usually not available on time
- Desired information may not be obtained
- Lacks representativeness of the whole population
Define active surveillance.
A method of data collection focused on specific diseases for a limited period, involving data collection from communities through surveys.
What are the advantages of active surveillance?
- Collected data is complete and accurate
- Information is collected in a timely manner
What are the disadvantages of active surveillance?
- Requires good organization
- It is expensive
- Requires skilled human power
- Not a continuous process
- Directed towards specific disease conditions
In what situations is active surveillance appropriate?
- Periodic evaluation of ongoing programs
- Programs with limited time of operation
- New disease discovery
- New mode of transmission
- Disease affecting a new subgroup
- Reappearance of previously eradicated diseases
List the activities carried out under surveillance.
- Data collection and recording
- Data compilation, analysis, and interpretation
- Reporting and notification
- Dissemination of information
What are features of a good surveillance system?
- Combination of active and passive surveillance techniques
- Timely notification
- Comprehensive actions taken in response to notifications
- Availability of strong laboratory services for accurate diagnoses
What is the integrated disease surveillance system?
A strategy that coordinates and streamlines various activities from different programs to maximize the use of scarce resources.
What types of diseases are included in the integrated disease surveillance system?
- Top causes of high morbidity and mortality
- Diseases with epidemic potential
- Internationally required surveillance diseases
- Diseases with effective control interventions
- Easily identifiable diseases
List epidemic-prone diseases included in the priority list.
- Cholera
- Diarrhea with blood (Shigella)
- Yellow fever
- Measles
- Meningitis
- Plague
- Viral hemorrhagic fevers
- Typhoid fever
- Relapsing fever
- Epidemic typhus
- Malaria
What diseases are targeted for eradication and elimination?
- Acute flaccid paralysis (AFP)/polio
- Dracunculiasis (Guinea worm)
- Leprosy
- Neonatal tetanus
What are other diseases of public health importance?
- Pneumonia in children under 5 years
- Diarrhea in children under 5 years
- New AIDS cases
- Onchocerciasis
- Sexually Transmitted Infections (STIs)
- Tuberculosis
True or False: Viral Hemorrhagic Fever (VHF) is on the national priority diseases list.
False
What is the purpose of surveillance?
To monitor health conditions and inform public health policy.
What is the difference between active and passive surveillance?
Active surveillance involves proactive data collection, while passive surveillance relies on data provided by health institutions.
What is the most important use of active surveillance?
To gather complete and timely data on specific diseases.
What is an advantage of the integrated disease surveillance strategy?
It maximizes the use of scarce resources by coordinating surveillance activities.
