Epidemiology Flashcards
Definitions/ Examples
Define medical term of Case Studies
They are based on real-life outbreaks and public health problems and were developed in collaboration with the original investigators and experts from the Centers for Disease Control and Prevention (CDC).
Case Studies (WHO)
From “Strengthening health security by implementing the International Health Regulations,” each case has learning objectives and documentation.
Documented disease outbreak cases to reinforce, update, improve knowledge and practices for health threats.
Source: https://guides.lib.berkeley.edu/publichealth/PHW250/casestudies#:~:text=Epidemiologic%20Case%20Studies&text=They%20are%20based%20on%20real,Control%20and%20Prevention%20(CDC).
Define etiology
The scientific cause, causes of a disease, or manner of causation of a disease or condition.
“a group of distinct diseases with different etiologies”
Define index cases
The earliest known or suspected case of disease infection in an outbreak.
Fomites
Fomites (also called a passive vector) are inanimate objects that can be contaminated when one of these objects comes into contact with bodily secretions, like nasal fluid, vomit, or feces. Serve as a mechanism for transfer between hosts. The classic example of a fomite is a park water Fountain from which many people drink. Infectious agents deposited by one person can potentially be transmitted to a subsequent drinker.
Source : https://en.wikipedia.org/wiki/Fomite
Correlation vs Association
Association is a very general relationship: one variable provides information about another.
On this scale -1 indicates a perfect negative relationship. High values of one variable are associated with low values of the other.
Likewise, a correlation of +1 describes a perfect positive relationship. High values of one variable are associated with high values of the other.
0 indicates no relationship. High values of one variable co-occur as often with high and low values of the other.
Correlation is more specific: two variables are correlated when they display an increasing or decreasing trend. Correlation means that they move together (positive correlation indicates increasing and decreasing together, negative correlation means they move in opposite direction). Linear correlation is more specific still; then they move in proportion, not just in the same (or opposite) direction.
Define Endemic outbreak
Endemic means a disease that is always present in a population within a geographic area, typically year-round. For example, malaria is an endemic disease in parts of Africa south of the Sahara desert.
Define Sporadic outbreak
An infectious disease which occurs only infrequently, haphazardly, irregularly, or occasionally, from time to time in a few isolated places, with no discernible temporal or spatial pattern.
Examples depend on the time and place, because a disease that is common in one area may be rare in another.
In the United States, tetanus, rabies, and plague are considered examples of sporadic diseases. Although the tetanus-causing bacteria Clostridium tetani is present in the soil everywhere in the United States, tetanus infections are very rare and occur in scattered locations because most individuals have either received vaccinations or clean wounds appropriately. Similarly the country records a few scattered cases of plague each year, generally contracted from rodent animals in rural areas in the western part of the country.
Define Epidemic outbreak
An infectious disease that is occurring more than usually within a given region.
Yellow fever, smallpox, measles, and polio are prime examples of epidemics.
An epidemic disease doesn’t necessarily have to be contagious. West Nile fever and the rapid increase in obesity rates are also considered epidemics. Epidemics can refer to a disease or other specific health-related behavior (e.g., smoking) with rates that are clearly above the expected occurrence in a community or region.
Define Pandemic outbreak
The World Health Organization (WHO) declares a pandemic when a disease’s growth is exponential. This means the growth rate skyrockets, and each day cases grow more than the day prior. In being declared a pandemic, the virus has nothing to do with virology, population immunity, or disease severity. It means a virus covers a wide area, affecting several countries and populations.
Covid
Incidence - Disease Attack Rate
A variant of an incident rate, applied to a narrowly defined population observed for a limited period of time, such as during an epidemic, (total cases reported within observed time out of the total population).
The incidence measures new cases that develop or are diagnosed in a month or a year. For example, if there are 100 new cases of plague within a city of 1,000 people in one year, the incidence rate would be 10%. Likewise, if there are 80 new cases of plague in a city of 1 million people in a year, the incidence rate would be 8 per 100,000 people. Both methods of representation of incidence rate are accepted as they are both numerical statistical measures that are clearly recognized by the epidemiology and public health industries.
Source: https://www.gideononline.com/blogs/epidemiology-terms/
Prevalence - Disease attack rate
Prevalence is the share of a population affected by a given condition at a specific point in time. It can be assessed for various conditions, including diseases, risk factors, and health behaviors. Prevalence captures the total number of cases at a given point.
For example, epidemiologists can study the prevalence of chickenpox in different countries and regions to identify areas where the disease is more common.
Further info at: https://www.gideononline.com/blogs/epidemiology-terms/
Mortality Rate - Disease attack rate
Mortality is another term for death. A mortality rate is the number of deaths due to a disease divided by the total population. If there are 25 lung cancer deaths in one year in a population of 30,000, then the mortality rate for that population is 83 per 100,000.
Source:
https://www.health.ny.gov/diseases/chronic/basicstat.htm#:~:text=A%20mortality%20rate%20is%20the,divided%20by%20the%20total%20population.
Morbidity Rate - Disease attack rate
Morbidity is another term for illness. A person can have several co-morbidities simultaneously. So, morbidities can range from Alzheimer’s disease to cancer to traumatic brain injury. Morbidities are NOT deaths.
Source:
https://www.health.ny.gov/diseases/chronic/basicstat.htm#:~:text=A%20mortality%20rate%20is%20the,divided%20by%20the%20total%20population.
SALVADO:
Morbidity rate=
cases of a disease existing at a particular
time or cases occurring in a defined period of time / 100,000
What are the Limiting or exacerbating Factors (as Kimura would say intrinsic, extrinsic, or social factors) in disease causation?
(RESH study guide)
Age, Occupation, Health, Environmental factors, Behavioral Risk Factors, Virulence, Immunity (highly susceptible population have acquired immunity), Vaccination
(Kimura Defines)
Intrinsic factors: AGE, sex, race, genetic factors, immunologic state of individual.
Extrinisic factors: Personal habits, nutritional state, psychological state.
Social factors: Religion, customs, socio-economic status, social mobility, geographic mobility, OCCUPATION, marital status, education, place of residence.
Virulence - Limiting or exacerbating factors
Factors that are produced by a microorganism and evoke disease are called virulence factors. Examples are toxins, surface coats that inhibit phagocytosis, and surface receptors that bind to host cells.
Environmental - Limiting or exacerbating factors
Environmental hazards—like water and air pollution, extreme weather, or chemical exposures—can affect human health in a number of ways, from contributing to chronic diseases like cancer or to acute illnesses like heat exhaustion.
Behavioral Risk - Limiting or exacerbating factors
Several behaviors that exert a strong influence on health are reviewed in this section: tobacco use, alcohol consumption, physical activity and diet, sexual practices, and disease screening.
Age - Limiting or exacerbating factors
Some hearing and vision loss are a part of normal aging as is the decline in immune function. Cardiovascular disease and osteoporosis and dementia are common chronic conditions at age 85.
Occupation - Limiting or exacerbating factors
Examples of such pairs are Occupational exposure to benzene and Leukaemia and Occupational ergonomic factors and Back and neck pain, stretch your body!!. Several risk factors are linked with more than one health outcome, e.g. Occupational exposure to asbestos is paired to Larynx cancer but also to Mesothelioma.
Occupational skin diseases or disorders. Examples include contact dermatitis, eczema, or rash caused by primary irritants and sensitizers or poisonous plants; oil acne; chrome ulcers; chemical burns or inflammations. Respiratory conditions.
BE SAFE!!
Immunity/ vaccination - Limiting or exacerbating factors
Natural immunity results from being infected by a disease-causing organism, whether the infection is symptomatic or not. (highly susceptible population have acquired immunity; People of the Fulani ethnic group are more resistant to malaria compared with genetically distinct ethnic groups, such as the Dogon people, in West Africa )
Vaccine-induced immunity results from being exposed to killed or weakened bacteria or viruses—or even just important pieces of them—through vaccination.
ACTIVE IMMUNITY - Immune system is responding to exposures
Sex - Intrinsic factors
Females have increased resistance to viral, bacterial, fungal, and parasitic organisms than males. Females are less susceptible to microbial infections. Females have a higher innate immune response than males.
Name the common modes of exposure aka portals of entry and exit.
REHS Study Guide (Kimura references)
Fecal/oral (oral/digestive
Second most common route of infection)
Exudates of mucous membrane (respiratory system Most common route of infection)
Bloodborne (Injections e.g. needle sticks)
Dermal exposure (skin body’s largest organ; dermatitis *Most common occupation disease by exposure to chemicals and pollutants)
(Eyes - Conjunctiva)
Describe the skin’s beneficial properties, maintenance, and how bacteria or toxins can enter/exit.
MOST COMMON OCCUPATIONAL DISEASE
Skin is the largest protective barrier that has trama defenses for temperatures. The skin has sensory signals for heat, cold , pain exposures. Resilient collagen tissues and has self repairing properties.
Personal hygiene is required to maintain clean skin.
Toxic material such as liquid solubles can penetrate that skin and may be excreted through sweating.
Describe the respiratory system’s defense mechanisms/ characteristics.
MOST COMMON ROUTE OF INFECTION
An important function of nasal passage is to warm, humidify, and clear the path of inhaling large particles.
Windpipe and Bronchi cilia carry the mucous with contaminates up to the esophagus.
Bronchial tubes cause a sneezing or coughing response to clear contaminates from the body.
Alveoli are tiny balloon shaped air sacs located at the end of bronchial where phagocytosis occurs (process when the white cells engulf an infectious or foreign cell, usually smaller than 0.5 microns).
