WEEK 4 Flashcards
What is the purpose of Epidemiology (“the study”)?
- describes health-related events by answering: who, what, when, and where by following trends in the population
- further expands to examine how & why by examining causality & modes of transmission
- results in implementing controls to prevent new illness, cure if possible, & rehabilitate or prevent complications
Define how to use the Epidemiologic Model
Host, Environment, Agent
What are the 2 different Modes of Disease Transmission
Direct transmission - contact between the person with the disease & another through skin-skin or sexual contact
Indirect transmission - involves a common vehicle or vector (water, vector, vehicle, etc.)
What is Natural History of Disease?
refers to the progress of a disease process in an individual over time, in the absence of intervention/tx
What does the process of the Natural History of Disease begin with & end with?
Begins with exposure to
Ends with recovery, disability, or death
What are the 2 phases of the Natural History of Disease?
- Pre-pathogenesis (process in the environment) &
Pathogenesis (process in the man)
Pre patho = primordial, primary prevention
Patho = secondary, tertiary, quaternary prevention
What is susceptibility?
- interacts with factors present or absent in other elements of the epidemiologic triangle
- factors may increase or decrease with susceptibility
Association vs Causation
- when do we use these?
When considering the relationship between exposures and health outcomes
Association = Is a specified health outcome more likely in people with a particular “exposure”? Is there a link? Association is a statistical relationship between two variables (Exposure/Outcome)
Causation = means that the exposure produces the effect. It can be the presence of an adverse exposure, e.g., using illicit drugs, or breathing in second hand smoke. Causative factors can also be the absence of a preventive exposure, such as not wearing a seatbelt or not exercising
What is the Web of Causation?
- are factors linking social determinants of health & biomedical factors
- rarely is there ever one causative factor to any disease or illness
Mortality Rates
“death rates”
Crude Mortality Rates
- compares the # of deaths from a specific cause within the entire population
Specific Mortality Rate
- compares the # of deaths from a specific cause in a particular subgroup with that whole subgroup
Morbidity Rates
- illness rates that give a picture of a population & a disease/ health challenge over time.
- suggests susceptibility or effectiveness of health promotion/tx strategies
ex. in a city with a population of 2 million in one year, 10,000 people are suffering from a particular disease
Prevalence Rates
specific disease process in a population at one given point in time
Formula = # of people with given disease in a population during a specified time period. Divided by the total in a given population at the same point in time
Incidence Rates
- describes the identification of new cases of a disease in a population over time
Formula = # of new cases of a given disease in a population during a specific period of time. Divided by average total population within the same specified time period
What was the first recorded worldwide threat from a communicable disease?
Bubonic plague “Black Death”
Smallpox
- type of virus?
- symptoms?
- who created the vaccine?
- is an acute contagious disease caused by the variola virus (orthopoxvirus family)
- starts with high fever, head + body aches, nausea/vomiting. Rash then starts as red spots on tongue + mouth which turn into sores & break open then spreading to the face/arms/hands/feet. Sores become pustules (firm to touch) then form a crust & scab.
- vaccine created by Edward Jenner in 1796
Tuberculosis
- type of virus?
- symptoms?
- reportable disease?
- latent TB infection?
- is caused by the mycobacterium tuberculosis (airborne) & is spread when someone w the disease of the lungs or throat coughs, sneezes etc.
- sickness or weakness, weight loss, fever, night sweats
(lungs) coughing, chest pain, coughing up blood - reportable but latent disease not reportable
- People with latent TB infection have TB germs in their bodies, but they are not sick because the germs are not active. These people do not have symptoms of TB disease, and they cannot spread the germs to others. However, they may develop TB disease in the future. They are often prescribed treatment to prevent them from developing TB disease.
- People with TB disease are sick from TB germs that are active, meaning that they are multiplying and destroying tissue in their body. They usually have symptoms of TB disease. People with TB disease of the lungs or throat are capable of spreading germs to others. They are prescribed drugs that can treat TB disease.
What disease spread quickly amongst Indigenous Peoples, & why?
TB spread quickly due to social conditions & low immunity
What is the chain of infection?
Infectious agent, Reservoirs in Healthcare, Portals of exit, Routes of transmission (refer to notes for more info), Portals of entry, Susceptible host
What are the possible 2 types of Infections an Reservoir can contract?
Endogenous flora = “within” “born from”
- we get infected with our own bacteria (own microflora)
Exogenous flora = “outside” “born from”
- involves a pathogen entering the pt’s body from their environment
What are the different types of Contact Precautions?
Droplet precautions, Droplet/contact precautions
What is the order of Donning PPE?
- Hand hygiene, Put on gown, Put on masks +/- N95, Put on Eyewear, Put on gloves
What is the order of Doffing PPE?
Remove gloves, Remove gown, Hand hygiene, Remove eye protection, Remove mask +/- N95, Hand hygiene
Herd Immunity / Community Immunity
is when a large portion of a community (the herd) becomes immune to a disease
“Live” Attenuated Vaccine
- who shouldn’t receive these?
- examples?
- contains a version of the living virus/bacteria that has been weakened so it will not cause serious disease in healthy immune systems
- people with weakened immune systems are not encouraged to receive live vaccines (contraindicated while receiving active chemotherapy/radiation)
- Measles, Mumps, Rubella (MMR) *received at 1 y/o, Varicella (chickenpox) *received at 15 months
What age do you receive the Measles, Mumps, Rubella (MMR) vaccine?
- what type of vaccine is it?
1 year old then @ age 4-6 (2 doses)
- “Live” Attenuated Vaccines
How do you break the chain of infection?
Break the chain of transmission
- can be done by appropriate use of barriers & adherence to hand hygiene
When do you receive the Varicella (chickpox) vaccine?
- what type of vaccine is it?
- at 15 months (can get a second dose)
- “Live” attenuated vaccine
“Non-live” Vaccines
- examples?
“Inactivated”
- made by inactivating/killing the germ in the process of making the vaccine
- typically require multiple doses to build immunity
- inactivated polio vaccine, Hepatitis A, Influenza, Rabies
When is the Inactivated Polio vaccine given?
- what type of vaccine is it?
- given at 2, 4, 6, 18 months (4 doses)
- “non live” vaccine
Toxiod Vaccines
- examples?
- prevent diseases caused by bacteria that produce toxins in the body
- in the process of making the vaccine, toxins are weakened so that they cannot cause illness (weakened toxins are called toxoids)
- Tetanus + Diphtheria
When is the Influenza vaccine given?
- type of vaccine?
- Can receive on every fall starting at 6 months
-“Nonlive” vaccine
When do you get the Heptatitis A Vaccine?
- type of vaccine?
- 12 through 23 months of age, then second dose 6 months after the first
- “nonlive” vaccine
When do you get the Tetanus + Diphtheria (TDAP) vaccine?
- type of vaccine?
- 2,4,6,18 months (4 doses)
- toxoid vaccine
Subunit Vaccines
- examples?
- include only a part of the pathogen instead of the entire organism (don’t contain live pathogen)
- Pertussis (whooping cough) component of the TDAP
When do you get the Pertussis (whooping cough) vaccine?
- type of vaccine?
- 2,4,6,18 months (4 doses)
- Subunit vaccine (component of TDAP)
Conjugate Vaccines
- examples?
- fight a type of bacteria that has antigens
- bacteria with antigens have an outer coating called polysaccharides that disguise the antigen, making it hard for immature immune systems to recognize and respond to it
- these vaccines connect the polysaccharides to antigens and helps the immune system respond
- Haemophilus influenza type B (HIB)
When do you get the Haemophilus influenza type B (HIB) vaccine?
- type of vaccine?
- 2,4,6,18 months (4 doses)
- conjugate vaccine
There are over ___ different bacterial viral & parasitic infections (STI’s)
30
What are the 4 reportable STI’s in Canada?
Chlamydia, gonorrhea, syphilis, & HIV
Entreic Infection
- enter the body through the mouth, and intestinal tract and affect the digestive system
- Primarily seen through eating/drinking contaminated foods or liquids
- Direct contact with contaminated feces or vomit is a secondary method for acquiring an infection
Food-Borne Infection + Intoxication
- Are acquired through the consumption of contaminated food
- The most common include:
Toxins released by bacterial growth in food (Clostridium botulism, Staphylococcus aureus, Bacillus cerens) or in the intestines (Clostridium perfringens)
Water-Borne Pathogens
Bacteria that enters water supplies through fecal contamination from animals or humans
Zootonic Diseases
Diseases transmitted between animals & humans
transmission occurs through bites, inhalation, ingestion, & direct contact
What is available after exposure to rabies with consultation with public health officials?
Post-exposure prophylaxis (PEP)
Vector-Borne Infections
- caused by viruses, bacteria, & parasites that living creatures carry & pass on
- disease carriers called “vectors” are usually mosquitoes, ticks (lyme disease)
What are the levels of preventative measures for a CHN?
Prophylaxis (vaccination)
Education
Screening
Isolation + Quarantine
