Bio260 Highline College Stage 01 – Disease Transmission Natural Phenomenon: How do epidemics get started and what can we do to prevent it from happening? What is a model? In science models are a set...

Bio260
Highline College
    Stage 01 – Disease Transmission
Natural Phenomenon: How do epidemics get started and what can we do to prevent it from happening?
What is a model?
In science models are a set of ideas that, together, are used to try to explain how natural phenomena might work. A model may be a graph, a diagram, a set of ideas set down in words, or anything that can be used to represent the phenomenon. For example, a drawing of a cell is not a real cell, but helps us to explain what a real cell might look like. Another example is a flow diagram of a metabolic pathway like glycolysis. Although it is not the real molecules going through real chemical reactions, it helps us to explain how the metabolic pathway works. Both of these are models that, although they are not the real biological phenomena, represent the phenomena and help us to explain how they work. Your textbook is FULL of models!! How were these models created? A scientist or a team of scientists would write down their initial model (a set of ideas of how they think something might work), test that model through li
ary research and experimentation, revise their model as new knowledge is learned, and then go through the process of testing and revising again and again. Hopefully, through this iterative process of creating, testing, and revising, their model comes closer and closer to explaining how that phenomenon actually works in nature. Models can then be used to predict how your system might respond if you pertu
ed it in some specific way. For this explanatory model you will become an epidemiologist working for the CDC. Your job is to explain how the COVID-19 pandemic might have started in the US and what the public can do to stop it and prevent it from happening in the future.
1. Using data to describe what is happening during an epidemic/pandemic:
During an epidemic/pandemic you will be obtaining a lot of different types of data in order to understand what the trends are in the data, and how the data can help you to understand what you need to do to stop it and to prevent it in the future.
· COVID-19: First, find different graphs in any of the following online resources (listed next page) that shows COVID-19 data about each one of these terms (1 term is to be used per graph).
· Copy and paste your graphs.
· Use APA7 to cite your sources (Purdue University APA Guide)
· Define the following terms
· And then explain the trend(s) in those graphs concerning that term.
· incidence                                
· mortality
· pandemic
· proportion of any population vaccinated in an area of King County that you choose.
· chance of testing positive, being hospitalized, and dying of COVID-19 when unvaccinated compared to being vaccinated.
· C. difficile: Second, find different graphs in any of the following online resources (listed next page) that shows data about C. difficile for each one of these terms (many terms can be used per graph, as long as you explain them).
· Copy and paste your graphs.
· Use APA7 to cite your sources (Purdue University APA Guide)
· Define the following terms
· And then explain the trend(s) in those graphs concerning that term.
· Incidence of Healthcare-Associated C. difficile cases over time (See HAICViz link below)
· Influenza: Third, find different graphs in any of the following online resources (listed next page) that shows data about Influenza for each one of these terms (many terms can be used per graph, as long as you explain them).
· Copy and paste your graphs.
· Use APA7 to cite your sources (Purdue University APA Guide)
· Define the following terms
· And then explain the trend(s) in those graphs concerning that term.
· incidence
· endemic
· epidemic
Online resources:    
· Seattle & King County Public Health (https:
www.kingcounty.gov/depts/health/covid-19/data/daily-summary.aspx)
· Washington State Department of Health (https:
www.doh.wa.gov/)
· Centers for Disease Control and Prevention (https:
www.cdc.gov/)
· World Health Organization (https:
www.who.int/)
· Johns Hopkins Coronavirus Research Center (https:
coronavirus.jhu.edu/map.html)
· HAICViz, CDC website to look at HAI data (https:
www.cdc.gov/hai/eip/haicviz.html)
2. Explaining the chain of infection for the virus SARS-CoV-2 (the virus that causes COVID-19)
· Draw a picture of the chain of infection (Fig 19.2).
Then explain each part of that chain as if you were an epidemiologist working to understand how a novel microbe is being transmitted. The CDC Website is a good resource for this section. https:
www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/how-covid-spreads.html
Be careful not to plagiarize!! Read it, then put it away. Use your knowledge of these terms from your textbook to explain how COVID-19 disease transmission happens.
Explain how SARS-CoV-2 is transmitted using each of the following key words:
· Reservoir – define this
· Humans
· Symptomatic
· Asymptomatic
· Non-human animals?
· Portals of Exit and Entry
· (draw a stick figure and label the possible portals for SARS-CoV-2)
· Disease Transmission
· Horizontal transmission
· Direct Transmission
· Direct contact
· Droplet transmission
· Indirect Transmission
· Ai
orne (droplet nuclei)
· Vehicle-borne
· Fomites
3. Factors to Conside
OK, so you’ve got data to help you to understand what is going on during this pandemic and you’ve na
owed how the chain of infection is happening for this particular pathogen. Now to consider how other factors about the pathogen, the host, and the environment affect the spread of disease.
· Characteristics of the Pathogen
· What is a virulence factor? How do they affect the spread of disease?
· How does a large dose compared to a small dose affect the spread of disease and symptoms?
· How does the length of the incubation period affect the spread of disease?
· Do we know any of these things for SARS-CoV-2? What are they? Provide references.
· Characteristics of the Host
· How does personal immunity and herd immunity affect the spread of disease? Define both terms and how they are different in your explanation.
· How does the general health of the person affect the spread of disease?
· How does the age of the person affect the spread of disease?
· How does the gender of the person affect the spread of disease?
· How do behavioral practices affect the spread of disease? Particularly with respect to COVID-19
· How does genetic background affect the spread of disease?
· Do we know any of these things for SARS-CoV-2? What are they? Provide references.
· Characteristics of the Environment
· What environmental factors should be considered in the spread of disease?
4. What are special considerations for healthcare institutions concerning disease transmission?
· Describe the chain of infection in a healthcare setting:
· Describe in detail the special reservoirs of infection there:
· Other patients
· Healthcare environment
· Healthcare workers
· Describe the modes of transmission there:
· Direct transmission
· Healthcare Personnel
· Indirect Transmission
· Describe the following types of HAIs and the Medical Devices associated with their use:
· CLABSI
· CAUTI
· SSI
· VAP
· Ai
orne
· Describe all of these Standard Precautions that are taken in a healthcare setting to prevent disease transmission (Don’t just list these! Actually provide a short description (sentence or bullet point) of each):
·
· Hand hygiene
· PPE
· Cough etiquette
· Patient placement
· Patient-care equipment
· Care of the environment
· Textiles and laundry
· Safe injection
· Safe practices for lumbar puncture procedures
· Worker safety
5. Understanding the basic reproductive number, R0 for COVID-19
· What is the definition of the basic reproductive number (in words)?
· What is the mathematical formula for R0? Explain what ß, S, and L mean.
· What happens when R0 > 1?
· What are the cu
ent hypotheses for the R0 for SARS-CoV-2? (do some research; cite your source)
· How can we reduce R0? In other words, what can we do to reduce ß? To reduce S? To reduce L?
· Using the terms “critical immunization threshold (pc)”, “R0”, and “herd immunity”, explain this graph:
· How did the SimBio Lab help you to understand the importance of vaccination and herd immunity?
· Provide specific examples from the Lab (like specific information about measles or smallpox).
· How does the SimBio Lab help you to understand the COVID-19 pandemic? Use the SIR model, R0, masks, physical/social distancing, and noncompliance in your explanation.
6. Microbial Structure
Wow! Now that we know a lot more about how diseases spread and what we can do to prevent them, let’s look more closely at the structure of these microbes so we can understand how to prevent their transmission with microbial control methods.
· Draw a SARS-CoV-2 virus
· Nucleic acid (be specific – what type?), capsid, nucleocapsid, envelope, spikes
· Fill out the following table:
    Viral structure
    Made out of ca
ohydrate, protein, lipid, DNA, RNA?
    nucleic acid
    
    capsid
    
    envelope
    
    spikes
    
· Draw a Clostridioides difficle (C. diff) bacterium
· Chromosome in nucleoid region, plasma mem
ane, cytoplasm, ribosomes, cell wall, capsule, flagella, pili, endospore, spore coat.
· Fill out the following table:
    Bacterial structure
    Made out of ca
ohydrate, protein, lipid, DNA, RNA (list all that apply)?
    Chromosome in nucleoid region
    
    Plasma mem
ane
    
    ribosomes
    
    Cell wall
    
    flagella
    
    Pili
    
7. Microbial control
One way that we can stop disease transmission is by killing or reducing the numbers of microbes in the environment.
What happens to a protein when it becomes denatured? What type of bonds
eak?
What would happen to a vegetative bacterium or a virus if its proteins were denatured?
How resistant are enveloped viruses to chemical and physical treatments?
How resistant are endospores to chemical and physical treatments?
Compare in detail how hand-washing vs alcohol-based sanitizers work.
Do they both work for SARS-CoV-2? Why or why not?
Do they both work for C. diff? Why or why not?
Describe two methods for sterilizing medical equipment and how they work to kill microbes. (Explain in detail how they work AND what they do to certain molecules of the microbes to kill them).
Describe two chemicals (and how they work) that you can use at home to get rid of SARS-CoV-2. (Explain in detail how they work AND what they do to certain molecules of the microbes to kill them).