Infectious Disease - Lecture 26 Flashcards
What does SARS stand for?
Severe Acute Respiratory Syndrome
What is SARS?
It’s a type of coronavirus
Why were the phases of the Toronto SARS Outbreak fluctuating?
Waves of infection were caused by weather and variants of mutation
How is Influenza Virus named?
With an H and N (molecules on the virus)
What did Influenza virus help us realize?
Infectious disease can arise from other things like animals and spread to humans.
What caused infectious disease mortality risk to drop?
Vaccines that helped slow viruses down but not bacteria
Sanitation improvement
Fought against bacteria and lowered mortality risk
Because of movement in WW1 sanitation was terrible, causing Spanish Flu. What did this lead to?
Spike in mortality risk
By how much per 100,000 cases did people die of infectious disease?
50 to 339 from 2019 to 2020 respectively
What is a Rnot
How many people an infected person can spread a infectious pathogen to
Rnaught of 1?
One infected person infects one person
Exponential growth
Rnaught has an exponential growth so the bigger rnaught is the more people get infected
Close contact with livestock
Livestock may have disease and can spread it to you
If you already have a disease and then get infected with a virus?
Increases your risk for mortality even more.
Symptoms of respiratory virus
Fever, Dry Cough, Fatigue, Shortness of breath
Why is fever a good thing?
Fever is showing that your body is fighting; it’s having an inflammatory response to fight it off.
Why is Covid-19 in water droplets good?
Because limitation of spread is limited to 6-8 feet. If airborne where virus can survive in air, it would be bad.
How did we act to fight off virus
Quarantine and isolate at home
What is isolation?
Separates sicks with contagious disease from those not sick.
What was unique about the Black Death
It was a bacteria infection; sanitation was poor which allowed it to kill
What is Covid’s global death marker
7th
Who was most affected by smallpox
Kids in the fall and winter; it was seasonal.
Variola Virus
Small pox virus which would affect skin and respiratory system
MMR Vaccine
Dropped measles cases
Understanding balance of risk with benefit
Taking vaccine or not
Anti-vax protest getting more momentum
Measles cases are increasing because of this recently
How does a vaccine work?
Primes your immune system to fight off the infection the next time it comes around.
How do Immune cells prepare to fight
Take the mRNA into cell and creates a spike protein which tells them where to find the virus and kill.
Disease or Syndrome
Pathological condition of the body; named based on symptoms
Infectious disease
Disease caused by an infectious agent (Know what caused the symptoms)
Can you take a vaccine for a bacterial infection?
No
Antibiotics for Viral Infection
No
When an infectious agent enters the body and reproduces; can lead to disease
Infection
Protozoa
Organism in food
Pathogen
Infectious agent
What’s carrying the pathogen
Host
How quick the infectious agent can spread
Virulence
Do Bacteria respond to antiviral medication
No, only antibiotics
Antiviral medication
Used to fight off viruses specifically
What are prions
Found in cow’s bone marrow; causes mad cow’s disease and they’re impossible to kill
Pathogens give you a symptom and it leads to recovery, survive infected or die.
Summary of how pathogens work
What hosts do viruses infect
Animals, plants, bacteria, usually a specific tissue
What hosts do bacteria infect
Animal & plants, and affect the organism entirely.
How are viruses different than bacteria in the way they reproduce
Uses DNA/RNA of host to reproduce while bacteria has it’s own DNA to reproduce.
Which is bigger?
Bacteria
Where do bacteria get their energy when reproduing?
Takes energy from cells of the host.
Surface proteins of Influenza allow the infection to do what?
The H’s and N’s; that allow virus to get in and out of the cell.
Antigen?
Surface proteins are markers to let your immune system know there is a foreign invader.
H1N1; what do the 1’s indicate?
Influenza; what subtype of H and N proteins is on the surface.
Hemagglutinin
Allows virus to enter host cell
Neuraminidase
Allows virus to escape host cell
How can you check the virulence of H’s and N’s
Based on Rnaught
Does Covid have surface proteins?
Yes, spike proteins not H’s and N’s
SARS mutated to give what main symptom?
Severe respiratory issue
What part does a bacteria have that a virus doesn’t to make it move
Flagella
Why was black death not possible to fix
It was a bacteria; no sanitation and antibiotics
How does antiviral medication work
Block surface proteins of viruses from replicating
Who discovered antibiotics
Alexander Flemming’s and his moldy bread
Bacteria that are antibiotic resistant
MRSA, C. difficile, CRE, and VRE
MRSA
staph bacteria passed through touch; found in medical equipment
C. difficile
In human feces, and passed through touching infected surface and touching mouth
CRE
Bowel and feces; in patients using ventilators, urinary catheters.
VRE
In intestines and female genital tract; spread through touch
What is sepsis?
Bacterial infection spreads into bloodstream
Why should you take all your antibiotics
Because you want to kill every single bad bacteria or else it will become resistant to it.
What is the best barrier of protection from disease
Skin
Lymphatic System
Apart of immune system; helps drain lymph which is made of WBC’s into bloodstream
Swollen Lymph Nodes
Means it can be infected
What does the spleen do?
Processes WBC and creates inflammation when there is an infection
Thymus gland
Located in the neck, creates T cells
What do leukocytes look for when hunting viruses and bacteria
Antigens
Macrophages take the antigen of engulfed invader and use it to track other invaders with the same antigen
Special Property
What happens when you get a wound.
Mast cells releases histamine increasing bloodflow
What does histamine do?
Causes inflammation so capillaries leak and release phagocytes; also alerts immune system to mobilize
What do the phagocytes do once released?
Engulfs the bacteria, dead cells and debris
How is the wound sealed?
Platelets move out of capillary to seal wound.
Why is histamine commonly released?
Allergic reaction
Too much histamine is bad as it can cause a terrible response
Amount of histamine
What are signs of inflammatory response?
Swelling, redness, heat, histamine causing blood vessels to dilate
What would happen if histamine response was too high?
Can go into respiratory failure because of overactive immune response
What are the two groups of immune cell responses
Innate and Adaptive
Macrophages, Mast Cells, Neutrophils, Basophils, Natural Killer Cells. (Born with these)
Innate Immune Cells
Body adapts/acquires them (T Cells, B cells)
Adaptive/Acquired Immune Cells
Why do B cells and T cells need to be made every time there’s a new infection
Because if the invader comes back but with different antigens, you need to have new T cells and B cells to fight them.
A non-specific defense that acts immediately after exposure
Innate Immunity
What are the main WBC’s in the non-specific defense fighting?
Macrophages and Neutrophils
What do the Neutrophils and Macrophages do after fighting invader?
Calls in “special forces” which are the acquired immunity cells like antibodies to remember the invader.
What are B cells?
Made in bone, produce antibodies once recognizing a specific antigen
Why are B cells double edged?
It only responds to virus of a specific antigen, so when mutation occurs the antibodies it produces won’t work. Hence, vaccines needed.
T cells have two sub cells
CD8 (supressor and killer) and CD4 (helper T-cell) primarily used in killing
Helper T cells are called in by macrophages and alert Killer T and B cells. T cells kill infected body cells and B cells produce antibodies that attack to virus so macrophages can destroy
Summary of Acquired Cells Job
