Week 10 + 11 + pre-midterm material Flashcards

Question

What is **immunogenicity**

Answer 1

Ability of an organism to create a immune response after an infection that is capable of providing protection against re-infection by the same or similar organisms

Answer 2

**Inapparent infection:**Has the disease/is infected but is asymptomatic - Usually short-lived **Carrier state:**Person or animal has the infectious agent, doesn't show symptoms and can still transmit it to others - Usually long-term

Answer 3

- No infection - Subclinical infection - Clinical infections w/ varying severity

Answer 4

- The foundation of epidemiology and public health - Key way to discovering emerging + re-emerging pathogens - Characterize disease in terms of person, place, and time - Only observing for intervention not testing it

Answer 5

- Quantifies the relationship between exposure and disease among 2 groups - Can't show causations, only how strongly 2 things are associated - Bradford hill criteria can be helpful to provide evidence for possible causal relationship

Answer 6

The number of existing cases of a disease at a point in time/ population **Numerator:**people who are ill, have specific symptoms, or evidence of infection but asymptomatic **Denominator:**number of people in the population who are susceptible to the disease or were exposed Expressed as proportion or percentage **Use of prevalence** - Tells us how many people have the disease - Estimates the probability that an individual will have the disease during a point in time - Estimates the cost associated with the specific disease - Project health care and other policy needs or issues

Answer 7

# of new cases of disease within a time period/ # of people at risk in the population at the BEGINNING of the specified time period The measure of the risk of developing the disease within a specified period of time **Cumulative Incidence** # of new cases of disease during a time period/ # of people at risk in the population at the BEGINNING of the specified time period **Incidence Rate** - Measure of the rate of development of a disease in a population - Measures how quickly people are developing the disease of new cases of disease during a time period/ # of person-years when people were at risk of developing the disease - Unit = person years of follow up (xx cases per 1000 person years of observation) **Use of cumulative incidence** - Estimates the probability that a person will develop the disease during a specific time period - Research on causes, prevention and treatment of disease

Answer 8

They are related to each other by duration of disease Prevalence ~ Incidence x Duration Can be seen using the bathtub model: incident cases/births/immigration/recoveries are coming in, bath water = prevalent cases, deaths/emigrations/recovery is going through the pipe **If disease duration is short** = the prevalence almost equals the incidence **If disease duration is long** = prevalence will include both new and previous cases and will be GREATER than incidence

Answer 9

1. the suspected agent had to be present in all infected individuals 2. the agent has to be isolated + grown in pure culture (it’s only the one agent in the culture) 3. the cultured agent will cause the disease once injected into a healthy and susceptible host 4. the agent that was injected into the host can then be reisolated

Answer 10

**microbiota:**a population of microbes that are in a area of an individual (example: GI tract) the microbiota can be different across different sites of the body and can be different from person to person **microbiome:** all of the genomes and genes of a microbiota **dysbiosis:** a change in the microbiota’s structure or function which creates a disruption in the homeostasis/balance between the microbial community and its host **mycobiome:** part of the microbiome consisting of the fungi that line in or on a host

Answer 11

- information about exposure and disease status is collected all at once - temporal: point in time

Answer 12

- picks sample based on people who has disease and who doesn’t have disease - looks back in time to collect information about exposure - temporal: point in time or retrospective data - best to use this design for when the disease is rare

Answer 13

- picks sample based on people who have been exposed and who has not been exposed - follows sample over time to see if they develop the disease or not - temporal: follows subjects over time - either prospectively or retrospectively

Answer 14

- picks sample based on people who have the same disease status but have been exposed to different things - sample gets followed over time to determine outcome - temporal: follows subjects over time - prospectively

Answer 15

-**Temporality:** cause comes first and then effect - Strength of Association: stronger the association = more likely the relationship is causal - **Consistency:** consistent findings from different studies and populations strengthens the likelihood that the relationship is causal - **Dose-response relationship:** greater exposure = greater the incidence of the disease (disease is occurring more often in the population?) - **Biological Plausibility:** if there’s a reasonable biological mechanism between exposure and disease known - this can increase the likelihood of there being a causal relationship - **Specificity:** if the exposure influences a specific outcome or population with no other explanation - **Coherence:** the findings between epidemiology and lab align with each other are draw to the same conclusion - **Experiment:** causation is more likely if the evidence is based on randomized experiments - **Analogy:** if there is known strong evidence of a casual relationship between a specific exposure and outcome - researchers should be more accepting of weaker evidence of there being a causal relationship between a similar exposure and outcome

Answer 16

**Gram positive** - Has multiple peptidoglycan layers - Is thick and rigid **Gram negative** - Has one peptidoglycan layer in between his outer and cytoplasmic membrane - It is flexible, porous, and helps with regulating osmosis of the cell

Answer 17

**mass spectroscopy using MALDI-TOF:** - a type of mass spectroscopy method - laser is used to ionize protein molecules which come from bacterial isolate (pure culture of the bacteria) - the now ionized molecules get put through a vacuum + the speed they travel at through the vacuum depends on its protein’s mass to charge ratio - the different speeds of the molecules are presented on to a screen - the speeds are unique to a species which can help identify the organism or the species of the organism **PCR - molecular based methods:** when we’re looking for a specific bacteria - can be **SINGLEPLEX** (1 pathogen) or **MULTIPLEX** (more than 1 pathogen that can cause the disease)

Answer 18

it’s a test to see if a drug works against the pathogen done in vitro - they put a bug and a specific concentration in a tube and look at the growth of the bug they are looking for the lowest concentration of drug that can stop the pathogen from growing - this is call the **MINIMUM INHIBITORY CONCENTRATION (MIC)**

Answer 19

**1. broth microdilution** the MIC is shown where the concentration has visibly stopped the bug’s growth - dark gray in this case or clear tube **2. gradient strip diffusion** the MIC is seen where the ellipse meets the strip **3. disk diffusion** measures the diameter of the area of growth inhibition large enough = the bacteria is susceptible to this drug/drug works against the bacteria too small = the bacteria is resistant to the drug

Answer 20

**Latency**: when the virus is hidden or inactivated in a host cell - when this occurs symptoms are not seen and can be difficult to detect viruses can either… - have **circular viral genome molecules** which is **outside** of the host cell’s chromosome - have **proviruses** be integrated in the host cell’s genome

Answer 21

an infection caused by a microorganism that normally doesn’t cause a disease but can become pathogenic and cause a disease when the immune system becomes weak

Answer 22

these are **positive single stranded** RNA viruses that create viral DNA the DNA gets integrated into the host cell’s chromosome **Provirus** = what the viral genome that gets integrated is called

Answer 23

**Antigenic drift** - point mutations (1 base) that causes slight change in the spike proteins/glycoproteins - for **influenza** - spike proteins HA + NA constantly have antigenic drift - this results in seasonal variations in influenza - vaccines are updated for each time the spike proteins change **Antigenic shift** - big changes in spike protein from reassortment (mixing of genetic material) - for **influenza** - 2 different influenza viruses (viruses that come from different species) end up infecting the same host cell + exchange genetic material - this leads to a new strain with the new mix of HA/NA proteins

Answer 24

**1. attachment** - viruses attach to the host cell via its receptors - viruses are tissue specific (**tissue tropism**) - they’re specific in the tissues they’re attacking **2. entry** - either the virus or the genetic material enters the host cell **3. genome replication + gene expression** - the genetic material gets replicated and those genes encode for **viral proteins** **4. assembly** - new viruses or viral particles get assembled **5. release** - new viral particles leave the cell and infect other cells

Answer 25

**PrEP** - people without HIV use this as a preventative measure - it is a cART - combination of antiretroviral therapy - decreases their chances of getting HIV - useful for when one partner has HIV and the other doesn’t or for people who inject drugs **PEP** - it is a cART - combination of antiretroviral therapy - emergency method for people who have been exposed to HIV - they take it for a few months after exposure - they have to start taking it 72 hours after being exposed

Answer 26

contains… - nucleic acid (DNA or RNA) - capsid/protein coat (this has the basic necessities/materials to create new virions) - MAY have envelope (small part of the host cell’s phospholipid bilayer when the virus buds off) - MAY have spikes (glycoproteins that allows virus to attach to the host cell’s receptors and enter)

Answer 27

**Yeasts** - single cells - reproduces via budding **Mold** - multicellular bodies - made up of filaments (protein) called **hyphae** - **Septate Hyphae** can have walls between hyphae - **Nonseptate Hyphae** does not have walls between hyphae **Dimorphic Fungi** - can be either yeasts or mold - depends on **environment** - 25 degrees = mold - 37 degrees = yeast

Answer 28

**Spectrum of activity**: the range or diversity of bacteria that the antibiotic targets **Narrow spectrum**: targets only a certain group of pathogens (e.g. ONLY gram-positive) **Broad spectrum**: targets a wide group of pathogens (e.g. both gp + gn)

Answer 29

**1. Bactericidal**: kills the target bacteria **2. Bacteriostatic**: stops the growth of the bacteria but doesn’t kill it - causes **reversible inhibition** which allows for bacteria to grow again once drug is eliminated

Answer 30

**1. Lag phase** = NO increase in number of living bacteria **2. Log phase** = exponential increase in number of living bacteria - actively dividing via binary fission - this phase is the best for antibiotics to target b/ this is where a lot of the bacteria is in the middle of being created + antibiotics can ruin this process - specifically antibiotics that target the synthesis of DNA, cell wall, and proteins **3. Stationary phase** = number of living and dead bacteria is the same, there is no increase or decrease to the amount of living bacteria, the amount is staying the same - nutrients get used up and waste products accumulate - the synthesis of nucleic acids, proteins, and peptidoglycans slow down which also makes them less susceptible to antibiotics - in this phase - bacteria may go into survival mode by creating virulence factors or endospores **4. Death or Decline phase** = exponential decrease in number of living bacteria

Answer 31

**Step 1: Crystal Violet** Stains cells purple or blue **Step 2: Iodine** Makes the CV adhere to the cell walls - Stains cells purple or blue **Step 3: Alcohol** Washes away the dye from gram-negative - GP: purple or blue - GN: colourless **Step 4: Safranin** Dyes GN cells - GP: purple or blue - GN: pink or red

Answer 32

Looks for an antibody response to the pathogen

Answer 33

**Silver stain**

Answer 34

**Virus** - acellular - NO cell wall - NO membrane, some have envelopes - NO ribosomes - Depends on host for replication - Carries either DNA or RNA (ss or ds) **Bacteria** - Prokaryotic - Peptidoglycan is the main component of the cell wall - Has membrane without ergosterol - 70s ribosome - 1 chromosome in the cytoplasm + plasmid - binary fission **Fungi** - Eukaryotic - Chitin + glucan are main components of the cell wall - Has membrane with ergosterol - 80S ribosome - Chromosome in nucleus, NO plasmids or extrachromosomal - Sexual + non-sexual reproduction **Humans** - Eukaryotic - NO cell wall - Has membrane without ergosterol - 80s ribosome - Chromosomes in nucleus - Sexual reproduction via meiosis

Answer 35

Selectively kills or stops the growth of microbial targets causing minimal or no harm to hosts Used for antimicrobial targets: antibacterial, antivirals, and antifungals

Answer 36

**1. Cell wall** **2. Plasma membrane** **3. Ribosomes** **4. DNA synthesis** **5. Metabolic pathways**

Answer 37

Antiretrovirals targets enzymes that are necessary for HIV viral replication - **reverse transcriptase** (creates viral DNA) - **integrase** (integrates the viral dna into the host DNA) - **protease** (releases the proteins to allow for HIV to mature)

Answer 38

**Polyenes:** - Mechanism - binds to ergosterol to create pores in the cell membrane causing cell leakage and death **Azoles:** - Mechanism - stops ergosterol synthesis which disrupts cell membrane formation **Echinocandins:** - Mechanism - stops beta-D-glucan synthesis which is a key component of the fungal cell wall - leads to cell lysis

Answer 39

Resistance happens when random mutations are able to overcome antimicrobials and get chosen and passed down to generations **Virus** - mutations in the enzymes (target site modification) **Bacteria** - Blocked entry (porins), pump out, inactivate drugs with enzymes, modify the target **Fungi** - modifies the cell wall/membrane

Answer 40

- Acute infection - Latency phrase - AIDS

Answer 41

90% of the people who got diagnosed with HIV - we want 90% of those people to be on treatment - we want 90% of those people to be suppressed

Answer 42

**1. Efflux pump** - beta-lactams - aminoglycosides **2. Blocked penetration** - tetracyclines - beta-lactams **3. Inactivation by enzymes** - macrolides - beta-lactams **4. Target modification** - vancomycin - beta-lactams

Answer 43

**Relative risk:**Proportion of people with the disease among exposed/proportion of people with the disease among the unexposed **Odds ratio:**odds of disease among exposed/odds of disease among unexposed OR = 1= exposure does NOT affect odds of outcome OR<1 = exposure is associated with lower odds of outcome OR>1 = exposure is associated with higher odds of outcome

Answer 44

Host where the parasite develops into the adult stage - Most often/not always - where the sexual reproduction occurs

Answer 45

Only harbours the parasite for a short amount of time - Usually a developmental stage is completed here

Answer 46

Similar to the intermediate host BUT does not have any developmental stages here - Can act as a safe reservoir for the the parasites to accumulate

Answer 47

Does NOT allow transmission back to the definitive host + prevents the parasite from completing its development

Answer 48

- Gets overlooked by entities that are vital in drug access (government, public health programs) - Not considered a high priority for the prevention or treatment because they don't usually impact people who live in high-income countries - Lack visibility because they usually do not cause dramatic outbreaks that kill large numbers of people **Control strategies:** - Antiparasitics (albendazole) - Vector control, sanitation/hygiene, food safety

Answer 49

any disease or infection that can be naturally transmitted from vertebrate animals to humans

Answer 50

living organism that can transmit infectious pathogens between humans OR from animals to humans **vector-borne diseases** diseases carried by arthropods

Answer 51

**Host (reservoir + human host)** - Source host can carry infection w/o disease - Phylogenetic similarity b/w source host + recipient host **Pathogen** - Wide host range, infects many host organisms - High mutation rate allows to adapt to new hosts - Ability to live in harsh environments **Environment** - Interaction b/w source + recipient host - Changing environment, behaviour, and climate - Loss of biodiversity

Answer 52

**Directly** - Increased temperatures - Drought - Variable precipitation - Extreme weather events **Vector-borne** **Indirectly** - Impacts on migration, population density, anmal-human interactions, biodiversity, food production

Answer 53

A collaborative and transdisciplinary framework that recognizes the interconnectedness b/w human health, animal health, and environmental health

Week 10 + 11 + pre-midterm material Flashcards

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