Public Health Flashcards
What is the #1 cause of death in the U.S.?
Cardiovascular disease
What is the #2 cause of death in the U.S.?
Cancer
What is the #3 cause of death in the U.S.?
Unintentional injuries
What is the #4 cause of death in the U.S.?
Chronic lower respiratory diseases
What is the #5 cause of death in the U.S.?
Stroke
What is the #6 cause of death in the U.S.?
Alzheimer’s Disease
What is the #7 cause of death in the U.S.?
Diabetes
What is the #8 cause of death in the U.S.?
Pneumonia and influenza
What is the #9 cause of death in the U.S.?
Nephritis, nephrosis, and nephrotic syndrome
What is the #10 cause of death in the U.S.?
Suicide
What is the CEA Winslow definition of public health?
The science and art of preventing disease, prolonging life, and promoting physical health and efficiency…
(PrevProlProm)
Name a few of the greatest public health achievements of the 20th and 21st centuries.
Immunizations Motor-vehicle safety Workplace safety Family planning Fluoridation of drinking water Infectious disease control
Describe Leavell and Clark’s Levels of Prevention (Primordial, primary, secondary, tertiary, and quaternary).
Primordial - Population measures (E.g. legislation)
Primary - Addressing individual risk factors (E.g. proper nutrition)
Secondary - Screenings (E.g. pap smears)
Tertiary - Disease treatment (E.g. a type 1 diabetic receiving insulin administration)
Quaternary - Reducing over-medicalization (E.g. strict opioid administration to prevent unnecessary use)
Define incidence rate.
The number of new cases of a disease over a certain period of time
Define prevalence rate.
The number of existing cases within a certain window of time
Define social determinants of health.
The social determinants of health are the conditions in which people are born, grow, live, work and age. These circumstances are shaped by the distribution of money, power, and resources at global, national and local levels. The social determinants of health are mostly responsible for health inequities - the unfair and avoidable differences in health status seen within and between countries (WHO definition).
What is the difference between absolute and relative poverty?
Absolute poverty is defined as living on less than $2 a day and refers to all individuals under this amount globally.
Relative poverty refers to the difference in wealth between an individual and those in their community (E.g. an individual that makes $40,000 per year living near an individual making $200,000 per year is relatively impoverished in comparison).
What is the federal poverty level?
The recognized U.S. poverty line.
Examples:
< $12,000 per year for individuals
< $16,500 per year for a family of two
(The amount steadily increases with the size of the family)
What is the absolute poverty level?
Living on less than $2 per day (1 billion individuals are in this bracket worldwide)
What is the difference between active and passive immunity?
While both are forms of acquired immunity, active immunity refers to immunity in which the individual synthesizes their own antibodies. Passive immunity refers to immunity in which the individual receives pre-synthesized antibodies from an external source.
Give an example of active natural immunity.
An individual gets exposed to a pathogenic antigen and begins synthesizing their own antibodies.
Give an example of active artificial immunity.
Vaccination
Give an example of passive natural immunity.
A mother passing her antibodies (IgA) to her baby through her breast milk
Give an example of passive artificial immunity.
Lab-synthesized gammaglobulins being administered (E.g. following a hepatitis needle stick or bite by a rabid dog)
What are live-attenuated vaccinations?
Vaccinations in which the pathogen in question has been weakened but not fully killed before being introduced to the patient (E.g. the Sabin polio or MMR vaccine)
What are inactivated (killed) vaccinations?
Vaccinations in which the pathogen in question has been killed before being introduced to the patient (E.g. the Salk polio vaccine)
What are component vaccinations?
Vaccinations in which the only a component of the pathogen in question is introduced to the patient (E.g. the pertussis portion of the DTaP vaccine)
Define herd immunity.
The resistance of a group to a disease due to the overall immunity of the group (A certain percentage of the population must be vaccinated to prevent infectious disease spread. This percentage depends on the disease in question)
Define R0
Pronounced R-naught
The number of people one sick individual will infect (On average)
Describe innate immunity.
Nonspecific mechanisms that protect the body against disease.
Examples: Skin, hair, mucus, macrophages, neutrophils, lysozyme secretions, stomach acidity, etc.
Describe acquired immunity.
Mechanisms that protect the body against specific, previously encountered antigens.
Examples: B-lymphocytes, T-lymphocytes, immunoglobulins
T/F The MMR vaccine causes autism?
False
Many large, well-designed studies have found no link between MMR and autism.
Autism usually becomes apparent around the same time MMR is given—no evidence of causality.
Autism probably has multiple components, including genetics (e.g., one study found that if one identical twin had autism, the chance that the second twin had autism was greater than 90%, but with fraternal twins the chance was less than 10%).
T/F Multiple vaccinations can overwhelm an infant’s immune system, so vaccines should be spread out on a long-term schedule.
False
Vaccines use only a tiny proportion of a baby’s immune system’s ability to respond; though children receive more vaccines than in the past, today’s vaccines contain fewer antigens (e.g., sugars and proteins) than previous vaccines. Smallpox vaccine alone contained 200 proteins; the 11 currently recommended
routine vaccines contain fewer than 130 immunologic components.
Delaying vaccines increases the time children will be susceptible to diseases. There is no evidence that spreading out the schedule
decreases the risk of adverse reactions.
What is an odds ratio?
An odds ratio (OR) is a measure of association between an exposure and an outcome. The OR represents the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure.
What type of study uses an odds ratio to report its conclusions?
A case-control study
Define epidemic.
An epidemic is a period of time with a higher than expected incidence rate but over a broader geographic region.
Define endemic.
The term endemic refers to a region where there is a persistent baseline incidence and prevalence rate.
Define pandemic.
A pandemic is an epidemic where the disease is being actively transmitted on multiple continents.
Define outbreak.
An outbreak is defined as a higher than expected incidence rate tied to a geographic focal point.
What are some modes of infectious disease transmission?
Airborne water-borne fecal-oral vector-borne fomite perinatal food-borne animal bites sexual transmission
Define incubation period.
The time between being infected with a pathogen and showing symptoms (Actively dividing pathogen)
Define latency period.
The time between being infected with a pathogen and showing symptoms (Non-actively dividing pathogen)
What is the difference between the latency period and the incubation period?
In an incubation period, the pathogen is actively dividing. In a latency period, it is not.
Define infectious dose.
The number of a certain type of pathogenic microb needed in order to cause disease in an infected individual.
What is the difference between eradication and elimination?
Eradication refers to the complete removal of a disease from the world (E.g. smallpox).
Elimination refers to the complete removal of a disease from a specific geographic region (E.g. polio).
Define pathogen.
A microorganism that can cause disease.
Are all infectious diseases widely contagious?
No (Think botulism or tetanus). They are infectious but not widely transmissible from person to person.
Describe fomite transmission.
Touching surface, object or person
Describe airborne transmission.
Respiratory drops in the air (Due to sneezing, coughing, breathing)
Describe vector-borne transmission.
Carried by non-host species to host (Typically insects)
Describe fecal-oral transmission.
Ingesting microscopic amounts of contaminated fecal matter
What are some other types of modes of transmission?
Water-borne Perinatal (mother to child) Food-borne Animal bites (Zoonotic) Sexual transmission
What are anti-helminthic drugs?
Anti-parasitic drugs
What are antibiotic drugs?
Drugs that kill bacteria or interfere with bacterial growth
What is a non-pharmacological intervention?
Non-drug related treatments.
E.g. hand washing, exercise, isolation of infected individuals
What are the characteristics of a bacteria?
Prokaryotic cells that can both be helpful and harmful to humans. They reproduce on their own (Unlike viruses).
Helpful bacteria work as our microbiome and protect us and help us with digestion.
What are the characteristics of a virus?
They are not alive. They are protein shells (Capsids made of protomers) that contain genetic material (Single- or double-stranded DNA or RNA) and require a host cell in order to replicate themselves. They hijack the host cell’s enzymes and other machinery.
Viral glycoproteins allow the cell to interact with host cells in order to inject their genetic material or to be completely endocytosed.
More complex viruses sometimes have a lipid coat around their capsid.
What are the characteristics of a parasite?
Multicellular (Usually) eukaryotic organisms (Like us). Things like malaria, leishmaniasis, hookworm, guinea worm, etc.
Define dynamics.
How we describe infectious disease movements, patterns, and behaviors over time and geography
Define system.
Any group of interacting parts that form a whole
Define a complicated system.
Has many interacting parts that need to work correctly in a sequence to reach the desired result. However, each step of the process is completely predictable based on the step before it
Define the results of a complex system. Can we easily predict them?
No, the results brought about by the interacting parts of a complex system are not directly predictable
Define emergent properties.
Behaviors or outputs of a system that arise from two or more interacting components that cannot be explained by either of them on their own
What is an epidemic curve?
A graph of the number of cases or incidence rate of cases versus time.
Define propagate.
To travel
What is human ecology?
How humans interact with and are impacted by their surrounding environment and each other
What is a node?
An individual entity in the network, like a person or a hospital
What is an edge (In relation to a node)?
What connects two nodes
What is a random network?
A lot of people/things randomly connected to each other with no rhyme or reason
What is a scale-free network?
A network where some nodes are more highly connected than others
What are network hubs?
Nodes that are more connected than others
What is synchronous spread?
The timing of an epidemic overlapping in multiple locations
What is (sexual) concurrency?
Individuals having multiple partners at the same time
What is compartmental flow?
We are essentially coming up with a fake scenario in which people flow from one “compartment” or stage to another
Describe a deterministic model.
The model does not worry about random effects, like individual differences in susceptibility. Everyone follows the same rules of probability about what compartment they are in at any given time.
Describe the SIR model.
“Susceptible, Infectious, and Recovered.” Each person is either in the S, I or R compartment at any given time. The simplest version of the SIR model doesn’t take into account birth and death.
What is the S in the SIR model?
Susceptible individuals (May become sick)
What is the I in the SIR model?
Infectious individuals (Are sick and may infect others)
What is the R in the SIR model?
Recovered individuals (Are no longer in danger of becoming sick again)
Describe a stochastic model.
A model that takes individuality into account. They are very commonly used and based off of the same mathematical principles as deterministic models. They just use more complicated probability formulas describing whether someone will move into the next compartment, and are not deterministic.
What is an agent-based model?
Helpful to study diseases that are very difficult to trace through a network to a particular infecting person (like respiratory diseases). They use computer simulations to estimate the behaviors of a real-world city, region or country. The simulations can help predict what emergent properties might occur as an infectious disease travels.
What is R0?
The number of infected individuals one person is expected to infect while they are infectious
What is the herd-immunity threshold?
The proportion of people that need to be immunized in order to eradicate a disease, or prevent an outbreak (Varies from disease to disease)
What is hysteresis?
A change in status. ex. a new emerging disease can cause an epidemic, and if not eliminated, reach a new stable equilibrium where it is now endemic
How do we calculate the number of people that will move from the S compartment to the I compartment?
cBSI/n
c = contacts Beta = P(Infected/contacted) S = susceptible I = infected n = population
How do we calculate the number of people moving from the I compartment to the R compartment?
1/DI
D = duration I = Infectious
What is Rt?
Real-time or effective reproduction. Our goal when trying to prevent infectious diseases is to push Rt below 1, so that the epidemic will die out. In essence, you want to “remove” susceptible or infectious individuals from the population faster than the disease spreads. Vaccines do this very effectively
What is the formula for R0?
cB/y
c = contact B = P(Infected/contacted) y = rate of recovery
What is our R0 goal?
R0 < 1 (The disease is not actively propagating)
What is the E in the S(E)IR system?
Exposed
What are agent-based models used for?
Predictions
Selective mixing is a trend of what kind of network?
Sexual networks
<p>Define ecology.</p>
<p>The study of factors influencing the abundance and distribution of organisms</p>
<p>Define competition and cooperation.</p>
<p>Competition - Driving force of natural selection (Remember viruses damaging each other and competing for resources)
Cooperation - Differing species working together to benefit all species involved (Remember biofilms)</p>
<p>What is a biofilm?</p>
<p>What is quorumsensing?</p>
<p>A biofilm is a collection of bacteria cooperating and working together. Biofilms often form on hospital catheters / instruments and are responsible for many nosocomial infections</p>
<p></p>
<p>Quorum sensing is the cell-to-cell communication that regulates the density of bacteria growth so they can share resources.</p>
<p>What is a habitat?</p>
<p>The physical area a species inhabits</p>
<p>What is an ecological niche?</p>
<p>The habitat + behaviors of a particular species</p>
<p>How many species can occupy the same ecological niche?</p>
<p>Only 1.
Either one species will evolve to separate the niches, or one will out-compete the other, resulting in its extinction. </p>
<p>How does climate change affect ecology (Particularly disease dynamics)?</p>
<p>1) Warming can cause a shift in timing, where epidemic peak may occur at a different time of year than it did in the past
2) Warming can cause more epidemic “cycles”, meaning that there may be two epidemic peaks in the same year
3) Warming can cause overall epidemic intensity to either increase or decrease, depending on whether the pathogen can well-tolerate the new climate. </p>
<p>What is it mean for a disease to be zoonotic?</p>
<p>A zoonotic disease is a disease that has its origins in a species other than humans
(This includes vector-borne diseases as well as direct zoonotic diseases)</p>
<p>What does it mean for a disease to be frequency-dependent?</p>
<p>Transmission rates increase with the number of infectious people, but it doesn’t matter how geographically dense they are.
(I.e. STDs and some vector-borne diseases)</p>
<p>What does it mean for a disease to be density-dependent?</p>
<p>Transmission rates increase with population density of the host.
(E.g. influenza)</p>
<p>What is it called when an area has everything necessary for disease to spread (Pathogen, climate, resources, etc.), but humans don't inhabit the area?</p>
<p>A silent zone</p>
<p>What happens when a large population enters a silent zone?</p>
<p>There will be an epidemic</p>
<p>What are the principal modes of transmission? (8)
| PAAWSFFF</p>
<p>Perinatal Airborne Animal bites Water-borne Sexual Fecal-oral Fomite Food-borne</p>
<p>What is the name of this type of zoonotictransmission cycle?</p>
<p>Human --> Human --> Human</p>
<p></p>
<p>Direct human-to-human</p>
<p>(E.g. influenza)</p>
<p>What is the zoonotic transmission cycle in which a disease principally found in animals is passed to a human (Who does not pass it to other humans)?</p>
<p>Direct zoonosis</p>
<p>(E.g. rabies)</p>
<p>What is the zoonotic transmission cycle if the disease can only be passed from human to human via an insect or animal?</p>
<p>Vector-borne</p>
<p>(E.g. malaria)</p>
<p>If a disease can only be passed to humans from animals via a vector, what is the zoonotic transmission cycle?</p>
<p>Vectored zoonosis</p>
<p>(E.g. encephalitis)</p>
<p>(Here's the trickiest one)</p>
<p>If a disease can only be passed to humans from animals via a vector, and then it is transmitted from human to human via a vector, what is the zoonotic transmission cycle?</p>
<p>Anthropo-zoonosis</p>
<p>(E.g. yellow fever)</p>
<p>What is a reservoir?</p>
<p>A host species for a viral disease that does not usually become seriously ill from the disease</p>
<p>What are some examples of common reservoirs?</p>
<p>Bats, mice, and birds</p>
<p>What is the term that describes the transference of a disease from one species to another?</p>
<p>A spillover event</p>
<p>How does biodiversity protect us from disease?</p>
<p>The greater the number of species in a given area, the fewer interactions humans are likely to have with a particular disease-carrying species (Remember the Lyme disease example). This is called the dilution effect.</p>
<p>What is disease emergence?</p>
<p>The process by which a disease gains strength in the general population following a spillover event</p>
<p>Are deer ticks born with Lyme disease?</p>
<p>Where do they typically get it?</p>
<p>No.</p>
<p>Usually, they get Lyme disease from theirfirst blood meal(If the meal is infected, as white-footed mice often are).</p>
<p>Describe the life cycle of a tick.</p>
<p>Uninfected larva hatch in late Summer --></p>
<p>The feed on a (possibly) infected small animal --></p>
<p>They molt and become nymphs till the end of Winter --></p>
<p>In Spring/Summer/Fall they feed on vertebrates --></p>
<p>Ticks that feed on deer mate and lay eggs</p>
Who is the main international player conducting global surveillance?
The WHO
What laws must the WHO operate under in order to conduct global surveillance?
The International Health Regulations (IHR)
What is the order of players involved in reporting global surveillance (From local data collection all the way to the WHO)?
Field surveillance –>
National focal point (E.g. CDC) –>
Regional contact point (E.g. The Pan-American Health Organization) –>
WHO
What weekly report does the CDC release on surveillance and research activities?
Morbidity and Mortality Weekly Report (MMWR)
What are syphilis, smallpox, and AIDS examples of (Regarding data collection in the U.S. around infectious disease control)?
These are examples of reportable diseases .
(AIDS, chickenpox, gonorrhea, hepatitis A and B, measles, mumps, rubella, salmonella, shigella, syphilis, and TB
What are some of the fundamental components of surveillance programs?
Catchment areas
Case-report forms (CRFs)
What is a catchment area? When should one be designated in forming a surveillance plan?
A catchment area is the defined geographic region in which the surveillance will be operated.
The catchment area designation is the first step in the surveillance program design.
What is a case-report form?
Data collection tool (Basically a survey) where information on sick -or suspected to be sick- individuals can be recorded.
What are the first three essential steps in planning and running a successful surveillance program? What are some important components of each?
- System design (Catchment area designation, disease identification protocols, reporting process set up, etc.)
- Data collection (CRFs, contact tracing, etc.)
- Collation (Data aggregation, standardization, and organization)
What are essential steps four and five in planning and running a successful surveillance program? What are some important components of each?
- Analysis (Statistical / epidemiological measures)
5. Interpretation (Rates, vulnerable / geographic areas, morbidity / mortality, etc.)
What are the final two essential steps in planning and running a successful surveillance program? What are some important components of each?
- Dissemination / Communication (Radio, social media, television, health departments, scientific journals, etc.)
- Program change (Target vulnerable populations, modify program procedures)
Define syndromic surveillance.
Uses non-diagnostic health data (E.g. Google searches or ambulance records) to determine how many people are symptomatic of a disease.
Remember GPHIN from the TED video shown in class. They prevented a SARS epidemic.
What can syndromic surveillance help us catch?
Very useful in the detection of emerging diseases, disease outbreaks, or bioterrorist threats.
What is the Emerging Infections Program?
CDC catchment zones scattered across the U.S. monitoring antibiotic-resistant bacteria, foodborne outbreaks, influenza, and nosocomial infections.
What is the Active Bacterial Core?
An EIP program responsible for collecting data surrounding bacterial disease trends.
How do we prevent epidemics and pandemics?
Early detection, early response
<p>Superbug</p>
<p>When there are high morbidity and mortality due to a bacteria that has become resistant, it is often referred to as a superbug.</p>
<p></p>
<p>Extra info: Resistance to pharmacotherapy is not only an issue for bacteria, but it can arise in cancer cells, parasites, fungi, and other infections. Bacteria with acquired resistance include TB, S. aureus, Acinetobacter, E. coli, and V. cholera.</p>
<p>Why mechanisms for resistance exist in nature</p>
<p>Microscopic organisms have been battling one another for millions of years by producing chemicals that can limit the growth of other organisms. Resistance to these chemicals has evolved in synchronization with them.</p>
<p>Mechanisms for resistance are therefore not new to human populations. They have been in development long before we ever started using antibiotics therapeutically. In fact, a large portion of your microbiome is already resistant to antibiotics you have never been exposed to.</p>
<p>(Example: Penicillinase was discovered in the natural bacterial population in samples that pre-date the use of therapeutic penicillin.)</p>
<p>Horizontal gene transfer</p>
<p>When a bacteria takes up DNA from another source, it is called horizontal (or lateral) gene transfer (HGT)</p>
<p>Genetic island/cassette</p>
<p>The part of a bacteria’s genome resulting from HGT is called a genomic island, or a genetic cassette.
Genomic islands can confer resistance in the new bacteria. </p>
<p>Vertical gene transfer</p>
<p>If a gene is inherited directly from a “parent” bacteria during reproduction, it is called vertical gene transfer (VGT).</p>
<p>Intrinsic resistance</p>
<p>In the case of intrinsic resistance, no mutation is necessary to confer resistance.
The bacteria simply overcomes the antibiotic by making more copies of the protein that the antibiotic targets. </p>
<p>Ways in which resistance can develop (change drug target, modify cell walls, metabolize antibiotic, etc.)</p>
<p>It is important to note that resistance genes exist in bacteria with or without selection (does not “cost” them anything).</p>
<p></p>
<p>There are many different biological mechanisms by which they work. These include:</p>
<p>1. changing the shape of the antibiotics target protein,</p>
<p>2. developing the ability to metabolize the antibiotic,</p>
<p>3. developing the ability to recognize and actively pump out the antibiotic</p>
<p>Conjugation</p>
<p>Transfer of genetic material from bacteria to bacteria through a sex pilus connection</p>
<p>Transduction</p>
<p>Transfer of genetic material from bacteria to bacteria via a bacteriophage (Virus that infects bacteria)</p>
<p>Transformation</p>
<p>Direct uptake of 'spilled' DNA from outside the bacterial cell into the bacteria</p>
<p>The roles of humans in creating resistance</p>
<p>1. Less than ½ of the therapeutic antibiotics in existence are for human use.</p>
<p>2. There is a dramatic overprescription of antibiotics in the U.S. and internationally (Often for viral infections).</p>
<p>3. In agriculture, antibiotics are often used prophylactically because it was thought that they improve weight gain of animals (not to treat or prevent infection).</p>
<p>What can be done to mitigate the problem of antibiotic resistance?</p>
<p>Identifying resistant bacteria earlier, and developing new methods for identifying antibiotics or other antimicrobial therapies.</p>
<p></p>
<p>For example, genotyping of strains in clinics to test for resistance is on its way to becoming common practice. Another common strategy is to use combinations of antibiotics, so that the bacteria is not able to acquire resistance. This is a method used often in the treatment of drug-resistant TB.</p>
<p>What is a vector-borne disease?</p>
<p>Diseases that are transmitted between hosts by another species</p>
<p></p>
<p>(The vector is typically not infected, but that is not true in cases such as malaria)</p>
<p>What specific ecological challenges do vector-borne diseases produce?</p>
<p>How do we eliminate/control the vector without wide-ranging ecological effects?</p>
<p></p>
<p>How will climate change affect vector and host distributions?</p>
<p>What are some methods to prevent vector-borne disease?</p>
<p>Indoor residual spraying</p>
<p>Bednets / window screens</p>
<p>Genetic modifications</p>
<p>Larvae extermination</p>
<p>Name four vector-borne diseases.</p>
<p>Malaria</p>
<p>Dengue fever</p>
<p>Zika</p>
<p>Chikungunya virus</p>
<p>Etc.</p>
<p>How is the chikungunya virus transmitted?</p>
<p>Where is it found?</p>
<p>What is its incubation period?</p>
<p>What are some associated signs/symptoms?</p>
<p>How is it treated?</p>
<p>Mosquito-borne</p>
<p>Central / Southeast Asia and Sub-Saharan Africa</p>
<p>1 - 12 days</p>
<p>Rash, fever, polyarthralgia, vomiting, headache</p>
<p>Anti-inflammatories</p>
<p>How is the Dengue fever virus transmitted?</p>
<p>Where is it found?</p>
<p>What are some associated signs/symptoms?</p>
<p>How is it treated?</p>
<p>The <em>Aedes aegypti</em> mosquito</p>
<p>More than 100 countries in both hemispheres</p>
<p>Crushing bone pain (It is often called 'bone break fever'), fever, lethargy, can be hemorrhagic</p>
<p>How is the Zika virus transmitted?</p>
<p>Where is it found?</p>
<p>What are some associated signs/symptoms?</p>
<p>The<em>Aedes Agypti</em>mosquito</p>
<p>Microindonesia, Brazil, several other locations</p>
<p>Usually, mild symptoms lasting a few days to a week</p>
<p>Causes microcephaly and Guillan-Barre Syndrome among infants of affected mothers</p>
<p>How long can Zika remain present in semen? How long should a woman wait after her symptoms abate to try to have children?</p>
<p>6 months</p>
<p>2 months</p>
<p>Where did HIV come from?</p>
<p>It is a zoonotic disease that originated in non-human primates as SIV.</p>
<p>When was HIV first reported in the U.S.?</p>
<p>1981</p>
<p>What populations are especially at risk for HIV transmission?</p>
<p>Intravenous drug users</p>
<p>Homosexual men (44x higher risk than heterosexual men)</p>
<p>Impoverished women (Especially those that have little sexual control in their relationships)</p>
<p>Prostitutes</p>
<p>Healthcare workers (Due to needle sticks and accidental fluid exchange)</p>
<p></p>
<p>African-Americans, Asian-Americans, and Pacific Islanders also experience higher rates of HIV in the US than is found in other ethnic groups (Likely from a socioeconomic or stigma-related disparity).</p>
<p>What does it mean that HIV is a retrovirus?</p>
<p>It means that, upon infection, the virus (RNA) is transcribed (By reverse transcriptase) to DNA and inserted into the host genome after infection. This makes it very hard to treat as it becomes part of our own DNA!</p>
<p>What does it mean that HIV is a lentivirus?</p>
<p>It replicates slowly. There can be long incubation and latency periods between infection and symptoms</p>
<p>How does HIV spread?</p>
<p></p>
<p>What is seroconversion?</p>
<p>HIV spreads via bodily fluids such as blood, blood products, semen, rectal or vaginal fluids, or breast milk.</p>
<p></p>
<p>Seroconversion is when the immune system first begins producing antibodies against HIV. This usually happens a few weeks after the initial infection.</p>
<p>What type of human cell is preferentially infected by HIV?</p>
<p></p>
<p>What are the initial signs/symptoms of infection?</p>
<p>The virus preferentially infects CD4+ Helper T-cells (A type of white blood cell).</p>
<p></p>
<p>Upon initial infection, there are acute symptoms which are typically flu-like.</p>
<p>When has an HIV infection officially advanced to AIDS?</p>
<p>When CD4+ Helper T-cell count below 200/ml (normal counts are 500-1500 per ml).</p>
<p>What are some of the rare infections that typify AIDS (Due to decreased host immune response)?</p>
<p>- Pneumocystic (fungal) pneumonias</p>
<p>- Pneumonia due to cytomegalovirus, toxoplasmosis, herpes simplex, or gastrointestinal protozoa</p>
<p></p>
<p>- Some patients develop a rare form of cancer called Kaposi’s sarcoma. The cancer is caused by Kaposi sarcoma herpesvirus (KSHV) that inserts its genes into the host (Kaposi’s sarcoma is 20,000 times more common in AIDS patients than in the general public).</p>
<p>What is ART/ARV? Do they fully cure HIV?</p>
<p>Antiretroviral Therapy</p>
<p></p>
<p>They do not fully cure the disease; they only keep the viral load down.</p>
<p>What is an HIV superinfection?</p>
<p>When an HIV-infected patient on ARV becomes infected with an additional strain of HIV (Double HIV infection).</p>
<p>What is vertical HIV transmission?</p>
<p>Transmission from an infected mother to her child.</p>
<p></p>
<p>Transmission can occur in utero, during delivery, or through breastfeeding. Breastfeeding is the most common type of transmission from mother to child.</p>
<p>How is HIV different in children than adults?</p>
<p>More recurring opportunistic bacterial and viral infections, (but they are less likely to develop Kaposi’s sarcoma) more rapid disease progression as well</p>
<p>How can vertical HIV transmission be prevented?</p>
<p>A special ARV regimen (Highly effective).</p>
<p></p>
<p>The Pediatric AIDS Clinical Trials Group (PACTG) 076 AZT regimen is a series of ARV drugs given in different amounts during pregnancy, delivery and just after birth to prevent transmission of HIV to a child.</p>
<p>What are a few general methods by which to prevent HIV spread?</p>
<p>Condomdistribution</p>
<p>Education</p>
<p>Prophylactic ARV treatment (reduces transmission by 60-80%)</p>
<p>Needle exchange programs</p>
<p>Male circumcision</p>
<p>Do all HIV-infected individuals in the U.S. know they are infected?</p>
<p>No. About 20% of HIV+ persons in the United States are unaware of their infection. </p>
<p>What is the bacterium responsible for TB infections?</p>
<p><em>Mycobacterium tuberculosis</em></p>
<p>What percentage of the world population is infected with latent TB today?</p>
<p></p>
<p>What percentage of those infected with latent TB will become sick with active TB at some point in their lifetimes?</p>
<p>33%</p>
<p></p>
<p>10%</p>
<p>How is TB spread?</p>
<p></p>
<p>What body system does it most commonly infect? Can it infect other systems?</p>
<p>Respiratory droplets (Airborne transmission)</p>
<p></p>
<p>Respiratory system</p>
<p></p>
<p>Yes, TB can disseminate to organs other than the lungs</p>
<p>What is Milliary TB?</p>
<p>Many small areas of local TB spread throughout an organ</p>
<p>What human cell in the respiratory tract is preferentially infected by TB bacterium?</p>
<p>Alveolar macrophages</p>
<p>After alveolar macrophages are infected by TB bacterium, what happens?</p>
<p>Immune cells surround the area, promote inflammation, and accumulate as dead cells</p>
<p></p>
<p>(This forms nodules called granulomas)</p>
<p>Does the immune system usually manage to wipe out all the TB bacterium on its own?</p>
<p>No, the immune system usually only manages to keep the bacterium at bay</p>
<p></p>
<p>(This is called latent TB and is true for 90% of infected individuals)</p>
<p>What is it called when a latent TB becomes active?</p>
<p>Reactivation</p>
<p>How is TB diagnosed?</p>
<p>The Mantoux Tuberculin test (TB antigen injected under the skin) and chest x-rays</p>
<p>What is a Gohn focus?</p>
<p>A TB granuloma large enough to be seen on x-ray</p>
<p>What is it called if a patient presents with a Gohn focus and regional lymph node involvement?</p>
<p>This is a Gohn complex</p>
<p>What is the difference between primary vs. secondary TB infection?</p>
<p>Primary infection is the initial host encounter with TB bacterium.</p>
<p></p>
<p>A secondary infection refers to EITHER being infected with TB after being cured OR reactivation of latent TB</p>
<p>What are the signs/symptoms of TB infection?</p>
<p>Fever, cough, bloody sputum, weakness, and chest pain.</p>
<p>What is the most common cause of death among AIDS patients?</p>
<p>TB</p>
<p>How is TB treated?</p>
<p>- 2 initial months of chemotherapy (antibiotics) and varying amounts of continuing treatment (No need to memorize drug names, but know it’s a drug cocktail given for months).</p>
<p>- Patients may be asked to take a complex regimen of drugs including:</p>
<p>Isoniazid (an anti-metabolite)</p>
<p>Rifampin (inhibits RNA polymerase)</p>
<p>Ethambutol (inhibits cell wall formation)</p>
<p>Pyrazinamide (converts to an acid and accumulates, killing the cell).</p>