Studied by 27 people
flashcards for weeks 1-4
Antonie van Leeuwenhoek
Dutch microbiologist who discovered protists and bacteria, and made the first microscope lenses
Johanna Westerdijk
Dutch botanist and first female professor in the Netherlands who led research into Dutch elm disease
Francis Collins
American geneticist who discovered the genes associated with cystic fibrosis and Huntington’s disease
Christiaan Eijkman
Dutch physician who conducted research with chickens on beriberi disease and discovered unpolished rice (which lacked vitamin B1) was causing this disease
Rachel Carson
American marine biologist whose book Silent Spring warned of the dangers to all natural systems posed by chemical pesticides such as DDT
Tu Youyou
Chinese pharmaceutical chemist who led research on treatments for malaria and discovered artemisinin and dihydroartemisinin. Through her accomplishments, she became the first Chinese woman to win a Nobel Prize.
animalcules
an archaic term for microorganisms, including bacteria, protozoans, and very small animals
Factor V Leiden
a hereditary point mutation of one of the clotting factors in the blood
disease taxonomy
a nomenclature system for the classification for diseases
World Health Organization
a specialized agency of the United Nations responsible for international public health
International Classification of Diseases (ICD)
a globally used medical classification system maintained by the WHO that is used in epidemiology, health management, and for clinical purposes
ICD Clinical Modification
a system used by physicians and other healthcare providers to classify and code all diagnoses, symptoms, and procedures recorded during hospital care
medical coding
a universal medical alphanumeric coding system for healthcare diagnosis, procedures, medical services, and equipment
circulatory (cardiovascular) system
circulates blood around the body via the heart, arteries, and veins, delivering oxygen and nutrients to organs and cells and carrying their waste products away
digestive system
system to absorb nutrients and remove waste via the gastrointestinal tract
endocrine system
glands located throughout the body that produce hormones which regulate a wide variety of bodily functions
integumentary system
system composed of skin, hair, nails, sweat, and other exocrine glands
immune system
a complex network of organs, cells and proteins that defends the body against infection, whilst protecting the body's own cells. The immune system keeps a record of every microbe it has ever encountered so it can recognize and destroy the microbe quickly if it enters the body again.
lymphatic system
maintains fluid levels in the body and produces antibodies for protection against infection and disease
muscular system
consists of all the body muscles (3 types: smooth, cardiac, and skeletal) which enable us to produce body movement
nervous system
collects and processes information from the senses via nerves and the brain, and tells muscles to contract to cause physical actions
central nervous system structures
brain and spinal cord
urinary (renal) system
filters blood through kidneys to produce and excrete urine to get rid of waste
reproductive system
the reproductive organs required for the production of offspring
respiratory system
brings air into and out of the lungs to absorb oxygen and remove carbon dioxide
structures of the upper respiratory system
nasal cavity and pharynx
structures of the lower respiratory system
the trachea, bronchi, lungs, and alveoli
skeletal system
composed of bones and cartilages that support and protect various body parts
disease etiology
the (underlying) cause of a disease
infectious disease agents
viruses, bacteria, fungi, protozoa, and helminths
genetic disease
a harmful mutation of a gene
environmental disease
too much of a bad thing, or not enough of a good thing
nutritional deficiency disease examples
scurvy, beriberi, anemia, goiter
thiamin
vitamin b1
mortality
number of deaths due to a disease divided by the total population
excess deaths
deaths that exceed the number of deaths expected each year
case fatality rate
the proportion of people who get a disease and also die from it
morbidity
another term for having a disease or illness
prevalance
the number of diseased individuals in a population (number of cases per number of people in the population)
incidence
number of new cases over a defined period of time
nationally notifiable disease
a disease that, when diagnosed, requires health providers to report to state or local public health officials
Covid-19 antigen test
an antigen test requires a nasal swab and directly detects SARS-CoV-2 viral protein, is very fast, and can be used to diagnose Covid-19. It cannot detect small amounts of the virus and it not very accurate for asymptomatic individuals.
Covid-19 PCR test
a PCR test requires a nasal swab and amplifies nucleic acids to detect viral RNA which helps make even small traces of the virus visible in a test sample. PCR tests are the most reliable and accurate, but must be performed by a healthcare provider and results take a few days.
Covid-19 antibody test
an antibody test is a blood test that detects the presence of Covid-19 antibodies, but cannot be used to diagnosis a current infection because antibodies are only present in individuals who have recovered or been vaccinated
DALY (Disability Adjusted Life Years)
measure of overall disease burden, expressed as cumulative number of years lost due to ill-health, disability, or early death
disease burden
the overall impact of an illness or disease, such as disability, impairment, injuries, and risk factors
disease definition
a particular abnormal condition that negatively affects the structure or function of all or part of an organism
symptoms vs signs
symptoms are noticed by the patient whereas signs are noticed by the physician
asymptomatic
absence of symptoms
presymptomatic
absence of symptoms but a positive test result
normativist
emphasize the undesirability of diseases and the harms and limitations they bring to a patient and/or society
naturavist
believe disease requires the presence of biological dysfunction (impairment of individual survival and reproduction)
Body Mass Index (BMI)
a person’s weight in kilograms divided by the square of height in meters
gut microbiome
the microbial communities in our digestive tract that can affect our health and weight
disease etymology
the origin of disease names
societal and personal impacts of disease names
the name of a disease can influence public perception
WHO guidelines for naming diseases
diseases should not be named after geographic locations, the names of people, occupations, animals, or food
infection
an invasion of the body by pathogens
types of pathogenic (infectious) organisms
parasites (protozoa and helminths), fungi, bacteria, viruses, and prions
local / systemic infections
local: confined to a small region of the body
systemic: widespread infection in many parts of the body (travels through blood or lymph)
focal infection
pathogens are localized in one region but cause acute or chronic disease/symptoms at another part of the body
primary / secondary infections
primary: the initial infection within a patient
secondary: infections that would not normally cause disease under normal conditions, but occur when an opportunity is provided (such as an infection due to an open wound)
acute / chronic / latent infectous diseases
acute: symptoms develop rapidly and disease runs its course relatively quickly
chronic: symptoms develop slowly and stay for a long time
latent: symptoms appear long after infection
opportunistic pathogens
pathogens that would not normally infect a healthy host, but when an opportunity is presented (such as an open wound), they can enter the body
communicable disease
disease that can be transmitted from one host to another
modes of communicable disease transmission
direct: human-to-human contact, such as shaking hands
indirect: contact with a fomite, such as touching a doorknob
airborne: droplets and microscopic particles called aerosols, expelled during sneezing, coughing, talking, etc.
bodily fluids: contact with an infected individual’s bodily fluids
contamination: fecal contamination of food or water
fomite
a non-living surface or object that can carry pathogens
non-communicable
disease arising from outside of hosts or from unhealthy behaviors
contagious disease
communicable diseases that are easily spread
congenital
a condition or trait that is present at or before birth
half-life of pathogens
can only survive on hands for a couple hours, but can survive up to a week on certain surfaces (however, viruses can only survive on copper for a few hours)
how does soap protect against pathogens?
destroys the lipid membranes of viruses
how does hand sanitizer help protect against pathogens?
the alcohol in hand sanitizer kills pathogens on skin
how do N95 masks prevent infection?
N95 respirators have a network of fibers that filter out any particles larger than 0.3 microns. N95s also have an electrocharged layer that makes virus material stick to it.
relative sizes of respiratory droplets, aerosols, and virus particles
droplets: 5-10 microns
aerosols: 1-3 microns
Covid-19: 0.1-0.5 microns
means to reduce airborne and droplet transmission
masks and social distancing
S-I-R model of disease spread
S(susceptible): individuals who are not yet infected and are healthy but don’t have antibodies
I(infected): individuals who are infected and contagious
R(recovered): individuals who are immune, no longer capable of spreading, and healthy with antibodies
R0 (basic reproduction number)
average number of new infections that one infectious person generates, in an entirely susceptible population, during the time they are infectious
R0 > 1 =
an epidemic will occur (the larger R0 is, the harder it is to stop the epidemic)
R0 < 1 =
infection will not spread
Rt (effective reproduction number)
the expected number of new infections caused by an infectious individual in a population where some individuals are no longer susceptible
ways to estimate R0 and importance of these methods
contact tracing and case reporting, both of which help locate the source of an outbreak and prevent spread
contact tracing
a process of identifying, assessing, and managing individuals who are infected or have been in contact with an infected individual
case reporting (surveillance)
collecting reports of of individuals with a disease
epidemic
an outbreak of disease that spreads quickly in a certain region
pandemic
an epidemic that is actively spreading beyond the initial individual region to other parts of the world
herd immunity and how to achieve it
when a large enough proportion of a population is immune or vaccinated, it limits further disease spread.
70-95% of a population would need to be immune/vaccinated to achieve herd immunity; equation: [1-(1 / R0)]x100%
vaccine hesitancy
reluctance or refusal to accept vaccination despite availability of vaccine services and supporting evidence
Faroe islands measles epidemic of 1781
an instance where a virus self-eradicated because the population was not big enough (50,000 people required to sustain a virus)
pathogen attenuation
purposeful weakening of pathogen virulence, while still keeping it viable to be used in vaccines
endemic disease
a consistently present disease in a certain population (without outside influence such as travel)
vaccination
a biological preparation that stimulates the body’s immune response and provides active acquired immunity to a particular infectious disease
zoonotic diseases
diseases spread between animals and humans
what animal is considered a reservoir host of diseases?
bats (because they are the only mammals that fly which helps with virus dispersal, and they roost in large numbers which aids transmission cycles)
spillover zoonoses
the transmission of a pathogen from an animal to a human, recognized as the predominant cause of many emerging infectious diseases
what was the epicenter of the Covid-19 pandemic?
a ‘wet market’ in Wuhan, China
lab leak theory
theory that the Covid-19 virus originated in a lab
vector-borne disease
a disease that results from an infection transmitted to humans and other animals by blood-feeding insects
Plasmodium life cycle and species
mosquito ingests parasite from the blood of an infected human carrier
parasites reproduce asexually in the midgut of mosquito and migrate to the salivary glands
during a blood meal, the malaria-infected female mosquito inoculates the parasite into a human host
once in a human’s blood, the parasite infects RBC’s and start replicating
infected RBC’s burst and release new parasites into the bloodstream
vector control
methods to limit or eradicate animal or insect carriers which transmit disease pathogens to humans
Note 
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