lecture 1 Flashcards
who do parasites affect?
people in tropical regions where the parasite is able to grow
infectious disease
can be transmitted from people to people
from surface to people
modes of contact
direct contact:
skin-to-skin contact
kissing
sexual intercourse
droplet spread:
sneezing
coughing
talking
indirect:
airborne- dust/droplets suspending in air contains pathogenic organism
vehicle born (e.e. by good water, blood, fomites)
vector borne (when vehicle is another organism)
how is Listeria spread
through food
life expectancy
- countries that control diseases better have higher life expectancy
- goes hand in hand with economic resources
life expectancy in the US
- overall gotten better despite fluctuations
- first dip = WW1
- second dip = Spanish flu
** driven by infant mortality, esp for Spanish flu
what have we done to improve our life expectancy?
- penicllin (discovery of antibiotics)
- vaccines
- clean water (before, people didnt used to separate waste water from drinking water)
life expectancy post covid
- dips in the curve for most countries
how to control infection
- break infectious cycle
chain of infection
- pathogen (bacteria, virus, fungi, parasite)
- reservoir (food, water, faces, people animals)
- portal of exit (faces, gouging/sneexing, bodily secretions)
- mode of transmission
- portal of entry (where pathogens cone into the new host- digestive tract or respiratory tract, or eyes/cut in sin)
- susceptible host: characteristic of host affect wether they get sick or not (e.g. try to change through things ike vaccination)
how to break links in the chain of infection
- prevent pathogen from being in the food
- control portal of exit (cover mouth, etc)
- sanitizing contaminated surfaces
- modify portal of entry (modify things to protect yourself)
- vaccines
- wearing a condom
- sewage disposal
- eliminate the vector (e.e.g eliminate the mosquitoes, etc)
types of infectious disease
- endemic
- epidemic
- outbreak
- pandemic
endemic
- consistently present throughout a specific population/rgion
- number of expected cases are always there
- e.g. something that comes with seasons, like how flu cases surge expectedly during the fall
- yellow fever
- lime disease in the summer (everyone’s outside, more rain more ticks, more interaction with that environment)
- malaria (Africa)
epidemic
- number of cases go up rapidly and unexpectedly across a specific geographical area or population
outbreak
- an epidemic in a smaller setting
e.g. in a hospital, daycare, nursing home
pandemic
- goes on a global scale
- cases popping up in different countries/continents at a fast rate with new cases appearing every day
immune system
- keeps pathogens from entering tissues
- detects and destroys the invading pathogen (cells)
- passes chemical messages along toother cells (cytokines, chemokine)
- quickly respond to the pathogen and prepares for next time (memory)- protection after infection or vaccination
immune system branches
- innate immunity
- adaptive immunity
for the most part work at the same time
innate immunity
- barriers
- cells and immune signalling (turns on adaptive immunity)
adaptive immunity
- t-cell immunity
- b-cell immunity
two main cells in adaptive immunity
main immune defenses
- anatomical barriers
- skin
- tissues
- commensal microbiota
commensal microbiota
(biological, chemical, mechanical forces)
- microorganisms that live in or on. our bodies
chemical forces
- digestive and respiratory tracts are lined and covered with barriers to keep the pathogens away
- e..g antimicrobial peptides, and cells that produce fatty acids on skin that lower the overall pH of the skin’s surface to keep pathogens under control, low pH of stomach and digestive enzymes that are produced
mechanical forces
(and chemical are important for digestive and respiratory tract)
- keep the pathogens flowing (for digestive and respiratory tract
- muscles that contract, saliva and mucus fro epithelial cells keep things flowing and not being able to attach of come inside our cells
urogenital tract
- covered with urine, mucus to keep things lfowing
- low ph
- antimicrobial peptides
- secretions
microbiota vs microbiome
- difference is that microbiota = organism
- microbiome = things they produce too, genomes, etc
microorganisms on our bodies
- they have co-eveolved with uss
- have adapted to the specific conditions of the different parts of our bodies
- diversity of microorganisms varies greatly between the areas
gastrointestinal tract
- specific distribution of microbes
many foods that we can only eat - - because of the microbes in our gut - helping. to keep the pathogens away because living and colonizing on tissue, on the surface, and all of the microbes are fighting for resources to grow
- microbiome helps us keep those pathogens away
can positively and negatively affect host health
- oppourntiunistic pathogens (when conditions are not favourable for them to grow, then it can cause disease
environmental factors that affect the way our microbiome is shaped
- diet
- lifestyle
- genetic factors
- promotes the presence of some microbes over others
microbes specify
- van be different for people with dry vs oily skin
immune cells
- white blood cells
- leukocytes, phagocytes and lymphocytes
leukocytes
- part of our blood
- two types ar ephagotcyes and lymphocyte
plasma
- yellow
- at top
- makes up 55 percent of blood
- has all different proteins in blood d (hormones, clotted factors, enzymes and antibodies)
one of main functions of immune system
produce antibodies
Buffy coat
- contains all the white blood cells
- (immune cells)
- included wbc and plateletes
red part
- erythrocytes (rbc)
professional phagocytic cells
(one class of immune cells)
- monocytes
- macrophages
- neutrophils
- dendritic cells
lymphocytes
(second class of immune cells)
- t cells
- b cells
- NK cells
hematopoaiesis
- starts with hematopeitc stem cell (self renewing)
- can go to myeloid progenitor or lymphoid progenitor
- these two give rise to all of the wbc and rbc and platelets, and everything in our blood
myeloid progenitor
-goes to phagyocytes
- important for our innate immmunity
lymphoid progenitor
- goes to lymphocytes
NK cells
- natural killer cells
neutorphuil
- uses chemical signalling to try to find the pathogen
- engulfs using phagocytosis, killing the pathogen
macrophage
- professional phagocyte
- uses igG signal antibodies to recognize the pathogen
proteins
- secreted by cells
- cytokines, complement proteins, antibodies
cytokines
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