Epidemiology & Pathogeneis Part 1 Flashcards
What does pathology mean?
Scientific study of disease
What does etiology mean?
Cause of a disease
What does pathogenies mean?
The way a disease develops, all structural and functional changes
What does infection mean?
Invasion or colonization of the body, by a pathogenic microbe
What does disease mean?
When an infection leads to a change in normal statues of health
Give me an example where is there an infection but no dieases?
HIV
What is another example is where people carry the infection but no disease?
Asymptomatic individuals
( covid, herpes )
What does host mean?
Any organism that harbors another organism
What does normal flora mean? What is their function ?
Permanent and usually not pathogenic microorganisms
( fight pathogenic micrograms )
What is resident flora?
Always present on or in the human body
What is transient flora?
Will come and go
( few hours to a few months )
What does birth mean?
Microorganism being to establish themselves
What are examples of normal flora?
Lactobacilli from mothers vagina
Do we have more cells or bacteria in our body? Typically?
Bacteria
What was the extensive and supported evidence about normal flora?
Keeping a healthy normal flora, directly decreases the chances of infection and disease
What is the human micro biome project that started in 2007?
A project to help identify all the microbes found in different parts of the body
What is a physical way that flora fights infection?
Skin barrier
What are the 3 ways flora fights off or works with infections?
Mutualism
Antagonism
Parasitism
What does mutualism?
Both organism benefit
What is an example of mutualism?
E. coli in intestine produces vitamin k and B
What is antagonism?
Competition between microorganism
( competitive exclusion )
( Normal flora vs pathogen )
What is an example of antagonism?
Bacteriocins
( proteins secreted by E. coli cause clostridium difficult to overgrow after antibiotic therapy )
What is parasitism?
One organism benefits and the other is harm
What is an example of parasitism? Any what?
Any successful pathogenic microorganisms
Does the host and normal flora exist together?
Yes
Does the normal flora live in symbiosis with the human body?
Yes
What does symbiosis mean?
Association between two or more species
What does commensalism mean?
One organism benefits and the other is not affected
What is an example of commensalism?
Staphylococcus epidermis, on our skin
( the normal flora usually benefits the host by preventing pathogens from over growing )
What is the main way that normal flora helps us fight pathogens ?
( best way to fight off infection )
Competitive exclusion, or metabolism
What is going on competitive exclusion? (3)
that the pathogen & flora are fighting of food, energy sources and space
How does competitive exclusion help our normal flora? (2)
By keeping it healthy
&
Decreasing the infection
What did competitive exclusion lead to?
Probiotics
What does micro biome mean?
All the microbes in the human body
Does almost every place in our body have microbes?
Yes
Where in the body do you not want microbes in? (2)
Brain & Spinal cord
Where is the most microbes in our body?
GI Tract
What types microbes will you find in blood?
Transient
As long as transient microbes don’t grow in the blood, is it safe?
Yes. As long as it doesn’t grow
What is an opportunistic organism?
They don’t cause disease, however under certain circumstances, they do
When does opportunist microbe knock? Or causes disease? (3)
- Normal flora is destroyed
- Host defenses mechanism compromised
- Normal protective barriers of host are disrupted
What are some examples of opportunists ? (3) and causes ?
( E, S, P,)
E. coli, cause UTI Id moved from intestine to urethra
S. Aureus- causes TSS
Pneumocystis jirocecii - pneumonia in AIDS patients
E. coli is the number one cause of UTI? ( urinary Tract infection )
Yes
What are the 3 evidence of disease? ( the 3 S’s )
Symptoms
Signs
Syndrome
What is symptoms ? Examples
Changes in body functions
Can not be seen, internally
( such as pain and stomach pain )
(Subjective)
What does sign mean? Examples ?
Changes that can be seen
( rash, fever, swelling )
( objective )
What does syndrome mean?
Specific symptoms and signs associated with a disease
What is subjective? Symptoms or signs?
Symptoms
What is objective ? Symptoms or signs?
Signs
Does opportunitistic organisms infect heathly people and how does it effect them?
They can, but they don’t cause disease
Why don’t they cause disease ( opportunities microorganisms ) to healthy people?
Cause they can touch, if someone has a fever
What are the 4 types of diseases? ( infectious ?)
Infectious
Communicable infectious diseases
Non communicable infectious diseases
Non infectious
How is infectious caused? (5)
By bacteria, viruses, fungi, Protozoa and helminthes
What is communicable infectious diseases?
Contagious
- can be spread from one host to another directly or indirectly
What does non communicable infectious diseases mean? (3)
Caused by individuals flora
Injection of pre formed toxins
Environment
Are communicable infectious diseases contagious?
Yes
Are non communicable infectious diseases contagious?
No
Are non communicable infectious diseases caught?
No, they are not spread
What is non infectious?
Cause by another fact than infectious organism
What are some examples of communicable infectious disease?
Flu, herpes, ring worm, covid etc
What are some examples non communicable infectious diseases ? (3)
Tetanus, Lyme disease , malaria
Is diabetes an infectious disease?
NO!
What does incidence mean?
Number of new cases contracted within a set population during a set time period
What is prevalence mean?
Total number of people infected within a population that has a disease any time
Which one is the indicator of a spread of disease? Incidence or prevalence?
Incidence
Which one includes old and new cases? Incidence or prevelance ?
Prevelance
What are the 4 occurrence of diseases ? ( the Ic’s )
Sporadic
Endemic
Epidemic
Pandemic
What does sporadic mean?
Occurs occasionally in a population
What does endemic mean?
A disease that is always found in the region
What does epidemic mean?
A diseases many people acquire in a very short period of time
What does pandemic mean?
Is an epidemic that occurs worldwide
What are examples of sporadic diseases?
Plague, malaria, Ebola
What are examples of endemic?
Flu, tetanus
Where would Ebola be considered endemic?
Africa
What are some examples of epidemic?
Flu season!!! November - January
What are some examples of pandemic?
Covid, swine flu
What are the 5 severity of duration of a disease?
Acute disease
Chronic disease
Subacute disease
Latent disease
Herd immunity
What is acute disease ?
Symptoms develop rapidly but the disease lasts a short period of time
What are some examples of acute disease?
Flu, colds, Ebola ( dies or recovers )
What is chronic diseases?
Symptoms develop slowly, last a longer period of time
What are chronic disease examples?
HIV, tuberculosis, fungal infections
What is subacute disease?
Intermediate between acute and chronic
What is examples of subacute disease?
Encephalitis
What is latent disease?
Causative agent is inactive for a time and then can re activate
What are some examples of latent disease?
Chicken pox & shingles
What is herd immunity?
Immunity in most of a population
(75-90% population)
What is the best way to get herd immunity?
Vaccination
What helps us identify a spread of infection? (5)
Where does it come from
How does it get into the body
How does it get out of the body
How is it transmitted
Where is it between and during disease
Do most pathogens die outside the host?
Yes
What does reservoir mean?
A continual source of the disease causing organism
( livings or inanimate objects )
Can a reservoir be living or inanimate objects ?
Yes, can be both
What are the 2 living reservoirs of infections?
Human and animals
What are human reservoirs considered as?
Carriers (asymptomatic people)
How does human reservoirs transmit infections?
Directly or indirectly
What are examples of human reservoirs? (5) viruses & diseases
HIV, diphteria, typhoid fever, heptatitis, gonorrhea
What are zoonoses?
Disease that occurs mainly in animals however can transmit into humans
What are some examples of animal reservoirs, zoonoses? (3)
Anthrax, bubonic plague, Lyme disease
How is animal reservoirs transmitted by?
Bites, feathers, food
What are the two non living reservoirs of infection?
Soil and water
What does soil mainly cause and give examples ?
Fungal disease
Clostridium tetani & bacillus anthracis ( tetanus & anthrax )
What is water infectious type and examples?
Contaminated by feces
E. coli. Polio, HAV, typhoid fever
What are the 3 modes of disease transmission?
Contact transmission
Vehicle transmission
Vector transmission
What are the 4 types of contact transmission?
Direct
Congenital
Indirect transmission
Droplet transmission
What is direct contact transmission?
Person to person
What are examples of direct contact transmission?
Kissing, sex, touching, shaking hands
What is congenital transmission?
Mother to fetus or newborn at birth
What are examples of congenital contact transmission?
Egg or Sperm
Placenta
Breast milk
Birth canal
What is indirect transmission?
Noliving object ( formites)
What are examples of indirect transmission?
Fomites
( syringe, drinking glass, toys )
What is droplet transmission?
Droplet nuclei
What are examples of droplet transmission?
Sneezing, coughing, talking
What are the 3 vechicle transmission?
Water, food, air,
(body fluid & blood )
What is vehicle transmission?
A non living carrier of an infectious agent from its reservoir to a host
How is water associated with vehicle transmission?
Fecal contamination
What are some examples of water in vechial transmission, diseases? (3)
Cholera, leptospirosis, shigellosis
How is food associated with vehicle transmission?
Uncooked and improper refrigeration ( food poisoning )
What are some examples of food in vehicle transmission? (3)
Botulism & typhoid fever & salmonella
How is air associated with vehicle transmission ?
Mucus droplets
What are some examples of air in vechicle transmission ? (3)
Histoplasmosis
Measles
Tuberculosis
What are vector transmission?
Insect ( anthropods )
What are the two vector transmission ?
Biological
Mechanical
What are biological vector transmission ?
Bitten by mosquitoes
What are examples of biological transmission ? (2)
Lyme disease
Malaria
What are mechanical transmission?
Mosquitoes feet or body part touches food or skin
What is passive and no replication of micrograms in vector transmission? Biological or mechanical?
Mechanical
What are examples of mechanical transmission? (2)
Shingellosis & typhoid fever
When aerosols containing pathogens spread disease from a distance of less than one meter is it considered?
Contact transmission
( more specific droplet transmission )
Droplet vs airborne difference?
Air long distance
Droplet less than a meter
Where would you put covid? Contact or airborne ?
Both !
What is a nosocomial infection?
Hospital acquired infection
What are the 3 factors that make nosocomial infections dangerous?
- Hospitals
- Compromised patients
- Chain of transmission
What are some examples of nosocomial infections?
Pseudomonas