Pathogenesis And Epidemiology Flashcards
Lives on the outside surface of an organism or Cohabiting with
Ex. Cow and bird
Ectosymbiont
Live within the host
Endosymbiont
One organism benefits the other is not harmed or helped
Commensalism
Symbiotic relationship, to organisms in opposition to one another
Ex. Yeast and bacteria in vagina
Antagonism
___________ breaks down peptidoglycan in bacteria in our tears
Lysozymes
The ability of a microbe to cause disease
Pathogenicity
The ability of The organism to invade and enter the host “ establish it self”
Invasiveness
Describes the degree or severity of disease. The Ability to induce severe disease (how bad)
Virulence
Opposite of virulence.
Attenuation
The cellular changes that occur within the host tissue. Can be used to access death rates instead of entire organism
Cytopathology
There is a correlation between mode of transmission and degree of ________
Virulence
Direct contact is less virulent and indirect is more
What are the direct contact transmissions?
Vertical transmission- from parent to offspring. Ex placenta
Horizontal transmission- Direct from person to person
Droplets-small particles that can only travel less than 1 m
What are in direct contact
Transmissions?
Formites- these are items you can touch
Vehicle-nonliving carrier of an infectious agent (food, water, airborne transmission)
What are vectorborne modes of transmission?
- biological vector- Active transmission, pathogen completes part of its lifecycle in the vector before being transmitted
- mechanical vector-doesn’t require the pathogen to multiply on or within the vector
Could be an animal or dirt, soil, or water. Can harbor pathogen‘s that can be transmitted to a new house to cost disease
Reservoir
Complex infectious cycles involve _____ as intermediatories
Ex: mosquitoes, ticks, mites. West Nile in birds (they don’t have it but mosquitoes transfer from birds to people)
Vector
Rickettsia rickettsii
Rocky Mountain spotted fever
The tick is both reservoir and vector for the pathogen
In Lyme disease, mice or other small mammals are the _______ , ticks are the _______ for the bacterium Borrelia burgdorferi
Reservoir, vector
In syphilis, humans are the ________, and transmission of the bacteria Treponema pallidum it’s through direct contact with the ______
Reservoir
What are the steps for a microbe to cause disease in a host?
- portal of entry
- surviving host defenses
- attaching firmly
- causing damage
- exit host (portal of exit)
_________ originates from outside the host body
_________ already exists within the body of the host
Exogenous
Endogenous
Involves piercing the skin or mucous membranes
Ex: injected through a needle, nail, insect bite
Parental route
Also known as “white death”.
Molecules that are secreted by some bacteria that will kill the hosts leukocytes
Leukoocidins
Type of white blood cell, then golf pathogen’s, some pathogens can evade them
Phagocytes
What can block phagocytosis or cause incomplete phagocytosis?
Bacterial capsules
Prevents fusion of lysosome and phagocytic vesicles
Protein A
Adaptation to invade and establish infection in house. Determines a degree of tissue damage that occurs
Virulence factors
Ex: cell wall components like LPS, capsules, pili (adhesions), fimbriae, enzymes, and toxins
What are some Exoenzymes that help bacteria induce disease?
“ spreading factors”
- collagenase (enzyme that breaks down the proteins and collagen)
- hyaluronidase (enzyme that breaks down hyaluronic acid)
- mucinase
- Kertatinase
How do you exoenzymes help bacteria induce disease?
- catalase-breaks down hydrogen peroxide into water and oxygen
- coagulase- conjugates Fibrogen in plasma leading to the formation of a fiber in clot. Can prevent phagocytosis, (gives the organism a chance to multiply within the fiberin clot, increasing the size of the infecting dose)
- kinases (streptokinase) enzymes that can break down the clots to spread in neighboring tissues
These are toxins secreted by live cells
Exotoxins
Toxins released when the cell is killed
Endotoxins (lipid A from LPS)
Entry of preformed toxin into the host?
What is it called if it’s in the blood?
Intoxications
Toxemia
Type of toxin produced by some bacteria. Induces red blood cell lysis
Degrade hemoglobin releasing iron
Hemolysins
Alpha hemolysins-partially degrades
Beta- completely degrade the hemoglobin
Gamma-does not produce hemolysis that degrade red blood cells and hemoglobin
Causes severe diarrhea, usually from fece contaminated food or water
cholera (vibrio cholerae)
cAMP activates ion transport; water follows to cause uncontrollable diarrhea
This is what the patient is feeling and describing
Symptoms
Like chills, headache, etc.
Something that can be observed or measured by the practitioner
Signs
Ex: fever, chest sounds, etc.
When the body cannot clear an infection. White blood cells surrounding the area of infection to prevent the microbes from spreading
Granuloma
Lasting effects that remain after the host has recovered (damage from the infection)
Sequelae
Describe the stages of infectious disease
- incubation period
- prodromal stage (A vague sense of starting to feel the infection)
- period of illness (Acme- highest Point of infection, fulminating-rapid and severe onset)
- convalescence period- period Where you either improve or death
First epidemiologist, studied Cholera in London
John Snow
Evaluate occurrence, determinate, distribution in control of health and disease in a defined human population.
determine the causative agent of disease, the source, and or reservoir, mechanisms of transmission, hosts and environmental factors in best control measures
Epidemiology
First identified case in an epidemic
Index case
The number of NEW cases in a given area, in a given time period
Incidence
Depends both on the incidence rate and duration of the illness. Number of TOTAL cases in a given area in a given time.
Prevalence
Incidence of deaths in a population during a certain period of time
Mortality rate
Proportion of illness in a population, usually per 1000 people
Morbidity rate
Types of nosocomial infections
Endogenous-brought into the hospital by the patient
Exogenous-The microbiota is different than the patient’s normal flora
Autogenous-caused by the microbiota of the patient despite whether it became part of the patient’s microbiota following and mission
Sheltering in place used for people who do not have the disease
Isolation
Isolating someone who may have been exposed but it’s not showing signs or symptoms yet
Quarantine
