Chapter 9 Flashcards
Infectious diesese
an illness caused by a pathogen
Epidemiology
Monitoring and controlling of disease to promote public health
Pathogens include?
Viruses, prions, bacteria, protozoans, helminths, fungi
Pathogen: definition
microorganism that can cause disease
Pathogen: Examples
Viruses, prions, bacteria, protozoans, helminths, fungi`
Opportunistic pathogens
pathogens that wait for the right time to infects host
True pathogens
infect host upon contact
Sporatic cases
isolated infections of a disease in a particular population
Endemic infections
routinely checked infections in a population or region (like head colds)
Epidemic
Widespread disease outbreak in a particular region during a specific time frame
Pandemic
When disease spreads beyond region
Emerging pathogens
Newley identified agents/pathogens that only caused sporadic cases
Reemerging pathogens
An infectious agent/pathogen that was under control but is now resurfacing
Zoonotic diseases
Pathogens that go from humans to animals
Noncommunicable
In terms of Micro, doesn’t spread from human to human (ie. zoonotic diseases)
Communicable diseases
Transmit from person to person
Contagious diseases
Diseases that are EASILY transferred from host to host
What does it mean when a patient is symptomatic?
During an active infection, the patient is showing signs and symptoms of infection
Signs
Objective indicators of infection, can be measured and verified (rashes, stool samples, fever)
Symptoms
Are what is sensed by the patient (what they feel)
Infection characterizations
Acute: rapid and onset progression
Chronic: slower onset progression
Latent: asymptomatic (no signs or symptoms)
Koch’s postulation
- Same organism must be present in every case
- Organism must be isolated from infected host and grown in new culture
- Isolated disease should cause same infection when introduced to host
- Organism must be isolated again from newly infected host
Koch’s postulation: limitations
Doesn’t apply to noninfectious diseases
Some diseases can’t be isolated
Some diseases are antiquated(weakened) in pure culture
Some microbes don’t infect nonhumans
Reservoirs
animate or nonaminate habitat where pathogen is naturally found
Sources
Spread infectious agents from reservoirs to hosts
Sources: types
Endogenous: pathogen comes from host’s body
Exogenous: pathogens come from outside hosts body
Exogenous sources: examples
Environmental
Animals
Humans
Endogenous sources: examples
Misplaced microbiota
Disrupted microbiota and opportunistic pathogens
Modes of transmission of pathogen
Direct and indirect contact
Direct transmission
infection from direct contact (like a bite, of touch, or swimming in a pond)
Vertical transmission
A type of direct contact when infection is passed from mother to baby during pregnancy, delivery, breast feeding
Indirect transmission
When there is no direct physical contact b/n host and pathogen
Indirect transmission: types
Airborne: pathogens that enter through respiratory route
Vehicle: pathogen on contaminated fomite (doorknob, needles, sheets)
Vector: Transmission by vectors
Vector transmission types:
Biological: Vector organism has a part in pathogens lifecycle (ticks and mosquitos)
Mechanical: Spreads disease without being a part of pathogens lifecycle (flies, rats, cockroaches)
What are the five stages of disease?
Incubation period
Prodromal period
Acute phase
Period of decline
Convalescent phase
Incubation period
time between infection and signs and symptoms
Prodromal period
Earliest symptoms develop
Acute phase
Peak of disease, all notable signs and symptoms present
Period of decline
Infection replication is under control and symptoms begin to go down
Convalescent phase
Recovery begins
Infectivity
How good infectious agent is good at infecting
Virulence
Severity of disease
Pathogenicity
Ability of infectious agent to cause disease
Epidemiology
Study of what is upon people, focuses on diseases in populations to better understand them and prevent illness
Goals of epidemiology
To educate about a new or existing disease in a population
intervene to protect and improve health in populations
Host range
collection of hosts that a pathogen can use as a partner
What is the importance of public education?
To break the epidemiology triangle by aiding people in understanding their role in preventing drug-resistant pathogens
Quarantine
Time away from general population. Diseases with short incubation times can be controlled with quarantine
Vector Control
Limiting number of biological vectors can help prevent spread of dangerous diseases
Healthcare- Acquired Infections (HAIs)
Diseases developed in from healthcare intervention
Common HAIs
Staph aureus
E coli
C difficile
P aeruginosa
Basic preventative measures of HAIs
Hand washing
Consistent use of personal protective wear (gloves, masks, and gowns)
Environmental sanitization
Equipment sterilization
Limiting patient transport
Single patient equipment use
Patient isolation (as needed)
Superbugs
HAIs drug resistant pathogens often originate in healthcare settings due to extensive antibiotic use
Eradication
when there is no longer of any cases of a pathogen in the world
Candidates for eradication
Easily identifiable
Treatable or preventable
Humans-specific
Note: Pathogens that can cause latent infections are harder to eradicate
