Lecture 10 Flashcards
Pathogenicity vs. Etiology
Secondary concern. How it progresses. What does it do. Infection invasive to the body by pathogen organisms OR disease where body is not able to perform normal functions
Primary concern. Cause of disease
What is pathology?
The study of disease
Made of etiology and pathogenicity
How many normal microflora and bacteria do we have in our bodies?
1x 10^13
1x 10^14 - more bacteria population but varies in type and population of each
What are the characteristics of microflora?
Localized to certain regions of body (mainly exposed areas)
Ex. Skin, respiratory, urinary tract
What is the role of microflora?
Prevents pathogen growth by:
Microbial antagonism - produce harmful substances to invading microbes (natural selection)
Competitive exclusion - use up nutrients and leave nothing for pathogens to grow with
Some microflora makes vitamin K & B for body
What are opportunistic pathogens?
Microbes that are part of normal flora and do not cause disease UNLESS:
- transferred to other body part
- human host becomes compromised (AIDS)
- normal flora is slipping
What is Koch’s studies?
Study based on germ theory of disease
The same pathogen should appear in every case of disease when isolated and inserted into healthy rat and found isolated again
What are exceptions to Koch’s study?
Some bacteria does not grow in pure culture
Some pathogens cannot infect lab animals
Many different microorganisms can cause the same disease
Vice versa
One pathogen can cause many different diseases
How are diseases clarified?
Symptoms based on patient feeling but very atypical and must also be verifiable
Physical signs like fever, swelling
Syndrome specific group of symptoms together for a specific disease
What is a communicable disease?
Spread from one host to another potentially
Ex. Chicken pox, STD
Director close contact
What is a contagious disease?
Easily spread via surface contamination from person to person very quick and easy to catch
What are the 5 different disease occurrences?
Sporadic - only happens sometimes ex. Hamburger disease
Endemic - low and constant levels of a disease ex. Cold, all year around
Epidemic - occurs in high numbers over short time ex. Influence flu
Pandemic - epidemic disease that occurs worldwide ex. Bird flu
Emerging infectious disease - newly identified
Ex. West Nile virus
What are the different severity and duration of diseases?
Acute - rapid developed and short duration
Chronic - slow to develop but lasts long with high spread likelihood ex tuberculosis
Latent - inactive fora period of time and can be reactivated ex. Herpes
Local infection vs. Systemic infection
Confined to small area of body
Microbes are spread through the body
- septicemia blood infection
- bacteremia bacteria in blood
- toxemia toxins in blood
- viremia virus in blood
What are the stages of diseases?
Incubation period - time b/w infection and first symptom
Prodromal period - early mild symptoms
Period of illness - most severe signs and symptoms (if this is not overcome u die)
Period of decline - signs and symptoms subside (hour or days and VERY vulnerable to other infection)
Period of convalescence - recovery occurs but pathogens can still be present and spread to others
What are the 3 different reservoirs for infection spreading?
Human - source of infection and spread to others at any stage or if they are asymptomatic
Animal - zoonosis disease that can spread to humans ex. Lyme disease from mice and ticks
Non living - soil and water ex. Used syringe and Kleenex
What are the 3 disease transmission types?
Contact transmissions
- direct contact ex. STD
- indirect contact ex. Used Kleenex
- droplet spread by short distance ex. Sneezing
Vehicle transmission
- waterborne ex. Improper water treatment
- airborne ex. Droplets in tuberculosis
- foodborne ex. Food poisoning salmonella
Vector transmission
- animals spreading disease ex. Lyme disease mice -> ticks -> humans
What does nosocomial infections mean?
Hospital acquired infections
How many patients become infected in hospital settings? Why?
5 - 15%
Factors
- resistant pathogens to disinfectant
- weakened state of patients
- chain of transmission: direct pass from staff to patient, indirect through tools and sheets, airborne by ventilation system
What are the 4 ways to control the spread of diseases?
Hygiene
- proper hand washing is the best!
- proper sterilization
- proper food and water prep
- proper sewage treatment
Vectors
- controlling insect vectors
- vaccination to domestic animals
Avoidance
- avoid infected using gloves and quarantine infected
Isolation
- people who are likely to get sick are kept safe
Ex. Bone marrow transplant
