Lecture #12 Flashcards
What is pathology?
The study of disease
What is etiology?
The cause of disease
What is pathogenicity?
The ability to cause disease
What is virulence?
Ability to cause harm
The higher the ______= better to cause disease
Virulence
What is pathogenesis?
How the disease develops
What is pathogen?
An organism that can cause disease
What is infection?
The invasion or colonization of the body by pathogenic organisms
What is disease?
Abnormal state where the body is not capable of performing normal functions (not being able to swallow)
What is transient microbiota?
Microbes that may be present for days or months and then disappear
Microbiota is localized where?
In certain regions of the body
Microbiota is found mostly in what areas of the body? Examples?
In exposed areas
Ex. Skin and tracts (exposed to the outside world)
How does microbiota benefit the host cell?
By preventing the growth of pathogens
What is microbial antagonism?
members of the microbiota produce substances harmful to invading microbes
What is competitive exclusion?
Microflora use up available nutrients preventing growth of pathogens
What is an example of competitive exclusion?
Clostridium Difficle is inhibited by the normal microbiota of the large intestine
If the normal microflora is eliminated (by an antibiotic treatment), what can clostridium difficile cause?
Infection
If infected with clostridium difficile, what can the infection lead to?
Fatal inflammation of the colon
What are two other benefits of microbiota (other than preventing pathogens)
- E.coli in the large intestine makes vitamin K and Vitamin B
- Some produce enzymes that aid in digestion
What are opportunistic pathogens?
Microbes that are part of the normal microbiota and do not normally cause disease
Opportunistic pathogens can cause disease if what 3 things happen?
- They are transferred another part of the body
- The human host becomes immunocompromised
- Microbiota is disturbed
How is E.coli an opportunistic pathogen?
It is a normal resident in the large intestine but if it is transferred to the urinary tract, it can cause infection
How’s streptococcus pneumonia an opportunistic pathogen?
It is a normal resident in the respirator tract but when the host is already weakened such as a cold, it can cause pneumonia
What is a symptom?
What a patient feels (pain, run down), variable
What is a sign?
An objective change that a physician can measure (swelling, fever, etc)
What is a syndrome?
A specific group of signs and symptoms that always accompany a particular disease
What can diseases be classified based on?
Their effect in the host population
What is a communicable disease? Give an example?
A disease that spreads from one host to another
Ex. chicken pox, measles and STD’s
What is a contagious disease? Give an example?
Easily spread
Ex. Chicken pox and measles
What is a non-communicable disease? Give an example?
Does not spread between hosts
Ex. Salmonellosis
What are the 5 stages of disease?
- Incubation period
- Prodromal Period
- Period of Illness
- Period of decline
- Period of Convalescence
What occurs in the incubation period?
The time between the infection and the first signs and symptoms
What occurs in the prodromal period?
Early and mild symptoms such as malaise ( feeling unwell)
What occurs in the period of illness?
Most severe signs and symptoms (immune response may cause some signs and symptoms
If a disease is not overcome in the period of illness, what occurs?
Death
What occurs in the period of decline? How long can it last?
- Signs and symptoms subside
- Can last for hours or days
During the period of decline, what can the patient be vulnerable to?
Secondary infections
What occurs in the period of convalescence?
Recovery occurs
What can still be present in the period of convalescence? How long?
The pathogen and can spread to others, and a person can continue to carry the pathogen for months
What is an acute disease? Example?
It rapidly develops and short duration
Ex. Influenza
What is a chronic disease? Example?
Slow to develop and continual in duration
Ex. Tuberculosis
What is a latent disease? Example?
Inactive for a period of time, can be reactivated
Ex. Coldsore- herpe simplex virus
The likelihood of disease occurring increases with the number of what?
Microbes introduced increase
How is infectious dose written?
ID50
What is ID50?
The amount of bacteria required to cause disease in 50% of the population
What is an example of an ID50? What occurs when it enters through skin, inhalation and ingestion?
Bacillus Anthracis
Skin: ID50= 10 to 20 endospores
Inhalation: ID50= 10000-20000 endospores
Ingestion: ID50= 250000-100000 endospores
What does LD50 stand for?
Lethal Dose that kills 50% of the infectious population
What is a local infection?
Confined to a small area of the body
What is a systemic Infection?
Microbes or toxin are spread through the body (can be through blood)
What is septicaemia?
Systemic infection of the blood
What is bacteremia?
Bacteria in the blood
What is toxaemia?
Toxins in the blood
What is an example of toxaemia? And what does it do
Clostridium tetani causes infection of the cut and releases tetanus toxin into the blood
What is viremia?
Virus particles in the blood
What is sepsis?
Life threatening systemic inflammatory response, usually due to bacteremia (low blood pressure, no blood filter and go into organ failure/shock)
