Unit 2 Intro to Infectious Diseases Flashcards
How was the bubonic plague transmitted?
Will we ever be free of disease?
Fleas bit rats who bit people too. Can be passed via respiration from human to human
No.
When this value is high, the spread of disease is low and vice versa. Defined as a population and how many people are immune to a disease.
Affected nowadays by vaccines.
What is the example of low herd immunity in human history? Another example is?
Herd Immunity
Native Americans and European Diseases (knowingly giving them smallpox, even)
Spanish Flu
Do infectious disease still take a heavy toll on human life?
Yes, but it has been lowered via vaccines, antibiotics, sanitation, medical care
Doesn’t apply in third world countries or poorer populations in developed countries
This is defined as a disturbance in normal functioning of an organism
Disease
This type of diseease is caused by a microbe and can be transmitted from host to host
Infectious Disease (Influenza, HIV, hep B, bacteria, fungi)
These are infections diseases of animals that can cause disease when transmitted to humans
Examples?
Zoonotic Disease
Rabies, West Nile Fever
In developed countries, why is it usually wild animals that give us rabies?
In what animal is West Nile Virus prominent? How do we become infected? Can it be passed on to someone else?
We vaccinate our domesticated animals
Birds. Mosquitos. No.
This is a bacterial disease spread by ticks who feed on deer.
Lyme Disease
This is a microbe frequently associated with disease production. It must cause harm (disease)
Pathogen
This is the mechanism by which a microbe uses to cause a disease state, it could be enzymes or toxins that cause damage to tissues.
Specific signs and symptoms are associated with specific diseases, however many viruses have the same symptoms which complicate diagnosis
Pathogenesis
This term refers to the replication of a microbe (sometimes pathogen) in or on its host.
Infection
Our normal flora infects us too. But its a pathogen infection if it causes damage
Do all pathogens have the same ability to cause disease?
These pathogens tend to produce disease readily in healthy hosts, usually a virus
When can it occur in bacteria?
No
Primary Pathogen
When they are not out normal flora, like cholera bacteria
This type of pathogen generally only cause disease when placed into an unusual site or when the host has a weakened immune system
Opportunistic pathogens
E. coli in the intestines, which can spread to other parts of our body like after appendicitis
Or developing pneumonia after having the flu, (weakened Immune system) or alcoholism
This is a measure of the severity of disease a pathogen can produce.
This is the proportion of infected individuals who develop the disease
Virulence
(0 virulence is not a pathogen)
Case-to-infection ratio (CTI)
Pathogens can weaken over time or show varying virulence levels due to________
Attenuated strains show INCREASED/DECREASED virulence
Avirulent strains can no longer cause _____
Genetic differences
Decreased (attenuated viruses are useful in vaccines, like chickenpox)
Disease
An individual infected with a pathogenic microbe who never exhibits overt signs or symptoms of the disease (asymptomatic) is called a
They can make other people sick
Typhoid Mary is a good example
Carrier
Typhoid fever is transported by the _________ route,
Fecal oral route. How people who ate Typhoid Mary’s cold prepared foods got sick
What must a microbe do to cause disease?
Gain entry to host Attach to and invade specific cells and/or tissues within the host Evade host defenses Obtain nutrients from the host Exit the host
This organism produces IgA protease, an enzyme that destroys IgA antibodies, evading the immune system
Neisseria gonorrhoeae
This organism has iron binding proteins to allow pathogen to acquire iron from the host
Alternatively, other organisms can lyse _____ cells
Mycobacterium tuberculosis
Red Blood Cells
