BIO 202 Exam #5 - Bradley University

Endemic disease

Characterized by regional location and periodic outbreaks

What are some examples of an endemic disease?

Malaria and the seasonal flu

Epidemic/pandemic diseases are characterized by

Widespread occurrence and rapid outbreak

Common source outbreak

High incidence levels and low amount of days (peaks very close to origin on a graph)

What's an example of a common source outbreak?

Food poisoning

Propagated epidemic outbreak

Person to person, wipes out everyone

What's an example of a propagated epidemic?

The common cold

What are disease reservoirs?

Sources of ongoing infection

What are the three locations for disease reservoirs?

Human, animal, and non-living

Human reservoirs

carriers may have inapparent infections or latent diseases (may not be symptomatic)

Animal reservoirs

zoonoses are diseases transmitted from animals to humans (examples: influenza and West Nile virus)

Non-living reservoirs

soil and water

Contact transmission

direct, indirect, droplet

Direct transmission

Physical contact w/infected source

Indirect transmission

Contact w/contaminated fomite

Droplet transmission

Contaminated droplets contact membranes (1M)

Vehicle transmission

Exposure to contaminated water, air, or food

Example of vehicle transmission

Cholera

Vector transmission

By saliva and feces from an insect/animal

Example of vector transmission

Lyme disease or E. Coli

Nosocomial infections

Healthcare acquired diseases/pathogens

Where do nosocomial infections come from?

Another person's flora, who is also nosocomial

What are the most common sites of nosocomial infections?

Urinary tract (40%), surgical wounds (19%), and respiratory tract (15%)

Pathogenicity

ability to cause disease

Virulence is the

Degree of ability to cause disease

ID 50 refers to

Infectious dose 50

LD 50 refers to

dose that is toxic to 50% of a population

Primary pathogens

Cause disease upon infection, normally not associated with the host

Opportunistic pathogens cause

Disease under some circumstances (within the normal flora)

When do opportunistic pathogens occur?

- someone is immunocompromised

- flora membranes are out of place

- disturbance of "normal flora balance"

The disease cycle

Contains transmission to a portal of entry, colonization in situ, damage to cell's tissues , and transmission from a portal of entry

What does the "transmission to a portal of entry" part of the disease cycle refer to?

Envades 1st-non-specific immune defenses and affects microbial load/attachments

What does the "colonization in situ" part of the disease cycle refer to?

Evasion of other immune defenses

What does the "damage to cell's tissues" part of the disease cycle refer to?

Invasion or inflammation, toxins that cause tissue damage

What does the "transmission from a portal of entry" part of the disease cycle refer to?

Transmission from a portal of entry

Which ways can transmission happen?

Horizontal, vertical, or whatever is appropriate for the portal of entry

Attachment is the first step to

Colonization

Attachment specifically determines

Host range of pathogen

How does attachment happen?

Pili, virus spikes, capsules, or teichoic acid

Colonization refers to

Multiplication and maintenance

What else does colonization do?

Competes with normal flora and effects barrier defenses (bile, sweat, and sebum)

Stealth tactics of diseases

Has to avoid phagocytosis, antibodies, and enzymes

Compliment

Labels things that are dangerous to the immune system

Exotoxins are ______ ________

Secreted proteins

Exotoxins have what kind of shape?

3D Shape, can be identified as an antigen

Exotoxins are ____-_________

Cell specific

What gram stain do exotoxins typically associate with?

Gram +

Exotoxins have HIGH/LOW LD50 levels?

Very low

What are some ways that exotoxins can be inactivated?

- they are heat labile, meaning they make toxoids

- they are strongly antigenic (antibodies are protective)

Super antigens

Excess off inflammatory cytokines

Low BP leads to

Shock

Shock from low BP leads to

Multiple organ failure

Example of super antigen?

toxic shock syndrome

Endotoxin are

Liposaccharide of Gram - Bacteria

Are endotoxins proteins?

No, they are not secreted either

Polysaccharides =

Weak

Lipid A is

Toxic, especially in the bloodstream

What type of bacteria does Lipids A refer to

Gram negative

What can Lipid A do?

Induces fever and shock (excess immune responses)

Lipid A is a _____ _______

Danger pattern

Endotoxin genes are __________

Chromosomal

What are the three things that Lipid A activates ?

Macrophages, compliment, and clotting cascade

Macrophages lead to

Inflammatory cytokines that cause fever and hypotension (shock)

Compliment leads to

Histamine released by mast cells that causes hypotension

Clotting cascade leads to

Disseminated intravascular coagulation (DIC)

Blood is supposed to be ______

Sterile

Infection leads to

Septic shock

Septic shock leads to

Multiple organ failure and death

Portal of entry

Establishes the next infection

Neutrophils

Do not perform antigen presentations

Pyogenic infections

Pus-forming infections

Macrophages perform

phagocytosis and do antigen presentation on MHC-II cells

What do macrophages secrete

"Pro-Inflammatory" cytokines

Pattern recognition receptors (PRR)

Allow the immune system to identify danger patterns

Pathogen associated molecular patterns

Recognizes danger patterns, general and always needed

TLR (toll-like receptors)

Are a type of pattern recognition receptors (PRR)

Where are TLR's found?

Macrophages and dendritic cells

Can the specificity of TLR's be changed?

No

Activated TLR's

Initiate intracellular signaling, that stimulated cytokine production

What do activated TLR's do?

- activate other cells/responses

- inflammation

- up-regulation of MHC-proteins

Cytokines are

Cell —> cell transmission and communication

What are PRRs?

pattern recognition receptors

Where are PRRs found?

The surface of phagocytes, dendritic cells, endothelial cells, & lymphocytes

What do PRRs respond to?

Danger patterns

What are the 2 functions of a PRR?

- activate the cell

- upregulation

What are the results of PRR activation?

Regulated cell response

Are natural killer and eosinophils antigen specific?

No

Eosinophils

Secrete, and they are weakly phagocytic

Normal inflammation

A non-specific response, localized in response to tissue damage or infection

What should you always think of when you think of MAST CELLS

Mast cells = inflammation = histamine

Fever may be _______

Beneficial

Fever is

Non-specific, systemic increase in body

What is fever caused by?

Pyrogens that come from outside the body

Cytokines are made ______ the body

Within

Types of interferons

Alpha + beta, and gamma

Alpha + beta interferons

Anti-antiviral response

Gamma interferons

Activates macrophages and promotes phagocytosis

Compliment refers to:

- inflammation

- opsonization

- microbe destruction

Inflammation and opsonization of compliment promote what?

Phagocytosis

Is compliment normal?

Yes, it is made all the time in the liver