micro exam 3: ch 15, 16, 17, 21

Epidemiology

study of spread, distribution and frequency of human disease

etiology

study of the cause of disease

predisposing factors

factors that make an individual more susceptible to a given disease

ex. age, gender, nutrition, genetic factors, climate, weather

morbidity

state of being ill/unhealthy

mortality

deaths per population

Incidence

number of new cases

Prevalence

total number affected in the population

endemic disease

disease constantly present in a population
ex. malaria

sporadic disease

occurs only occasionally
ex. typhoid

epidemic disease

disease acquired by many people in a short time
ex. tetanus, rabies, plague, flu

pandemic

worldwide epidemic
ex. AIDS

reservoir

natural habitat for a pathogen (living or nonliving)

definitive host

host in which parasite reaches sexual maturity

intermediate host

parasite goes through several immature life cycles or reproduces asexually

source

individual or object from which an infection is acquired

Carrier

individual that harbors infections and can spread them to others
- passive carrier: spread the infection without being infected by it
- active carrier: you are sick and infect someone else
- asymptomatic: sick and able to infect others but do not show symptoms

direct contact transmission

person to person via physical contact
horizontal - mother to child via breastmilk or placenta
vertical - physical touch, kissing or sex
droplet - spreading over distances less than 1 M sneezing and coughing

indirect transmission

transmission via inanimate objects, fomites

airborne transmission

pathogens carried by air, greater than 1 M

water-borne transmission

fecal contaminated water (drinking or bathing)

food-borne transmisson

ingestion of food containing pathogens

vector

animal carrying a disease

biological vector

help life cycle of a pathogen
ex. misquito

mechanical vector

transports without being infected
ex. fly

nonsocomial infection

Infection acquired while in a hospital or medical setting.

pathology

study of disease

Etiology

study of the cause of disease

Pathogen

A microorganism that causes disease

pathogenesis

study of how a disease develops

infection

successful colonization of a host by a microorganism

disease

abnormal state in which the body is not functioning normally

sign

change in the body that can be measured or observed
ex. vital signs

symptom

change in body felt by patient
ex. pain on scale of 1-10

syndrome

a specific group of signs and symptoms that accompany a disease

cyto-

cell

hepat-

liver

-pathy

disease

-emia

of the blood

-itis

inflammation

-lysis

destruction

-oma

tumor

-osis

abnormal condition

-derma

of the skin

infectious disease

a disease caused by a pathogen

non-infectious disease

A disease that is not caused by a pathogen

Types of non-infectious diseases

inherited, congenital, degenerative, nutritional deficiency, endocrine, neoplastic, idiopathic

types of infectious diseases

communicable, non communicable, iatrogenic, zoonotic

incubation period

no signs or symptoms

prodromal stage

general, non specific symptoms

period of illness

severe signs and symptoms

period of decline

pathogen decline/decrease - symptoms decrease

convalescent period

general return to normal function

acute

rapid development

chronic

slow development

latent

dormant periods

transient microbiota

temporarily present

resident microbiota

permanently present on host

Sites that harbor resident microbes

Santa Opens Presents Near Midnight Causing Ruckus Above Us Giving Vixen Evil Eyes

Microbial antagonism

normal flora preventing overgrowth/colonization by pathogens

endogenous infections

occur when normal flora is introduced to a site that was previously sterile

Primary/true pathogens

can cause infection and disease in healthy people

opportunistic pathogen

Pathogen that produces disease when the immunity of the host is compromised

Infectious dose (ID)

minimum number of microbes required for infection to proceed

ID and Virulence relationship

inversely related
High ID= low virulence
Low ID = high virulence
ex. measles have very high virulence and low ID
cholera has low virulence and high ID

pathogenicity

ability to cause disease

virulence

degree of pathogenicity

virulence factor

characteristics of pathogens that determine virulence
1. adhesion
2. resistance to host immunity
3. invasion
4. toxin secretions

Virulence factor - RESISTANCE TO HOST IMMUNITY

antiphagocytic factors, survive intracellular phagocytosis

Virulence factor - INVASION

exoenzymes - dissolve extracellular barriers to allow pathogen to penetrate cell

virulence factor - TOXIN SECRETION

toxins produced are endotoxins or exotoxins
endotoxins - not secreted, release after cell is damaged
exotoxins - secreted

characteristics of endotoxins

gram negative, lipopolysaccharide membrane, general symptoms (inflammation, fever) , heat resistant, LD50 is high

characteristics of exotoxins

typically gram positive, but can be negative.
protein membrane
specific damage to cells
heat sensitive, can be stable also
LD50 is low
ex. cholera, tetanus, botulinum, diphtheria

LD50

short term poisoning potential

Stages of pathogenesis

1. Exposure
2. Adhesion
3. Invasion
4. Infection

Exposure specifics

contact
portals of entry - microbe enters the body
exogenous agents - source is outside body
endogenous agents - already in body (normal flora)

pee!

infection specifics

Localized - confined to specific tissue
Systemic - spreads to several sites
Focal - localized pathogen spreads to 2nd location
Mixed - several microbes grow simultaneously
Primary - initial infection caused by one pathogen
Secondary - 2nd infection caused by another microbe

lloyd said fat morons prove stupid HAHAHA

Pathogens during preganncy

TORCH
T - toxoplasmosis
O- Syphilis
- chickenpox
- hepatitis B
- HIV
- fifth disease
R - rubella
C- cytomegalovirus
H- herpes

TORCH, T

toxoplasmosis

TORCH, O

O- Syphilis
- chickenpox
- hepatitis B
- HIV
- fifth disease

TORCH, R

rubella

TORCH, C

cytomegalovirus

TORCH, H

herpes

Immunology

the study of the body's second and third lines of defense

1st and 2nd line of defense are...

non-specific

1st line of defense includes

skin, mucous membranes, chemicals

2nd line of defense includes

phagocytosis, complement, interferon, inflammation, fever

the 3rd line of defense is...

specific

3rd line of defense includes

lymphocytes and antibodies

physical defenses (3)

1. physical/cellular barriers
2. mechanical defenses
3. microbiome

physical/cellular barriers include

skin, mucous membranes, endothelial cells

mechanical defenses include

shedding skin cells, Mucociliary sweeping, peristalsis, flushing of urine and tears

microbiome defenses include

resident bacteria of the skin, upper respiratory tract, gastrointestinal tract, genitourinary tract

Chemical defenses (4)

1. chemicals in enzymes and body fluid
2. antimicrobial peptides
3. plasma protein mediators
4. cytokines
5. inflammation eliciting mediators

chemical defenses include

- sebum
- sweat
- semen
- lysozyme
- acidic pH of skin
- gastric juice
- digestive juice
- vaginal secretions
- antimicrobial peptides
- plasma protein mediators

Cellular defenses (2)

1. granulocytes
2. agranulocytes

cellular defenses include

- hematopoiesis
- stem cells (precursor to blood cells)
- leukocytes - white blood cells
- granulocytes - lobed nucleus, granules present
- agranulocytes - un-lobed, no distinct granules

Neutrophil

granulocyte.
50-70%
lobed nuclei
lavender granules
phagocytes

Eosinophil

granulocyte
1-3%
bilobed nucleus
orange
destroy eukaryotic pathogens, like parasitic worms

basophils

granulocyte
0.5-1%
constricted nuclei
dark blue
release potent chemical mediators

lymphocytes

Agranulocyte
20-40%
specific immune response
B cells and T cells