michael bio chatper 11 yayayay

wait he didnt just spell the word rapper and leave out a p did he.

colonization

does not cause disease

infection

multiplication of a microbe in a host; produces inflammation.

disease

If the host loses to a microbe during infection. Damage is caused to host tissues and organs.

infectious disease

a pathologic state caused directly by microorganisms or their products.

microbiome

the population of microbes that reside in the body without causing disease.

sites previously known to harbor normal microbiota

• Skin and adjacent mucous membranes

• Upper respiratory tract

• GI tract, including mouth

• Outer urethra

• External genitalia (RJ doesn’t have this)

• Vagina (RJ has this)

• External ear canal

• External eye

additional sites now thought to harbor some normal microbiota

• Lower respiratory tract

• Bladder

• Breast/breast milk

• Amniotic fluids and fetus

sites where microbiota DNA has been detected

• Brain

• Bloodstream

factors that weaken host defenses

• Old age and extreme youth (infancy, prematurity)

• Genetic defects in immunity and acquired defects in immunity (AIDS)

• Surgery and organ transplants

• Underlying disease: cancer, liver malfunction, diabetes

• Chemotherapy/immunosuppressive drugs

• Physical and mental stress

• Pregnancy

• Other infections

5 ways newborns acquire microbiota

• In Utero

• Birth

• Milk

• Caregivers

• Environment

pathogen

relationship with host is parasitic and results in infection and disease

pathogenicity

potential to cause disease (true pathogens, opportunistic pathogens)

virulence

determined by a microbe’s ability to establish itself in a host and cause damage.

virulence factor

any characteristic or structure that contributes to the ability to establish and cause damage

Steps a microbe must take to get to the point where it can cause disease

1. Finding a portal of entry

2. Attaching firmly and negotiating the microbiome

3. Surviving host defenses

4. Causing damage

5. Exiting host

polymicrobial

disease caused by the presence of multiple microbes

• most infections are ______________

• Example: influenza leads to pneumonia

portals of entry

fecal (yum), oral, inhalation (most common), STD, and parenteral

exogenous

Organisms coming from outside the body.

endogenous

Organisms coming from somewhere in the same human host.

infectious dose (ID)

The minimum number of microbes necessary to cause an infection to proceed. Microorganisms with a smaller ________________ have greater virulence,

adhesion

Bacteria, protozoa, and fungi:

• Fimbriae (pili)

• Surface proteins

• Adhesive slimes/capsules

Viruses - specialized receptors

Parasitic worms - suckers, hooks, and barbs.

phagocytes

cells that engulf and destroy host pathogens by means of enzymes and antimicrobial chemicals

antiphagocytic factors

• Leukocidins: kill phagocytes outright

• Extracellular surface layer (slime or capsule)

• Some bacteria survive inside the phagocyte

three ways microbes cause damage to host

1. Enzymes or toxins (both endotoxins and exotoxins)

2. Inducing the host’s defenses to respond excessively or inappropriately

3. Epigenetic changes made to host cells by microbes

exoenzymes

Enzymes secreted by microbes that break down and damage tissues. They dissolve the host’s defense barriers to promote the spread of disease.

• Mucinase: digests the protective coating on mucous membranes

• Hyaluronidase: digests the substance that cements animal cells together

• Coagulase: causes clotting of blood or plasma

• Kinase: dissolves fibrin clots

Toxin

a specific chemical product of microbes that is poisonous to other organisms

• A _______ is named according to their target:

  • Neurotoxins act on the nervous system

  • Enterotoxins act on the intestine

  • Hemotoxins lyse red blood cells

  • Nephrotoxins damage the kidneys

exotoxin

small protein produced by bacteria with a specificity for a target

• Hemolysins: class of bacterial exotoxin that causes the RBC to hemolyze (burst and release hemoglobin pigment)

endotoxin

Chemical called: Lipopolysaccharide (LPS), part of the outer membrane of gram-negative cell walls

• Has a variety of systemic effects on tissues and organs

• Causes fever, inflammation, hemorrhage, and diarrhea

sign, symptom, and syndrome

Sign - objective evidence of disease as noted by an observer

Symptom - subjective evidence of disease as sensed by the patient

Syndrome - a disease identified by a certain complex of signs and symptoms

S/S of inflammation

Symptoms - pain and soreness

Signs - Edema, granulomas/abscesses, lymphadenitis

signs of blood infection

• Leukocytosis - increase in white blood cell levels

• Leukopenia - decrease in white blood cell levels

• Septicemia - a general state in which microorganisms are multiplying in the blood and are present in large numbers 

• Bacteremia or viremia - bacteria or viruses are present in the blood but not multiplying

asymptomatic

no noticeable symptoms are produced while the microbe is active in host tissues, and the host does not seek medical attention.

portals of exit

secretion, excretion, discharge, or sloughed tissue

• Respiratory tract, salivary glands, skin cells, fecal matter (yum), urogenital tract, blood.

latency

a dormant state of microbes in certain chronic infectious diseases

sequelae

long-term or permanent damage to tissues or organs caused by infectious disease

• Deafness, rheumatic heart disease, arthritis, paralysis

incubation period

• First stage of disease

• The time from initial contact with the infectious agent to the appearance of symptoms multiplying but not caused enough damage for symptoms

• Ranges from several hours to several years

• Majority: range from 2 to 30 days

prodromal stage

• 2nd stage of disease

• 1 to 2 day period when the earliest notable symptoms of infection appear

• Feeling of discomfort: head and muscle aches, fatigue, upset stomach, general malaise

acute phase

• 3rd stage of disease

• Infectious agent multiplies at high levels

• Fever and other prominent and specific signs and symptoms

• Extremely variable in length of this period

convalescent period

• 4th stage of disease

• Begins to respond to the infection and symptoms decline

• Strength and health gradually return

• Need to continue antibiotic

continuation phase

• 5th stage of disease

• Only some infections have this phase

• Either the organism lingers for months, years, or indefinitely after the patient is well or the organism is gone but symptoms continue

poop phase

• 6th stage of disease

• You poop out the microbe and then eat the poop to cycle back to stage 1.

This is the 5 stages of disease DIAGRAM

What fucking kind of diagram is this?

reservoir

Primary habitat of pathogen, often a human or animal carrier, but can also be soil, water, and plants

transmitter

individual or object from which an infection is acquired

4 types of reservoirs

• Animals (nonhuman) - mammals, birds, reptiles

• Human (actively ill)

• Human (carrier but not ill)

• Arthropods

5 types of carriers

• Asymptomatic

• Incubating

• Convalescent

• Chronic

• Passive

asymptomatic carrier

Infected but show no symptoms of disease.

• Gonorrhea, genital herpes with no lesions, HPV

incubating carrier

Spread the infectious agent during the incubation period.

• Infectious mononucleosis

convalescent carrier

Recuperating patients without symptoms; they continue to shed viable microbes and convey the infection to others.

• Hepatitis A

chronic carrier

Individuals who shelter the infectious agent for a long period after recovery because of the latency of the infectious agent

• Tuberculosis, typhoid fever

passive carrier

Medical and dental personnel who must constantly handle patient materials that are heavily contaminated with patient secretions and blood risk picking up pathogens mechanically and accidentally transferring them to other patients

• Various healthcare-associated infections

zoonosis

an infection indigenous to animals but naturally transmissible to humans. RJ is a fat, dirty, disgusting slob who poops all day and sniffs his own ballsack.

communicable

a disease in which an infected host can transmit the infectious agent to another host and establish infection in that host

contagious

a disease that is highly communicable, especially through direct contact.

• Influenza and measles

noncommunicable

an infectious disease that does not arise through transmission of the infectious agent from host to host

• Compromised person is invaded by their own microbiota

• Individual has accidental contact with a microbe that exists in a nonliving reservoir

• Infected persons do not become a source of disease to others

horizontal transmission

disease is spread through a population from one infected individual to another

• Direct contact - close contact

• Indirect transmission - an object or substance carries the agent

• Vector transmission - arthropods that harbor an infectious agent and transfer it to a human

vertical transmission

disease transmitted from parent to offspring via ovum, sperm, placenta, milk

healthcare associated infection

Infectious diseases acquired or developed during a hospital or health care facility stay

Most common examples:

• pneumonia

• gastrointestinal illness

• UTIs

• bloodstream infections

• surgical site infections

epidemiology

Study of frequency and distribution of disease and other health-related factors in defined populations

• Microbiology, anatomy, physiology, immunology, medicine, psychology, sociology, ecology, and statistics

Florence Nightingale

Laid the foundations of modern epidemiology

• Filth contributes to disease

• Brought about new methods in military field hospitals

  • Separating linens and towels for each patient

  • Cleaning of floors

  • Unclogging of sewage pipes

• Demonstrated that more men died of disease than traumatic injuries

reportable/notifiable diseases

Some diseases must be reported to authorities, and others are reported on a voluntary basis to organizations like the department of public health.

Examples - AIDS, COVID, measles, salmonella, tuberculosis

prevalence

A percentage; total number of cases in population ÷ total number of persons in population × 100

incidence

number of new cases in a designated time period ÷ total number of susceptible persons

• Usually reported per 100,000 persons

difference between incidence and prevalence

• Incidence = new cases and short time frame

• Prevalence = all cases long time frame

mortality rate

Measures the total number of deaths in a population due to a certain disease.

morbidity rate

number of persons afflicted with infectious rates

index case

first case that brought the epidemic to the attention of officials

endemic

an infectious disease that exhibits a relatively steady frequency over a long time period in a particular geographic locale

sporadic

occasional cases are reported at irregular intervals at random locales

epidemic

when statistics indicate that the prevalence of an endemic or sporadic disease is increasing beyond what is expected for a population

pandemic

spread of an epidemic across continents