Exam 3 Flashcards
invasion of colonization of the body by a pathogen
Infection
any change from a state of health
*can have infection without _________. Ex: HIV+ but not have aids
Disease
develops rapidly but lasts a short time
>Common cold
Acute Disease
develops slowly and is continual
>Heart disease
Chronic Disease
pathogen that remains inactive (not replicating) for extended period of time
Latent Disease
any disease that spreads from host to host
>Flu
Communicable Disease
a type of communicable disease that spreads from host to host
Contagious Disease
disease does not spread from host to host
>Heart disease, diabetes
Non-communicable disease
study of the cause of an infectious disease (microbe)
Etiology
objective manifestation of disease
>observed or measured by others
>fever, vomiting, rash, swelling….
Signs
subjective manifestation of disease
>felt by the patient
>pain, fatigue, nausea, dizzy, headache….
Symptoms
ability to cause disease
Pathogenicity
disease causing microbe
Pathogen
degree of pathogenicity (how bad?)
Virulence
the study of where and when infectious disease occur
Epidemiology
the number of new cases of a disease in a given population or area
>New cases of chlamydia in AZ in October 2022
Incidence
total number of cases of a disease in a given population or area
>HIV+ people in the US
Prevalence
occurs at a relatively stable frequency in any given population or area
>Sexually transmitted pathogens
Endemic Disease (never ENDemic diseases)
disease that occurs at a greater frequency in a given population or area
Epidemic Disease
epidemic that occurs simultaneously on more than one continent
Pandemic Disease
only a few cases occur (quite rare)
Sporadic Disease
What are some virulence factors?
Extracellular enzymes
Toxins
Anti-phagocytic factors
produced by bacteria. Secrete them into their environment
Extracellular Enzymes
Examples of extracellular enzymes
Hyaluronidase
Hemolysins
Coagulase
Kinase
Leukocidins
Collagenases
invades deeper into tissue
>breaks down extracellular matrix
ex: lawyer scraped knee playing basketball, Staphyloccocus aureus got deep into the bone within 12 hours
Hyaluronidase
let bacteria lyse RBC to get iron as a trace element
Hemolysins
forms a blood clot, hide from immune system
Coagulase
digest clots to remove itself (Streptokinase injected to break clot)
Kinase
decrease phagocytosis because they kill WBC
Leukocidins
break down collagen
Collagenase
Do antibiotics stop extracellular enzymes?
No, they have no effect on extracellular enzymes
Koch’s Postulates
- Suspected pathogen must be found in every case of the disease
- Isolate pathogen and grow it in pure culture in the lab
- Inject the pure culture into a healthy host and must get the exact same disease
- Re-isolate the pathogen from the experimental host + verify that it’s identical to what was put in
used to determine etiological agent(BACTERIA) of an infectious disease
Koch’s Postulates
Chemicals that harm tissues tissues or trigger host immune response that can cause damage in the host.
>Toxoid vaccines that are disabled toxins
Toxins
Type of toxin produced by some gram + and gram - bacteria
>Exported outside of bacterium that produce them.
>Transported throughout the body via circulatory system
>Gene for exotoxin production would be on a plasmid
>Exotoxins are made of protein, heat sensitive
Exotoxin
Types of Exotoxins:
Cytotoxin
Neurotoxin
Enterotoxin
Kill cell or affect function of the cell
>Diphtherias cytotoxin stops protein synthesis
Cytotoxin
Interfere with nerve function (synapse)
>Botulism toxin, tetanus toxins
Neurotoxin
Kill cells that line gastrointestinal tract,
>Chloera toxin
Enterotoxin
Type of toxin that gram negative bacteria lyse and release lipid A in outer membrane.
>Lipid A causes fever, inflammation, clots, hemorrhage, diarrhea, shock, death
>Typhoid fever, meningococcal meningitis
Endotoxin
decreases phagocytosis (WBC engulfing material)
>Capsules decrease phagocytosis. WBC can’t eat bacteria with capsule
Anti-phagocytic factors
2 Organisms living together
Symbiosis
3 Types of Symbiosis
Mutualism
Commensalism
Parasitism
Type of symbiosis that involves both organisms benefit from the symbiotic relationship
ex: GI bacteria + us ; normal flora
Vaginal flora +
Mutualism
Type of symbiosis which involves one organism is not affected (neutral)
>Staphylococcus aureus + us
Commensalism
Type of symbiosis that involves one organism benefits (microbe) other organism is harmed (host)
Parasitism
4 Types of Portals of Entry
Broken skin
Mucous membrane
Placenta
Parental Route
Portal of entry that deposits the pathogen directly into tissue
>Needle stick, bit
Parenteral route
Usually a pathogen exits the same way they entered via secretions
Ex: GI tract exit via feces, Urinary tract exit via urine, reproductive tract exit via semen/vaginal secretions, respiratory exit via droplets
Portals of Exit
Ways microbes hang on
-Giardia lamblia: suction cup
-Taeneia: suckers + hooks
-Having a glycocalyx
-Fimbrae
-Virus binds to its receptor on host cell
Reservoirs of Infectious Disease
- Animal reservoirs (zoonotic dis.)
- Human carriers
- Non-living Reservoirs (water, soil, food)
forms when bacteria adhere to a surface in an aqueous environment
>Bacteria begin to secrete a slimy, glue-like substance
>65% of human infections are biofilms
Biofilm
send chemical signals to each other to actually coordinate biofilm formation
Quorum sensing
________ in biofilm can increase antibiotic resistance
Conjugation
Part of bacterium that aid in biofilm formation, glycocalyx
Difficult for immune system to fight
Fimbrae
5 Stages of Infectious Disease
- Incubation
- Prodronal
- Illness
- Decline
- Convalesence
3 Modes of Transmission
Contact transmission
Vehicle transmission
Vector transmission
Contact Transmissions sub modes
Direct
Indirect
Droplet
Vehicle Transmission sub modes
Airborne
Waterborne
Food borne
Body fluid
Vector transmission sub modes
Biological
Mechanical
Pathogen in acquired in a healthcare setting
40,000 die ppl/year
205 die pp/day
Healthcare Acquired Infections
Common sites of infection
- Catheter
- Central line infection
- Ventilator/trach
Blood borne pathogens in occupations
Hep. B, C, HIV
Hepatitis: Transmission rate 6-30% from a single needle stick of an infected patient
>Vaccine
>Hep B immunoglobulin (antibodies) 90% effective in preventing transmission
Hep B Virus
Hepatitis: Transmission rate of 1.8% from a single needle-stick from an infected patient
>No vaccine
>No immunoglobulin to prevent transmission
>test, anti-viral drug
Hep C Virus
VIRUS: transmission rate 0.3% from a single needle stick of an infected patient
>No vaccines
>No immunoglobulin to prevent transmission
>anti-HIV meds right away
HIV