exam 4 review BIOL 2460 part 2

signs

measurable by clinician

ex.) fever

symptom

unmeasurable by clinician

ex.) stomach ache

syndrome

group of signs and symptoms to determine a disease

infectious

disease with direct effect of pathogen

communicable (contagious)

disease spreading person-to-person

latrogenic

disease from medical procedure

WHO’s international classification of diseases (ICD)

globally use org for diseases

nosocomial

disease from hospital setting

zoonotic

disease from animal

non-communicable

disease from non-living thing

ex.) soil or contaminated object

non-infectious

disease not from pathogen

ex.) genetics

communicable example

malaria:

infectious

zoonotic

non-communicable

sickle cell anemia:

non-infectious (genetic)

disease stages

incubation

prodromal

illness

decline

convalescence

incubation

replication begin

prodromal

host show sign & symptoms

illness

sign & symptom most severe in host

decline

pathogen start decrease

host immune system weak & vulnerable to 2nd infection

convalescence

host start recover

when can patients be contagious

all stages

acute disease

short

ex.) hours, week, day, flu

chronic disease

longer

ex.) months, years, lifetime, hepatitus

latent disease

come in episodes

pathogen replicate when disease active

ex.) chicken pox, herpes

robert koch wrong assumptions

pathogen found ONLY in disease individual

all subject equal susceptible to infection (different immune system)

all pathogen can be grown in culture

pathogenicity

ability of pathogen to cause disease

virulence

degree of pathogenicity

high virulent

bacillus anthracis induce severe sign & symptom

low virulent

rhinovirus induce low sign & symptom

median infectious dose (ID₅₀)

infect 50% of inoculated

median lethal dose (LD₅₀)

kill 50% of infected

primary pathogen

cause disease regardless of host microbiota or immune system

ex.) enterohemorrhagic e. coli

opportunistic pathogen

only cause disease that compromise host defense

ex.) immune system, protective barriers, normal microbiota

pathogenicity stages

exposure

adhesion

invasion

infection

transmission

exposure

pathogen exposed to portals of entry

mucosa portal worse portal

TORCH infections

pathogen that cross placental barrier as portal entry

adhesion

molecules/structures bind to host receptors

ex.) biofilm production of glycocalyx

invasion

colonization established

pathogen produce toxin to colonize body/tissue from immune system

ex.) helicobacter pylori urease production

effector protein

secreted to trigger entry

ex.) salmonella & shigella

surface protein

allow binding to host cell (trojan horse approach

local infection

small area of body

focal infeciton

pathogen spreads to secondary location

systemic infection

occurs throughtout body

ex.) septicemia

primary infection

can lead to secondary infection of different pathogen

transmission

requires new host through portal of exit

virulence factors

pathogen product that helps cause infection & disease

adhesins

protein that aid attachment to host receptors

bacteremia

bacteria in blood

viremia

viruses in blood

toxemia

toxins in blood

septicemia

bacteria present & multiplying in blood

can lead to septic shock

exoenzymes

extracellular enzyme use to invade host tissue

ex.) glycohydrolases, nucleases, phospholipases, proteases

glycohydrolases

degrades hyaluronic acid to promote spreading in tissue

ex.) hyaluronidase S in staphylococcus aureus

nucleases

degrade DNA by dying cells to trap bacteria

ex.) DNAse produced by s aureus

phospholipases

degrade phospholipid bilayer to cause cellular lysis

degrade membrane of phagosomes to escape in cytoplasm

ex.) phospholipase C to Bacillus anthracis

proteases

degrade collagen in connective tissue to promote spread

ex.) collagenase in Clostridium perfringens

endotoxins

lipopolysaccharides trigger host inflammatory response

cause fever & shock

exotoxins

protein produce Gram-positive

target receptor on specific cell

ELISA

use antibody to detect endotoxin

limulus amebocyte lysate (LAL)

test blood cell of horseshoe crab mixed with patient serum

intracellular targeting

a region - activity

b region - binding

membrane disrupting

phospholipases degrade bilayer membrane

ex.) bacillus anthracis & rickettsia

hemolysins & leukocidins

target RBC, WBC and other cells

superantigen

excessive production of cytokines by immune cell

ex.) s. aureus & toxic shock syndrome

host evasion

mechanism to evade phagocytosis

ex.) capsule enlarge bacteria cell

protease digest host antibody

antigenic drift

slight change in spike protein

one change

antigenic shift

major change in spike protein

gen arassortment

mycotoxins (virulence fungi)

produce by claviceps purpurea & aspergillus to contaminate grains & staple crops

ex.) corn

virulence protozoans

adhesins, toxins, antigenic variation

giardia lamblia use adhesive disk

microtubules attach intestines

plasmodium falciparum change protein for RBC, cause chronicity in malaria patients

virulence helminths

tissue penetration w/ proteases

roundworm produce cuticle to last longer against host

glycan gimmickry (helminth)

mimic host cell to evade immune system

schistosoma mansoni (helminth)

degrade host antibody to halt immune defense

etiology

study of cause of disease

epidemiology

study distribution & timing of disease

morbidity

number of individuals w/ disease

mortality

number of death from death

prevalence

total individual

incidence

new cases

sporadic

occasional w/o regional concentration

ex.) tetanus, rabies, plague

endemic

present in certain region

ex.) malaria, ebola, chicken pox

epidemic

large amount of cases

ex.) influenza, west nile

pandemic

epidemic that is cross continental

ex.) virulent influenza, ebola

CDC

publish morbidity & mortality weekly report (MMWR)

john snow

father of epidemiology

studied contaminated water pump in london for cholera

common source

single source for all infected people

ex.) broad street water pump

point source

common source for short time

ex.) potato salad

continuous source

continuous contamination

ex.) sewage from up stream

intermittent source

on & off contamination

ex.) rainfall runoff

propagated

direct/indirect person-to-person contact

ex.) no single source

florence nightingale

war nurse kept records of soldier illness & death

joseph lister

kept epidemiology data of hand washing for healthcare practices

used carbolic acid (phenol) to disinfect hands

observational study

not manipulated

ex.) descriptive, analytical, cohort method, case-control, cross-sectional

experimental study

manipulated

ex.) clinical trials

usually double-blind study

ethical concern

descriptive study

gather info on disease outbreak

analytical study

evaluate hypothesis

can be retrospective or prospective

retrospective study

data from past

prospective study

data from current group

through course of study

cohort method study

examine people who share similar characteristic

ex.) prospective/retrospective

case-control study

compare group w/ disease to group w/o

retrospective study

cross-sectional study

group randomly selected to compare disease & no disease

reservoir

long persisting pathogen