Infectious Dis. Flashcards
Infectious Dis
transmissible/ communicable dis.s
-w/ characteristic symptoms+ presence and growth pathogenic bio agents in host organisms.
Carrier
asymptomatic
-only dis. in hosts that b/cm ill after contact with asymptomatic ind.
Colonization
=required to devo ill
-presence of organisms NOT= to infectious dis.
Infectious Dis. Interest: Pre-antibiotics
^mortality Rs (poverty+ war) w/ little could do about dis.s
- inds D b/c of infection not wounds» experimental medi= common
- Greeks, Egyptians, Romans= forerunners o mod physicians
Infectious Dis. Interest: antibiotics
1950s= widespread use» ^devo+ improved treatment
-interest decreased (all dis.s would be wiped out)
Infectious Dis. Interest: 1980s
dramatic ^in infectious dis.s
Infectious Dis. Interest: 1990s
Infectious dis b/cm 1 o top 5 killers in US
AIDS Ds mostly due to 2ndary bacterial infects
Why Infect dis increase?
- older pop
- ^ o immuno-compromised pop. (organ trans, cancer therapy, invasive surgery)
- antibiotic resistence
- emerging infect dis.s
Emergence of Infect Dis: Ancient Hist
-Bact +Archaea=» endosymbionts in eukaryotic Cs
root nodules= N2 fixation
colonizing GI tract» nutrition, protective nature
-Bact +protozoan interaxns»_space; drivning force in infect dis.s (protozoa similar to phagocytic Cs)
-domesticated anis ^
Why MicroOrg infect host: Nutrition and Safety
- Host= stable, nutrient rich source, ideal for growth
- mjr role/ selective pressure in host Evo
emerging dis.
infect dis. incidences have ^ in last 20yrs
newly IDd or new strains (SARS, AIDS)
reemerging dis.s
known dis.s that have come back in diff form or location
West Nile, Dengue, TB
Why ^ in emerging/ reemerging dis.s?
microOrgs easier to detect
some submerge +reemerge over time
dis. patterns constantly changing
Mechs for emerging and reemergence
- microbial adaptation (genetic drift o Influenza A)
- changing hu. susceptibility (mass immunocompromised pop> HIV/AIDS)
- Climate and weather (zoonotic vectors w/ ^range/ new locations)
- varying hu. demographics+ trade (e.g. SARS)
- economy devo> food antibiotics=> resistance
- poverty, class, culture=> who mo susceptible
- War and famine
- bioterrorism
Genetic Drift
small, random genetic changes in small/ iso pop» new variant overtaking original pop
Types of emerging/ reemerging infect dis.s
new-new dis.
new-old dis
old-new dis
old-old dis.
New-new dis
- caused by newly discovered org (Bact. species)
- Difficult- know for sure b/c o poor historical records o infectious diseases
New-old dis
-caused by newly recognized pathogen, but org has been known
Old-new dis.
-old dis. w/ known causes thought to have been elim» reappeared
Old-old dis.
-old dis. w/ known causes now being recog by public and media.
Lyme dis
new-new dis
- Borrelia burgdorferi (Spirochete)
- gram -
- thin helical corkscrew
- tics on deer and mice= reservoirs
Why increase in lyme dis
- deer pop^ (reforestation, hunting limits, decrease in predators)
- hu. pop^ (move into/ closer to deer habitat)» hu. inserted into tic-mouse-deer cycle
- DIS. ONLY IN HU.S
Legionellosis (Legionnaire’s disease)
new-new dis
- Legionella pneumophila
- H2O pathogen> trans thru aerosols (AC units, H2O distribution)
- gram - (nds ^Fe)
- rod biofilm forming
epidemiology
study o factors affecting health+ illness o pops
(occurrence, distribution and determinants)=> medi interventions+ preventative measures
-tracking and gathering info
TB
old-new dis
- Mycobacterium tuberculosis
- gram +
- respiratory trans=> waxy tubercles in lungs
- recent comeback w/ physicians unable to ID dis
Cholera
old-new dis (S Am.)
- Vibrio cholerae
- gram -
- comma-shaped rod
- trans via sewage contaminated H2O
- gastrointestinal infect of enterotoxin
- 7 mjr pandemics
Epidemic
when new cases o a dis, in given hu pop, + during given period, exceed what “expected,” based on recent experience
Pandemic
an epidemic o infect dis that spread through hu pops across a large region
Reasons for reemergence
gene trans- recent in old strain
- Ecological condts prevent emergence» unkwn 20thc factor allowed resurface (e.g. farming practs)
- acquire new traits (antibiotic resistance) (e.g. MRSA)
Chlamydia trachomatis
old-old dis
- gram -
- minimal genome> obligate intraC pathogen?
- generally asymptomatic
- most common infect reported in USA
Why ^ in re/ emerging dis.s?
^ awareness/ detection
- mod medi (chemotherapy, longer life-span» immunocomp elderly, crowding)» opportunistic pathogens
- cul diffs of accepted B
Opportunistic pathogen: Burkholderia cepacia
pneunomia
-mouthwash= source (not respiration equipment)
Types of Infect Dis.
water-borne food-borne hospital acquired antibiotic resistance microbiota shift dis.s bioterrorism
Contributing factors o infect dis. events
ease of travel pop^ pop displacement agri changing socio-economic structures international conflicts pollution/ global warming
Water-borne dis.s
precious resource
- single source may serve numerous ppl» potential of many ppl to get sick
- precip and extreme weather associated w/ water-borne outbreaks
- flooding= most freq (Diarrhea-‐associated dis.s, cholera, typhoid, hepatitis (jaundice),+ leptospirosis)
