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42 terms


"The study of how disease is distributed in populations and the factors that influence or determine this distribution."
Leading Causes of Death
1900's death from micro organism, 2004-death cancer, heart attack-old or suffer because study of epidemiology
Public health & clinical practice today is influenced by population data:
Diagnosis is population based
Prognosis is population based
Therapy is population based
Hippocrates (460-377 BC)
described course of different illnesses & related them to season, geographic area and types of people
John Snow
1813- 1858
Incidence of cholera in London
father of epidimiology, pregerm thory disease, cholera how spread, relate location, social economy, economy status, published
Florence Nightingale
use statistics,infectious disease, cause control study,"First example of someone using healthcare data to affect government reforms in the interest of of preventing death and disease"
Objectives of Epidemiology
Identify cause & risk factors
What is the extent of disease in community
Study natural history of disease
Evaluate existing & new preventive measures
Provide a foundation for developing public policy
Classifying Infectious Diseases A. Behavior
1) Communicable

3) Highly communicable
Classifying Infectious Diseases B. Freq of Occurence
1) Sporadic
2) Endemic - constantly pres in low nos in population
3) Epidemic - many people, defined area, short period of time
4) Pandemic
Classifying Infectious Diseases C. Severity/Duration
1) Acute

2) Chronic

3) Latent
Spread of Infection A. Reservoirs
1) Human

2) Animal - 150 known zoonoses

3) Non-living - soil & water
Common source epidemic
Result-where they coming from, this disease high 4,5 days, rise sharp, drop sharp, classical bell shape, short of time, selective, large of case, contract ill same thing common source, cluse couple days, case of food poison, potato salad, illness from same place
Propagated epidemic
come and goes, took couple of month, case of Ebola, case death, desease from different source, people get sick, contact person to person, propagate epidemic
Spread of Infection B. Transmission 1. Contact
Direct -
physical contact

Indirect - fomite

Spread of Infection B. Transmission 2. Vehicle
Spread of Infection B. Transmission 3. Vector (living)

Spread of Infection C. Portals of exit
Resp tract
GI tract
Urogenital tract
Skin or wound
Language of Epidemiology
Mortality - incidence of ? in a pop

Morbidity - incidence of ? in a pop
Mortality -
incidence of ? in a pop-death of population
Morbidity -
incidence of ? in a pop-# of case and diseases
Patterns of Disease
Predisposing Factors-ITG
Immune health
terms of age
Genetics-Ex) HLA/MHC-haploid from parents, HLA. Sickle cell anemia-genetic mutation of hemoglobin gene, malaria,
Development/Progression of Disease
1) Incubation - infection & first sign of symptoms
2) Prodromal period- early, mild symptoms
3) Illness period
4) Decline period
5) Convalescence period
Outbreak Investigations
Worst waterborne disease-1986-94,1993-400,000 case
Reporting Outbreaks
CDC - pg 459,table 20.1
Epidemiological Investigation Handout
Gather data
Graph & analyze -
Nosocomial Infections
Def? delivered hospital
Acquired by 5-15% of patients/year
including extensive use antimicrobial drugs and invasive theraputic procedures, 3 factors, have come together for perfect indicate nosocomial
Results from the interaction of 3 factors:
Nosocomial Infections
1) Microorganisms in
the hospital-Sep. coccus, E.coli, ..,..
2) Compromised host-for sick, elderly sugergical process, immune stystem
3) Chain of transmission-only one we can control, wash hands frequently
Nosocomial Infections
#1 urinary track,
#2 surgical respiratory track
#3 surgical
Emerging Infectious Diseases
Any new, re-emerging or drug-resistant( MARSA, TB, BRE)infection whose incidence as increased in the past two decades.
Antimicrobial resistance is the ability of certain microorganisms to withstand attack by antimicrobials, and the uncontrolled rise in resistant pathogens threatens lives and wastes limited healthcare resources.misuse, over use
Emerging Infectious Diseases
Infectious diseases have been around as long as we have.Lamasis II, small pox,3-4000 yrs ago
Emerging Infectious Diseases Predictions - 1960s
Polio vaccine
WHO's smallpox eradication program
Decline in incidence of TB
1967- "War against infectious disease
has been won"
Emerging Infectious Diseases keeping eye,
H5N1 Influenza
Emerging Infectious Diseases
38 of these are novel human pathogens arising within the past 25 years.
2/3 of these are biral diseas shown up past 25 yrs.
Most are zoonotic-predictable, most virus came from animal
Emerging Infectious Diseases
Human pathogens making the jump
Ebola - ?
HIV-1 - chimps
HIV-2 - monkey
SARS- civet
H5N1 - birds
happen constently, do virus jump animal to human, factor cause germ jump 2 things ability capacity make that jump 1- share recepter viral recepter, carry animal virus for flus virus2- oppotunity- to make jump maybe we can control, ex) HIV what gave oppotunity eating consuming fresh meat viral, lyme disease jump deer to human-hunting, going out house...
1407 recognized human pathogens
538 - bacteria
317 - fungi
287 - helminths
208 - viruses
57 - protozoa
Infectious Disease Mortality Rate 1980-1996
By graphic-increased each yr
Emerging Infectious Diseases
Profile of likely emerging pathogen:
RNA virus
Broad host range
Genetically conserved receptor
Transmissable between humans
Occurs in region undergoing changes
Our role in Prevention of EIDs
Your role in the prevention of emerging infectious diseases
best practices
antibiotic use
food preparation
control exposure
awareness of risk
behavior change
Your role in education about emerging infectious diseases
-stay informed
---CDC Web pages
---MMWR on Web
---EID journal
-educate patients/ family /friend
know resources -who to call
your role in detection of
emerging infectious diseases
Participate in surveillance activities within your clinical settings
-be alert for "clues"; assess risk
know your resources-who to call for consltaion,
report to local health depatment.