Exam 02 Flashcards
need to add vaccine info but otherwise complete
Three factors in the epidemiological triangle
Agent, Host, Environment
Agent types
Infectious agents
Chemical agents
Physical agents
Host characteristics
genetic susceptibility
immutable characteristics (age, sex)
acquired characteristics
lifestyle factors
Environment characteristics
Climate
Plant and animal life
Human population distribution
Socioeconomic factors
Working conditions
The 5 Ws of Epidemiology, separated into descriptive and analytic
DESCRIPTIVE:
- what is the outcome?
- who is affected
- where are they
- when do events occur
ANALYTIC:
- how does it occur
- why are some affected more than others
What is the difference between descriptive and analytic epidemiology
descriptive looks at the distribution of health outcomes
analytic looks at the determinants of outcomes
epidemic
occurrence of disease in a community or region in excess of normal expectancy
two key historical figures of epidemiology
Hippocrates: ecological model
John Snow: father of epidemiology
Proportion
type of ratio in which denominator includes the numerator. e.g. x amount of sick people / x total people
rates
measure of frequency of a health event in a defined population, in a specific period of time. rates usually expressed per 100k population per year
risk
probability that an event will occur within a specified period of time
prevalence
number of existing cases, expressed in a percent; proportion!
e.g. deaths d/t heart disease over total number of deaths
incidence
number of new cases over number of people at risk; usually expressed as x cases/100k pop at risk annually; RATE!
attack rate
proportion of people who are exposed to an agent and develop the disease
e.g. ill people after exposure/total exposed
mortality rate limitations
can provide info about fatal diseases or events, but not info about level of existing disease in population.
Mortality vs Morbidity
Mortality: rate of deaths
Morbidity: disease prevalence, can be harder to attain
Primary sources of epidemiology data
collected directly through interaction with community members, + OG info for specific epidemiologic studies; NCHS, NHDS
Secondary sources of epidemiology data
Collected through existing reports on the community, including routinely collected data. Includes census, vital statistics/records, CDC data, data collected for other purposes, etc
Annual population estimate number
estimate of population at midyear as the denominator for annual rates, since pop. changes during the course of a year
Reliability
repeatability or consistency of a measure
Validity
accuracy measuring what is intended.
Includes sensitivity and specificity
Sensitivity
test ID those with the condition (true positive)
Specificity
test ID those w/o condition (true negative)
Bioterrorism
intentional release/dissemination of biological agents
common agents: anthrax, smallpox, plague
Signs of bioterrorism
- temporal or geographic clustering of illness
- unusual age distribution for a common disease
Surveillance
systematic collection, analysis, interpretation of data r/t occurrence of disease and health status of a given pop.
Passive surveillance
used more commonly by local and state health department and by providers who reports cases of notifiable disease; inexpensive
Active surveillance
purposeful, ongoing search for new cases of disease by PH personnel, via contacts, review of lab reports, hospital/clinic records
limited to special specific purposes, more expensive
Purpose of surveillance
assess public health status
define PH priorities
plan PH programs
evaluate programs
stimulate research
improve health
Types of epidemiological analytical studies
Cohort studies
Case control studies
Cross-sectional studies
Ecological studies
Clinical trial
Community trial
Cohort study
group of people sharing some characteristic or interest. watched for development of disease
Prospective: follow over time
Retrospective: past data
Case control study
sample from cohort rather than following entire cohort
Cross-sectional study
snap shot
Ecological study
bridge between descriptive and analytic study
Clinical trial
how effective is the new treatment? randomizing/blinding, with contrived/controlled environment
Community trial
large-scale community based
tests mass interventions, health promotion and disease prevention
Objectives of an investigation
- control and prevent disease or death
- ID factors that contribute to the outbreak of the disease and occurrence of event
- implement measures to prevent occurrences
What triggers an investigation of a disease
unusual increase in disease incidence
unusual event in the community
Different types of immunity
Active
- natural: infection
- acquired: vaccination
Passive
- natural: breast milk to child
- acquired: immunoglobulin
6 characteristics of an infectious agent
Infectivity, Pathogenicity, Virulence, Toxicity, Invasiveness, Antigenicity
Infectivity
ability to enter and multiply
Pathogenicity
producing a specific clinical reaction
Virulence
producing a severe pathological reaction
Toxicity
producing a poisonous reaction
Invasiveness
penetrate and spread through tissue
Antigenicity
stimulate an immunological response
Endemic
constant presence of a disease within a geographic area or population
Epidemic
disease in community or region in excess of normal expectancy
Pandemic
epidemic occurring worldwide and affecting large populations
Vertical transmission
passing of infection from parent to offspring via sperm, placenta, milk, or contact in vaginal canal at birth
Horizontal transmission
person-to-person spread of infection via…
- direct/indirect contact
- common vehicle
- airborne
- fomite
- vector borne
Emerging disease factors
Societalevents
Health care
Food production
Human behaviour
Environmental
Public health
Microbial adaptation
Lyme Disease - Stage 1
bullseye rash; fever, fatigue, malaise, HA, muscle pains, stiff neck, enlarged lymph nodes
Lyme Disease - Stage 2
additional leasions, HA, neurological abnorm, cardiac abnorm
Lyme Disease - Stage 3
recurrent attacks of arthritis and arthralgia
Lyme Disease location and dx
most commonly reported vector-borne disease in the US, usually in the summer during tick season.
Located in NE, mid Atlantic, north central states
with absence of lesion, Lyme is harder to dx, serological tests more accurate in stages 2 + 3
Rocky Mountain Spotted Fever s/sx
sudden onset of mod-high fever
severe HA
chills
deep muscle pain
malaise
rash on extremities, spreads to most of body
RMSF- transmission, immunity, dx, tx
not transmitted person to person
one attack = lifelong immunity
wood ticks
dx w serum titers
EARLY TREATMENT IS KEY! doxycycline
Main difference b/t Lymes and RMSF?
Lyme = bullseye
RMSF = rash on wrists and ankles, no bullseye
Vaccine hesitancy spectrum
People in the middle may refuse or delay vaccines, accept vaccines but uncertainly, or only get certain vaccines.
Primary vaccine concerns
- safety
- lack of confidence in effectiveness
- do not think they are at risk
- distrust
most people just need more information!
Levels of disease prevention: primary
reduce incidence of disease by preventing occurrence.
ex: responsible sexual behaviour, prophylaxis, vaccines, safe food handling, repellants for vectors, water inspection, BBP regulations, restaurant inspections
Levels of disease prevention: secondary
prevent spread of infection and/or disease once it occurs; focuses on rapid ID of potential contacts to a reported case
ex: immunoglobulin post-exposure, post-exposure rabies vaccine, TB screening for HCW, STD partner notification, HIV testing and treatment, quarantine
Levels of disease prevention: tertiary
Works to reduce complications and disabilities through treatment and rehabilitation
ex: PCP prophylaxis for AIDS, regular inspection of hands and feet for leprosy or DM pts with neuropathy
Foodborne disease transmission + examples
infection from eating food contminated with disease
ex: salmonella, e. coli
Differences between salmonella and e. coli
Salm: sudden HA, diarrhea, N, sometimes vomiting, almost always fever
E. coli: bloody diarrhea, abd cramps, rarely fever
Water-borne disease transmission + examples
animal or human fecal contamination in the form of viruses, bacteria, protozoa
ex: Hep A; typhoid, giardia, legionella, cryptosporidium; cholera
Vector-borne disease transmission + exmaples
transmitted by a vector - tick, mosquito, animal (zoonoses), etc
ex: lymes, RMSF, rabies, malaria
Parasitic infections
intestinal: tapeworms, flukes, roundworms
opportunistic: toxoplasmosis
2 sources of financial assistance for HIV tx
Ryan White HIV/AIDS treatment extension act of 2009
AIDS Drug Assistance Program (ADAP)
Malaria caused by…
Plasmodium (bloodborne parasite)
Potentially fatal disease, transmitted through bite of infected Anopheles mosquito
What is the most prevalent vector-borne disease in the world?
Malaria; 1/2 world is at risk!
eliminated from US, but can happen as Anopheles mosquito is in Southern US, Report to DOH
MalariaPrevention
No vaccine; some partial prot for young children
Protect against mosquitos
Best: antimalarial meds, started 1-2 wks before leaving country and continued 4-6 wks after returning
S/sx of malaria
Cyclical fever and chills up to one year after returning home
3 stages of HIV: Primary Infection
W/in about 1 month of contracting the virus.
Mononucleosis-like. WBC drops for brief time, self-limiting illness
S/sx: lymphadenopathy, myalgia, sore throat, lethargy, rash, fever
Antibody test at this point usually appears negative
3 stages of HIV: Clinical Latency
period when body shows no symptom.
gradual deterioration of the immune system during incubation period
can transmit virus to others
3 stages of HIV: Symptomatic disease
final stage of HIV, becomes AIDS
What is AIDS dx measurement?
CD4 T-lymphocyte count <200 with documented HIV infection
Modes of transmission of HIV
Sexual contact involving exchange of body fluids w/ an infected person
Sharing needles
Perinatal transmission during pregnancy or delivery, breastfeeding
Exposure to HIV-contam blood, organs, semen
How is HIV reported?
CDC
Tests for HIV (2)
HIV antibody test – indicates presence of antibody to HIV
EIA (enzyme linked immunosorbent assay) – Western blot; screens blood and other donor products
S/sx of HIV in children
failure to thrive, unexplained persistent diarrhea, dev. delays, bacterial infections
Employers and workers with AIDS
Increase PPE as they are immunocompromised
Adherence to HAART
Chronicity of AIDS
ADA protects clients against discrimination
Teach family how to care and support client with personal care
NO EVIDENCE OF TRANSMISSION OF AIDS AT A SCHOOL/WORK
Viral STDs
HSV (oral or genital, more like pimples or blisters), HIV, HPV (genital warts)
Bacterial STDs
gonorrhea, syphillis, chlamydia!
What is the risk for HSV in pregnancy
Increased risk of fatal newborn infection during vaginal delivery; concern; C-sections are recommended if active lesions are present.
If there is no clinical evidence of herpes lesions, deliver vaginally.
NOTE: a small amount of infants are infected in utero and infection can present as liver disease, encephalitis, or infection limited to the skin, eyes, or mouth
STD with highest risk factor for PID?
Gonorrhea - s/sx are asymptomatic in women, treatment may not be sought. Can spread to others through sexual activity and may not be recognized until someone has PID
S/sx of Chlamydia in adult women
dysuria, urinary frequency, purulent vaginal discharge
S/sx of Chlamydia in neonates
conjunctivitis, pneumonia
Which 2 STDs are frequently coinfections?
gonorrhea and chlamydia
tx with ceftriaxone and azithromycin
most common reportable disease in US
chlamydia
Stages of Syphillis: Primary
when syphillis is acquired sexually, bacterial infection forms as a lesion called a chancre at site of entry. Lesion starts out as a macula, progresses to a papule, and later ulcerates.
If untreated, chancre persists for 3-6 wks, then disappears.
Stages of Syphillis: Secondary
occurs when the organism enters the lymph system and spreads throughout the body
s/sx: rash, lymphadenopathy, mucosal ulceration
Stages of Syphillis: Tertiary
1/3 of untreated syphillis patient will show the following s/sx pf tertoaru syphillis:
- blindness, congenital damage, cardiovascular damage or syphilitic psychoses
- gummatous lesions of bones, skin, mucous membranes
- usually occurs several years after initial infection; rare in US d/t being cured w ABX, major problem in developing countries
Stages of Syphillis: latency period
when individual is free of s/sx but has serological evidence, may occur early or late in the infection
Is it possible to infect others in HSV if you are asymptomatic?
YES
Difference between HSV1 and HSV2?
Location!
HSV1: sores, saliva, mucous membranes in or around mouth
HSV2: vulva, vagina, upper thighs, buttocks, penis;
Is there a cure for viral STDs?
NO
What is the main danger of HPV infection?
cervical cancer, screen with pap smear
Hepatitis transmissions
Hep A: fecal-oral, contaminated food/water, sexual
Hep B: bloodborne, sexual, perinatal
Hep C: primarily bloodborne, also sexual and perinatal
Hep B prevalence in US;
steadily declined since HBV vaccination became available!
Hep B vaccine
3 IM injections; 2nd and 3rd doses are given 1 and 6 months after first
Hep C prevalence in US;
In 1980s, HCV spread rapidly, and 3.5 million people in US were chronically infected. # is decreasing d/t treatment and mortality.
Who is at greatest risk for Hep C?
past or current IV Drug User with Hep C prevalence rate of 50%
What level of prevention is blood product screening?
Primary
What level of prevention is patient-delivered partner therapy?
Providing patient with extra meds to give to partner and prevent reinfection; secondary prevention
What is the incubation period for TB?
4-12 wks
Many infected people turn latent and can reactive later
TST/PPD - Mantoux test
Intradermal injection
Read induration after 48-72 hours
POSITIVE: >5 immunosuppressed
>10 for DM, IV users, foreign-born, kids, HCW
> 15 for everyone over 4 yo
What are the three other tests for TB?
Chest xray, Sputum smear, quantiferon blood test
Best way to prevent STDs
Abstinence
Safe sexual behaviour
Masturbation, dry kissing, touching, fantasy, vag/oral sex w condom
Nurses attitudes re: sexual behaviour
should be comfortable discussing topics of sexual behaviour to properly assess pts; remain supportive and open
primary prevention for STDs
getting client to change bx and reduce risk
education early in life
vaccination for HPV, Hep A, Hep B
secondary prevention for STDs
annual screening for HIV
contact tracing
teaching and counselling - how to avoid self-reinfeciton, managing symptoms and preventing infection of others
teritary prevention for STDs
management of symptoms for chronic STDs
support groups
DOT
referrals to long-term care
infection control
standard precautions at home
mnmemonic for non IM vaccines
ORSMYV
Our Rude Sister Made You Vomit
Oral: Rotavirus
SQ: Measles, Yellow fever, Varicella
