Communicable Diseases Flashcards
6 functions of public health
health protection health surveillance disease and injury prevention population health assessment health promotion emergency preparedness and response
endemic
the steady presence of a disease in a defined geographic area or population
outbreak/epidemic
when the new cases of a disease exceed the normal occurrence during a given period of time
pandemic
when a disease spread affects a large number of populations worldwide
purpose of immune systems
respond to foreign proteins (antigens) in the body with the intention to resist infection
how we acquire immunity
active = host produces antibodies in response to an antigen
passive = host receives antibodies produced by another source
both have natural and artificial
benefits of vaccination
considered the most significant achievement in preventative medicine in north america
incidence of new cases of select diseases drop by 100%
prevention of morbidity and mortality in those vaccinated and those around them (herd immunity)
benefit to health and savings in direct health care costs
bacterial diseases that are vaccine preventable
streptococcus pneumoniae diphtheria (corynebacterium diptheriae) tetanus (clostridium tetani) pertussis (bordetella pertussis) neisseria meningities
viral diseases that are vaccine preventable
influenza (influenza A and B)
hepatitis B
measles, mumps, rubella, varicella
HPV
influenza
RNA virus
types A B and C
typing is based on types of surface proteins
A has subtypes B and C do not
A and B viruses cause seasonal epidemics while type C causes mild respiratory illness
A and B strains are included in each years influenza vaccine
transmission and symptoms of influenza
transmission = via droplets or contact with respiratory secretions of infected individuals
symptoms = fever, respiratory illness (cough, sore throat, nasal congestion), headache, myalgia (muscle pain), malaise (body weakness)
rare symptoms = encephalopathy (brain disease), acute respiratory distress syndrome
influenza incubation
incubation = 1 day before symptoms develop and 5 days after becoming ill
period person is contagious (communicability) = depends on age and health of person, influenza can spread from individuals with no symptoms
complications of influenza
pneumonia (bacterial and viral)
ear and sinus infections
dehydration
worsening of chronic health conditions such as congestive heart failure, asthma, or diabetes
groups at high risk of complications
adults older than 65 and those living in long term care facilities
children under 2 (all children under 5)
persons with chronic illness
immunosuppressed individuals
women who are pregnant or postpartum (within 2 weeks after delivery)
indigenous populations
obese individuals
impact of influenza
causes about 12,000 hospitalizations and 4,000 deaths in canada each year
in 2015-2016 there were 61 deaths from influenza, 1655 hospitalizations, and 263 people admitted to ICUs
influenza vaccine development
each february WHO provides a recommendation on the strains to be included in the vaccine for the northern hemisphere
two A viruses and one B virus are selected based on the characteristics of the current circulating influenza virus strains
a new vaccine is reformulated each year to protect against new influenza infections
FluWatch program objectives
detect flu outbreaks as early as possible
provide timely up to date information on flu activity in canada and abroad to health professionals
monitor circulating strains of the flu virus and assess their sensitivity to antiviral medications
provide information that WHO can use to make its recommendations on the best vaccine for seasonal flu shots
who is eligable for flu shots
all people 6 months of age or older who live, work, or go to school in alberta are eligible for a flu vaccine at no charge
population health approach
measure and analyze health status and SEDoH review evidence multiple strategies intersectoral collaboration upstream accountable for outcomes public involvement
socio-ecological determinants of health
income and social status social support networks social environments education work and working conditions physical environments biology and genetic endowment personal health practices and coping skills healthy childhood development health services culture gender
pneumococcal disease
infectious agent = streptococcus pneumoniae
acute and serious illness caused by the bacterium streptococcus pneumoniae
92 serotypes recognized worldwide, 15 of which cause the majority of disease
severity of streptococcus pneumoniae
pneumococcal pneumonia is the most common community-acquired bacterial pneumonia
estimated to affect approximately 100 of every 100,000 adults each year
complications = bacteremia, meningitis
vaccination for pneumococcal
infants and children pneumococcal vaccination at 2, 4, and 12 months of age
high risk groups get an additional dose at 6 months
adults = 65 years and older, high risk related to living situations or chronic illness, some high risk groups receive a booster
diphtheria
infectious agent = corynebacterium diptheriae
caused by release of diphtheria toxin by strains of corynebacterium diptheriae
mode of transmission for diphtheria
respiratory droplets
direct contact with exudate of respiratory secretions of infected people and exudate from skin lesions
most respiratory infections occur in dry cold months and are associated with crowded conditions
severity of diphtheria toxin
complications = if left untreated leads to multi-organ toxicity heart damage (myocarditis) nerve damage (neurotoxin) renal failure (kidney damage) fatality rate 5-10%
epidemiological history of diphtheria
in 1924 = 9000 cases reported in canada and was one of the most common causes of death in children aged 1-5
routine immunization initiated in 1930
by 1950 = substantial decrease in cases seen
in alberta from 1981-2003 there were 5 cases reported
tetanus mode of transmission
disease caused by release of the tetanus toxin (tetanospasmin) by the bacterium C. tetani
organism is found commonly in soil and environment
infection usually starts in a wound by organism in an anaerobic environment (leading to spore germination, growth and subsequent toxin production)
clinical presentation of tetanus
prevents release of inhibitory neurotransmitters leading to sustained contractions and various muscle groups, lock jaw
can affect both peripheral and autonomic nervous system
severity of tetanus
cases often require extensive ICU care
death usually from respiratory arrest or cardiac arrest (dysrhythmias)
epidemiological history of tetanus
1920-1930 = 40-50 deaths/year in canada
toxoid vaccine introduced in 1940
between 2000 and 2013 in canada a total of 42 cases were reported (over 60 years of age accounted for 55% of the cases)
between 1983-2003 in alberta a total of 10 cases (recent cases in males over 50 who lived in rural areas)
epidemiology of tetanus
outside of the developed world it continues to be an epidemic especially after natural disasters
over 10,000 cases/year worldwide
by 2000, 135 countries had eliminated neonatal tetanus and annual deaths fell 75% from about 790,000 newborns a year to around 200,000 per year
generally due to the practice of putting earth/dung on the umbilical area for healing
vaccination for tetanus
boosters are required every 10 years
pertussis transmission
infectious agent = bacterium called bordetella pertussis
spread through droplets in the air from an infected persons cough or sneeze
can also be spread through coming into contact with discharges from an infected persons nose or throat
stages of pertussis
catarrhal stage = lasts 7-10 days, discharge from nose, tearing, low grade fever, sneezing, cough, clinically indistinguishable from a viral upper respiratory tract infection
paroxsymal stage = 1-6-10 weeks, proxysms (bursts) of coughing fits followed by a long inspiratory “whoop”
after 2-3 months the paroxysmal stage is followed by the convalescent phase = paroxysms decrease and cough gradually improves
severity of pertussis
serious complications most often in infants
pneumonia, lumbar strain, rib fractures, collapsed lung, subdural hematoma, seizures, ecephalopathy (hypoxia)
babies younger than 1 = 1 out of 4 get pneumonia, 1 out of 100 will have convulsions, 3 out of 5 will have apnea, 1 out of 300 will develop encephalopathy (disease of the brain), 1 out of 100 die
incubation and communicability
symptoms appear between 7 to 10 days after exposure but could be delayed up to 20
most contagious during the first two weeks when symptoms resemble those of a common cold
contagiousness declines rapidly after that but may last up to three weeks
people are no longer contagious after five days of treatment with appropriate antibiotics
reasons for increasing incidence of pertussis
waning vaccine induced immunity of adults and adolescents
increased circulation of B. pertussis
decreased use of pertussis vaccine
heightened awareness of pertussis amongst healthcare providers
increased use of more accurate testing
increased public health reporting
neisseria meningitis
gram negative bacteria that colonizes in the oropharynx
transmission of neisseria meningitis
usually via direct contact with nasal secretions
can be transmitted via aerosols/respiratory droplets from colonized individuals
period of communicability in those with invasive disease usually lasts until 24 hours after institution of appropriate antibiotic therapy
severity of neiserria meningitis
complications = meningococcal meningitis sepsis pneumonia conjunctivitis pericarditis
epidemiological trends for neisseria meningitidis
believed that 5-10% of the adult population carries neisseria meningitidis in their throat at any given time
since 1950 the incidence has remained at less than 2.1 per 100,000
in canada less than 1 per 100,000
the epidemiology changes overtime with regards to serotypes causing disease
measles in 2013-2014
from 2000-2013 in the calgary zone had 20 cases spread out over that period
as of july 2013 nearly 30 cases in 6 provinces (BC, AB, ON, QB, NB, PEI)
as of april 2014 there were 22 cases in alberta
2018 there were 27 cases in canada with 6 in alberta
why is varicella dangerous
very unpleasant itchy rash which can cause permanent scarring
pneumonia and swelling of the brain
pregnant women exposed to chicken pox may giver birth to babies with severe deformities
modes of transmission for hepatitis B
perinatal = breastfeeding ok as long as neonate receives HBV vaccine and HBlg at birth
transfusion
sexual transmission
nosocomial infection (infected healthcare workers)
organ transplant
epidemiological trends of HBV
prevalence of HBV carriers in north america is 0.1-2%
highest areas of infection are in asia (10-20%) including china, se asia, sub-saharan africa
range in world prevalence due to age at infection
in asia more people are infected in utero or at an early age
ethical principles
respect for autonomy
nonmaleficence
beneficence
distributive justice
respect for autonomy
rights of individual to self-determination
this is rooted in societys respect for individuals ability to make informed decisions about personal matters
nonmaleficence
first do no harm
it is more important to not harm than to do them good
beneficence
actions that promote the well being or best interest of others
distributive justice
society has the duty to the individual in need
everyone has the right to receive equitable access to the basic needs of life including healthcare
role of public health in communicable disease management
collect, analyze, and communicate cases of a reportable disease
support and advice for treating health care providers
identification of potential contacts
provision of preventative vaccinations
outbreak control
