Lecture 17: Epidemiology&Public Health Flashcards
epidemiology
- science that evaluates occurrence, determinants, distribution, and control of health and disease in a human population
Epidemiologist
- one who practices epidemiology
Centers for disease control and prevention (CDC)
- main epidemiological agency in the US
- develop and carry out disease prevention and control
- environmental health
- health promotion and education activities
World health organization (WHO)
- international counterpart, based in Switzerland
Sporadic disease
- occurs occasionally or at irregular intervals in human population
- ex. tetanus, rabies, plague
Endemic disease
- maintains a steady, low level frequency at a moderately regular interval
- Ex: seasonal cold and flu
Hyper-endemic disease
- gradually increase in frequency above endemic level but no to epidemic level
- ex. dengue fever
Outbreak
- sudden, unexpected occurrence of disease
- usually in a limited segment of population
Epidemic
- outbreak affecting many people at once
- index case
Index case
- first person identified in an epidemic
Pandemic
- increase in disease occurrence within a large population over at least two countries around the world
John Snow
- Father of epidemiology
Incidence
- measure occurrence of new cases of a disease during a defined time period
Prevalence rate
- total number of individuals infected at any one time
Prevalence rate
total # of cases in population/ total population X 100
Morbidity rate
of new cases of disease in population/ # of individuals in population
Mortality
- number of deaths from a disease per number of cases of the disease
Mortality rate
of deaths due to a given disease/ size of total population with the same disease
Communicable disease
- can be transmitted from person to person
Two types of epidemics
- common source epidemic
- Propagated epidemic
Common source epidemic
- noncommunicable and results from a single, common source
Propagated epidemic
- one infected individual placed into a susceptible population, infection propagated to others
Herd immunity
- threshold percentage of the population having immunity so when isolated cases reemerge, there is no escalation of the disease through the population
Category A pathogen
- highest threat to public health
- high mortality rate
Category B pathogen
- second highest priority
- moderate morbidity and low mortality rates
Category C pathogen
- third highest priority
- emerging pathogens with potential for high morbidity
One-health thinking
Focuses on ecological and social factors that influence development of emerging and reemerging diseases
Reasons for Emergence
- World population growth and urbanization
- Crowded workplaces and public transportation
- Increased international travel
- Mass migrations of people
- Climate change
Hospital acquired infections (HAI)
- Nosocomial: associated with healthcare settings
- causes by noninvasive bacteria from normal microbiota
- many hospital strains are antibiotic resistant
Common Hospital acquires infection (HAI)
- Urinary tract infections
- surgical site infections
- bloodstream infection
- Pneumonia
Endogenous sources
- Catheter-associated urinary tract infections
- surgical site infections
- Central line associated bloodstream infections
Exogenous sources
- Animate sources: hospital staff, patients, visitors
- Inanimate sources: flowers, food, computers
two types of prevention and control of epidemics
- reduce/ eliminate source or reservoir
- reduce number of susceptible individuals
Reduce or eliminate source or reservoir of infection
- Social distancing and isolation of carriers, destruction of
animal reservoirs, treatment of water and sewage to
reduce contamination.
Reduce number of susceptible individuals and raise the general level of herd immunity
Immunizations and prophylactic treatment to prevent infection.
Vaccine
- Preparation of one or more
microbial antigen that induce protective
immunity
Immunization
- occurs when host’s
immune system has responded to the
vaccine
Immunize the people
- Vaccines attempt to induce antibodies
- activated T cells to protect host from future infection
Inactivated Vacines
- Killed
- effective, but less immunogenic
- often requires boosters
- ex. Polio
Attenuated Vaccines
- live but weakened
- effective at stimulation both humoral and cell mediated immunity
- single dose
- can have serious adverse reactions
Acellular/ subunit vaccines
- capsular polysaccharides
- recombinant surface antigens
- inactivated exotoxins (toxoids)
Bioterrorism
- intentional use of viruses, bacteria, fungi, or their toxins to produce death or disease in humans, animals, and plants
Indicators of Bioterrorism
- Sudden spike in unusual (non-endemic) diseases
- sudden increased numbers of zoonoses, diseased animals or vehicle-borne illnesses
