Infectious and Communicable Diseases Flashcards
Infectious disease
caused by an infectious agent - i.e. tetanus
Communicable disease
Transmission (directly or indirectly) from an infected person - i.e. Measles
Transmission
any mechanism by which an infectious agent is spread
- Direct: immediate transfer of an infectious agent from one infected host or reservoir to a portal of entry into the new host (biting, kissing, sexual intercourse, or direct contamination into the mucous membranes)
- Indirect: usually through a vector or a vehicle
- Airborne: occurs through droplet or dust
- —droplet: result from the evaporation of fluids from droplets through coughing, sneezing, talking; i.e. TB, Legionnaires)
- —dust: particles in which microorganisms can become airborne and be breathed in to create disease; i.e. Hantavirus
Chain of Infection
minimum requirements for an infectious or communicable disease to occur
- Agent or pathogen (virus, bacteria, fungus, parasites, chemicals)
- Reservoir or source (animate, inanimate, environmental)
- Portal of exit (escape method)
- Mode of transmission (direct, indirect, airborne)
- Portal of entry (how getting into new host)
- Susceptible host (an organism that can be infected by a pathogen - i.e. immunocompromised)
Vector
form of living organism that transmits diseases to a susceptible host
Vehicle
inanimate objects called fomites
Pathogenicity
ability to cause disease, i.e. Clostridium botulinum and salmonella
Virulence
ability to cause serious disease or death
Zoonoses
diseases that are transmissible to humans from animals
Incubation period
the time period between initial contact with an infectious agent and the first appearance of disease symptoms
Period of infectivity
the time during which an infectious agent may be transferred directly or indirectly from an infected reservoir/host to another person
Immunity
increased resistance on the part of the host to a specific agent
- -Acquired: prior infection or immunization
- -Passive: placental transfer, immune globulin
- -Herd: when 85% of the population is immune to specific agents
Prevention
- Primary: intervening before the agent enters the host and causes pathological changes.
- –isolation, quarantine, segregation, personal surveillance
- Secondary: detecting disease at the earliest possible time to begin tx and stop progression
- Tertiary: limits the progression of disability
Carrier
person or animal who harbors an infectious organism and transmits the organism to others while having no symptoms of the disease
Outbreak Investigation
- Establish the existence of an outbreak
- Describing cases by person, place, time
- Common source of outbreak
- Propagated outbreak
Surveillance
continual dynamic method for gathering data about the health of the general public for the purpose of primary prevention of illness - how do we break the chain of infection
CDC
Centers for Disease Control and Prevention; major agency that protects the nation’s health by developing guidelines that promote health by developing guidelines
Food borne diseases
Resulting from insufficient cooking of food, preparing the food too soon before eating, contaminated food being used, cross contaminations, food prep by infected persons
Nurse: watch for hand washing, how to purchase food, how to store food, proper cooking and cleaning techniques
i.e. Campylobacteriosis, listeriosis, salmonellosis, E.coli
Waterborne diseases
1 billion people lack access to safe drinking water
Nurse: need QI, how to target water quality improvements
i.e. diarrhea disease, cholera, cancer and tooth/skeletal damage, schistosomiasis
Vector-borne diseases
Lyme disease, malaria, west nile virus, zooneses (hantavirus, avian influenza, cat scratch fever, rabies), parasites, etc.
Emerging Infectious Disease
Newly identified clinically distinct infectious disease or re-appeareance (or reemergence) of a known infectious disease, i.e. pertussis, SARS, Avian influenza, H1N1 swine flu, C.diff, MRSA, mumps, measles
-Convergence model: illustrating the interaction of 13 factors that contribute to the emergence of infectious diseases (microbial adaptation and change, human susceptibility, climate and weather, ecosystems, land use, eco-development, international travel, technology and industry, social determinants, war and famine, lack of political will, intent to harm [terrorism], human factors and behavior)
- Microbe to human interactions
- -genetic and biological
- -physical/environmental
- -ecological
- -social, political, and economic
Antigenic drift
the SLOW and progressive genetic changes that take place in DNA and RNA as organisms replicate in multiple hosts, causing changes in influenza viruses year to year
i.e. with influenza: gradual change, point mutations in H and N, occurs in both A and B viruses
Antigenic shift
the SUDDEN CHANGE in DNA and RNA resulting in a new strain of the mircoorganism and people have little or no acquired immunity
i.e. with influenza: re-assortment of genes, sudden change, explosive spread, occurs only in influenza A viruses
Epidemiologic Triad
Change in the behavior of the humans - the host
Change in the behavior of the microbes - the agent
Change in the environment
