Infectious and Communicable Diseases

Question 1

Infectious disease

Answer 1

caused by an infectious agent - i.e. tetanus

Question 2

Communicable disease

Answer 2

Transmission (directly or indirectly) from an infected person - i.e. Measles

Question 3

Transmission

Answer 3

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

Question 4

Chain of Infection

Answer 4

minimum requirements for an infectious or communicable disease to occur

1. Agent or pathogen (virus, bacteria, fungus, parasites, chemicals)
2. Reservoir or source (animate, inanimate, environmental)
3. Portal of exit (escape method)
4. Mode of transmission (direct, indirect, airborne)
5. Portal of entry (how getting into new host)
6. Susceptible host (an organism that can be infected by a pathogen - i.e. immunocompromised)

Question 5

Vector

Answer 5

form of living organism that transmits diseases to a susceptible host

Question 6

Vehicle

Answer 6

inanimate objects called fomites

Question 7

Pathogenicity

Answer 7

ability to cause disease, i.e. Clostridium botulinum and salmonella

Question 8

Virulence

Answer 8

ability to cause serious disease or death

Question 9

Zoonoses

Answer 9

diseases that are transmissible to humans from animals

Question 10

Incubation period

Answer 10

the time period between initial contact with an infectious agent and the first appearance of disease symptoms

Question 11

Period of infectivity

Answer 11

the time during which an infectious agent may be transferred directly or indirectly from an infected reservoir/host to another person

Question 12

Immunity

Answer 12

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

Question 13

Prevention

Answer 13

• 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

Question 14

Carrier

Answer 14

person or animal who harbors an infectious organism and transmits the organism to others while having no symptoms of the disease

Question 15

Outbreak Investigation

Answer 15

• Establish the existence of an outbreak
• Describing cases by person, place, time
• Common source of outbreak
• Propagated outbreak

Question 16

Surveillance

Answer 16

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

Question 17

CDC

Answer 17

Centers for Disease Control and Prevention; major agency that protects the nation’s health by developing guidelines that promote health by developing guidelines

Question 18

Food borne diseases

Answer 18

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

Question 19

Waterborne diseases

Answer 19

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

Question 20

Vector-borne diseases

Answer 20

Lyme disease, malaria, west nile virus, zooneses (hantavirus, avian influenza, cat scratch fever, rabies), parasites, etc.

Question 21

Emerging Infectious Disease

Answer 21

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

Question 22

Antigenic drift

Answer 22

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

Question 23

Antigenic shift

Answer 23

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

Question 24

Epidemiologic Triad

Answer 24

Change in the behavior of the humans - the host
Change in the behavior of the microbes - the agent
Change in the environment