Ch. 3 Epidemiology and Communicable Diseases

Question 1

Epidemiological Triangle

Answer 1

involves relationships among an agent, host, and environment

their interaction forms a web of causality, which increases or decreases risk for disease

host
environment
agent

Question 2

Agent

Answer 2

factors that cause the disease

physical- noise, temp
infectious- viruses, bacteria
chemical- toxins, drugs

Question 3

host

Answer 3

living being that agent or the environment influences

Question 4

environment

Answer 4

setting or surrounding that sustains the host

physical environment- geography, water/food supply, presence of reservoirs/ vectors

social environments-
access to health care, high-risk working conditions, poverty

Question 5

Incidence

Answer 5

number of new cases in the population

Question 6

prevalence

Answer 6

number of existing cases in the population

Question 7

crude mortality rates

Answer 7

overall death rates

Question 8

epidemic

Answer 8

rate of disease exceeds the usual (endemic) level of the condition in defined population

Question 9

Pandemic

Answer 9

condition occurs when an epidemic occurs in multiple countries or continents

Question 10

Communicable diseases

Answer 10

leading causes of communicable disease deaths include ARI (pneumonia and influenza), HIV/AIDS, diarrheal diseases, TB, malaria, and measles

viral hepatitis, STIs also pose a significant risk

CDC recommends routine immunizations

Question 11

Populations at risk for communicable diseases

Answer 11

• young children
• older adults
• immunosuppressed clients
• clients who have a high-risk lifestyle-
• international travelers-
• health care workers-

Question 12

Chain of Infection

Answer 12

Causative agent

reservoir (sick person)

portal of exit (cough)

mode of transmission (pencil)

portal of entry

susceptible host

Question 13

Modes of Transmission

Answer 13

vertically (parent to offspring)- sperm, placenta, vaginal contact during birth, consuming human milk

horizontally (person-person)- contact with a person or objects the person has touched, the air, contaminated body fluids, food, and water (vehicles), living creatures (vectors)

Question 14

Airborne
droplets or particles

Answer 14

• measles (airborne)
• chickenpox (airborne)
• TB (airborne)
• Pertusis (droplet)
• influenza (droplet)
• SARS (droplet)

Question 15

Foodborne

Answer 15

food infection
- norovirus
- salmonellosis
- hep A
- trichinosis
- e. coli

food intoxication (bacterial growth, chemical contamination, disease-producing substances)
- staphylococcus aureus
- clostridium botulinium

Question 16

waterborne

Answer 16

fecal contamination of water

• cholera
• typhoid fever
• bacillary dysentery
• giardia lamblia

Question 17

Vector-borne

Answer 17

• west nile virus
• lyme disease
• rocky mountain spotted fever
• malaria

Question 18

direct contact infections

Answer 18

STIs: HIV/AIDS, chlamydia, gonorrhea, syphilis, HPV, genital herpes, hep B, C, D

infectious mononucleosis

pinworms (enterobiasis)

impetigo

lice, scabies

Question 19

Active immunity
vs
Passive immunity

Answer 19

active- production of antibodies by the body in respone to infection or immunization with a specific antigen

passive- from mother to newborn or through immunoglobulins, plasma proteins, antitoxins