Comm. Health - Epidemiology: Communicable Disease Control
Terms
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- What was the leading cause of death in 1900?
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- infectious disease
**leading cause of death today is chronic disease - Emerging Infectious Diseases
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- diseases with an increased incidence in the past 2 decades or potential to increase in the near future
- include newer & known infectious diseases - Elimination
- remove the disease from a large area
- Eradication
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have a permanent elimination around the world
(ex. smallpox) - Epidemiological Triangle (Triad)
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1. Host - any living species
2. Agent - living or object factor that must be present or absent in order for disease or condition to develop
3. Environment - everything that is external to the host or agent. (Host and Agent have reciprocal relationship) - Types of Agents
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1. Nutritive agent - ex. lack of Ca+, Vit D, or Phosphorus
2. Chemical agent - ex. pesticides
3. Physical agent - ex. radiation, heat, cold, machinery
4. Infectious agent - ex. viruses, bacteria, fungi, parasites - Vectors
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- Non-human organisms
- often insects
- role in the transmission of infectious agent from source to host - Vector-borne diseases
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ex. ticks (cause Lyme disease); mosquitos (cause West Nile virus & Malaria)
- 4 Host Factors that influence the spread of disease:
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1. Resistance
2. Immunity
3. Herd Immunity
4. Infectiousness - Resistance
- Ability to withstand infection
- Immunity
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- passive immunization: mother transfers antibodies to fetus or infant through breastfeeding
- active immunization: vaccines - Herd Immunity
- when a lot of people in the community are immunized, it blocks the spread of diseases
- Infectiousness
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a measure of the potential ability of an infected host to transmit the infection to other hosts.
(ex. measles - extremely infectious) - 2 Modes of Transmission:
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1. Vertical Transmission (parent passing infection to offspring through sperm, placenta, milk, or contact in vaginal canal at birth)
2. Horizontal Transmission (person-to-person spread of infection); can happen in 3 ways: Direct contact, indirect contact or airborne - Direct Contact
- immediate transfer of disease from an infected host to a susceptible host (touching others)
- Indirect Contact
- human host has contact with vehicles (ex. doorknobs) or vectors that support and transport the infectious agent
- Airborne
- microorganisms are suspended in the air and spread to a suitable port of entry (ex. coughing & sneezing)
- Incubation Period
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time interval between invasion by an infectious agent and the 1st appearance of S&S of the disease
(infected, but do not know they have it yet) - Communicable Period
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time interval during which an infectious agent may be transferred directly or indirectly from an infected person to another person
(time it takes for infectious to spread from agent to host) - 5 Components of a comprehensive public health response to outbreaks of illness:
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1. DETECT the outbreak
2. Determine the CAUSE
3. Identify FACTORS that place people at risk
4. Implement measures to CONTROL the outbreak
5. INFORM medical & public communities about treatments, public consequences & preventative measures - Vaccines
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- most effective method for preventing and controlling communicable diseases
- vaccines control diseases such as polio, diphtheria, pertussis, & measles
- most children are immunized by the time they enter school
- recommended, but not compulsory - Be alert for communicable diseases in regions where:
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1. groups obtain exemption from immunization
2. immunization is incomplete
3. international visitors are frequent - Partner Notification (Contact Tracing)
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confidentially identifying & notifying exposed sexual & injection drug-use partners of clients who have a reportable STI
(ex. HIV, gonorrhea, clamydia, & syphilis) - Directly Observed Therapy (DOT)
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* common for noncompliant TB patients
- if clients prematurely stop taking medication, the bacterium may become resistant
- this can affect entire community of susceptible people
- CHN observes & documents clients taking their TB drugs - Multisystem approach to control communicable diseases:
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1. Improve host RESISTANCE
2. Improve safety of ENVIRONMENT
3. Improve public health SYSTEMS
4. Facilitate POLITICAL & SOCIAL changes (to ensure better health for all people)