Communicable Disease Prevention Exam Flashcards
(123 cards)
Communicable disease
- Contagious (transmissible/spread from person to person)
- Not all infectious diseases
- eg. Corona virus, HIV, flu
Infectious disease
- All modes of transmission (e.g. includes vectors, food borne)
- All communicable diseases
- eg. Malaria, tetanus, food poisoning
Infectivity
- Ability of an organism to infect a susceptible host
- Measured by attack rate
Pathogenicity
- Ability of an agent to produce disease
- Measured by proportion of clinically apparent infection
low/high
Virulence
- Severity of the disease after infection occurred
- Measured by case fatality rate
Immunogenicity
Ability to confer immunity after infection
Unapparent disease
- Asymptomatic active infection/disease
- Measured by lab test
Factors that determine impact
A. The characteristics of infectious agent
B. The characteristics of the host
C. The characteristics of transmission
D. The characteristics of the environment and its influence
Latency period
The time interval between when an individual or host is infected by a pathogen and when they become infectious (images in OneNote)
Incubation period
Incubation period is the time elapsed between exposure to a pathogenic organism and when symptoms and signs are first apparent (images in OneNote)
Reservoir
Any person, animal, arthropod, plant, soil, or substance, or a combination of these, in which an infectious agent normally lives and multiplies, on which it depends primarily for survival, and where it reproduces itself in such a manner that it can be transmitted to a susceptible host
Types of reservoir: Human reservoir, Animal reservoir, Non-living reservoir
Carrier
Carrier is an infected person or animal that harbors a specific infectious agent in absence of discernible clinical disease and serves as a potential source of infection to others
Types (image in OneNote): Convalescent, Healthy, Temporary, Chronic
Cases
Cases are persons with clinical disease
- Primary: person who brings the disease into the
population
- Index: the first case to be discovered by the healthcare
system during an outbreak
- Secondary: all cases infected by the primary case
- Tertiary: all cases infected by any secondary case
(Mild cases are more important sources of infection than severe cases)
Subclinical cases
Subclinical cases the disease agent multiply in the host but does not manifest by signs and symptoms. Dominant role in maintaining the chain of infection in the community
Zoonotic disease
An infectious disease that is transmissible under natural conditions from vertebrate animals to humans
Portal of exit
The path by which a pathogen leaves its host. This usually corresponds to the site where the pathogen can be localised (examples in OneNote)
Portal of entry
The path/route by which a pathogen enters a susceptible host. The route must provide access to tissues in which the pathogen can multiply or a toxin can act.
Bioterrorism
A bioterrorism attack as “the deliberate release of viruses, bacteria or other germs (agents) used to cause illness or death in people, animals, or plants”
Disease transmission
Direct contact, droplet, indirect contact (vector, vehicle and airborne)
Endemic
Endemic is the constant presence of a disease or an infectious agent in a population within a geographical area. Infection remains at a steady level. Often refers to usual prevalence.
Hyper endemic
Hyper endemic refers to persistent, high levels of disease occurrence
Sporadic
Sporadic refers to a disease that occurs infrequently or irregularly
Exotic
Exotic diseases are those that are imported into a country in which they do not naturally occur
Cluster
Cluster refers to an aggregation of cases grouped in place and time that are suspected to be greater than the number expected, even though the expected number may not be known, and they are not linked epidemiologically