Flashcards in Lec 01 Overview and Epidemiology of Infectious Diseases Deck (19)
How is IDS epidemiology different from epidemiology in general?
* a case can also be an exposure to other patients
* subclinical infections influence epidemiology because they affect transmission
* contact patterns play a major role
* immunity plays a role
* there can be urgent and emergent situations at different levels
Infectious diseases, as a whole, is the leading cause of mortality worldwide. (T/F)
What demographics are disproportionately affected by infectious diseases?
young, elderly, people from low-income countries
What is the rank of the country in terms of TB prevalence?
What conditions facilitate the spread of infectious diseases?
* globalization of food supply
* overuse of antibiotics
* growth of mega-cities
* increasing proximity to disease vectors
* climate change
* transborder spread of diseases
How are infectious diseases classified?
* established infectious diseases
* newly emerging infectious diseases
* reemerging infectious diseases
What is colonization?
* presence of organism in the tissues without clinical and subclinical infection
* no signs and symptoms and no inflammatory response but the organism can replicate and organisms can be recovered by culture
What is a carrier?
* individual colonized with organisms but shows no evidence of disease
* able to transmit the organism
What are the components of the infectious disease triad?
host, agent, environment
What conditions are necessary for an agent to be considered epidemiologically important?
* can be transmitted through the environment
* causes infection
* produces clinical disease
What is infectiousness?
relative ease by which an agent is transmitted to other hosts
What are the determinants of infectiousness?
* characteristics of the portals of entry and exit
* agent's ability to survive away from the host
* ability to infect nonhuman hosts
How do you compute for the Reproductive Number?
P x C x D
P - probability of transmission per contact
C - contacts per unit
D - duration of infectiousness
What is infectivity?
* capability of the agent to enter, survive, and multiply in the host
* measured by the secondary attack rate
How do you compute for the secondary attack rate?
number of infected/number of susceptible and exposed
What is pathogenicity?
* extent to which overt disease is produced in an infected population
* number of patients with clinical disease/total number of infected
What are the patterns of disease occurrence?
sporadic, endemic, hyperendemic, epidemic, pandemic
What are the three main modes of transmission?
point-source outbreak, person-to-person outbreak, continuous-source outbreak