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An infectious disease is said to be endemic when it can be sustained in a population without the need for external inputs. This means that, on average, each infected person is infecting exactly one other person (any more and the number of people infected will grow sub-exponentially and there will be an epidemic , any less and the disease will ...
In epidemiology, force of infection (denoted ) is the rate at which susceptible individuals acquire an infectious disease. [1] Because it takes account of susceptibility it can be used to compare the rate of transmission between different groups of the population for the same infectious disease, or even between different infectious diseases.
For the full specification of the model, the arrows should be labeled with the transition rates between compartments. Between S and I, the transition rate is assumed to be (/) / = /, where is the total population, is the average number of contacts per person per time, multiplied by the probability of disease transmission in a contact between a susceptible and an infectious subject, and / is ...
Mass vaccination to induce herd immunity has since become common and proved successful in preventing the spread of many contagious diseases. [22] Opposition to vaccination has posed a challenge to herd immunity, allowing preventable diseases to persist in or return to populations with inadequate vaccination rates. [45] [46] [47]
Computer simulations of infectious disease spread have been used. [33] Human aggregation can drive transmission, seasonal variation and outbreaks of infectious diseases, such as the annual start of school, bootcamp, the annual Hajj etc. Most recently, data from cell phones have been shown to be able to capture population movements well enough ...
In epidemiology, particularly in the discussion of infectious disease dynamics (mathematical modeling of disease spread), the infectious period is the time interval during which a host (individual or patient) is infectious, i.e. capable of directly or indirectly transmitting pathogenic infectious agents or pathogens to another susceptible host ...
The serial interval in the epidemiology of communicable (infectious) diseases is the time between successive cases in a chain of transmission. [1]The serial interval is generally estimated from the interval between clinical onsets (if observable), in which case it is the 'clinical onset serial interval'.
Disease diffusion occurs when a disease is transmitted to a new location. [1] It implies that a disease spreads, or pours out, from a central source. [2] The idea of showing the spread of disease using a diffusion pattern is relatively modern, compared to earlier methods of mapping disease, which are still used today. [3]