Basic models can illustrate how diseases spread through populations.
Importance of minimizing host contacts for controlling disease spread, highlighted during the COVID pandemic.
Social isolation aims to reduce disease transmission by limiting host interactions.
Effectiveness determined by the disease's transmission coefficient and infectivity.
Example: Measles is extremely infectious and can be contracted easily in an enclosed space.
High transmission rates for airborne diseases where one infected individual can infect many.
Female mosquitoes are the primary vectors as they require blood meals for reproduction.
Blood Meals: A female mosquito needs two blood meals for reproduction.
Disease transmission occurrence depends significantly on host density; however, mosquito biting behavior demonstrates that density may not always influence spread.
A mosquito that bites only two individuals would transmit the disease regardless of whether it's in a room with two or a hundred people.
Disease spread doesn't always correlate with host population density.
If the transmission vector (e.g., mosquitoes) bites a limited number of hosts, spread remains constant irrespective of overall density.
Key: Increase or decrease in infected individuals determines the control measures.
Vaccination crucial for controlling measles outbreaks.
Unvaccinated individuals are highly susceptible to infection, while vaccinated ones have high resistance.
Population shifts from susceptible to infected, with potential recovery leading to immunity.
Dominance of one disease variant may arise due to its improved transmission efficiency, showcasing natural selection within disease spread.
Concept of R0 (basic reproduction number):
R0 > 1: Indicates increasing number of infected individuals over time.
R0 < 1: Indicates a decreasing number of infected individuals, leading towards potential eradication.
Vaccination effectively reduces the susceptible population, leading to lower infection rates.
Herd immunity concept: Achieved when enough individuals are immune, protecting the entire population even if some remain susceptible.
Science operates within a sociopolitical framework influencing policy decisions.
Scientists provide data and evidence but cannot dictate public behavior; decisions must consider multiple aspects of society.
Epidemiologists aim for herd immunity to decrease susceptible individuals below a critical threshold.
Effective herd immunity provides a buffer against outbreaks even if some vulnerable individuals exist.