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Parasite/pathogen
Pathogens in populations
Question | Answer |
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What is epidemology? | - The study of how often diseases occur in different groups of people and why - draws on knowledge from individual cases - applies that knowledge to a defined population (usually the population at risk) |
What is an endemic disease? | - a disease constantly present in a region or population, with a low spread |
What is an epidemic? | - a sudden increase in infection cases spreading through a large population |
What is a pandemic? | - a sudden increase in infection that spreads across countries, continents and sometimes the whole planet |
What is etiology? | - the cause(s) of a disease |
What is prevalence? | - the # of existing cases of a given disease at a given point in time |
What is incidence? | - the # of new cases of a given disease over a specific time period |
What is virulence? | - severity of disease |
What is mortality rate? | - aka the death rate (# of deaths in given time period due to a particular disease) |
What is Ro? | - the basic reproductive rate for a disease. A proxy measure for how contagious a disease is. - the number of cases that any given case could cause R0 = 1 means each case leads to 1 other case |
What is morbidity? | - the rate of disease in a population (useful for diseases with low case-fatality) |
From individuals to populations | - clinical observations inform about the health status of an individual - epidemiology informs about the health status of a population |
The 5 W's | 1. What is the health concern? (the causative pathogen) 2. Who is it affecting? (Determine who your population is) 3. Identify a sample (that hopefully represents your population) 4. Surveillance: monitor for patterns and changes over time and space |
Ecology of the very small | Undertstanding ecology means understanding: - the pathogen - the host - any vectors or intermediate hosts - the context/environment |
Understanding the host | TB is caused by the pathogen Mycobacterium tuberculosis Meerkats are highly social animals with complex group dynamics Also true for badgers where isolated individuals are at risk of having TB - more social animals are at an increased risk of TB |
Understanding the pathogen | Closely related parasites can have different effects on the same host species Plasmodium relictum results in lower productive success for the blue tit host whereas Plasmodium circumflexum results in lower survival for the blue tit host |
What are temporal scales? | if you sample seasonally but your pathogen kills your host quickly (within a season), your sampling is inaccurate |
What are spatial scales? | consider the landscape e.g tick-borne Lyme disease at a small scale shows a + link between human disease risk (amplification effect) and biodiversity but at a larger scale shows the opposite (dilution effect) |
Ecological rules that apply to pathogens | 1. Understand your species (pathogen, host and any vectors) 2. Understand their habitat (the context) 3. Monitor the populations 4. Respond to populations changes (manage your population) 5. And repeat |