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Parasit-Eco Epi
Parasit-Eco Evo
| Question | Answer |
|---|---|
| prevalence | (# infected hosts/ # of hosts examined)*100; percent of hosts infected; snapshot at one time |
| incidence | # of new infections in a given time period/total number of hosts at the beginning of the time period; rate of new infections occurring in a time period |
| pandemic | worldwide epidemic |
| pandemic example | HIV, H1N1 |
| epidemiology | the ecology of disease; all aspects of the pathogen (biology), host (biology), environment, social conditions, behavior, etc. that contribute to or influence the maintenance of a disease |
| epidemic | the presence of a disease is at levels higher than what normally is expected |
| epidemic example | diabetes in the US |
| endemic | a disease pathogen is present in an area and is expected to be there |
| endemic example | Lyme disease in WI |
| terms used when estimating parasite numbers and distribution | endemic, epidemic, epidemiology, pandemic, incidence, intensity, mean intensity, density, prevalence, overdispersion, underdispersion |
| parasites always live at ______ trophic levels than the host and are at least ___________ | higher; secondary consumers |
| types of parasite metabolism | anaerobic or aerobic-- specialized for the host and current life cycle (may switch between life cycles) |
| type of parasite metabolism in the intestines | anaerobic |
| type of parasite metabolism in the blood and tissues | aerobic OR anaerobic |
| niche | role in an ecological community; simplified definition: an organism's place/habitat |
| short term host reactions | individual response to the impact of a parasite is to mount an immune response against the parasite; differ among individuals and sometimes make the disease worse |
| long term host reactions | reaction of the population and species, coevolving with the parasite population (seen when the host is susceptible to the parasite) |
| the host as an environment | rich, stable (ex. temperature), well-controlled environment; protection from outside; like an island surrounded by an abiotic environment ("patchily distributed") |
| parasite evolutions to "jump spaces" | use a vector, have a lot of kids, long life span, behavior modification of the host |
| parasites coevolve _______ because they have ______ and ________ | well; short generation times; large populations (evolve quickly) |
| intensity | the number of parasites of a given species in a particular host |
| what is the intensity of 10 pinworms in 1 mouse? | intensity= 10 per mouse |
| what is the prevalence if 10 out of 20 mice are infected? | prevalence= 50% |
| mean intensity | used if you have more than one host to count |
| what is the mean intensity of 10 mice with a total of 75 pinworms? | mean intensity= 7.5 worms per mouse |
| density | the number of parasites/ova per unit area/weight/volume, etc. |
| example of density | number of eggs per gram of feces |
| overdispersion | general rule in parasite populations; relatively few hosts carry the majority of parasites in a population; aka: Crofton's principle; in general, most of the host population is carrying a few or no parasites |
| two terms used to describe parasite populations in relation to the host | overdispersion and underdispersion |
| underdispersion | parasites are evenly spread out in the population |
| microparasite | microscopic, small |
| macroparasite | big; can see with the naked eye, pick up, etc. |
| micropredator | blood-feeding arthropod that feeds on multiple hosts in a population; BAD definition because predators kill the host |
| micropredator example | horse fly |
| parasites have a(n) __________ life history | r-selected |
| characteristics of r-selected species | high reproductive rate, short life span, little or no maternal care of the young-- evolved to generate a fantastic number of progeny |
| end results of having a high reproductive rate | increased chance of host encounter (usually only a small % "make it" |
| types of parasite reproduction | sexual and asexual: polyembryony, internal budding, hermaphroditism, schizogony, binary fission, and hydatid budding |
| evolutionary associations between parasites and hosts come about by _______ or ________ | descent; colonization |
| descent | long shared evolutionary history, considerable coevolution |
| colonization | "recent" encounter has established a new relationship; "new" relationships are usually more damaging to the host |
| descent example | cladogram where an entire section is all parasites and has a common ancestor |
| colonization example | cladogram where only new, unrelated branches contain parasites; no common ancestor |
| adaptations for transmission | parasite reproduction and behavioral adaptations |
| behavioral adaptations | attributes that increase a parasite's chance of encountering a new host, often by increasing chance of predation by the IH; parasite products alter host brain chemistry or change host morphology |
| pathogenicity | implies degree of disease; how sick are you?; individual concern |
| virulence | the effect on host reproduction; evolutionary concern-- species "cares"; lowers transmission rate of genes |
| do high levels of pathogenicity and virulence make a parasite more successful? | who knows?; in general, with high virulence, higher selection for host resistance is seen |
| red queen hypothesis | hosts constantly build more complex defenses and parasites constantly evolve more complex adaptations to overcome their defenses (higher specilization); evolutionary arms race |
| consequences of red queen hypothesis | driving force for (1) high parasite evolution rates (2) adaptive radiation (speciation) in parasites |
Created by:
Jean-O
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