Parasites, Pathogens, Disease (W7-L1) Flashcards
Parasite
Organism that exploits another living organism, called the host, causing it some degree of harm
Endoparasites
Live inside the host
ex. Worms, Protozoa
Ectoparasites
Parasites that live on the host
ex. ticks, lices
Pathogens
Type of parasite that includes bacteria, viruses
Intermediate Host
Host used by the parasite before it reaches the primary host
ex. Guiniea Worms
- larve live in water flea until consumed by a human, then live in a human
Population Cycles
Occur when individuals die or become immune
ex. Scottish bird
Reproductive Value
number of individuals infected by an individual
for a disease to disappear, R<1
Reproductive Value Naught
Number of individuals infected by an individual in a naïve population
How do you calculate the number of people required to cause the disease to disappear?
R0-1/R0
Virulence
ability for a pathogen to cause its host damage
depends on multiple factors, with transmissibility as the primary factor
most virulent diseases are ones that have just entered the population
Direct Transmission
when a pathogen is transmitted from one host to the next
ex. cold
less likely to kill or harm the host since that would not favor the spreading of the pathogen
Indirect Transmission
More likely to kill and harm
ex. malaria
parasite uses another mechanisms to transfer to other hosts, debilitating hosts to reproduce
Immunity vs Tolerance
Immunity: will not catch the disease
Tolerance: not impacted by the disease, but can still carry it
Spillover
Diseases that passed form one species to another
Zoonoses
Type of spillover
Diseases spread form animal to human
