parasitism

What does SIR stand for?

• S = Susceptible

• I = Infected

• R = Recovered/Immune

What does susceptible mean?

Individuals who can catch the disease

What does infected mean?

Individuals who currently have the disease

What does recovered mean?

Individuals who recovered and are immune

What is the total population equation?

S+I+R=N

What is the equation for the change in infected individuals?

dI/dt=βSI−mI

dt/dI: rate of change in infected individauls over time
I: currently infected
S: susceptible individuals
β: transmission rate
mI: loss to number of infected

What does m equal?

m=α+ν

When can a disease spread?

dI/dt>0
infections are increasing

What is the susceptible threshold equation?

S​=m/β​

What is the susceptible threshold?

The minimum susceptible population needed for a disease to spread.

What happens when S is above the threshold?

The disease can spread.

What happens when S is below the threshold?

Infections decrease and the disease cannot sustain its spread.

How do vaccines work in the SIR model?

They move individuals from Susceptible (S) to Recovered/Immune (R)

What is herd immunity?

When enough people are immune that disease transmission is greatly reduced.

What happens when vaccination increases?

Susceptible individuals decrease, making disease spread harder.

What does a biomedical researcher study?

Diseases inside the body, symptoms, cells, immune responses, and treatments.

What does an ecologist study?

How diseases interact with organisms, populations, and the environment.

What is the main difference between an ecologist and a biomedical researcher?

Biomedical researchers focus on the individual body; ecologists focus on populations and ecosystems.

What are zoonotic diseases?

Diseases that naturally spread between animals and humans.

Name three examples of zoonotic diseases.

Rabies, Lyme disease, and Ebola.

What does prevalence mean?

How common a disease is in a population.

What three organisms are involved in Hawaiian avian malaria?

• Honeycreepers (birds)

• Culex mosquitoes (vectors)

• Malaria (parasite)

Why are high-elevation forests safer for Hawaiian birds?

They are colder, limiting mosquito survival and malaria transmission.

How does climate change affect Hawaiian honeycreepers?

Warming allows mosquitoes and malaria to move higher up mountains, shrinking safe habitats.

How does climate change affect disease transmission?

Changes temperature and moisture, allowing diseases and vectors to spread into new areas.