Database Reference
In-Depth Information
However, even in this relatively crude state, these models are useful tools that can
offer great insight and help in formulating hypotheses about the behavior of disease
outbreaks in the real world.
12.4.4 Questions and Tasks
5
describe a phenomenon where species diversity may serve to reduce disease risk
to humans. Some studies suggest that the number of human cases of WNV is de-
creased in areas of high bird diversity because the bird hosts, which develop the
highestviremia and transmit the disease most efficiently when bitten by a mosquito,
are a lower relative proportion of the total population.
1. How would you explore the potential effects of avian community diversity on
human risk of disease in this model? (Hint: Try a sensitivity analysis and graph
MOSQUITO % INFECTED).
WNV EXPANDED SEASONAL MODEL
BIRD INFECT(t)
=
BIRD INFECT(t
−
dt)
+
(BIRD INFECTING
−
Bird I to R
−
BI DYING
−
BI DYING WNV) * dt
INIT BIRD INFECT
=
0
INFLOWS:
BIRD INFECTING
=
BITE RATE*TRANSMISSION EFFICACY M TO B*BIRD SUSC/
TOTAL BIRD POPULATION * MOSQ INFECT *
MOSQ BREEDING SEASON
OUTFLOWS:
Bird I to R
=
BIRD INFECT * BIRD RECOVERY RATE
BI DYING
BIRD INFECT * BIRD DEATH RATE
BI DYING WNV
=
=
BIRD INFECT * WNV DEATH RATE
BIRD RECOV(t)
=
BIRD RECOV(t
−
dt)
+
(Bird I to R
−
IMMUNITY LOSING
−
BR DYING) * dt
INIT BIRD RECOV
=
0
INFLOWS:
Bird I to R
=
BIRD INFECT*BIRD RECOVERY RATE
OUTFLOWS:
IMMUNITY LOSING
=
BIRD RECOV*IMMUNITY LOSS RATE
BR DYING
=
BIRD RECOV*BIRD DEATH RATE
BIRD SUSC(t)
=
BIRD SUSC(t
−
dt)
+
(IMMUNITY LOSING
+
BIRD BIRTHING
−
BIRD INFECTING
−
BS DYING) * dt
INIT BIRD SUSC
=
1000
INFLOWS:
IMMUNITY LOSING
=
BIRD RECOV*IMMUNITY LOSS RATE
