Database Reference
In-Depth Information
control of this disease costs about $150 million per year. The Centers for Disease
Control predicts that global warming and the deterioration of the inner city could
increase the prevalence of the disease
1
.
Our model is based on St. Louis encephalitis in Illinois with much of the data
coming from the work of Dr. Thomas Monath, adjunct of the Harvard School of
Public Health
2
. The central guiding question is: How do different mosquito de-
velopmental thresholds affect the incidence of St. Louis encephalitis in the human
population?
Generally, we had to model three populations—humans, birds, and mosquitoes—
with the mosquito acting as the connection vector between the other two. Due to
rapid changes in the mosquito populations, the emigration schedules of birds, and
the rapidly changing temperatures, we chose a daily modeling time step with a
Julian calendar for seasonal change, precipitation, and the timing of temperature
changes. Temperature and available mosquito breeding sites (standing water) are
the conditions that determine the reproduction success of the mosquito population.
We created a simple model to produce a realistic but stochastic representation of
temperature (Figure 5.1) and standing water (Figure 5.2).
Mos1DD
M1CumDD
M1
ClearM1
Mos1Dev
T1
Annual Temp Cycle
M2CumDD
Low
Mos2DD
High
ClearM2
Mos2Dev
M3CumDD
Std of Temp
M2
T2
High
Mos3Dev
ClearM3
Mos3DD
M3
T3
Fig. 5.1
1
CDC website, Division of Vector-Borne Diseases, Domestic Arboviral Encephalitis, St. Louis
Encephalitis, 13 July 2001.
2
Monath, T.P. 1993. Arthropod-borne viruses. In: Morse, S.S., (Ed.). Emerging Viruses, Oxford
University Press, New York, pp. 138-148. See also his volume by CRC on Arboviruses, 1989.
