Dengue Outbreak Transmission Risk Simulator
Motivated by Florida county emergency declarations over unseasonal dengue clustering, this clinical vector modeling tool computes Ross-Macdonald Vectorial Capacity (C), dynamic Basic Reproduction Number (R₀), and coupled SEIR-SEI host-mosquito epidemic waves.
Transmission Metrics & Epidemic Trajectory
120-Day Horizon IntegrationCoupled SEIR-SEI Dynamics Over Time
Intervention Impact Assessment Matrix
| Intervention Strategy | Effective R₀ | Peak Daily Cases | Attack Rate | Containment Status |
|---|
Mathematical Transmission Foundation
Dengue transmission does not propagate person-to-person directly. It relies on the Aedes aegypti or Aedes albopictus vector biting an infectious human during the viremic window, surviving the temperature-dependent extrinsic incubation period (n), and taking subsequent blood meals on susceptible humans.
C = (m * a² * pⁿ) / -ln(p)
Basic Reproductive Rate (Ross-Macdonald):
R₀ = (m * a² * b * c * pⁿ) / (r * μ_v) = (C * b * c) / r
where:
m = vector-to-human ratio
a = daily human biting rate
p = daily vector survival probability
n = extrinsic incubation period (EIP) days
b, c = transmission efficiency constants (human ↔ vector)
r = human viral clearance rate (~0.2 /day)
Public Health Countermeasures & Florida Declarations
Why did Florida declare county emergencies?
When summer and autumn temperatures remain above 28°C with elevated humidity and standing rainwater, the extrinsic incubation period shrinks from ~15 days down to under 8 days. Because mosquito lifespan is short, a shorter EIP exponentially increases the proportion (pⁿ) of vectors that survive to become infectious, triggering rapid community clustering.
Vector Control Mechanics: Adulticiding vs. Larviciding
Adulticiding (fogging) directly depresses daily mosquito survival p. Because p appears to the power n in the numerator and in the denominator as -ln(p), even modest reductions in adult survival (e.g., from 0.88 to 0.76) yield precipitous drops in R₀, often bringing it below the critical threshold of 1.0. Larviciding reduces recruitment density m linearly.
Model Assumptions and Verification
This simulator integrates a deterministic coupled 7-compartment ordinary differential equation system (Susceptible, Exposed, Infectious, Recovered humans; Susceptible, Latent, Infectious vectors) numerically across a 120-day horizon using Euler integration at dt = 0.05 days.