This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: 3. Pure SIVS (commonly called SIRS) epidemic dS dt = IS + V dI dt = IS I = I ( S ) dV dt = I V dN dt = dS dt + dI dt + dV dt = N ( t ) = N V = N ( S + I ) dS dt = IS + N ( S + I ) ( ) Thus we have a dynamic system in variables S and I (2 nd and last eqs.) Susceptible nullcline: dS dt = IS + N ( S + I ) ( ) = IS + I = N S ( ) I = N S ( ) S + Infectious nullcline: dI dt = I =0 or S = / . S I ! / " N...
View Full Document
- Fall '10