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. 2014 May 2;4:4846. doi: 10.1038/srep04846

Table 1. Description of parameters and variables in model (5).

Parameters Value Unit Comments resource
Am(t)   week−1 The immigration number of migratory bird  
Am1 [3 × 106, 1 × 107] year−1 The immigration number of migratory bird Assumed
Aw1 [5 × 1010/520, 5 × 109/520] week−1 The average birth number of resident bird. Assumed
Ap (1.0438 × 109)/8 week−1 The birth number of domestic fowl. [a]
Ah (2.269741 × 108)/70/52 week−1 The birth number of human. 24
dm(t)   week−1 The emigration rate of migratory bird.  
dw 1/520 week−1 The natural mortality rate of resident bird. [b]
dp 1/8 week−1 The sale rate of domestic fowl. [c]
dh 1/70/52 week−1 The natural death rate of human. [d]
βmm   week−1 Im(t)-to-Sm(t) transmission rate.  
βm   week−1 Vm(t)-to-Sm(t) transmission rate.  
βwm   week−1 Vw(t)-to-Sm(t) transmission rate.  
βww   week−1 Iw(t)-to-Sw(t) transmission rate.  
βw   week−1 Vw(t)-to-Sw(t) transmission rate.  
βmw   week−1 Vm(t)-to-Sw(t) transmission rate.  
βpw   week−1 Vp(t)-to-Sw(t) transmission rate.  
βpp   week−1 Ip(t)-to-Sp(t) transmission rate.  
βp   week−1 Vp(t)-to-Sp(t) transmission rate.  
βwp   week−1 Vw(t)-to-Sp(t) transmission rate.  
βph   week−1 Ip(t)-to-Sh(t) transmission rate.  
βh   week−1 Vp(t)-to-Sh(t) transmission rate.  
p   week−1 Confirmed rate of the infected population.  
rm [1, 10] week−1 The discharging quantity of H7N9 virus by Im. Assumed
rw [1, 10] week−1 The discharging quantity of H7N9 virus by Iw. Assumed
rp [1, 10] week−1 The discharging quantity of H7N9 virus by Ip. Assumed
δ(T(t))   week−1 The natural mortality rate of virus.  
q 0.8 × 7 week−1 The effective disinfection rate. [e]
σh 7/3.3 week−1 The reciprocal of the incubation period. 21
μh 0.36 week−1 The mortality rate of human caused by H7N9. 21
φm [1/4, 2] week−1 The recovery rate of migrant birds. Assumed
φw [1/4, 2] week−1 The recovery rate of resident birds. Assumed
φp [1/4, 2] week−1 The recovery rate of domestic poultry. Assumed
φh   week−1 The recovery rate of human.  
Sm(0) Am1 individual The initial number of the susceptible migratory bird.  
Im(0)   individual The initial number of the infective migratory bird.  
Sw(0) Aw1/dw individual The initial number of the susceptible resident bird.  
Iw(0)   individual The initial number of the infective resident bird.  
Sp(0) 1.0483 × 109 individual The initial number of the susceptible domestic fowl. [a]
Ip(0)   individual The initial number of the infective domestic fowl.  
Sh(0) 2.269741 × 108 IU The initial number of the susceptible human. 25
Eh(0) 0 individual The initial number of the exposed human.  
Ih(0) 0 individual The initial number of the infected human.  
Vm(0) 0 individual The initial quantity of H7N9 virus in environment discharged by migrant birds.  
Vw(0) 0 individual The initial quantity of H7N9 virus in environment discharged by resident bird.  
Vp(0) 0 individual The initial quantity of H7N9 virus in environment discharged by poultry.  

[a]The Laboratory of Animal Epidemiological Surveillance, China Animal Health & Epidemiology Center, Qingdao, Shandong, People's Republic of China.

[b]The lifetime of passerine birds, which will mature earlier, is only three or four years old. Large birds, such as eagle, eagle, etc., will need 8 to 11 years to arrive sexual maturity. In this paper, the average lifetime of resident birds is taken as 10 years.

[c]When domestic poultry grow to 8 weeks, they are the most flesh and will be sold by farmers. So, the sale coefficient is .

[d]dh is the reciprocal of the lifetime of human and the lifetime of human is taken as 70 years.

[e]Assuming the effective disinfection rate in every disinfection is 80% and trading markets are disinfected every day, the disinfection rate every week is 7 × 0.8.