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Table 1 The parameters used in the model along with their definitions and simulated values

From: Slaving and release in co-infection control

Parameter Definition (all rates are daily) Simulated values
P1, P2 Parasite species 1 and 2 n/a
S Susceptible host proportion Dynamic
I 1 , I 2 , I 12 Host proportions infected with P1, P2 and both Dynamic
E 1 , E 2 , E 12 Environment contaminated with P1, P2 and both Dynamic
λ 1 , λ 2 Rate at which new infections are established 0.1216328
β 1 , β 2 Rate at which hosts contaminate the environment 1.216328x10-2, x10-3
β 1 | 12 , β 2 | 12 Rate at which co-infected hosts contaminate the env. 0.1-10 x β1, x β2
α 1 , α 2 Relative susceptibility to heterologous parasite infection 0.1-10
μ Natural mortality rate of hosts (~50 yr life expectancy, parasite-induced host mortality can be modelled by μi > 0) 5.479452x10-5
ν 1 , ν 2 Mortality rates of the free-living P1 and P2 stages 0.1
γ 1 , γ 2 Host recovery rate from P1 and P2 infection (~2 yr) 1.369863x10-3
γ 1 | 12 , γ 2 | 12 Recovery rate from P1 and P2 infection when co-infected 1.369863x10-3
  1. Parameterisation was consistent with major human infections with gastro-intestinal nematodes and longevity of free-living stages mostly reflects hookworm biology [36, 38, 39]. For comparison purposes, transmission rates in the absence of between-parasite interactions were set to ensure a basic reproduction number of 1 (for P2) and 10 (for P1), but were allowed to vary across a wide range of interspecific effects. Chemotherapy was simulated by increasing the host recovery rate(s); sanitation was simulated by reducing the rate at which hosts contaminate the environment.