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Table 1 Parameter values estimated using maximum likelihood methods and used in the numerical evaluations of model predictions for each parasite

From: What impact will the achievement of the current World Health Organisation targets for anthelmintic treatment coverage in children have on the intensity of soil transmitted helminth infections?

Parameter Ascaris Trichuris Hookworm Source
Basic Reproductive number, R0 2.12 1.72 2.34 Fitted
Adult worm life expectancy 1 year 1 year 2 years [12]
Negative binomial clumping parameter, k 0.90 0.38 0.35 Fitted
Density dependence fecundity parameter, ɣ 0.07 0.0035 0.08 Fitted
Age-specific transmission parameter, βi for age group i’s contact with infectious reservoir. Relative egg contribution by age, ρi, proportional to βi. 0.22, 1.88, 1, 0.53 0.5, 2.13, 1, 0.28 0.03, 0.09, 1, 2.5 Fitted
Drug efficacy as a proportion of worms killed by Albendazole 0.99 0.50 0.95 [14]
Source of age - mean intensity profile for fitting Elkins et al. South India [15] Bundy et al. St Lucia [20] Bradley et al. Zimbabwe [17] -
  1. The age intensity profiles from the cited sources based on worm expulsion were used to derive estimate of R0, βi and k. The values of ɣ were derived from egg per gram of faeces and worm expulsion counts [transmission age groups: Ascaris and hookworm: 0–2;2–5;5–15;15+; Trichuris: 0–2;2–7;7–12;12+]