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Table 2 Parameters used for modelling the age distribution of infection, and the distribution of high intensity infections

From: Global numbers of infection and disease burden of soil transmitted helminth infections in 2010

Species Age class (in years) Age weight for prevalence Aggregation parameter ( k) Morbidity threshold1  
Light intensity2 Medium intensity High intensity
Hookworms 0-5 0.75 f(prevalence)3 1 2000 4000
  5-10 1.2 f(prevalence)3 1 2000 4000
  10-15 1.2 f(prevalence)3 1 2000 4000
  15 plus 1.0 f(prevalence)3 1 2000 4000
A. lumbricoides 0-5 0.75 0.54 - 90 250
  5-10 1.2 0.54 - 130 375
  10-15 1.2 0.54 - 180 500
  15 plus 1.0 0.54 - 180 500
T. trichiura 0-5 0.5 0.23 - 50 105
  5-10 0.75 0.23 - 75 160
  10-15 0.9 0.23 - 100 210
  15 plus 1.0 0.23 - 100 210
  1. 1Intensity of infection for hookworm is expressed in terms of eggs per gram of faeces, for A. lumricoides and T. trichiura in worm burden. 2There is insufficient evidence to quantify the impacts of light intensity infection for A. lumbricoides and T. trichiura, and as such no disability weighting is applied to this group. 3Aggregation parameter is estimated as a function of prevalence (p) : k = 0.12p + 0.175p2 + 0.0008.