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TABLE A17-2Projected Health Impact-LF Related

Impact #1Individuals ProtectedDisease PreventedDALYs Averted
6.6 million newborns1.4 million cases of hydrocele3.2 million DALYs
800,000 cases of lymphedema2.8 million DALYs
4.4 million cases of subclinical disease?
Assumptions and Reasoning
  1. 66 million babies born into at-risk areas under MDA 2000-2007 (discounted for infant mortality) (PRB, 2005-2006)
  2. LF infections occur in 10% of at-risk population (Ottesen, 2006)
  3. 12.5% of LF infections result in lymphedema, 20.8% in hydrocele, 66.7% in subclinical damage (Ottesen, 2006)
  4. Disability weights (based on Global Burden of Disease methods): 0.105 for lymphedema, 0.073 for hydrocele; onset at age 20; life span is Region-specific
  5. LF transmission (estimated by mosquito infection rates) falls progressively to 50%, 25%, 12%, 6%, and 0% pre-MDA levels after each of the first 5 MDAs respectively
Impact #2Individuals ProtectedDisease PreventedDALYs Averted
9.5 million people6.0 cases of hydrocele14 million DALYs
3.5 million cases of lymphedema12 million DALYs
Assumptions and Reasoning
  1. 570 million individuals (at minimum) treated under MDAs 2000-2007. The maximal number of individuals treated in any single MDA was determined for each country. The sum of these numbers indicates the minimum total number of individuals treated.
  2. LF infections occur in 10% of at-risk (i.e., treated) population (Ottesen, 2006) (here 57 million) with 1/3 having clinical manifestations and 2/3 having subclinical disease (Ottesen, 2006) (here 38 million)
  3. To maintain this 1/3:2/3 ratio 50% of those with subclinical disease must progress to overt disease (62.5% manifesting hydrocele [11.9 million] and 37.5%, lympehedema [7.1 million]) (Ottesen, 2006)
  4. If treatment halts progression in only 50% of the subclinical cases (a conservative estimate [Shenoy et al., 2003]), 9.5 million people would have been protected from developing overt disease (6 million hydrocele; 3.5 million lymphedema)
  5. Disability weights**: 0.105 for lymphedema, 0.073 for hydrocele; onset at age 20; life span, Region-specific
  6. Treated individuals will not become re-infected in context of diminished LF transmission in MDA-covered areas

doi: 10.1371/journal.pntd.0000317.t002


Cover of The Causes and Impacts of Neglected Tropical and Zoonotic Diseases
The Causes and Impacts of Neglected Tropical and Zoonotic Diseases: Opportunities for Integrated Intervention Strategies.
Institute of Medicine (US) Forum on Microbial Threats.
Washington (DC): National Academies Press (US); 2011.
Copyright © 2011, National Academy of Sciences.

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