Mathematical Modeling of Programmatic Requirements for Yaws Eradication

Emerg Infect Dis. 2017 Jan;23(1):22-28. doi: 10.3201/eid2301.160487.

Abstract

Yaws is targeted for eradication by 2020. The mainstay of the eradication strategy is mass treatment followed by case finding. Modeling has been used to inform programmatic requirements for other neglected tropical diseases and could provide insights into yaws eradication. We developed a model of yaws transmission varying the coverage and number of rounds of treatment. The estimated number of cases arising from an index case (basic reproduction number [R0]) ranged from 1.08 to 3.32. To have 80% probability of achieving eradication, 8 rounds of treatment with 80% coverage were required at low estimates of R0 (1.45). This requirement increased to 95% at high estimates of R0 (2.47). Extending the treatment interval to 12 months increased requirements at all estimates of R0. At high estimates of R0 with 12 monthly rounds of treatment, no combination of variables achieved eradication. Models should be used to guide the scale-up of yaws eradication.

Keywords: MDA; NTDs; Treponema pallidum; bacteria; bacterial infection; eradication; mass drug administration; mathematical modelling; neglected tropical diseases; yaws.

MeSH terms

  • Anti-Bacterial Agents / therapeutic use*
  • Azithromycin / therapeutic use*
  • Computer Simulation
  • Disease Eradication / methods
  • Disease Eradication / statistics & numerical data*
  • Female
  • Humans
  • Male
  • Markov Chains
  • Models, Statistical*
  • Neglected Diseases / epidemiology
  • Neglected Diseases / prevention & control*
  • Recurrence
  • Treponema pallidum / pathogenicity
  • Treponema pallidum / physiology
  • Tropical Climate
  • Yaws / epidemiology
  • Yaws / prevention & control*
  • Yaws / transmission

Substances

  • Anti-Bacterial Agents
  • Azithromycin