Fig 2. General formula for calculating out-of-pocket payments.

• TDC = Total Direct Costs (in US$ 2005)
• NTD = Neglected Tropical Disease
• c = Country
• y = Year PS1 = Number of prevalent cases with sequela 1
• PS2 = Number of prevalent cases with sequela 2
• DCS1 = Annual direct costs sequela 1
• DCS2 = Annual direct costs sequela 2
• H = percentage of individuals seeking health care
• D = Annual discount rate (%)
• t = Time (years beyond 2010).