A neglected sand-flea disease gets its first global burden estimate

Tungiasis, a parasitic skin disease caused by sand fleas that burrow into the feet, has been given its first global burden estimate — and the number is not small. Researchers modelling the disease across endemic countries put the loss at up to 379,645 disability-adjusted life-years (DALYs) a year (95% uncertainty interval 361,792–398,309), rising to 575,298 (548,948–602,597) once secondary complications are included [s1].

The gap the study fills is the striking part. Tungiasis has been on WHO's official list of neglected tropical diseases, and named in the agency's 2021–2030 road map, since 2021, yet its burden had never actually been estimated [s1][s2]. That absence is itself a symptom of neglect: a disease that generates no burden figure tends to generate no funding, no targets and no place in national plans.

What the disease is

Tungiasis is a zoonotic skin infection endemic to sub-Saharan Africa and Latin America, caused by fleas of the genus Tunga that embed themselves in the skin — most often through the feet, after contact with infested soil [s1]. The embedded flea triggers inflammation, intense itching and pain, and can open the door to secondary bacterial or viral infection, gangrene and lasting disfigurement [s1]. It is a disease of poverty in the most literal sense: it concentrates in poor rural communities and in crowded, unhygienic settlements, tracking the same deprivation that drives so much of the neglected-disease agenda [s1].

How the estimate was built

Because tungiasis is not routinely counted, the authors had to model it rather than tally cases. They used a prevalence-based DALY approach centred on years lived with disability, drawing prevalence ranges from a scattered and highly variable body of local reports [s1]. To handle that heterogeneity they fitted a Bayesian hierarchical model and ran a Monte Carlo simulation of 1,000 iterations across a 52-week period, producing mean DALY estimates for each endemic country with uncertainty intervals attached [s1].

That method is a strength and a caveat at once. It is the honest way to produce a first number from patchy data — the wide machinery of uncertainty intervals is doing real work — but it also means the estimate rests on the quality of underlying prevalence surveys, which are uneven. The figure should be read as a first, deliberately uncertain benchmark, not a precise count.

Where the burden falls

The burden is heavily concentrated. Adjusted for population size, the model estimates 24.2 DALYs lost per 100,000 people each year, or 36.4 once comorbidities are counted, with the weight of disease falling on sub-Saharan Africa and, in Latin America, on Brazil [s1]. Within the African region the burden is driven by large at-risk populations — rural communities and urban slum dwellers living inside the ecological zone where the flea transmits [s1].

To place the figure, the authors compare it against other neglected diseases whose burden is already recognised: in absolute terms tungiasis is comparable to soil-transmitted helminths and echinococcosis, and greater than toxocariasis and fascioliasis [s1]. That comparison is the argument. Diseases in that band attract control programmes and research funding; tungiasis, lacking a burden number until now, largely has not.

Why a number changes things

A burden estimate is not a treatment, but in the political economy of neglected diseases it is often the precondition for one. Elimination and control targets, the kind WHO's road map sets out, need a baseline to measure against, and donors and health ministries allocate against quantified need [s2]. Tungiasis is preventable and treatable — it is fundamentally a disease of housing, footwear and sanitation — which is what makes an unmeasured burden a particular waste [s1].

The estimate places tungiasis among the neglected diseases that carry real, quantified weight yet still lack the attention given to the onchocerciasis and guinea-worm elimination efforts that dominate the neglected-disease headlines, and alongside the access gaps in snakebite care that keep other skin- and bite-related conditions off the priority list. The next step the authors implicitly call for is the same one that moved better-known diseases forward: turn a first modelled figure into the routine surveillance that would let it be counted properly.

Sources

• Estimation of the global burden of tungiasis in endemic countries using a disability adjusted life-years modelling approach — BMC Global and Public Health, 31 August 2026
• Ending the neglect to attain the Sustainable Development Goals: a road map for neglected tropical diseases 2021-2030 — World Health Organization, 2021