Mar 26, 2019; Lancet . https://doi.org/10.1016/S2214-109X(19)30072-5

Abstract

Background
Podoconiosis is a type of tropical lymphoedema that causes massive swelling of the lower limbs. The
disease is associated with both economic insecurity, due to long-term morbidity-related loss of productivity, and intense
social stigma. Reliable and detailed data on the prevalence and distribution of podoconiosis are scarce. We aimed to fill
this data gap by doing a nationwide community-based study to estimate the number of cases throughout Rwanda.

Methods
We did a population-based cross-sectional survey to determine the national prevalence of podoconiosis.
A podoconiosis case was defined as a person with bilateral, asymmetrical lymphoedema of the lower limb present for
more than 1 year, who tested negative for Wuchereria bancrofti antigen (determined by Filariasis Test Strip) and specific
IgG4 (determined by Wb123 test), and had a history of any of the associated clinical signs and symptoms. All adults
(aged ≥15 years) who resided in any of the 30 districts of Rwanda for 10 or more years were invited at the household
level to participate. Participants were interviewed and given a physical examination before Filariasis Test Strip and
Wb123 testing. We fitted a binomial mixed model combining the site-level podoconiosis prevalence with continuous
environmental covariates to estimate prevalence at unsampled locations. We report estimates of cases by district
combining our mean predicted prevalence and a contemporary gridded map of estimated population density.

Findings
Between June 12, and July 28, 2017, 1 360 612 individuals—719730 (53%) women and 640 882 (47%) men—
were screened from 80 clusters in 30 districts across Rwanda. 1143 individuals with lymphoedema were identified, of
whom 914 (80%) had confirmed podoconiosis, based on the standardised diagnostic algorithm. The overall prevalence
of podoconiosis was 68·5 per 100000 people (95% CI 41·0–109·7). Podoconiosis was found to be widespread in
Rwanda. District-level prevalence ranged from 28·3 per 100 000 people (16·8–45·5, Nyarugenge, Kigali province) to
119·2 per 100 000 people (59·9–216·2, Nyamasheke, West province). Prevalence was highest in districts in the North
and West provinces: Nyamasheke, Rusizi, Musanze, Nyabihu, Nyaruguru, Burera, and Rubavu. We estimate that
6429 (95% CI 3938–10088) people live with podoconiosis across Rwanda.

Interpretation
Despite relatively low prevalence, podoconiosis is widely distributed geographically throughout
Rwanda. Many patients are likely to be undiagnosed and morbidity management is scarce. Targeted interventions
through a well coordinated health system response are needed to manage those affected. Our findings should inform
national level planning, monitoring, and implementation of interventions.