Unprogrammed Deworming in the Kibera Slum,Nairobi: Implications for Control of Soil-Transmitted Helminthiases

Background: programs for control of soil-transmitted helminth (sth) infections are increasingly evaluating national mass drug administration (mda) interventions. however,“unprogrammed deworming” (receipt of deworming drugs outside of nationally-run sth control programs) occurs frequently. failure to account for these activities may compromise evaluations of mda effectiveness. methods: we used a cross-sectional study design to evaluate sth infection and unprogrammed deworming among infants (aged 6–11 months),preschool-aged children (psac,aged 1–4 years),and school-aged children (sac,aged 5–14 years) in kibera,kenya,an informal settlement not currently receiving nationally-run mda for sth. sth infection was assessed by triplicate kato-katz. we asked heads of households with randomly-selected children about past-year receipt and source(s) of deworming drugs. local non-governmental organizations (ngos) and school staff participating in school-based deworming were interviewed to collect information on drug coverage. results: of 679 children (18 infants,184 psac,and 477 sac) evaluated,377 (55%) reported receiving at least one unprogrammed deworming treatment during the past year. psac primarily received treatments from chemists (48.3%) or healthcare centers (37.7%); sac most commonly received treatments at school (55.0%). four ngos reported past-year deworming activities at 47 of >150 schools attended by children in our study area. past-year deworming was negatively associated with any-sth infection (34.8% vs 45.4%,p = 0.005). sac whose most recent deworming medication was sourced from a chemist were more often infected with trichuris (38.0%) than those who received their most recent treatment from a health center (17.3%) or school (23.1%) (p = 0.05). conclusion: unprogrammed deworming was received by more than half of children in our study area,from multiple sources. both individual-level treatment and unprogrammed preventive chemotherapy may serve an important public health function,particularly in the absence of programmed deworming; however,they may also lead to an overestimation of programmed mda effectiveness. a standardized,validated tool is needed to assess unprogrammed deworming. © 2015 this is an open access article,free of all copyright,and may be freely reproduced,distributed,transmitted,modified,built upon,or otherwise used by anyone for any lawful purpose.