Background
Scabies and impetigo are endemic in many tropical, low- and middle-income countries. Mass drug administration (MDA) with ivermectin has emerged as a control strategy for these conditions. In 2019, Timor-Leste Ministry of Health planned to implement MDA including ivermectin for the control of lymphatic filariasis, so we undertook a baseline assessment of scabies and impetigo to better understand local epidemiology and contribute to future surveys assessing the impact of MDA.
Methods
A cross-sectional school survey was conducted in April–May 2019 at six primary schools in a semi-urban (Dili) and two rural (Ermera and Manufahi) settings. Children under 19 years of age present at school on survey days were eligible to participate, of whom we enrolled 1183. Trained health workers interviewed and examined 1043 participants to clinically diagnose scabies using the 2020 International Alliance for the Control of Scabies (IACS) diagnostic criteria, as well as impetigo. Prevalence was adjusted for age and sex. Mixed-effects logistic regression models were used to analyse odds of scabies and impetigo infection. All models accounted for clustering at the school level through the use of random effect terms. Population attributable risk of scabies as a cause of impetigo was also estimated.
Results
The overall weighted prevalence of scabies was 30.6%. Children in rural Manufahi were more likely to have scabies than those in semi-urban Dili (53.6% vs 28.2%, adjusted odds ratio [AOR] 3.5). Most cases of scabies were mild (3 to 10 lesions), and lesions were usually distributed on more than one body region. Scabies prevalence was lower among 10 to 14 year olds compared to 5 to 9 year olds. Overall weighted prevalence of impetigo was 11.3%. Relative to Dili, children in rural Ermera and Manufahi were twice as likely to have impetigo. Impetigo was twice as common in children with scabies than in those without, corresponding to an attributable risk of scabies as a cause of impetigo of 22.7%.
Conclusions
Scabies and impetigo prevalence in Timor-Leste is among the highest reported globally, particularly in rural areas. Scabies infestation was strongly associated with impetigo. Comprehensive control strategies are urgently needed in Timor-Leste.
There is evolving interest in alternate microscopy techniques and quantitative polymerase chain reaction (qPCR) to evaluate soil-transmitted helminth (STH) burden. Using data from a cross-sectional survey of 540 schoolchildren across six primary schools in three municipalities of Timor-Leste, we compared the performance of microscopy using sodium nitrate flotation (SNF) and qPCR in determining STH prevalence and infection intensity. Prevalence by qPCR was higher than SNF for Ascaris lumbricoides (17.5% versus 11.2%), hookworm (8.3% versus 1.2%), and Trichuris trichiura (4.7% versus 1.6%). Agreement between SNF and qPCR was fair for hookworm (κ = 0.21) and moderate for A. lumbricoides (κ = 0.59) and T. trichiura (κ = 0.44). Nearly all infections were light intensity by SNF, whereas qPCR identified 36.1% as moderate or heavy infections using cycle threshold to eggs per gram conversion formulas. Quantitative polymerase chain reaction is a promising diagnostic technique, though further studies validating infection intensity correlates are required.
Strong, enduring partnerships exist between the Northern Territory and Timor-Leste, and in recent years collaborations have led to significant developments in health system capacity in Timor-Leste. Laboratory strengthening has been a key focus; improved diagnostic microbiology capability, especially in the National Health Laboratory, is having an impact on individual patient management and outcomes, epidemiological surveillance, and public health responses to communicable disease challenges including antimicrobial resistance.
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