Dataset Information

A first nation-wide assessment of soil-transmitted helminthiasis in Fijian primary schools, and factors associated with the infection, using a lymphatic filariasis transmission assessment survey as surveillance platform.

ABSTRACT: BACKGROUND:Soil-transmitted helminthiasis (STH) is endemic in Fiji but its prevalence is not known and likely to have changed after a decade of mass drug administration (MDA) for lymphatic filariasis (LF). By linking with LF transmission assessment surveys (LF-TAS), we undertook the first nation-wide assessment of STH in Fijian primary schools, as well as an analysis of factors associated with STH infections. METHODOLOGY/PRINCIPAL FINDINGS:A cross-sectional assessment for STH was conducted in all four Divisions of Fiji from 2014 to 2015. In the Western, Central, and Northern Divisions, schools were sub-sampled after LF-TAS, while, in the Eastern Division, schools were selected via simple random sampling. For the diagnosis of STH, stool samples were examined by coproscopy with a single Kato-Katz thick smear (KK) and the formol-ether-acetate concentration technique, except for the samples from the Eastern Division where only KK was used. Mean prevalence of any STH among class 1-2 students at the national level was 10.5% (95% CI: 6.9-15.5). Across the three Divisions via LF-TAS, the prevalence levels for ascariasis were 8.7% (95% CI: 4.3-16.6), hookworm 3.9% (95% CI: 2.3-6.6) and trichuriasis 0%. In the Eastern Division, ascariasis prevalence was 13.3% (95% CI: 6.4-25.6), and hookworm 0.7% (95% CI: 0.2-2.5), with one case of trichuriasis. Among class 3-8 students, ascariasis prevalence was lower. Lower risk of any STH was associated with wearing shoes (adjusted OR 0.54, 95% CI: 0.32-0.90) and having piped water from the Fiji Water Authority at home (adjusted OR 0.48, 95% CI: 0.25-0.92). CONCLUSIONS:After a decade of community-based LF-MDA, STH in school-age children in Fiji is now close to 10%, but localities of endemicity remain. Preventive chemotherapy should be maintained in areas with elevated STH prevalence alongside targeted delivery of integrated WASH interventions. LF-TAS has provided an opportunity to develop future public health surveillance platforms.

SUBMITTER: Kim SH

PROVIDER: S-EPMC7518615 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature

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A first nation-wide assessment of soil-transmitted helminthiasis in Fijian primary schools, and factors associated with the infection, using a lymphatic filariasis transmission assessment survey as surveillance platform.

Kim Sung Hye SH Stothard J Russell JR Rinamalo Milika M Rainima-Qaniuci Meleresita M Talemaitoga Nemani N Kama Mike M Rafai Eric E Jang Seoyun S Kim Ji Young JY Oh Yoo Min YM Kim Eun-Min EM Hong Sung-Tae ST Lowry John H JH Verweij Jaco J JJ Kelly-Hope Louise A LA Choi Min-Ho MH

PLoS neglected tropical diseases 20200925 9

<h4>Background</h4>Soil-transmitted helminthiasis (STH) is endemic in Fiji but its prevalence is not known and likely to have changed after a decade of mass drug administration (MDA) for lymphatic filariasis (LF). By linking with LF transmission assessment surveys (LF-TAS), we undertook the first nation-wide assessment of STH in Fijian primary schools, as well as an analysis of factors associated with STH infections.<h4>Methodology/principal findings</h4>A cross-sectional assessment for STH was ...[more]

PMID: 32976499

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Project description:BackgroundMass drug administration (MDA) for lymphatic filariasis (LF) programs has delivered more than 2 billion treatments of albendazole, in combination with either ivermectin or diethylcarbamazine, to communities co-endemic for soil-transmitted helminthiasis (STH), reducing the prevalence of both diseases. A transmission assessment survey (TAS) is recommended to determine if MDA for LF can be stopped within an evaluation unit (EU) after at least five rounds of annual treatment. The TAS also provides an opportunity to simultaneously assess the impact of these MDAs on STH and to determine the frequency of school-based MDA for STH after community-wide MDA is no longer needed for LF.Methodology/principal findingsPilot studies conducted in Benin and Tonga assessed the feasibility of a coordinated approach. Of the schools (clusters) selected for a TAS in each EU, a subset of 5 schools per STH ecological zone was randomly selected, according to World Health Organization (WHO) guidelines, for the coordinated survey. In Benin, 519 children were sampled in 5 schools and 22 (4.2%) had STH infection (A. lumbricoides, T. trichiura, or hookworm) detected using the Kato-Katz method. All infections were classified as light intensity under WHO criteria. In Tonga, 10 schools were chosen for the coordinated TAS and STH survey covering two ecological zones; 32 of 232 (13.8%) children were infected in Tongatapu and 82 of 320 (25.6%) in Vava'u and Ha'apai. All infections were light-intensity with the exception of one with moderate-intensity T. trichiura.ConclusionsSynchronous assessment of STH with TAS is feasible and provides a well-timed evaluation of infection prevalence to guide ongoing treatment decisions at a time when MDA for LF may be stopped. The coordinated field experiences in both countries also suggest potential time and cost savings. Refinement of a coordinated TAS and STH sampling methodology should be pursued, along with further validation of alternative quantitative diagnostic tests for STH that can be used with preserved stool specimens.

Project description:BackgroundBurkina Faso is endemic with soil-transmitted helminth infections. Over a decade of preventive chemotherapy has been implemented through annual lymphatic filariasis (LF) mass drug administration (MDA) for population aged five years and over, biennial treatment of school age children with albendazole together with schistosomiasis MDA and biannual treatment of pre-school age children through Child Health Days. Assessments were conducted to evaluate the current situation and to determine the treatment strategy for the future.Methodology/principal findingsA cross-sectional assessment was conducted in 22 sentinel sites across the country in 2013. In total, 3,514 school age children (1,748 boys and 1,766 girls) were examined by the Kato-Katz method. Overall, soil-transmitted helminth prevalence was 1.3% (95% CI: 1.0-1.8%) in children examined. Hookworm was the main species detected, with prevalence of 1.2% (95% CI: 0.9-1.6%) and mean egg counts of 2.1 epg (95% CI: 0-4.2 epg). Among regions, the Centre Ouest region had the highest hookworm prevalence of 3.4% (95% CI: 1.9-6.1%) and mean egg counts of 14.9 epg (95% CI: 3.3-26.6 epg). A separate assessment was conducted in the Centre Nord region in 2014 using community-based cluster survey design during an LF transmission assessment survey (TAS). In this assessment, 351 children aged 6-7 years and 345 children aged 10-14 years were examined, with two cases (0.6% (95% CI: 0.2-2.1%)) and seven cases (2.0% (95% CI: 1.0-4.1%)) of hookworm infection was identified respectively. The results using both age groups categorized the region to be 2% to <10% in STH prevalence according to the pre-defined cut-off values.Conclusions/significanceThrough large-scale preventive chemotherapy, Burkina Faso has effectively controlled STH in school age children in the country. Research should be conducted on future strategies to consolidate the gain and to interrupt STH transmission in Burkina Faso. It is also demonstrated that LF TAS provides one feasible and efficient platform to assess the STH situation for post LF MDA decision making.

Project description:BackgroundAchieving target coverage levels for mass drug administration (MDA) is essential to elimination and control efforts for several neglected tropical diseases (NTD). To ensure program goals are met, coverage reported by drug distributors may be validated through household coverage surveys that rely on respondent recall. This is the first study to assess accuracy in such surveys.Methodology/principal findingsRecall accuracy was tested in a series of coverage surveys conducted at 1, 6, and 12 months after an integrated MDA in Togo during which three drugs (albendazole, ivermectin, and praziquantel) were distributed. Drug distribution was observed during the MDA to ensure accurate recording of persons treated during the MDA. Information was obtained for 506, 1131, and 947 persons surveyed at 1, 6, and 12 months, respectively. Coverage (defined as the percentage of persons taking at least one of the MDA medications) within these groups was respectively 88.3%, 87.4%, and 80.0%, according to the treatment registers; it was 87.9%, 91.4% and 89.4%, according to survey responses. Concordance between respondents and registers on swallowing at least one pill was >95% at 1 month and >86% at 12 months; the lower concordance at 12 months was more likely due to difficulty matching survey respondents with the year-old treatment register rather than inaccurate responses. Respondents generally distinguished between pills similar in appearance; concordance for recall of which pills were taken was over 80% in each survey.SignificanceIn this population, coverage surveys provided remarkably consistent coverage estimates for up to one year following an integrated MDA. It is not clear if similar consistency will be seen in other settings, however, these data suggest that in some settings coverage surveys might be conducted as much as one year following an MDA without compromising results. This might enable integration of post-MDA coverage measurement into large, multipurpose, periodic surveys, thereby conserving resources.

Project description:BACKGROUND:During the past 20 years, enormous efforts have been expended globally to eliminate lymphatic filariasis (LF) through mass drug administration (MDA). However, small endemic foci (microfoci) of LF may threaten the presumed inevitable decline of infections after MDA cessation. We conducted microsimulation modeling to assess the ability of different types of surveillance to identify microfoci in these settings. METHODS:Five or ten microfoci of radius 1, 2, or 3 km with infection marker prevalence (intensity) of 3, 6, or 10 times background prevalence were placed in spatial simulations, run in R Version 3.2. Diagnostic tests included microfilaremia, immunochromatographic test (ICT), and Wb123 ELISA. Population size was fixed at 360,000 in a 60 x 60 km area; demographics were based on literature for Sub-Saharan African populations. Background ICT prevalence in 6-7 year olds was anchored at 1.0%, and the prevalence in the remaining population was adjusted by age. Adults≥18 years, women aged 15-40 years (WCBA), children aged 6-7 years, or children≤5 years were sampled. Cluster (CS), simple random sampling (SRS), and TAS-like sampling were simulated, with follow-up testing of the nearest 20, 100, or 500 persons around each infection-marker-positive person. A threshold number of positive persons in follow-up testing indicated a suspected microfocus. Suspected microfoci identified during surveillance and actual microfoci in the simulation were compared to obtain a predictive value positive (PVP). Each parameter set was referred to as a protocol. Protocols were scored by efficiency, defined as the most microfoci identified, the fewest persons requiring primary and follow-up testing, and the highest PVP. Negative binomial regression was used to estimate aggregate effects of different variables on efficiency metrics. RESULTS:All variables were significantly associated with efficiency metrics. Additional follow-up tests beyond 20 did not greatly increase the number of microfoci detected, but significantly negatively impacted efficiency. Of 3,402 protocols evaluated, 384 (11.3%) identified all five microfoci (PVP 3.4-100.0%) and required testing 0.73-35.6% of the population. All used SRS and 378 (98.4%) only identified all five microfoci if they were 2-3 km diameter or high-intensity (6x or 10x); 374 (97.4%) required ICT or Wb123 testing to identify all five microfoci, and 281 (73.0%) required sampling adults or WCBA. The most efficient CS protocols identified two (40%) microfoci. After limiting to protocols with 1-km radius microfoci of 3x intensity (n = 378), eight identified all five microfoci; all used SRS and ICT and required testing 31.2-33.3% of the population. The most efficient CS and TAS-like protocols as well as those using microfilaremia testing identified only one (20%) microfocus when they were limited to 1-km radius and 3x intensity. CONCLUSION:In this model, SRS, ICT, and sampling of adults maximized microfocus detection efficiency. Follow-up sampling of more persons did not necessarily increase protocol efficiency. Current approaches towards surveillance, including TAS, may not detect small, low-intensity LF microfoci that could remain after cessation of MDA. The model provides many surveillance protocols that can be selected for optimal outcomes.

Project description:BackgroundThe Global Programme to Eliminate Lymphatic Filariasis (GPELF) was launched in response to the call proposed at the 50th World Health Assembly. The goal of the GPELF is to ensure that all the countries where the disease is endemic would have been transmission-free or would have entered post-intervention mass drug administration (MDA) surveillance by 2020. However, several countries are still not on track to discontinue MDA as planned. Thus, issues remain regarding the achievement of stated goals and how to effectively monitor the disease in the post-control and post-elimination phases.Main textChina was once a lymphatic filariasis (LF) endemic country with heavy disease burden. There were three milestones in the LF control phase of China, including: the proposal that the major focus of the control strategy should be on infectious sources; the three regimens of diethylcarbamazine (DEC) administration according to LF endemic extent; and the establishment of the threshold for LF transmission interruption. It has been ten years since China entered the post-elimination stage (declaration of LF elimination in China was in 2007). Two schemes and a diagnostic criterion were issued to guide all levels of disease control and prevention workers that conduct LF surveillance, as well as those caring for chronic filariasis patients. Regular training courses are held to maintain LF control skills in grass-root institutions. The Notifiable Diseases Reporting System, which included LF in 2004, plays an important role in LF post-elimination surveillance. Until now, no resurgence of LF cases has been detected, except for LF residue foci being found in Fuchuan County of the Guangxi Zhuang Autonomous Region. To confirm that transmission is no longer achievable after a decade since the declaration of LF elimination in China, it is expected within the next two years a transmission assessment survey, conducted in previous LF-endemic areas.ConclusionsDEC-fortified salt can help accelerate the progress of GPELF before the sprite phase. Sophisticated diagnostic criteria, systematic surveillance regimes, the Direct Network Report system, and regular trainings can effectively prevent the recrudescence of LF during surveillance phases.

Project description:BackgroundMathematical models are increasingly being used to evaluate strategies aiming to achieve the control or elimination of parasitic diseases. Recently, owing to growing realization that process-oriented models are useful for ecological forecasts only if the biological processes are well defined, attention has focused on data assimilation as a means to improve the predictive performance of these models.Methodology and principal findingsWe report on the development of an analytical framework to quantify the relative values of various longitudinal infection surveillance data collected in field sites undergoing mass drug administrations (MDAs) for calibrating three lymphatic filariasis (LF) models (EPIFIL, LYMFASIM, and TRANSFIL), and for improving their predictions of the required durations of drug interventions to achieve parasite elimination in endemic populations. The relative information contribution of site-specific data collected at the time points proposed by the WHO monitoring framework was evaluated using model-data updating procedures, and via calculations of the Shannon information index and weighted variances from the probability distributions of the estimated timelines to parasite extinction made by each model. Results show that data-informed models provided more precise forecasts of elimination timelines in each site compared to model-only simulations. Data streams that included year 5 post-MDA microfilariae (mf) survey data, however, reduced each model's uncertainty most compared to data streams containing only baseline and/or post-MDA 3 or longer-term mf survey data irrespective of MDA coverage, suggesting that data up to this monitoring point may be optimal for informing the present LF models. We show that the improvements observed in the predictive performance of the best data-informed models may be a function of temporal changes in inter-parameter interactions. Such best data-informed models may also produce more accurate predictions of the durations of drug interventions required to achieve parasite elimination.SignificanceKnowledge of relative information contributions of model only versus data-informed models is valuable for improving the usefulness of LF model predictions in management decision making, learning system dynamics, and for supporting the design of parasite monitoring programmes. The present results further pinpoint the crucial need for longitudinal infection surveillance data for enhancing the precision and accuracy of model predictions of the intervention durations required to achieve parasite elimination in an endemic location.

Dataset Information

A first nation-wide assessment of soil-transmitted helminthiasis in Fijian primary schools, and factors associated with the infection, using a lymphatic filariasis transmission assessment survey as surveillance platform.

Publications

A first nation-wide assessment of soil-transmitted helminthiasis in Fijian primary schools, and factors associated with the infection, using a lymphatic filariasis transmission assessment survey as surveillance platform.

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