Stace Maples

All Publications

• Diarrheal Disease Attributed to Shigella spp. and Enteroinvasive Escherichia coli among Children at Households in Haiti: A Case-Control Study. The American journal of tropical medicine and hygiene Sriguha, I., Kuyt, S. R., Cajusma, Y., Cato, E., Brinkley, L., Sayeed, M. A., Maples, S., Beau De Rochars, V. M., Leung, D. T., Maurelli, A. T., Baril, C., Klarman, M. B., Nelson, E. J. 2025

  Abstract

  Infections from Shigella spp./enteroinvasive Escherichia coli (EIEC) are considered leading causes of diarrheal disease globally. However, there is a notable paucity of studies from Caribbean nations to guide regional public health interventions. A case-control study was conducted as part of a cross-sectional healthcare study in Haiti. Households were identified using a geospatially randomized method, and families with children under 5 years of age were consented and enrolled. Rectal swabs from child participants were tested for Shigella spp./EIEC via real-time polymerase chain reaction testing using the invasion plasmid antigen H gene target. Two case definitions were used: "diarrheal symptom" (DS) cases were defined as those reporting DSs ≤7 days ago; "acute diarrhea" (AD) cases were defined as those who also presented with ≥3 loose stools in the past 24 hours and onset <7 days ago. A total of 568 households were enrolled, and samples from 732 children were analyzed. The rates of Shigella spp./EIEC detection were 11% (22/193) and 6% (33/539) among DS cases and controls, respectively, and 19% (8/43) and 7% (47/689) among AD cases and controls, respectively. Shigella spp./EIEC was attributed to DS in 6% (95% CI: 0.4% to 11%) of cases and AD in 13% (95% CI: 0% to 25%) of cases. The adjusted odds of having DS increased by 84% (adjusted odds ratio [aOR] = 1.84; 95% CI: 1.02 to 3.27) and AD increased by 183% (aOR = 2.83; 95% CI: 1.14 to 6.36) when Shigella spp./EIEC was detected. The rates of bloody diarrhea were minimal (<1%; 6/732). In the present case-control study, the detection of Shigella spp./EIEC was common and attributed to symptomatic disease. These results align with previous global health studies. Shigella spp./EIEC represent an important public health target for intervention once the security situation improves in Haiti.

  View details for DOI 10.4269/ajtmh.25-0183

  View details for PubMedID 41187340

• Leveraging deep learning models to increase the representation of nomadic pastoralists in health campaigns and demographic surveillance. PLOS global public health Liu, B., Maples, S., Kong, J., Fava, F., Jenson, N., Chelanga, P., Charles, S., Hassell, J., Robinson, L. W., Glowacki, L., Barry, M., Wild, H. B. 2025; 5 (4): e0004018

  Abstract

  Nomadic pastoralists are systematically underrepresented in the planning of health services and frequently missed by health campaigns due to their mobility. Previous studies have developed novel geospatial methods to address these challenges but rely on manual techniques that are too time and resource-intensive to scale on a national or regional level. To address this gap, we developed a computer vision-based approach to automatically locate active nomadic pastoralist settlements from satellite imagery. We curated labeled datasets of satellite images capturing approximately 1,000 historically active settlements in the Omo Valley of Ethiopia and the Samburu County of Kenya to train and evaluate deep learning models, studying their robustness to low spatial resolutions and limits in labeled training data. Using a novel training strategy that leveraged public road and water infrastructure data, we closed performance gaps introduced by shortages in labeled settlement data. We deployed our best model on a region spanning 5,400 square kilometers in the Omo Valley of Ethiopia, resulting in the identification of historical settlements with a 270-fold reduction in manual review volume. Our work serves as a promising framework for automating the localization of nomadic pastoralist settlements at a national scale for health campaigns and demographic surveillance.

  View details for DOI 10.1371/journal.pgph.0004018

  View details for PubMedID 40273062

  View details for PubMedCentralID PMC12021161

• Opportunities to catalyse improved healthcare access in pluralistic systems: a cross-sectional study in Haiti. BMJ open Klarman, M., Schon, J., Cajusma, Y., Maples, S., Beau de Rochars, V. E., Baril, C., Nelson, E. J. 2021; 11 (11): e047367

  Abstract

  OBJECTIVE: To identify determinants of intended versus actual care-seeking behaviours in a pluralistic healthcare system that is reliant on both conventional and non-conventional providers and discover opportunities to catalyse improved healthcare access.DESIGN: Cross-sectional study.SETTING AND PARTICIPANTS: In Haiti 568 households (incorporating 2900 members) with children less than 5 years of age were randomly sampled geographically with stratifications for population density. These households identified the healthcare providers they frequented. Among 140 providers, 65 were located and enrolled.OUTCOME MEASURES: Household questionnaires with standardised cases (intentions) were compared with self-recall of health events (behaviours). The connectedness of households and their providers was determined by network analysis.RESULTS: Households reported 636 health events in the prior month. Households sought care for 35% (n=220) and treated with home remedies for 44% (n=277). The odds of seeking care increased 217% for severe events (adjusted OR (aOR)=3.17; 95% CI 1.99 to 5.05; p<0.001). The odds of seeking care from a conventional provider increased by 37% with increasing distance (aOR=1.37; 95% CI 1.06 to 1.79; p=0.016). Despite stating an intention to seek care from conventional providers, there was a lack of congruence in practice that favoured non-conventional providers (McNemar's chi2 test p<0.001). Care was sought from primary providers for 68% (n=150) of cases within a three-tiered network; 25% (n=38/150) were non-conventional.CONCLUSION: Addressing geographic barriers, possibly with technology solutions, should be prioritised to meet healthcare seeking intentions while developing approaches to connect non-conventional providers into healthcare networks when geographic barriers cannot be overcome.

  View details for DOI 10.1136/bmjopen-2020-047367

  View details for PubMedID 34810180

• High-throughput low-cost nl-qPCR for enteropathogen detection: A proof-of-concept among hospitalized patients in Bangladesh. PloS one Flaherty, K. E., Grembi, J. A., Ramachandran, V. V., Haque, F., Khatun, S., Rahman, M., Maples, S., Becker, T. K., Spormann, A. M., Schoolnik, G. K., Hryckowian, A. J., Nelson, E. J. 2021; 16 (10): e0257708

  Abstract

  BACKGROUND: Diarrheal disease is a leading cause of morbidity and mortality globally, especially in low- and middle-income countries. High-throughput and low-cost approaches to identify etiologic agents are needed to guide public health mitigation. Nanoliter-qPCR (nl-qPCR) is an attractive alternative to more expensive methods yet is nascent in application and without a proof-of-concept among hospitalized patients.METHODS: A census-based study was conducted among diarrheal patients admitted at two government hospitals in rural Bangladesh during a diarrheal outbreak period. DNA was extracted from stool samples and assayed by nl-qPCR for common bacterial, protozoan, and helminth enteropathogens as the primary outcome.RESULTS: A total of 961 patients were enrolled; stool samples were collected from 827 patients. Enteropathogens were detected in 69% of patient samples; More than one enteropathogen was detected in 32%. Enteropathogens most commonly detected were enteroaggregative Escherichia coli (26.0%), Shiga toxin-producing E.coli (18.3%), enterotoxigenic E. coli (15.5% heat stable toxin positive, 2.2% heat labile toxin positive), Shigella spp. (14.8%), and Vibrio cholerae (9.0%). Geospatial analysis revealed that the median number of pathogens per patient and the proportion of cases presenting with severe dehydration were greatest amongst patients residing closest to the study hospitals."CONCLUSIONS: This study demonstrates a proof-of-concept for nl-qPCR as a high-throughput low-cost method for enteropathogen detection among hospitalized patients.

  View details for DOI 10.1371/journal.pone.0257708

  View details for PubMedID 34597302

• Electronic decision support and diarrhoeal disease guideline adherence (mHDM): a cluster randomised controlled trial LANCET DIGITAL HEALTH Khan, A. I., Mack, J. A., Salimuzzaman, M., Zion, M. I., Sujon, H., Ball, R. L., Maples, S., Rashid, M., Chisti, M. J., Sarker, S. A., Biswas, D., Hossin, R., Bardosh, K. L., Begum, Y. A., Ahmed, A., Pieri, D., Haque, F., Rahman, M., Levine, A. C., Qadri, F., Flora, M. S., Gurka, M. J., Nelson, E. J. 2020; 2 (5): E250–E258

  Abstract

  Acute diarrhoeal disease management often requires rehydration alone without antibiotics. However, non-indicated antibiotics are frequently ordered and this is an important driver of antimicrobial resistance. The mHealth Diarrhoea Management (mHDM) trial aimed to establish whether electronic decision support improves rehydration and antibiotic guideline adherence in resource-limited settings.A cluster randomised controlled trial was done at ten district hospitals in Bangladesh. Inclusion criteria were patients aged 2 months or older with uncomplicated acute diarrhoea. Admission orders were observed without intervention in the pre-intervention period, followed by randomisation to electronic (rehydration calculator) or paper formatted WHO guidelines for the intervention period. The primary outcome was rate of intravenous fluid ordered as a binary variable. Generalised linear mixed-effect models, accounting for hospital clustering, served as the analytical framework; the analysis was intention to treat. The trial is registered with ClinicalTrials.gov (NCT03154229) and is completed.From March 11 to Sept 10, 2018, 4975 patients (75·6%) of 6577 screened patients were enrolled. The intervention effect for the primary outcome showed no significant differences in rates of intravenous fluids ordered as a function of decision-support type. Intravenous fluid orders decreased by 0·9 percentage points for paper electronic decision support and 4·2 percentage points for electronic decision support, with a 4·2-point difference between decision-support types in the intervention period (paper 98·7% [95% CI 91·8-99·8] vs electronic 94·5% [72·2-99·1]; pinteraction=0·31). Adverse events such as complications and mortality events were uncommon and could not be statistically estimated.Although intravenous fluid orders did not change, electronic decision support was associated with increases in the volume of intravenous fluid ordered and decreases in antibiotics ordered, which are consistent with WHO guidelines.US National Institutes of Health.

  View details for DOI 10.1016/S2589-7500(20)30062-5

  View details for Web of Science ID 000529152400014

  View details for PubMedID 33328057

• Africa's Nomadic Pastoralists and Their Animals Are an Invisible Frontier in Pandemic Surveillance. The American journal of tropical medicine and hygiene Hassell, J. M., Zimmerman, D. n., Fèvre, E. M., Zinsstag, J. n., Bukachi, S. n., Barry, M. n., Muturi, M. n., Bett, B. n., Jensen, N. n., Ali, S. n., Maples, S. n., Rushton, J. n., Tschopp, R. n., Madaine, Y. O., Abtidon, R. A., Wild, H. n. 2020

  Abstract

  The effects of COVID-19 have gone undocumented in nomadic pastoralist communities across Africa, which are largely invisible to health surveillance systems despite the fact that they are of key significance in the setting of emerging infectious disease. We expose these landscapes as a "blind spot" in global health surveillance, elaborate on the ways in which current health surveillance infrastructure is ill-equipped to capture pastoralist populations and the animals with which they coexist, and highlight the consequential risks of inadequate surveillance among pastoralists and their livestock to global health. As a platform for further dialogue, we present concrete solutions to address this gap.

  View details for DOI 10.4269/ajtmh.20-1004

  View details for PubMedID 32918410

• A Cluster-based, Spatial-sampling Method for Assessing Household Healthcare Utilization Patterns in Resource-limited Settings. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America Yu, A. T., Shakya, R. n., Adhikari, B. n., Tamrakar, D. n., Vaidya, K. n., Maples, S. n., Date, K. n., Bogoch, I. I., Bern, C. n., Qamar, F. n., Yousafzai, M. T., Garrett, D. O., Longley, A. T., Hemlock, C. n., Luby, S. n., Aiemjoy, K. n., Andrews, J. R. 2020; 71 (Supplement_3): S239–S247

  Abstract

  Implementation of population-based surveys is resource intensive and logistically demanding, especially in areas with rapidly changing demographics and incomplete or no enumeration of the underlying population and their residences. To remove the need for pre-enumeration and to simplify field logistics for the population healthcare utilization survey used for the Surveillance for Enteric Fever in Asia Project in Nepal, we incorporated a geographic information system-based geosurvey and field mapping system into a single-stage cluster sampling approach.A survey was administered to ascertain healthcare-seeking behavior in individuals with recent suspected enteric fever. Catchment areas were based on residential addresses of enteric fever patients using study facilities; clusters were randomly selected from digitally created grids using available satellite images and all households within clusters were offered enrollment. A tablet-compatible geosurvey and mapping system that allowed for data-syncing and use in areas without cellular data was created using the ArcGIS suite of software.Between January 2017 and November 2018, we surveyed 25 521 households in Nepal (16 769 in urban Kathmandu and 8752 in periurban Kavrepalanchok), representing 84 202 individuals. Overall, the survey participation rate was 90.9%, with geographic heterogeneity in participation rates within each catchment area. Areas with higher average household wealth had lower participation rates.A geographic information system-based geosurvey and field mapping system allowed creation of a virtual household map at the same time as survey administration, enabling a single-stage cluster sampling method to assess healthcare utilization in Nepal for the Surveillance for Enteric Fever in Asia Project . This system removed the need for pre-enumeration of households in sampling areas, simplified logistics and could be replicated in future community surveys.

  View details for DOI 10.1093/cid/ciaa1310

  View details for PubMedID 33258933

• Making Pastoralists Count: Geospatial Methods for the Health Surveillance of Nomadic Populations. The American journal of tropical medicine and hygiene Wild, H., Glowacki, L., Maples, S., Mejia-Guevara, I., Krystosik, A., Bonds, M. H., Hiruy, A., LaBeaud, A. D., Barry, M. 2019

  Abstract

  Nomadic pastoralists are among the world's hardest-to-reach and least served populations. Pastoralist communities are difficult to capture in household surveys because of factors including their high degree of mobility over remote terrain, fluid domestic arrangements, and cultural barriers. Most surveys use census-based sampling frames which do not accurately capture the demographic and health parameters of nomadic populations. As a result, pastoralists are "invisible" in population data such as the Demographic and Health Surveys (DHS). By combining remote sensing and geospatial analysis, we developed a sampling strategy designed to capture the current distribution of nomadic populations. We then implemented this sampling frame to survey a population of mobile pastoralists in southwest Ethiopia, focusing on maternal and child health (MCH) indicators. Using standardized instruments from DHS questionnaires, we draw comparisons with regional and national data finding disparities with DHS data in core MCH indicators, including vaccination coverage, skilled birth attendance, and nutritional status. Our field validation demonstrates that this method is a logistically feasible alternative to conventional sampling frames and may be used at the population level. Geospatial sampling methods provide cost-affordable and logistically feasible strategies for sampling mobile populations, a crucial first step toward reaching these groups with health services.

  View details for DOI 10.4269/ajtmh.18-1009

  View details for PubMedID 31436151

• MAKING PASTORALISTS COUNT: HEALTH SURVEILLANCE OF A NOMADIC POPULATION USING A GEOSPATIALLY DERIVED SAMPLING FRAME Wild, H., Glowacki, L., Maples, S., Mejia-Guevara, I., Hiruy, A., Krystosik, A., Bonds, M., LaBeaud, A., Barry, M. AMER SOC TROP MED & HYGIENE. 2018: 659–60

  View details for Web of Science ID 000461386605149

• DEVELOPMENT AND PRELIMINARY CLINICAL EVALUATION OF A MOBILE TECHNOLOGY FOR DIARRHEAL DISEASE OUTBREAK MANAGEMENT Nelson, E. J., Haque, F., Ball, R., Maples, S., Khatun, S., Ahmed, M., Rahman, M., Kache, S., Chisti, M., Sarker, S., Schoolnik, G., Rahman, M. AMER SOC TROP MED & HYGIENE. 2017: 538–39

  View details for Web of Science ID 000412851503270

• Evaluation of a Smartphone Decision-Support Tool for Diarrheal Disease Management in a Resource-Limited Setting. PLoS neglected tropical diseases Haque, F., Ball, R. L., Khatun, S., Ahmed, M., Kache, S., Chisti, M. J., Sarker, S. A., Maples, S. D., Pieri, D., Vardhan Korrapati, T., Sarnquist, C., Federspiel, N., Rahman, M. W., Andrews, J. R., Rahman, M., Nelson, E. J. 2017; 11 (1)

  Abstract

  The emergence of mobile technology offers new opportunities to improve clinical guideline adherence in resource-limited settings. We conducted a clinical pilot study in rural Bangladesh to evaluate the impact of a smartphone adaptation of the World Health Organization (WHO) diarrheal disease management guidelines, including a modality for age-based weight estimation. Software development was guided by end-user input and evaluated in a resource-limited district and sub-district hospital during the fall 2015 cholera season; both hospitals lacked scales which necessitated weight estimation. The study consisted of a 6 week pre-intervention and 6 week intervention period with a 10-day post-discharge follow-up. Standard of care was maintained throughout the study with the exception that admitting clinicians used the tool during the intervention. Inclusion criteria were patients two months of age and older with uncomplicated diarrheal disease. The primary outcome was adherence to guidelines for prescriptions of intravenous (IV) fluids, antibiotics and zinc. A total of 841 patients were enrolled (325 pre-intervention; 516 intervention). During the intervention, the proportion of prescriptions for IV fluids decreased at the district and sub-district hospitals (both p < 0.001) with risk ratios (RRs) of 0.5 and 0.2, respectively. However, when IV fluids were prescribed, the volume better adhered to recommendations. The proportion of prescriptions for the recommended antibiotic azithromycin increased (p < 0.001 district; p = 0.035 sub-district) with RRs of 6.9 (district) and 1.6 (sub-district) while prescriptions for other antibiotics decreased; zinc adherence increased. Limitations included an absence of a concurrent control group and no independent dehydration assessment during the pre-intervention. Despite limitations, opportunities were identified to improve clinical care, including better assessment, weight estimation, and fluid/ antibiotic selection. These findings demonstrate that a smartphone-based tool can improve guideline adherence. This study should serve as a catalyst for a randomized controlled trial to expand on the findings and address limitations.

  View details for DOI 10.1371/journal.pntd.0005290

  View details for PubMedID 28103233

• Uncovering Latent Metadata in the FSA-OWI Photographic Archive DIGITAL HUMANITIES QUARTERLY Arnold, T., Maples, S., Tilton, L., Wexler, L. 2017; 11 (2)

  View details for Web of Science ID 000406669600017

• Is a Cholera Outbreak Preventable in Post-earthquake Nepal? PLoS neglected tropical diseases Nelson, E. J., Andrews, J. R., Maples, S., Barry, M., Clemens, J. D. 2015; 9 (8): e0003961

  View details for DOI 10.1371/journal.pntd.0003961

  View details for PubMedID 26270343

• Ottoman Iceland: A Climate History ENVIRONMENTAL HISTORY Mikhail, A. 2015; 20 (2): 262-284

  View details for DOI 10.1093/envhis/emv006

  View details for Web of Science ID 000354713900005

• Reframing Ethnicity: Academic Tropes, Recognition beyond Politics, and Ritualized Action between Nepal and India AMERICAN ANTHROPOLOGIST Shneiderman, S. 2014; 116 (2): 279-295

  View details for DOI 10.1111/aman.12107

  View details for Web of Science ID 000337535600004