Performance of a mobile phone app-based participatory syndromic surveillance system for acute febrile illness and acute gastroenteritis in rural Guatemala

Background: with their increasing availability in resource-limited settings,mobile phones may provide an important tool for participatory syndromic surveillance,in which users provide symptom data directly into a centralized database. objective: we studied the performance of a mobile phone app-based participatory syndromic surveillance system for collecting syndromic data (acute febrile illness and acute gastroenteritis) to detect dengue virus and norovirus on a cohort of children living in a low-resource and rural area of guatemala. methods: randomized households were provided with a mobile phone and asked to submit weekly reports using a symptom diary app (vigilant-e). participants reporting acute febrile illness or acute gastroenteritis answered additional questions using a decision-tree algorithm and were subsequently visited at home by a study nurse who performed a second interview and collected samples for dengue virus if confirmed acute febrile illness and norovirus if acute gastroenteritis. we analyzed risk factors associated with decreased self-reporting of syndromic data using the vigilant-e app and evaluated strategies to improve self-reporting. we also assessed agreement between self-report and nurse-collected data obtained during home visits. results: from april 2015 to june 2016,469 children in 207 households provided 471 person-years of observation. mean weekly symptom reporting rate was 78% (range 58%-89%). households with a poor (<70%) weekly reporting rate using the vigilant-e app during the first 25 weeks of observation (n=57) had a greater number of children (mean 2.8,sd 1.5 vs mean 2.5,sd 1.3; risk ratio [rr] 1.2,95% ci 1.1-1.4),were less likely to have used mobile phones for text messaging at study enrollment (61%,35/57 vs 76.7%,115/150; rr 0.6,95% ci 0.4-0.9),and were less likely to access care at the local public clinic (35%,20/57 vs 67.3%,101/150; rr 0.4,95% ci 0.2-0.6). parents of female enrolled participants were more likely to have low response rate (57.1%,84/147 vs 43.8%,141/322; rr 1.4,95% ci 1.1-1.9). several external factors (cellular tower collapse,contentious elections) were associated with periods of decreased reporting. poor response rate (<70%) was associated with lower case reporting of acute gastroenteritis,norovirus-associated acute gastroenteritis,acute febrile illness,and dengue virus-associated acute febrile illness (p<.001). parent-reported syndromic data on the vigilant-e app demonstrated agreement with nurse-collected data for fever (kappa=.57,p<.001),vomiting (kappa=.63,p<.001),and diarrhea (kappa=.61,p<.001),with decreased agreement as the time interval between parental report and nurse home visit increased (<1 day: kappa=.65-.70; ≥2 days: kappa=.08-.29). conclusions: in a resource-limited area of rural guatemala,a mobile phone app-based participatory syndromic surveillance system demonstrated a high reporting rate and good agreement between parental reported data and nurse-reported data during home visits. several household-level and external factors were associated with decreased syndromic reporting. poor reporting rate was associated with decreased syndromic and pathogen-specific case ascertainment.