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Table 2 Summary of key characteristics of current schistosomiasis surveillance systems in China

From: Surveillance systems for neglected tropical diseases: global lessons from China’s evolving schistosomiasis reporting systems, 1949–2014

  NIDRS Sentinel Routine National
Active/passive Passive Active Active Active
Year initiated 1950s (1989 for schistosomiasis) 1990 1950s 1989
Reporting unit Individuals in hospitals Sentinel village Village Village
Coverage All hospitals Nine sentinel villages All villages in endemic counties 1% of villages in endemic provinces
Time frame Real-time, within 24 hours of patient diagnosis Yearly All villages sampled over ~3 years, reporting occurs at completion of each village’s survey Periodic every 6-9 years: 1989, 1995, 2004
Purpose Aid understanding of disease patterns; provide evidence for policy-making Longitudinally and objectively monitor how the schistosome-endemic situation changes over time Evaluate control measures Clarify the endemic status of schistosomiasis as established by the previous national survey
Information collected Individual cases (demographics, patient residence, diagnosis, treatment and hospital) Snail habitat, human infection prevalence and intensity, bovine infection prevalence Snail habitat, human infection prevalence Human infection prevalence and intensity, bovine infection prevalence, snail habitat
Diagnostics Clinical and laboratory IHA screen then Kato-Katz and miracidium hatch IHA screen then Kato-Katz ELISA screen then Kato-Katz
Major changes 2004: Replaced paper-based monthly or yearly reporting with internet-based real-time reporting system 2011: Added Miracidium Hatch Test to diagnostic procedure 2011: Replaced yearly reporting with internet-based parasitic disease reporting that occurs after completion of each village survey 2004: Inclusion criteria expanded to include areas with prevalence >0.5% from previous criterion of >1%
Strengths Inexpensive, Algorithms can be created to automatically detect outbreaks of emerging or reemerging disease Provides longitudinal measures of disease prevalence and intensity Provides greatest coverage since it samples all endemic villages in the province Provides a nationwide estimate of schistosomiasis prevalence
Limitations Underreporting of chronic cases; potential underreporting of acute cases due to political pressure; potential information bias associated with variable clinical and diagnostic capacities of reporting sites; non-response bias associated with reporter fatigue Sampling occurs at limited sites (20 in 1989, 80 in 2005); longitudinal follow-up over decades can yield non-response bias resulting from participation and reporter fatigue; potential selection bias associated with the choice of villages to sample longitudinally Variable clinical and diagnostic capabilities can lead to information bias; potential selection bias associated with choice of survey sites, since those in charge of surveillance are also in charge of control efforts; potential reporting bias as funding can be tied to disease control success; potential non-response bias resulting from participation fatigue and temporary rural-to-urban migration Occurs rarely and survey methods change, making it difficult to assess temporal patterns; only includes 1% of endemic villages in each province
  1. IHA: indirect hemagglutination assay; Village: administrative village, with typical population of ~1000 people.