High-Resolution Spatial Surveillance of Sexually Transmitted Disease Risk in Urban Japan Using Hierarchical Hexagonal...

Area of Science:

• Public Health
• Geographic Information Systems
• Epidemiology

Background:

• Sexually transmitted diseases (STDs) require urgent public health interventions.
• Existing surveillance methods may lack the spatial resolution to capture localized risk behaviors and short-term fluctuations.

Purpose of the Study:

• To evaluate the utility of hierarchical hexagonal grids (H3) and Quantum Geographic Information System (QGIS) for anonymously monitoring STD-related risk behaviors.
• To assess the method's ability to capture localized clustering and short-term fluctuations with high spatial resolution.

Main Methods:

• A field survey collected GPS data (date, time, location, gender) of estimated commercial sex workers and involved males in an urban Japanese district.
• Data were processed in QGIS and aggregated using H3 resolutions 13 (43.9 m²) and 14 (6.3 m²).
• Observed fluctuations during a police intervention were analyzed.

Main Results:

• H3 resolution 14 detected small clusters (up to four observations) near intersections; resolution 13 revealed broader patterns.
• Spatial clustering varied by time and gender.
• A police intervention caused a ~70% temporary reduction in observations, followed by a rapid recovery, visualized on the H3 grid.

Conclusions:

• High-resolution H3 and QGIS analysis offers a practical, anonymous method for monitoring spatial dynamics of STD risk behaviors.
• The approach is independent of administrative boundaries, enhancing generalizability for infectious disease surveillance.
• This method supports evidence-based public health nursing and flexible responses to infection trends.