Spatiotemporal patterns in British racing and equestrian sports: Implications for pathogen transmission

The widespread assumption that there is minimal potential for pathogen transmission between British racehorse and sport horse populations remains unverified by empirical evidence.

To characterise spatiotemporal patterns of horse attendance at racing and other sport events in Great Britain in 2018.

Spatiotemporal analysis.

Publicly available data from British Horseracing Authority, British Dressage, British Eventing, Endurance GB, and British Showjumping events in Great Britain during 2018 were analysed. Horse attendance was summarised by discipline, month, and season. Venue density was mapped with kernel density estimation. Sport venues within 5 km of racecourses with horse attendance within 24 h of racing were identified and Kulldorff's spatial scan statistic was used to detect significant time-space clustering of venue use.

Excluding showjumpers, 49,012 horses competed in 8314 events across 598 venues during 2018, generating over 400,000 horse-venue attendances. Most horses (97.2%; n = 47,635/49,012) competed in a single discipline. Venue attendances peaked in summer and were concentrated in southeast England. There were five significant space-time clusters of venue-events within 5 km and 24 h of each other involving 5 racecourses and 8 sport venues. The most likely cluster was in the southeast of England, between January and July, with a relative risk of 62.54.

Inconsistent horse identification precluded horse-level analysis of showjumping data.

Racehorse and sport horse populations competing in Great Britain are largely separate, but limited opportunities for local or indirect pathogen spread do exist during peak seasons in areas with high venue density.