As disease elimination programs succeed, the remaining reservoirs of infection become increasingly focal and difficult to identify. Disparities in transmission intensity, intervention coverage and effectiveness, population shifts, and the environment may result in areas, or foci, with an elevated incidence and/or prevalence compared to their surroundings. New sampling strategies are needed to find these sites of persistent infection (aka 'hotspots') to enable the delivery of targeted treatment or monitoring. While the concept of identifying and addressing disease ‘hotspots’ has been embraced by other public health programs for quite some time (e.g., malaria), it is a relatively new and important concept for NTD programs looking to reach the final mile of disease elimination. Within the NTD community, the specific use cases and diagnostic tools used to identify hotspots may differ by disease; however, the challenge of identifying and defining the boundaries of persistent infection is a cross-cutting and pressing concern for many infectious diseases including lymphatic filariasis, onchocerciasis, trachoma, leprosy, chagas, visceral leishmaniasis, buruli ulcer, human african trypanosomiasis, yaws, and malaria.

The purpose of this 2-day meeting was to bring together statistical, epidemiological and disease-specific experts to explore and debate the different tools and approaches that might be used to identify focal areas of persistent infection in the context of disease elimination or surveillance. The ultimate goal of the meeting is to emerge with a more clearly defined set of program challenges related to the identification and delimitation of ‘hotspots’ and the accompanying sampling strategies that can be piloted through OR to address these challenges.