Verifying interruption of transmission or elimination of Schistosoma japonicum must consider schistosome infections in wild rodents.

Abstract

Following the exciting announcement that Anhui Province, one of the historically most heavily Schistosoma japonicum endemic regions in China, has been officially declared to have achieved the goal of province-wide transmission interruption of schistosomiasis, we raise two concerns that merit further consideration. Firstly, S. japonicum is zoonotic, and in China it is known that humans, livestock, and wild animals such as rodents are major reservoirs of infection. While S. japonicum infections both in humans and bovines have recently been reduced to zero prevalence, infection persists at moderate to high levels within rodents with, for example, prevalence's reported of up to 12.81% within Anhui Province over last 5 years. Therefore, surveillance of schistosome infections in wild animals, at least in rodents, must be included in the criteria of verifying transmission interruption or elimination in China. Secondly, regarding how the official procedure of verification of transmission of interruption was assessed, we propose that a more accurate survey design and foci selection would be based, at least in part, upon areas where schistosome infections in either humans, domestic/wild animals and/or snails have recently been documented. This is particularly urgent, not only in terms of the long-term sustainability of disease control in China, but because many other countries are now fully acknowledging the zoonotic potential of schistosomiasis and are/or will soon enter this final elimination phase as officially outlined in the WHO's 2021-2030 Neglected Tropical Diseases Roadmap.