Detection of schistosome cercariae in water: A systematic review of traps and attractants.

Environmental surveillance of schistosome cercariae concentrations in water bodies constitutes an important complementary indicator to human schistosomiasis infection data. Schistosoma cercariae traps can be one means of environmental surveillance. To advance these cercariae trap technologies, it is first necessary to synthesise the existing evidence on schistosome cercariae attractants and traps. Six databases were last searched in April 2025. Studies were screened to include primary research on schistosome cercariae traps and attractants with quantitative outcomes, excluding studies assessing kinesis or stages other than attraction. Results were narratively synthesised due to methodological heterogeneity. A bespoke tool was used to assess methodological quality. A total of 1951 papers were found across six online databases. The broad search string retrieved many papers that were deemed to be outside the scope of the review, meaning only eleven studies were included in this review. The attractants included light, temperature, natural oils, beeswax, fatty acids, and pifithrin. Eight studies tested traps on S. mansoni, one studied S. japonicum, one studied both S. japonicum and S. mansoni, and one studied S. haematobium. For S. mansoni, based on two studies, light was reportedly the most effective attractant, with cercariae capture percentages of 87-98%. Based on the limited evidence, beeswax alone was reportedly the least effective, giving cercariae capture percentages of 0.0-9.2%. Based on two studies, S. japonicum cercariae showed a greater attraction to chemicals than S. mansoni, with capture percentages as high as 83.2%. Future studies should focus on consistency to allow comparability, whilst increasing the variety of schistosome species studied and testing new trap designs. This study can therefore guide the development and deployment of cercariae traps to provide insight into the contamination status of water bodies. This will serve as a useful tool in monitoring the progress towards the elimination of schistosomiasis as a public health concern.