Snail molecular xenomonitoring of urogenital schistosomiasis transmission in Zanzibar

Schistosomiasis is a freshwater parasitic disease. Better tools for monitoring and surveillance of its transmission are required to help control the disease. We aim to provide and validate molecular xenomonitoring tools for the wide-scale surveillance and monitoring of urogenital schistosomiasis (UGS) transmission.

The study will take advantage of a five-year elimination programme – the Zanzibar Elimination of Schistosomiasis Transmission (ZEST) 2012-2017 – which has identified communities that have responded differently to control efforts. This provides a unique opportunity to evaluate the utility of the molecular xenomonitoring tools to detect the different levels of transmission or prevalence of human infection. We will develop a novel highly-sensitive high-throughput species-specific xenomonitoring methodology for UGS. We will then investigate the focal distribution and abundance of snail vectors in individual human water contact sites and how this correlates to transmission. This will clarify the role of the Bulinus snail in the transmission of UGS in Zanzibar. We will then provide a methodology to enable the detection of very low transmission levels and to certify the elimination and interruption of UGS transmission. We will also investigate why there are persisting hot spots for transmission that exist despite multiple intervention strategies.

The results of this study will assist with the monitoring and control of the transmission of UGS in Zanzibar.