Table 1. Example of field observations at typical schistosomiasis transmission sites.

The measurements and estimates in the field were taken in the study site Ziniaré in Burkina Faso during the dry season in March 2011. NA indicates that this measure was not applicable. The typical transmission sites are illustrated in Fig 2. The habitat variable vegetation coverage was assessed based on the standard FAO LCCS form, flow velocity was categorized based on visual inspection, water temperature was measured using a hand-held digital thermometer, and estimation of the overall suitability of the transmission site resulted from knowledge on habitat preferences of species from the literature.

	Permanent water body	Rice field	Irrigated crops	River water	Seasonal water body	Dry river bed	Dry sink
Vegetation coverage	NA	75%	60%	NA	30%	20%	20%
Flow velocity	Stagnant	Stagnant	Slow flowing	Stagnant	NA	(Fluent: erosive river bed)	NA
Water tem-perature	26.2°C	28.5°C	32°C	31°C	NA	NA	NA
Estimated suitability	High	High	Moderate	Moderate	Moderate	Low	Low