2. Materials and methods
Six ponds with high Melanoides tuberculata numbers (>250 snails scooped per person per hour, maximum sample time per pond 4 h) were sampled in September 2009.
The ponds were located in Nghia Lac and NghiaPhu communes, Nam Dinh province, Vietnam.
Both communes have a history of endemic FZTs and are known for raw-fish-eating behavior of humans and small-scale
aquaculture farming (Dung et al., 2010; Phan et al., 2011).
The six fish ponds ranged in size from 290 m2 to 8190 m2.
Rice was only cultivated in pond 4 in about 25% of pond area.
One pond was inhabited by ±400 ducks in an enclosure of ±2330 m2, no snails were
found within the enclosure.
Further description of ponds is shown in Table 1