Prevalence of trematode cercariae within freshwater snails at the Ross River reservoir is presented, with
special attention to Trichobilharzia sp(p). (Digenea:Schistosomatidae), known causative agents of
schistosome dermatitis. Three pulmonate snails-a lymnaeid, Austropeplea lessoni, and two planorbids,
Gyraulus gilberti and Amerianna carinata-and one prosobranch snail, Thiara balonnensis, were
common in the reservoir. These snails were infected with trematode cercariae representing six different
families. Both Austropeplea lessoni (4.5%) and G. gilberti (1.8%) act as intermediate hosts of
Trichobilharzia sp(p). Trematode infection levels increased as snail size increased. The implication for
surveillance techniques is that only the larger snails (A. lessoni > 10 mm, G. gilberti > 3 mm and
Amerianna carinata >6 mm) require dissection to determine the prevalence of trematode infections.
Effects of temperature and trematode infection on the foraging behaviour of their snail hosts
