Infection with the food-borne trematodiasis, liver fluke Opisthorchis viverrini, is a major public health
concern in Southeast Asia. While epidemiology and parasitic incidence in humans are well studied, ecological
information on the O. viverrini intermediate hosts remains limited. This study aimed to investigate
the factors affecting the distribution and abundance of the first intermediate host, Bithynia siamensis
goniomphalos snails. Water quality and snails were sampled in 31 sites in Muang District, Khon Kaen
Province, Thailand from June 2012 to January 2013 to characterize the B.s. goniomphalos snail habitats.
Species relative abundance and Shannon’s diversity and evenness indices were employed to describe
snail compositions and diversities across different habitat types. Statistical analyses were conducted to
examine the extent to which the water quality variables and species interactions account for the relative
abundance of B.s. goniomphalos snails. The results showed that the freshwater habitats of ponds, streams
and rice paddies possessed significantly different abiotic water qualities, with water temperature and
pH showing distinct statistical differences (P < 0.05). Different habitats had different snail diversity and
species evenness, with high B.s. goniomphalos snail abundance at rice paddy habitats. The differences in
snail abundance might be due to the distinct sets of abiotic water qualities associated with each habitat
types. The relative abundance of B.s. goniomphalos snails was found to be negatively correlated with that
of Filopaludina martensi martensi snails (r = −0.46, P < 0.05), underscoring the possible influence of species
interaction on B.s. goniomphalos snail population. Field work observations revealed that rice planting seasons
and irrigation could regulate snail population dynamics at rice paddy habitats. This study provides
new ecological insights into the factors affecting Bithynia snail distribution and abundance. It bridges
the knowledge gap in O. viverrini disease ecology and highlights the potential effect of anthropogenic
irrigation practices on B.s. goniomphalos snail ecology.