Fish-borne zoonotic trematode (FZT) infections affect the health of more than 18 million
people around the world, particularly in Asian countries. Nile tilapia (Oreochromis niloticus)
is a white meat fish that has an increasing national and international market. The objective
of this study was to determine the prevalence of FZT metacercarial infections in Nile
tilapia from cage and pond aquaculture systems and in wild-caught fish from Suphan Buri,
Nakhon Pathom and Chachoengsao provinces, Thailand. Fish were collected from four cages
in Suphan Buri and four ponds in Nakhon Pathom provinces between September–October
2011 and April–May 2012 and wild-caught fish were collected in May 2012. All fish were
examined for metacercariae by a pepsin digestion and metacercariae identified using morphological
and molecular methods. During the first sampling of tilapia the prevalence of
metacercariae in cage culture fish were 2.5% and 10% in pond culture fish. During the second
sampling, metacercariae was found in 2.0% of tilapia from cage and none from the
ponds. Of the 150 wild-caught fish, a total of 80 (53.3%) were found to be infected with
metacercariae, mostly the zoonotic species Stellantchasmus falcatus, Haplorchis pumilio and
Procerovum varium. The results revealed a low risk for FZT in Nile tilapia cultured in cage
and pond aquaculture systems. However, the high prevalence of FZT in wild-caught fish
indicates a high potential for spillover from wild reservoir hosts and underscores the need
for vigilance and good management practices by the aquaculture sector.