Fasciolosis is an important emerging foodborne zoonotic disease
caused by two trematode species, Fasciola hepatica
(F. hepatica) and Fasciola gigantica, found in temperate andtropical zones, respectively. The parasites infect herbivorous
animals including livestock of economic importance, such as
cattle, buffalo, sheep, and goats, leading to substantial losses
to livestock industry, especially with respect to milk, meat
production, and labor (Spithill et al. 1999). In addition,
humans can be accidentally infected by Fasciola spp. Human
fasciolosis is recognized as a significant public health problem
that may be underestimated in most endemic countries due to
the sharing of habitats with other closely related parasites,
inadequate treatment, and prevention. The World Health Organization
(WHO) reported that approximately 2.4 million
people have been infected by this disease worldwide, and
180 million people are at risk of new infection. Presently,
the control strategy of Fasciola infection relies on anthelmintic
drugs, and the most effective one in current use is
triclabendazole (Fairweather 1999). However, due to
prolonged administration of the drugs to obtain an effective
outcome, drug resistance has been reported in many countries,
including Australia, Ireland, and Argentina (Overend and
Bowen 1995; Fairweather and Boray 1999; Olaechea et al.
2011). Therefore, researchers have sought alternative control
strategies to overcome the drug resistance problem. Vaccines
are thought to be a more sustainable; several have been experimentally
tested and found to be effective with high levels of
safety, cost-effectiveness, and environmentally friendly.