The present invention describes a method of controlling parasitic helminths by probiotic food mediated RNAi knockdown of essential helminth genes, which are responsible for locomotion, nutrient assimilation, attachment and neuromuscular function. For this purpose, RNAi vectors capable of producing parasite target specific dsRNA were developed and paired with probiotics by transformation. These probiotics are the administered to the subjects, which colonized the gut and were taken up by helminth cohabiting the same niche during feeding. The probiotic on degradation in the parasite gut releases the dsRNA molecules that when up by the parasite intestinal cells were processed further to siRNA which degraded the functional RNAs of helminth using the pre-existing parasite RNAi components. Knocking down the essential target RNAs resulted in loss of function of essential proteins that led to the killing of the parasite and their clearance from the host.
