The invention provides a formulation for treatment or prevention of a parasitic infection such as a protozoan or helminths infection, for example: Giardia. The formulation comprises at least one ganglioside, which may be selected from the group consisting of: GD3, GM1, GM2, GM3, GD1b, NANA, and sialic acid. The formulation may be used to supplement foods or liquids, for example: infant formula, baby food, baby cereal, juice, dehydrated camping food, or bottled water.